Learning objectives

Key terminology

Importance of taking a full clinical history

A good, accurate clinical history is the foundation of a successful interaction with a healthcare professional. Obtaining the history is the critical first step in determining the etiology (cause) of a patient's problem. It is sometimes possible to make a diagnosis based on the history alone. It is important to recognize that fact, and to act on symptoms that require urgent attention. The healthcare professional must obtain focused, detailed information from the patient to begin to formulate a differential diagnosis. The professional must then combine the history with the findings of a physical examination and with results from investigations (eg, laboratory investigations) to arrive at the definitive diagnosis. The healthcare professional can then implement an appropriate treatment plan.

A good interviewer listens to the patient, asks simple open questions and takes cues from the patient's answers. Interviewing skills and the ability to elicit the necessary information improve with experience. When the interviewer and patient have good rapport, the patient feels comfortable openly discussing sensitive subjects. It is also important that the environment is safe, private, and free from distractions as far as possible.

A thorough history includes information on:

Presenting complaint

• The symptoms for which the patient is seeking medical help and the duration of symptoms, eg, chest pain for two months

History of the presenting complaint

• The details of the presenting complaint, eg, crushing chest pain that radiates to the jaw during exercise

Past medical history

• Any previous illnesses or surgeries

Medications 

• Details of medications (herbal, over the counter, or pharmaceutical) the patient is currently taking

Allergies

• What the patient is allergic to and what the allergic reaction is

Family history

• A list of inheritable disorders in the patient's family, such as diabetes

Social history

• Includes details of living arrangements, drug use, occupation, and sexual history

Systems review

• Systematic enquiry into all other organs to ensure the clinician identifies and addresses other possible incidental findings

The human body is a complex structure made up of cells with unique functions that work together to sustain life. Anatomy is organized into levels - body systems (eg, the cardiovascular system) that are made up of organs (eg, the heart), which are composed of different tissues (eg, muscular or valvular). Each tissue type is composed of cells (eg, heart muscle cell or myocardial cell).

There are many different types of cells, each with a specific structure and function.

• White blood cells circulate in the blood whereas muscle cells are firmly attached to each other or to tendons
• Skin cells reproduce constantly whereas nerve cells in the brain do not reproduce at all
• The function of certain cells in the pancreas is to produce a hormone (insulin) whereas the function of nerve cells in the spine is to conduct electrical impulses

Cells themselves can be broken down into smaller parts (cellular anatomy), each part with its own function.

The cell is made up of the cell membrane and cell contents.

Cell contents

Within the cell membrane there are two major components:

• The nucleus
  • The nucleus is surrounded by a nuclear membrane that separates the contents of the nucleus from the cytoplasm
  • The nucleus contains the genetic material that controls reproduction and cell division
  • The genetic material consists of DNA, arranged in a structure called chromatin
  • Chromatin is stored inside the nucleus in small clumps called nucleoli
  • DNA contains all the information needed for the cell to carry out a specific function, such as make insulin, repair itself, or replicate in order for the body to work
  • This information must be transcribed and translated from the DNA before the cell can carry out that function

• The cytoplasm
  The cytoplasm consists of organelles, small functional units within the cytoplasm which perform the cell's functions:

  • Mitochondria
  • Ribosomes
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes

It is essential for the cell to be in homeostasis (equilibrium) for it to function normally.

There are several possible causes of injury to cells. Depending on the severity of the insult, the injury may be reversible or irreversible.

Cell injury may be a result of:

• Hypoxia and anoxia
• Toxins
• Bacteria or viruses
• Inflammation or immune reactions
• Genetic disorders and metabolic disorders

Cell adaptations
After prolonged exposure to stimuli (as mentioned above), the cell may adapt and change to its new environment. If the stimulus is removed, the cell may return to its normal structure and function. Sometimes however, these adaptations are irreversible.

Possible cell adaptations are:

• Atrophy
• Hypertrophy
• Hyperplasia
• Metaplasia
• Dysplasia

When adaptation to the noxious stimuli is not possible, cell injury occurs.

Reversible cell injury
When a demand is placed on the cell that is within the cell's ability to adjust and restore homeostasis, injury to the cell is reversible. An example of this is the changes that occur during a brief period of low oxygen (hypoxia):

• Oxygen is essential for the production of energy in the cell
• The receptors on the cell membrane now have less energy to function properly because there is less oxygen
• The receptors on the membrane allow water to enter the cytoplasm because they do not have the energy to regulate the entry
• When the transient period of hypoxia has ended, the amount of oxygen available to produce energy increases
• With enough energy to regulate the water content, the receptors pump the excess water out of the cell
• The cell returns to a homeostatic state
• Because the nucleus codes for all the proteins in the body, any structural damage to intracellular proteins that may have occurred during this transient hypoxia (eg, to cell membrane proteins) is repaired as the proteins are resynthesized (by transcription and translation) by the nucleus

Irreversible cell injury
When the demand placed on the cell exceeds its ability to adjust and restore homeostasis, the injury to the cell is irreversible. An example of this is the changes that occur during a prolonged period of low oxygen (hypoxia) or an absence of oxygen (anoxia).

• The nucleus does not function properly
• The mitochondria do not produce enough energy to meet the cell's needs
• The plasma membrane loses its regulatory function
• The nuclear changes are the most important as the cell cannot survive without a functional nucleus
  • Transcription and translation to repair damaged proteins cannot occur
• The nuclear changes can be seen clearly under a microscope
• The cell dies and its contents may be released into circulation, where they may be detected in blood tests, such as Troponin I being detected after heart-muscle cell death (myocardial infarction)

Cell death
Cell death occurs because the cell has reached the end of its natural life span or because it has been damaged beyond repair. Some cells may be replaced by stem cells that differentiate into the specific type of injured cell (eg, skin cells). Other cells are not able to be replaced and continued cell loss will result in organ dysfunction (eg, brain cells).

Cell death can occur by two different mechanisms, necrosis, and apoptosis.

• Necrosis
• Apoptosis

Inflammation is the body's response to injury from any cause. It has a protective role, and assists in repairing the body, but side effects, such as a high fever, may become harmful.

Inflammation is a series or "cascade" of events that are interconnected. This cascade may occur over a short time (acute inflammation) or over a longer time (chronic inflammation).

Inflammation involves multiple body systems (nerves, blood vessels, blood cells, inflammatory mediators).

Pathogenesis:

• The cardinal signs of inflammation are heat (from the increased cell activity and increased blood flow), redness (from dilatation of blood vessels and increased blood flow), swelling (from increased fluid shifting into the area), and pain. The patient will also experience loss of function in the injured area.
• Chemical mediators
  • Chemical mediators are released in response to an injury
  • They can either be preformed, and stored in cells to be released immediately, or be made on demand
  • The chemical mediators have numerous effects on cells and blood vessels
  • The most important effects are:
    • Vasodilation or vasoconstriction of arterioles
    • Increased vessel wall permeability
    • Activation of inflammatory cells
    • Directing inflammatory cells to the source of inflammation (eg, bacteria)
    • Breaking down injured tissue
    • Pain
    • Fever
  • The most important chemical mediators in inflammation are:
    • Histamine
    • Bradykinin
    • Complement cascade
    • Arachidonic acid derivatives
• Hemodynamic changes
  • After an injury, chemical mediators signal the muscles of the arterial walls to relax, causing dilatation of the arteries
  • Dilatation of the arteries allows more blood to flow to the area
  • The increase in blood accounts for the warmth, redness, and swelling in the tissue. This is known as hyperemia
  • The capillaries also dilate and fill with blood
  • The pressure from the increased volume is transmitted from the capillaries to the venules and veins
  • This extra fluid accumulates, exerting pressure on the vessel walls
  • The extra fluid leaks out through the vessel walls into the injured tissue. This is known as edema
• Vessel wall changes
  • The vessel walls become more permeable (leaky)
  • There are four causes of this:
    • The increased pressure the extra blood exerts on the vessel wall
    • The slowed circulation brings less oxygen to the vessel wall and the cell membranes lose their regulatory capacity (see "reversible cell injury")
    • White blood cells and platelets adhere to the endothelial cells
    • Chemical mediators released by inflammatory cells prompt a change in the cell wall permeability
• Inflammatory cell activity
  • The increased vessel permeability allows inflammatory cells to move across the vessel wall into the damaged tissue
  • Chemical mediators attract the inflammatory cells to the damaged tissue - this is known as chemotaxis
  • Inflammatory cells are largely white blood cells, which are the body's primary defence system
  • The increased blood flow to the area and increased vessel wall permeability enables inflammatory cells to invade the damaged area
  • PMNs ingest any bacteria that are present and/or other cell debris by the process of phagocytosis
  • Once the source of inflammation is removed, the process of healing can begin

Acute inflammation may resolve spontaneously once the cause is removed and when the chemical mediators have stopped being produced. Healing begins with the laying down of a connective tissue framework for the new cells and tissue to grow on. New blood vessels are formed to supply the new tissue. If there is considerable tissue destruction, acute inflammation may never resolve and may become chronic inflammation.

Neoplasia literally means "new growth." It describes an uncontrolled growth of cells. These cells are not regulated by the normal cell processes that usually destroy abnormal cells and prevent them from replicating (apoptosis). It is important to note that the words neoplasm, tumor, and cancer are used interchangeably in health care. However, all cancers are not solid tumors; for example, leukemia is a cancer of the bone marrow or blood. Also, tumors or neoplasms may be either benign or malignant. The word cancer is widely accepted to be synonymous with malignant tumors.

As normal cells mature, they differentiate. Differentiation occurs when genes in stem cells are expressed, allowing the stem cells to assume a specific, specialized function. Neoplastic cells have lost the ability to differentiate. Neoplastic cells are different to normal cells in that:

• Their growth is no longer regulated by normal cell processes
• Their growth is excessive
• Their growth is disorganized and does not follow the normal pattern of cell growth or development

Other cellular changes that may result in neoplasia begin as adaptive reactions to abnormal stressors. After prolonged exposure to abnormal stimuli, the cell may adapt and change to meet its new environment. If the stimulus is removed, the cell may return to its normal structure and function. However, if stimuli are noxious or toxic, and exposure is prolonged, these adaptations become irreversible, and the cell becomes neoplastic.

