Ischaemic heart disease
Encyclopedia
Ischaemic or ischemic heart disease (IHD), or myocardial ischaemia, is a disease
characterized by ischaemia
(reduced blood supply) of the heart muscle, usually due to coronary artery disease (atherosclerosis
of the coronary arteries). Its risk increases with age, smoking
, hypercholesterolaemia (high cholesterol
levels), diabetes
, and hypertension
(high blood pressure), and is more common in men and those who have close relatives with ischaemic heart disease.
Symptoms of stable ischaemic heart disease include angina (characteristic chest pain
on exertion) and decreased exercise tolerance. Unstable IHD presents itself as chest pain or other symptoms at rest, or rapidly worsening angina. Diagnosis of IHD is with an electrocardiogram
, blood test
s (cardiac markers), cardiac stress test
ing or a coronary angiogram
. Depending on the symptoms and risk, treatment may be with medication
, percutaneous coronary intervention
(angioplasty) or coronary artery bypass surgery
(CABG).
It is the most common cause of death in most Western countries, and a major cause of hospital admissions. There is limited evidence for population screening, but prevention (with a healthy diet and sometimes medication for diabetes, cholesterol and high blood pressure) is used both to prevent IHD and to decrease the risk of complications.
The medical history
distinguishes between various alternative causes for chest pain (such as dyspepsia
, musculoskeletal pain, pulmonary embolism
). As part of an assessment of the three main presentations of IHD, risk factor
s are addressed. These are the main causes of atherosclerosis
(the disease process underlying IHD): age, male sex, hyperlipidaemia (high cholesterol
and high fats in the blood), smoking
, hypertension
(high blood pressure), diabetes
, and the family history
.
The medical history
distinguishes between various alternative causes for chest pain (such as dyspepsia
, musculoskeletal pain, pulmonary embolism
). As part of an assessment of the three main presentations of IHD, risk factor
s are addressed. These are the main causes of atherosclerosis
(the disease process underlying IHD): age, male sex, hyperlipidaemia (high cholesterol
and high fats in the blood), smoking
, hypertension
(high blood pressure), diabetes
, and the family history
.
(ECG/EKG), both for "stable" angina and acute coronary syndrome. An X-ray of the chest
and blood test
s may be performed.
Myeloperoxidase
has been proposed as a biomarker.
s may be used to induce both symptoms and detect changes by way of electrocardiography (using an ECG), echocardiography
(using ultrasound
of the heart) or scintigraphy
(using uptake of radionuclide
by the heart muscle). If part of the heart seems to receive an insufficient blood supply, coronary angiography
may be used to identify stenosis
of the coronary arteries and suitability for angioplasty
or bypass surgery
.
generally takes place in the emergency department
, where ECGs may be performed sequentially to identify "evolving changes" (indicating ongoing damage to the heart muscle). Diagnosis is clear-cut if ECGs show elevation of the "ST segment", which in the context of severe typical chest pain is strongly indicative of an acute myocardial infarction
(MI); this is termed a STEMI (ST-elevation MI), and is treated as an emergency with either urgent coronary angiography
and percutaneous coronary intervention
(angioplasty with or without stent
insertion) or with thrombolysis
("clot buster" medication), whichever is available. In the absence of ST-segment elevation, heart damage is detected by cardiac markers (blood tests that identify heart muscle damage). If there is evidence of damage (infarction
), the chest pain is attributed to a "non-ST elevation MI" (NSTEMI). If there is no evidence of damage, the term "unstable angina" is used. This process usually necessitates admission to hospital, and close observation on a coronary care unit
for possible complications (such as cardiac arrhythmias - irregularities in the heart rate).
Depending on the risk assessment, stress testing or angiography may be used to identify and treat coronary artery disease in patients who have had an NSTEMI or unstable angina.
of the coronary arteries. The arteries become "furred up" by fat-rich deposits in the vessel wall (plaques).
Stable angina is due to inability to supply the myocardium (heart muscle) with sufficient blood in situations of increased demand for oxygen, such as exertion.
Unstable angina, STEMI and NSTEMI are attributed to "plaque rupture", where one of the plaques gets weakened, develops a tear, and forms an adherent blood clot
that either obstructs blood flow or floats further down the blood vessel, causing obstruction there.
, and control of high blood pressure.
drugs may be used to reduce the rate of occurrence and severity of angina attacks. Treatments for acute coronary syndrome and established coronary artery disease is discussed above in "diagnosis". Revascularization for acute coronary syndrome has a significant mortality benefit. Recent evidence suggests that revascularization for stable ischaemic heart disease may also confer a mortality benefit over medical therapy alone.
Treatment of coronary artery disease includes addressing "modifiable" risk factors. This includes suppression of cholesterol (usually with statin
s), even in those with statistically normal cholesterol levels, control of blood pressure
, blood sugar
s (if diabetic), regular exercise and a healthy diet. Smokers are encouraged to stop smoking.
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
characterized by ischaemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
(reduced blood supply) of the heart muscle, usually due to coronary artery disease (atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
of the coronary arteries). Its risk increases with age, smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
, hypercholesterolaemia (high cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
levels), diabetes
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, and hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure), and is more common in men and those who have close relatives with ischaemic heart disease.
Symptoms of stable ischaemic heart disease include angina (characteristic chest pain
Chest pain
Chest pain may be a symptom of a number of serious conditions and is generally considered a medical emergency. Even though it may be determined that the pain is non-cardiac in origin, this is often a diagnosis of exclusion made after ruling out more serious causes of the pain.-Differential...
on exertion) and decreased exercise tolerance. Unstable IHD presents itself as chest pain or other symptoms at rest, or rapidly worsening angina. Diagnosis of IHD is with an electrocardiogram
Electrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...