• Hypertrophy
• Hyperplasia
• Metaplasia
• Dysplasia

Potential causes of cancer are known as carcinogens.

Benign neoplasms

Benign neoplasms generally have a better prognosis than malignant neoplasms. Whilst some, like non-Hodgkins lymphoma, cause high morbidity and mortality, benign neoplasms can generally be treated with good results. Benign tumors may be distinguished from malignant tumors by their macroscopic, microscopic, cellular, and chromosomal characteristics.

Examples of benign tumors are:

• Lipomas - a benign collection of fat cells commonly found under the skin, which are commonly removed
• Fibroadenomas of the breast - most breast lumps found are a benign collection of gland cells in the breast that are very commonly seen in women, and easily removed
• Meningiomas - a benign collection of cells of the membrane surrounding the brain that may compress the underlying brain tissue, but are easily removed. Symptoms cease after removal

Macroscopic features

• Benign tumors are often surrounded by a capsule, so the abnormal tissue is sharply demarcated from normal tissue
• The tumor expands out into normal tissue
• Damage to normal tissue is due to the tumor compressing the adjacent area, causing atrophy
• Their clear distinction from normal tissue means they can be removed easily

Microscopic features

• Cells in benign tumors are well differentiated - they closely resemble the cells of the normal tissue from which they have arisen

Cellular features

• All the cells in a benign tumor have the same appearance
• The cell nuclei are a normal shape and uniform in size
• There is a normal amount of cytoplasm
• The nucleus is a small part of the cell content
• There is an even distribution of chromatin and the nucleoli are not prominent
• There are fewer cells undergoing cell division than in malignant tumors

Chromosomal studies

• Benign cells have a normal number of chromosomes

Biological features

• Benign cells retain their normal function to a certain extent, so the amount of energy directed towards cell division is less than in malignant cells
• Benign tumors therefore grow more slowly than malignant tumors
• Benign tumor cells do not metastasise

Malignant neoplasms

Malignant neoplasms have a poorer prognosis than benign neoplasms and can result in death.

Malignant tumors may be distinguished from benign tumors by their macroscopic, microscopic, cellular, and chromosomal characteristics.

Examples of malignant tumors are:

• Melanoma - a type of skin cancer
• Leukemia - cancer of the white blood cells or leucocytes
• Small-cell and non-small-cell lung cancer
• Ductal carcinoma of the breast, or breast cancer
• Adenocarcinoma of the bowel, or bowel cancer
• Testicular cancer
• Ovarian cancer

Macroscopic features

• Malignant tumors lack capsules
• Malignant tumors are not separated from the normal tissue - the abnormal cells invade the normal tissue
• Because the normal and abnormal tissue cannot be easily distinguished, it is difficult to remove malignant tumors

Microscopic features

• Cells in malignant tumors are very poorly differentiated - they may not resemble the tissue of origin at all and can exhibit anaplasia

Cellular features

• Cells in a malignant tumor may have a different appearance - this is known as pleomorphism
• The cell nuclei vary in size and shape
• There is a variable amount of cytoplasm
• The nucleus is large and occupies a significant part of the cell
• There is a surplus of chromatin and it is irregularly distributed
• The nucleoli are very prominent
• There are many cells undergoing cell division

Chromosomal studies

• Malignant cells often do not have a normal number of chromosomes
• There are also deletions, translocations, and additions to parts of the chromosomes

Biological features

• All the cell functions are directed towards rapid division and growth, so malignant tumors grow more rapidly than benign tumors
• Malignant tumor cells are able to metastasize

Benign tumors of the heart are rare. Malignant tumors are even rarer. Atrial myxomas are benign and make up 50% of benign cardiac tumors. Other benign tumors are rhabdomyomas and fibromas: these are generally found in infants and children. Secondary tumors (metastases) are always malignant. They may spread to the pericardium from surrounding tissue like the lung or breast, but this happens very rarely.

Pathogenesis

• Myxomas usually form in the left atrium
  • They may develop from embryonic cells in the endocardium
  • They grow on a stalk and swing in the blood flow, and so may intermittently obstruct flow through a valve
• Rhabdomyomas grow in groups in the heart wall
  • They develop from muscle cells during infancy
• Fibromas are single tumors that grow on the heart valves
  • They develop from the heart's fibrous tissue cells
• Sarcomas are the most common malignant primary tumors
  • They may develop from blood vessel tissue

Clinical presentation

• Signs and symptoms
  • Asymptomatic
  • Shortness of breath
  • Arrhythmias
  • Heart failure
  • Murmurs
  • Cardiac tamponade from bleeding into the pericardial sac

• Investigations
  • Procedures
    • Echocardiography (transesophageal may give a better picture)
    • ECG
    • CT chest
    • Cardiac MRI
    • Cardiac catheterization for biopsy

Treatment

• Surgery
  • Malignant primary cancers cannot be surgically removed so chemotherapy or radiation is used
  • Benign tumors can generally be surgically removed
    • However, if they affect a crucial part of the cardiac anatomy like the conduction system in the intraventricular septum, they cannot be removed
  • Rhabdomyomas either regress without treatment or do not grow in size and do not require treatment

Prognosis

• Primary malignancies are fatal
• Patients in whom surgery is impossible will usually die from arrhythmias

Complications

• Emboli

Edema

Edema is when excess fluid collects in the interstitial space and/or body cavities. Normally outflow of fluid at the arteriolar end is balanced by inflow at the venous end, with any left over fluid in the interstitial space removed by the lymphatic system. Edema occurs when the forces that promote movement of fluid out of the circulation exceed the forces that keep fluid in the circulation. Edema may be localized to a particular organ, for example, pulmonary edema, or it may be generalized throughout the body, as in kidney failure.

The fluid may be either an exudate or a transudate.

• Exudates are typically found in inflammation and the fluid contains high levels of protein and blood cells. Exudates have a serum total protein ratio of > 0.5
• All other fluid collections are transudates, containing less protein and fewer cells. They occur when water, mainly, moves between fluid compartments due to changes in intravascular pressures. The edema in heart failure is a transudate

There are several mechanisms by which fluid shifts occur, causing edema.

• Vessel walls may be more permeable and allow fluid to leak through into the tissue
  • This occurs in inflammation
• Increased blood volume in the vessels exerts hydrostatic pressure on the vessel wall that further increases permeability
  • In heart failure, the heart cannot circulate blood effectively, causing blood to pool. The pooling increases the pressure on the local vessels
• Loss of sodium (salt) and albumin from the body lowers the osmolality inside the vessel, thereby lowering the osmotic pressure in the vessel
  • Nephrotic syndrome causes a loss of sodium in the urine, and liver cirrhosis reduces the amount of albumin the liver synthesises
• When hydrostatic pressure is high and/or osmotic pressure is low inside the vessel, fluid moves from the vessel into the surrounding tissue
• Obstruction of the lymphatic system, which normally drains fluid from tissue, will allow excess fluid to remain in the tissue
  • The local lymphatic system may be blocked by a tumor

• Hyperemia is the increase in volume of blood in a vessel when dilatation of the arterioles allows more blood to flow into that vessel
• This is known as "active hyperemia"
• This may also be seen during exercise
  • When the superficial arterioles of the face dilate to regulate body temperature, the face looks pink and flushed
• "Passive hyperemia" occurs as a result of congestion of blood when it is poorly circulated
• In heart failure, deoxygenated blood pools in the venous system
  • The tissue takes on a bluish color, known as cyanosis
  • The congestion of fluid can also lead to edema

Hemorrhage, or bleeding, is the loss of blood from the cardiovascular system.

• Bleeding can be from the heart, the aorta, arteries, capillaries, or veins
• Bleeding may be into internal structures or cavities in the body, such as a cerebral hemorrhage into the brain, bleeding into an aneurysm in the aortic wall or bleeding into the chest (hemothorax)
• Internal hemorrhage forms hematomas, which are blood-filled swellings or collections
• Bleeding may also be to the external environment when the skin is penetrated
• Both internal and external hemorrhage cause a loss of circulating blood volume
• Clinical presentation depends on the volume, rate, and duration of blood loss
• Significant hemorrhage may result in a loss in blood pressure and inadequate perfusion of vital organs, and death
• Blood loss may be acute or chronic and may recur
• Chronic blood loss can cause anemia

Cardiac hemorrhage
Aortic hemorrhage
Arterial hemorrhage
Capillary bleeding
Venous hemorrhage

Bleeding stops when a clot forms over the injured area. Along with red blood cells, white blood cells, and plasma, blood contains platelets and clotting factors. Clotting factors are activated upon injury and platelets are attracted to the site of injury to form the clot.

Thrombosis is the formation of a clot. Fibrin in the blood forms a lattice framework upon which blood cells and platelets bind to form a thrombus, or clot.

Clotting is initiated by the coagulation cascade, following injury to the endothelial surface of a blood vessel. If this sequence is initiated in the absence of bleeding, pathological thrombi form instead, as in the case of deep vein thrombosis.

Three factors predisposing to the formation of pathological thrombi in the absence of bleeding, such as deep vein thrombosis, are:

• Endothelial cell damage
• Hemodynamic changes
• Hypercoagulability

Thrombi may occur in:

• The chambers of the heart (intramural thrombi): a myocardial infarction
• On the heart valves, as a result of bacterial infections in endocarditis
• In arteries overlying atherosclerotic plaques
• In dilated varicose veins
• In microscopic capillaries

Pathogenesis

• Endothelial cells are normally antithrombotic, to prevent unnecessary and potentially dangerous formation of clots
• However, when endothelial cells are damaged, they become prothrombotic
• Mediators of inflammation activate the endothelial cells, which initiate the coagulation cascade
• Clotting factors in the blood promote the synthesis of thrombin
• Thrombin promotes the synthesis of fibrin, which assembles as a framework at the site of injury
• Blood cells, platelets, and other blood proteins congregate on this framework
• Platelets promote clotting by inhibiting anti-clotting compounds like heparin, and by directly stimulating clotting
• The thrombus attaches to the damaged endothelial cells of the vessel wall, and seals over the injured area
• Once the endothelial cells are repaired, the thrombus is dissolved and circulation is restored

Thrombosis

Clinical significance of thrombi is:

• Thrombi may occlude vessels
  • Thrombi over atherosclerotic plaques in coronary artery disease lead to myocardial infarction
• Thrombi may narrow the lumen of the blood vessel, reducing blood flow
  • Heart failure is a consequence of chronic ischemia caused by reduced blood flow
• Thrombi give rise to emboli
  • If improperly anchored to the cell wall, the whole clot, or part of the clot, may break off (embolize)
  • The thromboembolus travels around in the circulation and may occlude a distant vessel, leading to ischemic infarction of the tissue that vessel supplies oxygen to
  • An example of this is when a clot dislodges from a deep vein thrombosis and travels to the lungs, causing a pulmonary embolus

• An infarction is usually due to thrombosis and embolism
• There is no blood flow to the tissue (ischemia) so there is no oxygen and nutrition being delivered to the tissue
• This leads to the irreversible damage and death of that tissue (infarction)
• Infarcts may occur in arteries or veins
• Infarcts can be described as pale infarcts or red infarcts based on their gross appearance

Infarction

• Infarcted tissue may be repaired, replaced with scar tissue, or reabsorbed
  • Liver cells have a high capacity to repair themselves (regeneration capacity)
  • The necrotic tissue in the heart is replaced with scar tissue, which impedes its ability to contract
  • Necrotic brain tissue is liquefied and reabsorbed, leaving a cavity

An embolus is a free-floating mass in the circulation that is transported to various anatomical sites by blood. The most common embolus is a thromboembolus that originates from a clot. Emboli may also be:

• Liquid emboli
  • Fat emboli enter the circulation after fractures
  • Amniotic emboli enter the uterine veins during delivery
• Gaseous emboli
  • Air emboli can be injected into veins, for example, during IV drug use
• Solid particle emboli
  • Fragments of cholesterol, bone marrow, and tumors may enter the circulation

The clinical significance of emboli is that they occlude vessels, causing ischemia.

• Venous emboli
  • The most significant complication of a venous embolus is pulmonary embolus
  • The thromboembolus originates from a deep vein and travels to the lungs, either partially or completely occluding a pulmonary vessel
  • A large "saddle" embolus in the pulmonary trunk is usually fatal
  • Smaller emboli cause pulmonary infarcts, seen as triangular areas of ischemia on a CT scan

Embolism resulting
from thrombi

• Arterial emboli
  • Arterial emboli may originate in the heart chambers after arrhythmias, or on heart valves after bacterial endocarditis
  • The most significant complication of arterial emboli is cerebral embolization, resulting in a stroke

Shock is the collapse of the circulatory system. It can be caused by different mechanisms. It results in inadequate perfusion of tissues. Inadequate perfusion, like infarction, means there is less oxygen and fewer nutrients delivered to the tissue, and cell function is impaired. Shock, however, is systemic, and results in damage to many organ systems.

There are several types of shock:

• Cardiogenic shock
  • The heart cannot pump sufficiently to maintain circulation
  • This is common after a myocardial infarction, in heart failure, and in valvular heart disease
• Hypovolemic shock
  • There is a significant loss in circulating volume
  • This occurs after major bleeding, diarrhoea, vomiting, and burns
• Distributive shock
  • There is widespread vasodilatation, which reduces blood pressure and therefore reduces perfusion to vital organs
  • Systemic vasodilatation occurs in anaphylaxis (anaphylactic shock), sepsis (septic shock), and spinal cord injuries (neurogenic shock)
• Obstructive shock
  • Blood flow is obstructed, impeding circulation
  • This occurs in several conditions, such as cardiac tamponade, tension pneumothorax, or pulmonary embolism

Early stages of shock can be compensated.

• In early stages of heart failure:
  • The heart rate increases (tachycardia) to pump more blood per minute
  • Vasoconstriction of peripheral arterioles redirects blood to vital organs and away from non-vital organs like the skin and gut
  • Reduced urine output attempts to increase the available circulating volume
  • Blood pressure is maintained and vital organs are well perfused

As shock progresses, the body cannot compensate, but shock may be reversible with treatment.

• As the heart failure progresses:
  • Blood pressure and cardiac output decrease, resulting in hypotension
  • Fluid accumulation in the lungs (pulmonary edema) and anoxia lead to an increase in respiratory rate
  • The kidneys are so poorly perfused they cannot produce urine (oliguria)
  • Medical intervention can reverse these abnormalities

End stage severe shock is irreversible.

• End stage heart failure is characterized by complete circulatory collapse, severe hypoperfusion of vital organs, and impaired vital body functions
• Irreversible shock has a high mortality

Atherosclerosis is a process that affects large and medium sized arteries. Cell injury to the inner layer of the vessel wall (endothelium) leads to the accumulation of a lipid-rich plaque in the wall. Atherosclerosis is often referred to as "hardening" of the vessels as these plaques lead to loss of elasticity of the vessel wall. The two main adverse consequences are rupture of the plaque, resulting in obstruction of blood flow and ischemic tissue injury; or enlargement of the vessel wall causing an aneurysm.

Most morbidity and mortality results from atherosclerosis to the coronary vessels, known as coronary artery disease (CAD); the cerebral vessels (cerebrovascular disease or CVD); and the aorta and its branches. Similar events occur in other body systems like the intestines, kidneys, and legs (known as peripheral vascular disease or PVD). Atherosclerosis-related diseases contribute to many deaths in the United States annually.

Pathogenesis

• The initial injury to the cells that line the vessel wall may be caused by a physical force like hypertension, or other mechanisms such as metabolic changes
• This is followed by deposition of blood platelets and lipids at the site of injury
• Growth factors from the platelets then cause the muscle cells of the vessel wall to proliferate and absorb cholesterol and other lipids
• These muscle cells typically transform into foam cells (cells made up of fatty deposits)
• When the affected muscle cells die, they release the fatty deposits, which attract macrophages
• The macrophages in turn take up the fat material and become foam cells themselves
• As this process evolves the fatty deposit in the vessel wall enlarges and obstructs the lumen of the vessel
• As a repair mechanism to the initial injury, collagen is deposited over the fatty deposit, thus forming a fibrous cap
• The combination of soft lipid material covered by a fibrous cap in a vessel wall is known as an "atheroma"
• The atheroma expands and causes various degrees of stenosis (narrowing) in the vessel lumen
• As the central lipid material expands, the fibrous cap may also burst, allowing the fatty tissue to rupture into the lumen of the vessel. This is known as "ulceration"
• Ulceration of the vessel wall attracts platelets and forms a clot or "thrombus"
• Stenosis or thrombus may lead to partial or complete occlusion of the lumen, restricting the blood flow to the part of the body that the vessel supplies
• Lack of nutrients and oxygen causes the cells in these ischemic areas to die
• Fragments of the thrombus may break off (embolize) and lodge in other smaller vessels around the body, causing the same type of cell death to the areas those vessels supply
• Atheroma plaques may also lead to enlargement of the vessel, causing aneurysms

Atherosclerosis

Risk factors

Non-modifiable factors
Modifiable factors

Clinical presentation

• Signs and symptoms
  Occlusion of the lumen of any vessel will lead to tissue ischemia in the organ served by that vessel, due to lack of nutrients and oxygen:
  • Heart: lumen occlusion of 50% to 75% generally leads to symptoms of angina. Complete occlusion will lead to a myocardial infarction
  • Brain: lumen occlusion leads to symptoms of TIA and stroke
  • Legs: lumen occlusion, usually with exercise, leads to claudication
  • Kidneys: atherosclerotic changes cause kidney hypoperfusion, which reduces excretion of fluids, causing hypertension, and eventual end stage kidney failure
  • Intestines: acute occlusion may cause intestinal infarction, which has a high mortality. Chronic changes may cause poor absorption, poor digestion, and may lead to constipation

• Investigations
  • Laboratory tests
    • Lipid profile
    • Glucose
  • Procedures
    • Blood pressure
    • Exercise stress testing
    • Echocardiography
    • Computer tomography brain imaging
    • Ankle/brachial index
    • Cardiac catheterization with angiography
    • Magnetic Resonance Angiography

Treatment/Management

• Lifestyle changes including exercise, smoking cessation, and weight loss
• Medication
  • Aspirin
  • Statins (lipid lowering medication)
  • Antihypertensive medication
• Interventions
  • Angioplasty (with or without) stenting
  • Carotid endarterectomy
  • Coronary artery bypass graft
  • Peripheral vessel bypass surgery

Prognosis

• Unless risk factors for atherosclerosis are well controlled, the disease process can affect many different organ systems

Complications

• Coronary artery disease
• Cerebrovascular disease
• Peripheral vascular disease

The basic pathology of coronary artery disease (CAD) is atherosclerosis. The mechanism by which atherosclerosis affects the myocardium is through ischemia from occlusion of the coronary arteries. The clinical presentation of someone with CAD depends on the:

• Extent of occlusion
• Rapidity with which ischemia develops
• Extent of atherosclerotic changes in other coronary arteries
• Location of the occlusion
• Presence of other diseases such as hypertension

Pathogenesis

• Atherosclerosis makes the coronary arteries rigid and hard
• In cross section the lumens of the arteries are narrowed from atheromatous plaques and thrombi
• If the narrowing is slow with the chronic build up of atheroma:
  • The hypoperfusion to the muscle is chronic
  • The ischemia to the heart muscle is incomplete, slow, and progressive
  • The patient may initially be asymptomatic if the occlusion is less than 50% of the lumen
  • The patient may begin to experience angina when the occlusion is approximately 75% of the lumen
  • The patient will eventually develop heart failure due to an inefficient pump from chronic ischemia
• If the occlusion is sudden from rupture of a plaque:
  • The occlusion is 100% of the lumen
  • The anatomical area supplied by the artery is completely ischemic and will infarct
    • Occlusion of the left anterior descending artery (LAD) accounts for approximately 50% of cases and results in an anterior wall infarct
    • Occlusion of the left circumflex branch of the left coronary artery accounts for 15% to 20% of cases and results in a lateral wall infarct
    • Occlusion of the right coronary artery accounts for 30% to 40% of cases and results in right ventricle and left posterior wall infarct
  • Microscopic appearance after infarct
  • Gross appearance after infarct

Risk factors

• Non-modifiable factors
• Modifiable factors

Angina is a common presentation in coronary artery disease. It occurs as a result of reduced coronary blood flow caused by atherosclerotic stenosis. Myocardial ischemia, when blood flow to the heart muscle does not meet the muscle's demand for oxygen, results in chest pain.

Angina

Clinical presentation

• Signs and symptoms
  • Retrosternal chest discomfort or pain
  • Usually described as pressure, heaviness, squeezing, burning, or choking
  • Pain may radiate to neck, jaw, and shoulders, but an absence of radiating pain does not exclude angina
  • Typically precipitated by exertion, eating, exposure to cold or stress
  • Lasts approximately 1 to 5 minutes
  • Relieved by rest or nitroglycerin
  • May be accompanied by shortness of breath, sweating, nausea
• Investigations
  • Procedures
    • Electrocardiography
    • Ambulatory electrocardiography monitoring
    • Chest x-ray
    • Exercise stress test
    • Echocardiography
    • Angiography

Treatment

• Lifestyle changes including exercise, smoking cessation, and weight loss.
• Medication
  • Sublingual nitroglycerin (acute and prophylactic)
  • Long acting nitrates
  • Aspirin
  • Statins (lipid lowering medication)
  • Beta-blockers, calcium channel blockers, ACE inhibitors
• Interventions
  • Angioplasty (with or without stenting)
  • Coronary artery bypass graft

Prognosis

• Uncontrolled risk factors worsen prognosis
• Poor ventricular function worsens prognosis
• Patients with stable angina and good ventricular function have a relatively good prognosis

Complications

• Myocardial infarction
• Congestive heart failure
• Cardiac arrest

A myocardial infarction (MI) is a medical emergency when the blood supply to the heart is cut off causing the heart muscle involved to die. The most common cause of an MI is a ruptured atheroma in the coronary arteries. Less commonly a clot formed in the heart chamber during an arrhythmia breaks off (embolizes) and becomes lodged in the coronary artery. Coronary artery spasm may also uncommonly result in an MI.

Myocardial infarction

Clinical presentation

• Signs and symptoms
  • Asymptomatic, with changes recorded only by electrocardiography (ECG)
  • Retrosternal chest discomfort or pain
  • Some patients do not experience chest pain at all, but rather pain in the neck or arm
  • Patients with diabetes may have no pain at all
  • Pain is usually described as pressure, heaviness, squeezing, burning, or choking
  • Pain may radiate to the neck, jaw, arms and shoulders, but an absence of radiating pain does not exclude a myocardial infarction
  • Typically precipitated by exertion, eating, exposure to cold, or stress
  • Pain more severe and longer lasting than angina
  • Not relieved by nitroglycerin
  • Shortness of breath
  • Sweating
  • Nausea
  • Arrhythmias (often felt as an erratic pounding of the heart)
  • Loss of consciousness
  • Shock
  • Feeling of "impending doom"
  • Sudden death

• Investigations
  • Laboratory tests
    • Cardiac enzymes
• Procedures
  • Electrocardiography
  • Echocardiography
  • Angiography
  • When instrumentation is used to remove an occlusion and restore flow in the vessels, it is called angioplasty

Treatment

• Admission to Emergency Department and Coronary Care Unit of the nearest hospital
• Medication:
  • Oxygen
  • Morphine for pain
  • Nitrates (sublingual or intravenous)
  • Thrombolytic therapy (Heparin) to prevent clot formation
  • Beta blocker to slow heart rate and workload
  • ACE inhibitor, statin, and long-term aspirin prescribed on discharge
• Interventions
  • Angioplasty (with or without stenting)
  • Coronary artery bypass graft
  • Cardiac rehabilitation

Prognosis

• Most deaths occur within hours or days of the MI occurring
• 10% die within one year
• Those who are at greater risk of death are those people with heart failure, arrhythmias, or angina following their MI

Complications

• Heart failure
• Myocardial rupture
• Scar tissue formation
• Ventricular aneurysm
• Emboli
• Ventricular arrhythmias
• Pericarditis
• Hypotension
• Death

Peripheral Vascular Disease (PVD) is caused by atherosclerotic changes to the arteries supplying the major organs of the trunk and extremities of the body. It usually occurs together with atherosclerosis of the coronary and cerebral arteries. The clinical presentation depends on the site involved.

Pathogenesis

• The initial injury to the cells that line the vessel wall may be caused by a physical force such as hypertension, or other mechanisms such as metabolic changes
• This is followed by deposition of blood platelets and lipids at the site of injury
• Growth factors from the platelets then cause the muscle cells of the vessel wall to proliferate and absorb cholesterol and other lipids
• The muscle cells typically transform into foam cells (cells made up of fatty deposits)
• When the affected muscle cells die, they release the fatty deposits, which attract macrophages
• The macrophages in turn take up the fat material and become foam cells themselves
• As the process evolves, the fatty deposit in the vessel wall enlarges and obstructs the lumen of the vessel
• As a repair mechanism to the initial injury, collagen is deposited over the fatty deposit, forming a fibrous cap
• The combination of soft lipid material covered by a fibrous cap in a vessel wall is known as an "atheroma"
• The atheroma expands and causes various degrees of stenosis (narrowing) in the vessel lumen
• As the central lipid material expands, the fibrous cap may burst, allowing fatty tissue to rupture into the lumen of the vessel. This is known as "ulceration"
• Ulceration of the vessel wall attracts platelets and forms a clot or thrombus
• Stenosis or thrombus may lead to partial or complete occlusion of the lumen, restricting the blood flow to the part of the body that the vessel supplies
• Lack of nutrients and oxygen cause the cells in these ischemic areas to die
• Fragments of the thrombus may break off (embolize) and lodge in other smaller vessels around the body causing the same type of cell death to the areas those vessels supply
• Atheroma plaques may also lead to enlargement of the vessel causing aneurysms

Atherosclerosis in
peripheral vessels

Risk factors

• Non-modifiable factors
• Modifiable factors

Clinical Presentation

• Signs and symptoms
  • Peripheral vascular disease in the limbs
  • Peripheral vascular disease in the renal arteries
  • Peripheral vascular disease in the intestinal arteries

• Investigations
  • Physical examination
    • Blood pressure
    • Check for pulses
    • Check color and temperature
  • Laboratory tests
  • Glucose and lipid profile to assess risk factors
  • Procedures
    • Ankle/brachial index
    • Doppler ultrasound
    • Peripheral angiography
    • Magnetic resonance angiography

Treatment

• Lifestyle changes to modify risk factors
• A regular exercise program of walking 30 minutes three times a week improves muscle function and reduces claudication. The patient must stop and rest when symptoms occur and then start walking again once symptoms resolve
• Good foot care to prevent ulcers, sores, and infections that may be slow to heal
• Medication:
  • Thrombolytic therapy to dissolve and prevent clots
  • Medication to manage risk factors
• Interventions
  • Angioplasty (with or without stenting)
  • Endarterectomy surgery
  • Bypass surgery
  • Amputation

Prognosis

• Sudden occlusion of the intestinal arteries has a high mortality rate

Complications

• Amputation
• Sudden death

Polyarteritis nodosa

Polyarteritis nodosa is an autoimmune inflammation of medium sized arteries with subsequent ischemia in the affected organs or tissues. It is a multi-system disease. This condition is much rarer than atherosclerosis.

Pathogenesis

• The cause is uncertain but it may be triggered by viral or bacterial infections or by certain drug reactions
• The body's immune system mounts an attack on the artery
• Neutrophils destroy the artery wall
• Thrombi occlude the lumen at the site of injury
• Aneurysms may form at the site of injury

Clinical presentation

• Signs and symptoms
  • Symptoms depend on which organ is affected
  • Muscle and joint pain
  • Fever
  • Parasthesia of the extremities
  • Weakness
  • Weight loss
  • Kidney failure with low urine output and hypertension
  • Abdominal pain and diarrhea
  • Chest pain and heart attacks if there is cardiac involvement
  • Headaches and seizures if there is brain involvement
  • Bumpy irregular skin surface when skin is involved

• Investigations
  Largely a diagnosis of exclusion (when symptoms and tests cannot be explained by any other disease process)
  • Procedures:
    Arterial biopsy is required for diagnosis.

Treatment

• Stop any drugs that may be contributing
• Treat any infections that may be contributing
• High dose steroids
• Immunosuppressive drugs if steroids fail

Prognosis

• Without treatment 88% of patients die within 5 years

Complications

• Aneurysms
• Kidney failure
• Fatal infections from immunosuppression

Temporal (or giant cell) arteritis

This is chronic inflammation of large arteries, especially the temporal artery of the scalp and other head arteries. It is uncommon and mainly affects people over the age of 60.

Pathogenesis

• Unknown cause
• Under the microscope there is evidence of immune cells infiltrating the artery wall and narrowing the lumen

Clinical Presentation

• Signs and symptoms
  • Severe temporal headache
  • Swollen, bumpy appearance of a temporal artery
  • Painful scalp
  • Blurred vision
  • Blindness
  • Painful jaw while chewing or talking
  • Neck and shoulder pain

• Investigations
  • Laboratory tests
    • Elevated inflammatory markers in the blood
  • Procedures
    • Biopsy of the temporal artery

Treatment

• High dose steroids

Complications

• Blindness

Raynaud's disease

This condition occurs when small arteries, usually in the extremities, constrict excessively when exposed to various environmental factors, such as cold; or to certain drugs or activities that stimulate the sympathetic nervous system, such as strong emotions.

Clinical presentation

• Signs and symptoms
  • Cold fingers and toes
  • Patchy cyanosis in peripheries
  • Parasthesia and burning sensation is common
  • Rewarming restores normality
  • In prolonged attacks the peripheries may become smooth, shiny, tight, and painful
• Investigations
  • Doppler ultrasound to look for a blocked artery

Treatment

• Protect extremities from exposure to cold
• Cease smoking, because smoking constricts vessels
• Medications used for hypertension may be useful as they dilate blood vessels
• Sympathetic nerves may be cut to stop the reflex constriction of arteries in response to stimuli

Varicose veins occur primarily because veins have thinner, less robust walls than arteries. Once these walls become dilated or stretched for extended periods of time they remain stretched. Consequently, the venous valves - which usually prevent pooling or backflow of blood - become incompetent in the dilated veins. Varicose veins are easily recognized as tortuous, dilated superficial veins, usually of the lower leg.

Pathogenesis

• The cause is both environmental and genetic
• Long periods of standing leads to stagnation of blood in the lower limb veins and predisposes to formation of varicosities
• The walls of veins are intrinsically weak
• The veins become wider
• They take a visibly tortuous or "snakelike" course beneath the skin
• The widening of the veins causes the cusps of the valves to separate
• The blood now leaks back through the incompetent valves
• Blood cannot return to the heart and pools in the lower leg
• The extra blood in the veins causes them to stretch further
• Blood flow is slow through these veins, which predisposes to formation of clots

Varicose veins

Clinical presentation

• Signs and symptoms
  • Visibly enlarged, tortuous veins in the lower limb
  • Pain
  • Inflammation or bleeding of the veins
  • Itchy rash or brown discolored area
• Investigations:
  • Physical examination
  • Procedures
    • X-rays
    • Ultrasonography

Treatment

• Elevation of leg at rest relieves symptoms
• Elastic stockings to compress veins and prevent more stretching
• Injection therapy (sclerotherapy)
• Surgery

Complications

• Dermatitis
• Thrombophlebitis
• Bleeding
• Ulcers

This is the formation of clots in the deep veins. It is more common in the deep veins of the leg than of the arm.

Pathogenesis

• Three main factors may lead to the formation of a clot, causing DVT:
  • Trauma to the area
  • An increased tendency to clot
  • Slow blood flow
• Once a clot is formed it may break off and travel in the circulation to the heart and be propelled on to the lungs causing a pulmonary embolism (PE)
• A small PE causes death of a section of the lung it blocks
• A large PE can block all the blood coming to the lungs needing oxygenation, leading to sudden death

Deep vein
thrombosis

Clinical presentation

• Signs and symptoms
  • Small clots may be asymptomatic
  • Warm, swollen, painful calf
  • Chest pain indicating pulmonary involvement
• Investigations
  • Laboratory
    • Elevated D-dimer level
  • Procedures
    • Doppler ultrasound
    • Computer tomography of the pulmonary arteries

Treatment

• Rest and elevation to prevent dislodging of the clot initially
• Medication
  • Anticoagulants to prevent enlargement of the clot
  • Medication to dissolve the clot in certain cases of PE
• Compression stockings and remobilization once anticoagulants commenced
• Interventions
  • Inferior vena cava filter
• Emergency medical evaluation for suspected PE
• Prevention is necessary for people at high risk of DVT
  • Frequent mobilization in long flights
  • Prophylactic anticoagulants following surgery or during extended bed rest

Complications

• Sudden death from PE

Hypertension is elevated blood pressure. It describes systolic and diastolic blood pressure above the normal range (systolic > 120 mmHg and diastolic > 80 mmHg). Consistent readings of 140 (systolic) and 90 (diastolic) are considered hypertensive. Blood pressures above this range are classified as mild, moderate, or severe hypertension depending on the elevation above normal. Hypertension may contribute to the development and progression of atherosclerosis and it often precedes coronary artery disease, but it may also occur in isolation. Hypertension is an important risk factor for stroke and the development of left ventricular hypertrophy and heart failure.

In about 90% of patients, there is no definite cause identified, and this is known as essential or primary hypertension. The pathogenesis may include lifestyle, diet, genetic factors, and occupation. Secondary hypertension occurs in about 10% of cases and is related to pathological processes such as renal artery stenosis, an endocrine tumor, or it may be in response to medications. It can often be eliminated once the underlying cause is treated or removed.

Pathogenesis

There are three determinants of blood pressure: circulating blood volume, cardiac output (CO), and total peripheral resistance (TPR) of the vasculature. Each can be modified upward or downward to affect blood pressure.

• Blood volume
• Cardiac output
• Peripheral resistance

Risk factors

• Non-modifiable factors
• Modifiable factors
• Secondary hypertension has a wide variety of causes involving many body systems. Some causes are:
  • Sleep apnea
  • Dietary liquorice intake
  • Phaeochromocytoma
  • Polycystic kidneys
  • Cushing's syndrome
  • Drugs
  • Pregnancy
  • Renal artery stenosis
  • Coarctation of the aorta

Clinical presentation

• Signs and symptoms
  • Asymptomatic
  • Headache
  • Visual changes
  • Dizziness
  • Fatigue

• Investigations
  • Physical examination
  • Laboratory tests
    • Urea, creatinine, electrolytes, and urinalysis
    • Test glucose and lipid profile as risk-factor screening for coronary artery disease
  • Procedures
    • Blood Pressure
    • Echocardiography
    • Electrocardiography
    • Chest x-ray

Treatment

• Lifestyle changes, such as diet (reduced salt intake), exercise, stopping smoking, reducing alcohol intake, weight loss
• Medication
  • Antihypertensives

Prognosis

• Hypertension can generally be well controlled with medication and lifestyle changes
• Uncontrolled hypertension will contribute to atherosclerosis, myocardial infarctions, stroke, arrhythmias, congestive heart failure, and sudden death
• Uncontrolled hypertension will have specific harmful effects on target organs like the heart, eyes, and kidneys

Complications

• Cardiomegaly
• Cerebrovascular disease (strokes and transient ischemic attacks)
• Myocardial infarction or angina
• Hypertensive retinopathy
• Hypertensive nephropathy
• Hypertensive encephalopathy
• Accelerated atherosclerosis in peripheral vessels

Congestive heart failure occurs when the heart is unable to pump blood around the body efficiently. The result of an inefficient pump is that less blood flows to organs. Blood that should return to the heart is not circulated and causes congestion in the veins and lungs. Both sides of the heart may be affected, to different extents. Left ventricular heart failure (LVF) results in vascular congestion in the lungs, and breathing difficulties. Right ventricular heart failure (RVF) causes blood to accumulate in the legs, abdomen, and liver.

Heart failure

Pathogenesis

The heart fails to pump efficiently because of either systolic or diastolic dysfunction.
a. Systolic dysfunction:

• The systolic phase of the cardiac cycle is when the ventricles contract to push the blood out of the heart. When the ventricles contract less strongly, less blood is pumped out
• Diseases that may cause systolic dysfunction

b. Diastolic dysfunction:

• The diastolic phase of the cardiac cycle is when the ventricles relax to allow blood to fill the chamber before the next beat. If the ventricles do not relax, less blood enters the ventricles to be pumped out
• Diseases that may cause diastolic dysfunction

The body will attempt to compensate for this by:

• Releasing epinephrine or norepinephrine
• Retaining salt and water in the kidneys
• Ventricular hypertrophy

Clinical presentation

• Signs and symptoms
  • Weakness
  • Fatigue
  • Poor appetite
  • Weight loss/weight gain
  • Decreased urine production
  • Fluid accumulation (edema) in the legs, abdomen, lungs
  • Shortness of breath
  • Palpitations
  • Abnormal heart sounds - "gallop rhythm"
  • Displaced apex beat
  • "Crackles" in the lung fields
  • Arrhythmias
  • Orthopnea (shortness of breath on lying flat)
  • Paroxysmal nocturnal dyspnea
  • Acute pulmonary edema
• Investigations
  • Laboratory
    • Full blood count
    • Urea and electrolytes
    • Creatinine
    • Liver function tests
    • Brain-typenatriuretic peptide (BNP) is a specific blood marker for heart failure
    • Urinalysis
  • Procedures:
    • Chest x-ray
    • Electrocardiography
    • Echocardiography

Treatment

• Specific treatment should be targeted at specific causes eg, blood transfusion for anemia or mitral valve repair for mitral stenosis
• Lifestyle modification to control risk factors, especially dietary salt restriction and daily fluid restriction
• Medication:
  • Diuretics remove excess fluid. This is the mainstay of heart failure management
  • ACE inhibitors
  • Digoxin
  • Angiotensin receptor blockers
  • Beta blockers
• Procedures:
  • Thoracentesis
  • Angiography
  • Heart transplant may be an option for younger patients with reversible cause for their heart failure, eg, dilated cardiomyopathy
  • Cardiac rehabilitation
  • Monitoring weight changes daily as an outpatient allows the patient to address fluid accumulation with a doctor in a timely manner

Prognosis

• Heart failure is largely a chronic condition of the elderly where the aim is to improve endurance, improve quality of life, and life expectancy
• Prognosis depends on the severity of disease. Patients with mild heart failure have a life expectancy of > 10 years
• Overall annual mortality is 10%
• In an older patient for whom transplant is not an option, maintaining quality of life with palliative care becomes the focus

Complications

• Acute pulmonary edema is a medical emergency
• Arrhythmias
• Death

Cardiomyopathies are structural or functional abnormalities of the heart muscle. There are many causes for these changes. Cardiomyopathies may also be idiopathic (have no known cause).

Cardiomyopathy is classified as dilated, hypertrophic, or restrictive.

Pathogenesis

In dilated cardiomyopathy, the ventricle chambers enlarge (dilate), the walls become thinner and the ventricle cannot pump effectively. This is the most common form of cardiomyopathy and the third leading cause of heart failure.

Dilated
cardiomyopathy

Causes

• Coronary artery disease
• Myocarditis
• Alcohol
• Chemotherapy drugs
• Pregnancy
• Connective tissue disorders
• Genetic forms account for 20% to 40% of cases with an autosomal dominant or recessive pattern of inheritance

Clinical presentation

• Signs and symptoms
  • Shortness of breath on exertion
  • Chest pain
  • Arrhythmias
  • Abnormal heart sounds
  • As the disease progresses, findings are the same as presentation of heart failure

• Investigations
  • Physical examination findings
  • Procedures
    • Electrocardiography
    • Echocardiography
    • Chest x-ray
    • Cardiac magnetic resonance imaging
    • Cardiac catheterization

Treatment

• Specific treatment should be targeted at specific causes, eg, treat coronary artery disease to prevent further myocardial infarction
• Medication:
  • All cases are treated with anticoagulants to prevent thrombi in chamber walls
  • Treat symptoms of heart failure
• Surgery
  • Most common reason for heart transplant procedures

Prognosis

• 70% of cases die within five years
• Prognosis worsens as the wall becomes thinner
• Arrhythmias offer worse prognosis
• Men survive half as long as women
• African Americans survive half as long as Caucasians
• 50% of deaths are sudden and related to arrhythmias

Complications

• Heart failure
• Arrhythmias
• Death

Cardiomyopathies are structural or functional abnormalities of the heart muscle. There are many causes for these changes. Cardiomyopathy may be idiopathic.

Pathogenesis

In hypertrophic cardiomyopathy the ventricular muscles thicken (hypertrophy) and become stiff, which does not allow the ventricle to fill properly. This will cause less blood to be pumped out of the heart.

• Hypertrophic cardiomyopathy may be inherited as an autosomal dominant trait and be present at birth
• It may be acquired later in life in cases where tumors cause acromegaly or pheochromocytoma

Hypertrophic
cardiomyopathy

Clinical presentation

• Signs and symptoms:
  • Fainting
  • Chest pain
  • Shortness of breath
  • Characteristic heart sounds
  • Palpitations
  • Arrhythmias
  • Sudden death
• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac catheterization

Treatment

• Specific treatment should be targeted at specific causes, eg, removal of tumors with surgery
• Medication
  • Beta blockers and calcium channel blockers slow heart rate and reduce force of contraction of the heart to give more filling time
• Surgery
  • Removal of the excess heart muscle may relieve symptoms when medication fails

Prognosis

• 4% of cases die each year
• Death is usually secondary to arrhythmia
• Death may be due to chronic heart failure, but this is less common
• People with genetic disorders may choose to undergo genetic counseling before planning a family
• People may also undertake regular prophylactic scanning in families with a history of hypertrophic cardiomyopathy

Complications

• Heart failure
• Infective endocarditis
• Arrhythmias
• Sudden death

Cardiomyopathies are structural or functional abnormalities of the heart muscle. There are many causes for these changes. Cardiomyopathy may be idiopathic.

Pathogenesis

In restrictive cardiomyopathy, the ventricles become stiff but not thickened and they do not fill well. It is the least common form of cardiomyopathy and the cause is usually unknown.

• There are two types:
  • Heart muscle is either replaced by scar tissue, or
  • Substances infiltrate and accumulate in the heart muscle, eg, iron from hemochromatosis

Restrictive
cardiomyopathy

Clinical presentation

• Signs and symptoms
  • Fainting
  • Chest pain
  • Shortness of breath
  • Palpitations
  • Arrhythmias
• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac magnetic resonance imaging
    • Cardiac catheterization

Treatment

• Specific treatment should be targeted at specific causes, eg, regular venesection for hemochromatosis to prevent build up of iron
• Medication
  • Treatment used for heart failure may not help
• Surgery
  • Heart transplantation may be the only cure

Prognosis

• 70% of cases die within five years of diagnosis

Complications

• Heart failure
• Arrhythmias
• Cardiac cirrhosis
• Death

Inflammatory heart disease refers to infection and subsequent inflammation of the heart tissues and structures surrounding the heart. It includes endocarditis, myocarditis, and pericarditis. Endocarditis is infection of the endocardial (inner) surface of the heart and is usually caused by bacteria or fungi. Myocarditis is infection of the muscle tissue and is usually caused by viruses or parasites. Pericarditis is infection of the pericardial (outer) surface of the heart and may be caused by viruses or bacteria.

The endocardial surface of the heart, including the heart valves, is constantly exposed to blood and therefore to any pathogen that may be travelling in the blood. Any process that damages the endocardial lining predisposes to endocarditis in the presence of bacteria. Acute bacterial endocarditis develops within a few days and may be life threatening. Subacute bacterial endocarditis develops gradually over weeks or months.

Pathogenesis (common events)

• Injury to the skin, mouth, or gums may allow bacteria to enter the blood stream
• Surgical, medical, or dental procedures may allow bacteria to enter the blood stream
• Pre-existing conditions such as congenital heart defects or valve heart disease allow bacteria to adhere to the damaged surface of the valves
• Alternatively, in normal healthy valves, an aggressive bacterial infection may cause the initial damage to the surface and allow further adhesion
• Staphylococcus or streptococcus species are usually responsible
• Bacteria release enzymes that break down (lyse) the valve tissue
• The influx of inflammatory cells causes further breakdown of the valve tissue
• Platelets, fibrin, and more bacteria accumulate in the damaged areas
• The fibrin and thrombus material grows into "wart like" vegetations
• The bacteria can continue to destroy the valve tissue, altering the tissue's shape and structure
• The valves cannot function properly to separate blood flow through the chambers of the heart as it beats
• Either the valves become stenotic, hindering blood flow from one chamber to the next, or they become incompetent and leak during systole
• Parts of the vegetations may break off, travel around the body and be deposited in other organs like the brain, kidneys, coronary arteries, and extremities of the fingers and toes
• These are called septic emboli
• When they are deposited, they cause ischemia to the peripheral tissue, and may develop into micro abscesses
• The abscesses weaken the vessel wall and the vessel bulges out or ruptures (mycotic aneurysm)

Infective
endocarditis

• Acute bacterial endocarditis
  • The onset is rapid, with rapid destruction of the valves
  • Valves need not be previously damaged - normal valves are often affected
  • Rapid progression to heart failure - sometimes within a week
  • Precipitating factor is often IV drug use
  • The thrombi on the valves are produced by the bacteria
  • Embolization, abscess formation, and neurological involvement are common complications

• Sub acute bacterial endocarditis
  • The onset is more gradual and the disease takes an extended course
  • Bacteria are deposited on previously damaged valves, and invade pre-existing thrombi rather than producing them
  • Heart failure occurs over a period of weeks to months
  • Precipitating factor is often dental therapy
  • Complications are usually from embolization and slow valve damage

Common risk factors:

• Congenital heart defects
• Previous rheumatic heart disease
• Previous endocarditis
• Valvular heart disease
• Cardiac surgery or catheterization
• Intravenous drug addiction
• Immunosuppresion
• Artificial (prosthetic) heart valves
• Calcification of heart valves with age

Clinical presentation

a. Acute bacterial endocarditis

• Signs and symptoms
  • Rapid onset
  • High fever
  • Tachycardia
  • Fatigue
  • Characteristic heart murmurs caused by rapid valve destruction
  • Signs of heart failure from valvular insufficiency
  • Splinter hemorrhages from septic emboli

b. Sub acute bacterial endocarditis

• Signs and symptoms
  • Gradual onset
  • Mild fever or afebrile
  • Mild tachycardia
  • Fatigue
  • Weight loss
  • Anemia
  • Splinter hemorrhages from septic emboli
  • Micro abscesses
  • Osler nodes or Janeway lesions
  • Characteristic heart murmurs caused by valve destruction
  • Signs of heart failure from valvular insufficiency

• Investigations
  • Laboratory tests:
    • Blood cultures
  • Procedures:
    • Echocardiography

Treatment

• Medication
  • High dose intravenous antibiotics (as per bacterial sensitivity on blood culture) Prophylactic antibiotic use during surgical, medical, or dental procedures in people with known structural heart abnormalities such as congenital heart defects
  • Symptomatic treatment of heart failure
• Surgery
  • To repair valves or remove vegetations

Prognosis

• Good prognosis where appropriate antibiotics are available for common bacteria
• Prophylactic antibiotic use during future surgical, medical, or dental procedures
• For less common fungal infections or virulent bacteria, cure rates are lower
• History of intravenous drug use offers a lower cure rate
• Cure rates in prosthetic valves are lower
• Without treatment, acute bacterial endocarditis is fatal

Complications

• Abscesses
• Recurrent endocarditis
• Mycotic aneurysms
• Septic emboli causing stroke, myocardial infarctions (MI), kidney failure
• Heart failure from valvular dysfunction
• Pericarditis
• Death

Inflammatory heart disease refers to infection and subsequent inflammation of the heart tissues and structures surrounding the heart. It includes endocarditis, myocarditis, and pericarditis. Endocarditis is infection of the endocardial (inner) surface of the heart and is usually caused by bacteria or fungi. Myocarditis is infection of the muscle tissue and is usually caused by viruses or parasites. Pericarditis is infection of the pericardial (outer) surface of the heart and may be caused by viruses or bacteria.

Myocarditis is difficult to study, diagnose, and treat as it has many causes and a wide range of clinical presentations, and may even be asymptomatic. The most common cause is acute viral myocarditis, which may be mild and not present to a doctor, or may be aggressive and result in heart failure.

Pathogenesis

• Viral or parasitic pathogens enter the blood stream
• The muscle cells take up the pathogens, which destroy the muscle cells
• The cells die of cytotoxic necrosis within one to two days
• In the cells that survive, viral RNA is integrated into the muscle cell over the next few days
• The body's defense cells (lymphocytes) target the foreign viral RNA inside the remaining muscle cells and destroy it, killing the cell in the process
• The area of cell death in the muscle wall reduces the pumping action of the heart and may result in dilated cardiomyopathy
• It may be caused by:
  • Viral infection from a variety of viruses
  • Toxic myocarditis from medications, environmental toxins, insect stings, or radiation therapy
  • Immune mechanisms in diseases like rheumatoid arthritis

Clinical presentation

• Signs and symptoms
  • Non-specific symptoms like fatigue, mild shortness of breath, myalgias
  • Preceding flu-like viral illness
  • Chest pain
  • Shortness of breath
  • Fainting
  • Palpitations
  • Symptoms of heart failure
  • Symptoms of dilated cardiomyopathy
• Investigations
  • Laboratory tests
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac magnetic resonance imaging
    • Cardiac biopsy

Treatment

• Supportive care of viral illness
• Medication
  • Treatment of heart failure symptoms
• Surgery
  • Heart transplant for fulminant (acute) heart failure

Prognosis

• Simple mild cases self resolve
• More severe cases have poorer outcomes
• Transplant cases have more chance of rejection

Complications

• Dilated cardiomyopathy
• Pericarditis
• Heart failure
• Arrhythmias
• Sudden death

Inflammatory heart disease refers to infection and subsequent inflammation of the heart tissues and structures surrounding the heart. It includes endocarditis, myocarditis, and pericarditis. Endocarditis is infection of the endocardial (inner) surface of the heart and is usually caused by bacteria or fungi. Myocarditis is infection of the muscle tissue and is usually caused by viruses or parasites. Pericarditis is infection of the pericardial (outer) surface of the heart and may be caused by viruses or bacteria.

Pericarditis is inflammation of the pericardial sac, the two membrane layers lining the heart. Infection may be isolated but often co-exists with other heart infections (myocarditis) or occurs as a result of infection of surrounding tissue like the lung.

Pathogenesis

• Pericarditis is usually caused by a bacterial or viral infection
• Fungal and parasite causes are rarer
• It may occur following rheumatic heart disease
• Autoimmune diseases like systemic lupus erythematosus or rheumatoid arthritis may affect the pericardium
• Other causes of pericarditis are myocardial infarction, open heart surgery, kidney failure, drugs, trauma, and radiation injury
• Pericarditis is always associated with a fluid exudate in the pericardial sac, the appearance of which depends on the pathogen or etiology
• In viral infection, the fluid is described as "serous fluid", and is clear and yellow
• In rheumatic or early bacterial infection, there is generally more damage; the fluid is described as "serofibrinous fluid", giving a "bread and butter" appearance similar to when two slices of buttered bread are pulled apart
• In bacterial infections, usually staphylococcal or streptococcal, the fluid is described as a "purulent exudate", and contains pus
• A late complication of all forms of pericarditis is constrictive pericarditis; the pericardium becomes fibrosed and prevents diastolic relaxation and filling of the heart
• If too much fluid accumulates in the pericardial sac, the pressure on the heart restricts the heart's ability to pump and "cardiac tamponade" occurs, which is a medical emergency 

Pericarditis

Clinical presentation

• Signs and symptoms
  • Fever
  • Chest pain made worse by lying down, coughing, deep breathing, swallowing
  • Pericardial "rub" heard with stethoscope as the layers of pericardium move against each other
  • Heart failure symptoms
  • Cardiac tamponade with loss of consciousness and sudden death
• Investigations
  • Laboratory tests
    • Elevated inflammatory markers and possible elevation of cardiac enzymes
  • Procedures:
    • Electrocardiography
    • Chest x-ray
    • Echocardiography

Treatment

• Specific treatment for specific causes, eg, antibiotics for bacterial infection
• Medication
  • To control pain and reduce inflammation (nonsteroidal anti-inflammatory drugs and prednisone)
• Surgery
  • Pericardiocentesis
  • Surgical removal of the pericardium if pericarditis recurs

Prognosis

• Depends on cause but simple viral pericarditis usually resolves within a few weeks

Complications

• Cardiac tamponade
• Constrictive pericarditis

Rheumatic heart disease (RHD) is a major complication of rheumatic fever (RF). RF generally affects children and young adults and follows a streptococcal throat infection. It affects the skin, joints, brain, heart, and kidneys. The damage to these organs is from an inflammatory reaction to the infection rather than from the infection being passed on to these organs. RHD is a pancarditis affecting all layers of the heart (endocarditis, myocarditis, and pericarditis). Up to 39% of RF cases develop some degree of RHD.

Pathogenesis

• RF presents approximately two weeks after a "strep throat", a group A streptococcal infection of the throat and/or upper airways
• During the infection, the body identifies proteins on the bacteria as foreign and attacks them
• The antibody formed in the blood is called antistreptolysin-O and indicates a recent streptococcal infection
• Unfortunately, some human organs have similar proteins, and the antibody begins to attack these organs - "innocent bystanders"
• This is an autoimmune inflammatory reaction
• In rheumatic endocarditis, the formation of vegetations is similar to that of infective endocarditis, except that there are no bacteria found in RHD (sterile vegetations)
  • Damage to the left side of the heart is greater than to the right side
  • The vegetations destroy the valves and the chordae tendinae that open the valves
  • Either the valves become incompetent and leak during systole, or they become stenotic, hindering blood flow from one chamber to the next
    • Mitral regurgitation - blood leaks from the left ventricle to the left atrium during systole
    • Aortic regurgitation - blood leaks from the aorta to the left ventricle during diastole
    • Mitral stenosis - blood flow is reduced from the left atrium to the ventricle during diastole
    • Aortic stenosis - blood flow is reduced from the left ventricle to the aorta during systole
  • Mitral and aortic valves are most commonly affected
  • Tricuspid valve is sometimes affected
  • Pulmonary valve is rarely affected
• In myocarditis, the characteristic finding is Aschoff bodies
  • These are collections of macrophages and lymphocytes surrounding a central area of necrotic tissue
  • They destroy the myocardium and if they occur in the conduction system of the heart they may cause arrhythmias
• In pericarditis, there is a fibrinous exudate around the epicardium and in the pericardial space
• Myocardial dysfunction in RHD is mostly due to either myocarditis or valve dysfunction leading to heart failure

Rheumatic heart
disease

Clinical presentation

A diagnosis of RHD can be made only after confirmation of RF. The Jones criteria are used for RF diagnoses.

• Jones major criteria are:
  • Polyarthritis (joint inflammation)
  • Carditis (heart inflammation)
  • Chorea (neurological movement disorder)
  • Subcutaneous nodules
  • Erythema marginatum (skin disease)
• Jones minor criteria are:
  • Joint pain
  • Fever
  • Evidence of previous streptococcal infection
  • Previous rheumatic fever
  • Elevated erythrocyte sedimentation rate (ESR)
  • Electrocardiograph (ECG) changes

RF is diagnosed if two major or one major and two minor criteria are fulfilled.

• Signs and symptoms:
  • Fever
  • Chest pain
  • Tachycardia
  • Palpitations
  • Heart murmurs
  • Heart failure symptoms
  • Pericardial rub
• Investigations:
  • Laboratory
    • Blood tests show anti streptococcal antibodies
    • Blood inflammatory markers are raised
  • Procedures
    • Electrocardiography
    • Echocardiography

Treatment

• Enforced rest in acute stages of the disease to decrease workload of the heart
• Medications
  • Eradication of streptococcal pathogens with antibiotics, usually penicillin
  • To control pain and reduce inflammation - like aspirin, ibuprofen, or corticosteroids
  • To treat heart-failure symptoms
• Surgery
  • Heart valve surgery to repair or replace valves

Prognosis

• Rheumatic fever (RF) is considerably rarer now due to the availability of antibiotics to treat streptococcal infections at an early stage
• RF cases usually recover over 12 to 15 weeks
• Rheumatic heart disease (RHD) with damaged valves results in lifelong risk of bacterial endocarditis
• RHD with valve disease requires lifelong monthly antibiotic prophylaxis, especially before any dental or surgical procedures, to prevent further damage to the valves
• RF with carditis without valve disease still requires lifelong monthly antibiotic prophylaxis to prevent this deterioration

Complications

• Infective endocarditis is common due to valve damage
• Recurrent rheumatic fever infection (common)
• Valve replacement surgery
• Emboli
• Anemia
• Heart failure
• Arrhythmias

Mitral stenosis (MS) is a narrowing of the mitral valve, increasing resistance to blood flow from the left atrium to the left ventricle during diastole.

The heart valves regulate blood flow through the heart. The valves are made up of leaflets or cusps that open to allow blood flow and close to prevent back flow at different times during the heart beat cycle. On the right side of the heart, the tricuspid valve separates the right atrium and right ventricle and the pulmonary valve opens into the pulmonary arteries from the right ventricle. On the left side of the heart, the mitral valve separates the left atrium and left ventricle, and the aortic valve opens into the aorta from the left ventricle. Cardiac function is impaired if these valves malfunction, either by leaking (regurgitation) or by narrowing (stenosis). The aortic and mitral valves are most commonly affected.

Pathogenesis

• Most common cause is rheumatic heart disease
• Mitral stenosis can be congenital
• Myxomas or large obstructive clots in the left atrium can cause similar symptoms
• The left atrium works hard to pump the blood into the left ventricle against resistance
• The left atrium enlarges
• Blood is unable to flow efficiently through the heart, so back pressure builds up from the accumulation of blood, and if high enough can result in fluid collection in the lungs (pulmonary edema)
• Pressure is transmitted backwards through the circulation into the pulmonary veins

Mitral stenosis

Clinical presentation

• Signs and symptoms
  • Asymptomatic if mild
  • Chest pain
  • Symptoms of heart failure
  • Palpitations
  • Arrhythmias
  • Characteristic diastolic murmur
• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac catheterization

Treatment

• Medication
  • To control arrhythmias
  • To treat heart failure symptoms
  • Anticoagulants to prevent thrombus formation and emboli
• Surgery
  • Balloon valvuloplasty attempts to stretch and open up the valve
  • Surgery to repair the valve
  • Surgery to replace the stenotic valve with a prosthetic valve

Prognosis

• Depends on the severity of the disease

Complications

• Arrhythmias
• Emboli
• Infective endocarditis
• Heart failure

Mitral regurgitation (MR) is the leaking of blood from the left ventricle back to the left atrium when the ventricle contracts during systole.

Pathogenesis

• The most common cause of MR is rheumatic heart disease
• Other causes may be damage to the supporting structures of the valve by myocardial infarction, trauma, or endocarditis
• The leaking of the blood backwards increases the volume and pressure in the left atrium, which may cause atrial hypertrophy
• The left ventricle also enlarges as it tries to pump harder to the aorta to compensate for the blood being lost to the atrium
  • That pressure is transmitted backwards through the circulation into the pulmonary veins
  • If pressure is high enough, it can result in fluid collection in the lungs (pulmonary edema)

Mitral regurgitation

Clinical presentation

• Signs and symptoms
  • Asymptomatic if mild
  • Palpitations
  • Arrhythmias
  • Characteristic ejection systolic murmur
  • Chest pain
  • Shortness of breath
  • Fatigue
  • Symptoms of heart failure

• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac catheterization

Treatment

• Medication
  • To control arrhythmias
  • Anticoagulants to prevent clot formation and emboli
  • To treat heart failure symptoms
• Surgery
  • The valve is repaired
  • The valve is replaced with a prosthetic valve

Prognosis

• Depends on left ventricular function

Complications

• Atrial fibrillation
• Emboli
• Infective endocarditis
• Heart failure

Aortic stenosis (AS) is a narrowing of the aortic valve, increasing resistance to blood flow from the left ventricle to the aorta during systole.

Pathogenesis

• The left ventricle works harder to pump blood out to the body through the narrowed valve
• The ventricular walls hypertrophy as a result
• Thicker walls reduce the filling space inside the ventricle, so less blood is pumped out
• A thicker heart muscle requires more blood supply from the coronary arteries
• Eventually the blood supply is insufficient and myocardial ischemia results in heart failure
• The most common cause of aortic stenosis is age-related calcification of the valve
• Rheumatic fever and rheumatic heart disease are also causes
• Mitral regurgitation may be congenital

Aortic stenosis

Clinical presentation

• Signs and symptoms
  • Fainting
  • Chest pain
  • Palpitations
  • Symptoms of heart failure
  • Characteristic systolic murmur
  • Sudden death
• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac catheterization

Treatment

• Medication
  • To treat heart failure symptoms
• Surgery
  • Balloon valvuloplasty attempts to stretch and open up the valve
  • Surgery to repair the valve
  • Surgery to replace the stenotic valve with a prosthetic valve

Prognosis

• Average survival is less than five years
• Incidence of sudden death is 15% to 20%

Complications

• Arrhythmias
• Infective endocarditis
• Heart failure
• Sudden death

Aortic regurgitation (AR) occurs when blood leaks from the aorta into the left ventricle when the ventricle relaxes during diastole.

Pathogenesis

• In diastole the left ventricle relaxes to allow blood to flow in from the atrium
• At the same time bloods leaks back from the aorta
• The volume and pressure in the left ventricle increases
• The muscle wall hypertrophies and the chamber dilates to compensate for the extra volume
• As the leak increases even the compensatory hypertrophy may not be able to pump enough blood for the body's needs
• This leads to heart failure
• The most common cause is rheumatic heart disease
• The aortic valve may be weakened by aortic dissection or aneurysms
• Aortic regurgitation may be congenital
• It may be as a result of infective endocarditis

Aortic regurgitation

Clinical presentation

• Signs and symptoms
  • Asymptomatic if mild
  • Chest pain
  • Symptoms of heart failure
  • Characteristic diastolic murmur
• Investigations
  • Physical examination
  • Procedures
    • Electrocardiography
    • Chest x-ray
    • Echocardiography
    • Cardiac catheterization

Treatment

• Medication
  • To treat heart failure symptoms
• Surgery
  • The valve is repaired
  • The valve is replaced with a prosthetic valve

Prognosis

• Depends on the severity of the disease

Complications

• Arrhythmias
• Emboli
• Infective endocarditis
• Heart failure

Congenital heart disease (CHD) is a collection of defects within the structure and function of the heart or large vessels around it that is present at birth. CHD may or may not be picked up on sonography during the pregnancy. In utero, the fetal blood supply is dependent on maternal blood supply. Symptoms of CHD may become evident at birth, in infancy or childhood, or only much later in life.

Pathogenesis

• The heart is completely formed and functional in the first ten weeks of fetal life
• The exact etiology is unknown, but evidence suggests that toxic substances like alcohol, viral infections like rubella ("German measles") and exposure to radiation in this formative stage lead to heart defects
• Chromosomal abnormalities like trisomy 21 (Down syndrome) are associated with particular heart defects
• The defects may be grouped according to their structural abnormalities
  • Hypoplasia
    • Either the left or the right ventricle fails to develop and therefore cannot pump blood out. It is very rare, but it is the most serious form of CHD. It requires a patent foramen ovale and patent ductus arteriosus (PDA) to ensure survival until surgery can be performed. This is called hypoplastic left (or right) heart syndrome
  • Obstruction
    • This occurs when valves, arteries, or veins are narrowed or blocked. It may result in hypertrophy of the heart chambers, hypertension and eventual redirection (shunting) of blood in the wrong direction in the circulation. Examples of this are pulmonary valve stenosis, aortic valve stenosis, and coarctation of the aorta
  • Septal defects
    • The septum separates the two sides of the heart. It is relatively common to have defects or holes in the septum between the atria or ventricles, leading to mixing of the blood from the two sides and reducing the amount of oxygen getting to the body. Ventricular septal defects are the most common form of CHD, followed by atrial septal defects. They both cause left-to-right shunts.
  • Other defects may not conform to these specific groups
    • Transposition of the great vessels
    • Tetralogy of Fallot
    • Patent ductus arteriosus

Defects may also be divided according to whether they cause cyanosis or not.

• Cyanotic
  • Tetralogy of Fallot
  • Transposition of the great vessels
  • Tricuspid atresia
  • Total anomalous pulmonary venous return
  • Hypoplastic left or right heart syndrome
• Non-cyanotic
  • Ventricular septal defect (VSD)
  • Atrial septal defect (ASD)
  • Patent ductus arteriosus (PDA)
  • Coarctation of the aorta (although this may sometimes cause cyanosis)

Clinical presentation

• Signs and symptoms
  • Asymptomatic
  • Failure to grow or put on weight
  • Impaired tolerance for exercise
  • Difficulty breathing or eating
  • Sweating
  • "Blue baby" - cyanosis of peripheries like tongue or fingertips
  • Murmurs
  • Heart failure symptoms
  • Others may depend on specific condition
• Investigations
  • Physical examination
  • Procedures
    • Echocardiography
    • ECG
    • Chest x-ray
  • Others may depend on specific condition

Treatment

• Symptoms may resolve
• Small defects may not require treatment
• Medication:
  • To control heart failure
• Surgery:
  • Timing depends on the severity of symptoms
  • Balloon angioplasty or balloon valvuloplasty for narrowed vessels and valves respectively
  • Shunt creation to direct blood in the correct direction
  • Heart transplant
• Others may depend on specific condition

Prognosis

• Depends on the specific condition

Complications

• Infective endocarditis
• Arrhythmias
• Heart failure
• Others may depend on specific condition

References

Systematic reviews

Jolliffe J, Rees K, Taylor R, Thompson D, Oldridge N, Ebrahim S. Exercise based rehabilitation for coronary heart disease. Cochrane database systems review. 2001.

Retrospective study

Suaya JA, Shepard DS, Normand S, Ades P, Prottas J, Stason W. Use of cardiac rehabilitation by medicare beneficiaries after myocardial infarction or coronary bypass surgery. Circulation. 2007; 116: 1653-1662.

Thomas R, King M, Lui K, et al. AACVPR/ACC/AHA 2007. Performance Measures on Cardiac Rehabilitation for Referral to and Delivery of Cardiac Rehabilitation/Secondary Prevention Services. Journal of the American College of Cardiology. 2007;50:1400-1433.

Reviews

Alaeddini J, Shirani J. Angina Pectoris. Emedicine. December 19, 2007. Available at: http://emedicine.medscape.com/article/150215-overview Accessed March 9, 2009.

Berul C, Miyake C. Hypertrophic Cardiomyopathy. Emedicine. November 11, 2008. Available at: http://emedicine.medscape.com/article/890068-followup Accessed March 17, 2009.

Blackstock UA, Sinert R. Dilated Cardiomyopathy. Emedicine. September 30, 2008. Available at: http://emedicine.medscape.com/article/757668-overview Accessed March 17, 2009.

Brusch JL. Infective Endocarditis. Emedicine. December 7, 2007. Available at: http://emedicine.medscape.com/article/216650-overview Accessed March 17, 2009.

Chin T, Chin E, Siddiqui T, Sundell A. Rheumatic Heart Disease. Emedicine. October 10, 2008. Available at: http://emedicine.medscape.com/article/891897-overview Accessed March 18, 2009.

Howes DS, Booker EA. Myocarditis. Emedicine. August 5, 2008. Available at: http://emedicine.medscape.com/article/759212-overview Accessed March 17, 2009.

Hypertension: MedlinePlus Medical Encyclopedia. April 6, 2007. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000468.htm Updated April 23, 2009. Accessed March 9, 2009.

Kaloudis PJ, Viccellio P, Fan R. Restrictive Cardiomyopathy. Emedicine. July 3, 2008. Available at: http://emedicine.medscape.com/article/757822-treatment Accessed March 12, 2009.

Risk Factors and Coronary Heart Disease. American Heart Association. March 10, 2009. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4726 Accessed March 10, 2009.

Weinrauch LA. Heart Failure. Medline Plus Medical Encyclopedia. September 23, 2008. Available at: http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/000158.htm Accessed March 16, 2009.

Textbooks

Damjanov I. Pathology for the Health Professions. Kansas City, Kansas: Elsevier Saunders; 2006.

The Merck Manual of Medical Information. New York, NY: Pocket Books; 2003.