, blood test
Blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
s (cardiac markers), cardiac stress test
Cardiac stress test
Cardiac stress test is a test used in medicine and cardiology to measure the heart's ability to respond to external stress in a controlled clinical environment....
ing or a coronary angiogram
Coronary catheterization
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional purposes....
. Depending on the symptoms and risk, treatment may be with medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
, percutaneous coronary intervention
Percutaneous coronary intervention
Percutaneous coronary intervention , commonly known as coronary angioplasty or simply angioplasty, is one therapeutic procedure used to treat the stenotic coronary arteries of the heart found in coronary heart disease. These stenotic segments are due to the build up of cholesterol-laden plaques...
(angioplasty) or coronary artery bypass surgery
Coronary artery bypass surgery
Coronary artery bypass surgery, also coronary artery bypass graft surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease...
(CABG).
It is the most common cause of death in most Western countries, and a major cause of hospital admissions. There is limited evidence for population screening, but prevention (with a healthy diet and sometimes medication for diabetes, cholesterol and high blood pressure) is used both to prevent IHD and to decrease the risk of complications.
The medical history
Medical history
The medical history or anamnesis of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information , with the aim of obtaining information useful in formulating a diagnosis and providing...
distinguishes between various alternative causes for chest pain (such as dyspepsia
Dyspepsia
Dyspepsia , also known as upset stomach or indigestion, refers to a condition of impaired digestion. It is a medical condition characterized by chronic or recurrent pain in the upper abdomen, upper abdominal fullness and feeling full earlier than expected when eating...
, musculoskeletal pain, pulmonary embolism
Pulmonary embolism
Pulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
). As part of an assessment of the three main presentations of IHD, risk factor
Risk factor
In epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.-Correlation vs causation:...
s are addressed. These are the main causes of atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
(the disease process underlying IHD): age, male sex, hyperlipidaemia (high cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
and high fats in the blood), smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
, hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure), diabetes
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, and the family history
Family history (medicine)
In medicine, a family history consists of information about disorders from which the direct blood relatives of the patient have suffered. Genealogy typically includes very little of the medical history of the family, but the medical history could be considered a specific subset of the total history...
.
Signs and symptoms
Ischaemic heart disease may be present with any of the following problems:- Angina pectoris (chest painChest painChest pain may be a symptom of a number of serious conditions and is generally considered a medical emergency. Even though it may be determined that the pain is non-cardiac in origin, this is often a diagnosis of exclusion made after ruling out more serious causes of the pain.-Differential...
on exertion, in cold weather or emotional situations) - Acute chest pain: acute coronary syndromeAcute coronary syndromeAcute coronary syndrome is usually one of three diseases involving the coronary arteries: ST elevation myocardial infarction , non ST elevation myocardial infarction , or unstable angina ....
, unstable anginaUnstable anginaUnstable angina is a type of angina pectoris that is irregular. It is a type of acute coronary syndrome.It can be difficult to distinguish from non–Q-wave myocardial infarction.-Definition:...
or myocardial infarctionMyocardial infarctionMyocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
("heart attack", severe chest pain unrelieved by rest associated with evidence of acute heart damage) - Heart failure (difficulty in breathing or swelling of the extremities due to weakness of the heart muscle)
The medical history
Medical history
The medical history or anamnesis of a patient is information gained by a physician by asking specific questions, either of the patient or of other people who know the person and can give suitable information , with the aim of obtaining information useful in formulating a diagnosis and providing...
distinguishes between various alternative causes for chest pain (such as dyspepsia
Dyspepsia
Dyspepsia , also known as upset stomach or indigestion, refers to a condition of impaired digestion. It is a medical condition characterized by chronic or recurrent pain in the upper abdomen, upper abdominal fullness and feeling full earlier than expected when eating...
, musculoskeletal pain, pulmonary embolism
Pulmonary embolism
Pulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
). As part of an assessment of the three main presentations of IHD, risk factor
Risk factor
In epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.-Correlation vs causation:...
s are addressed. These are the main causes of atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
(the disease process underlying IHD): age, male sex, hyperlipidaemia (high cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
and high fats in the blood), smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
, hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure), diabetes
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, and the family history
Family history (medicine)
In medicine, a family history consists of information about disorders from which the direct blood relatives of the patient have suffered. Genealogy typically includes very little of the medical history of the family, but the medical history could be considered a specific subset of the total history...
.
Diagnosis
The diagnosis of ischaemic heart disease underlying particular symptoms depends largely on the nature of the symptoms. The first investigation is an electrocardiogramElectrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...
(ECG/EKG), both for "stable" angina and acute coronary syndrome. An X-ray of the chest
Chest X-ray
In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...
and blood test
Blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
s may be performed.
Myeloperoxidase
Myeloperoxidase
Myeloperoxidase is a peroxidase enzyme that in humans is encoded by the MPO gene. Myeloperoxidase is most abundantly expressed in neutrophil granulocytes . It is a lysosomal protein stored in azurophilic granules of the neutrophil...
has been proposed as a biomarker.
Stable angina
In "stable" angina, chest pain with typical features occurring at predictable levels of exertion, various forms of cardiac stress testCardiac stress test
Cardiac stress test is a test used in medicine and cardiology to measure the heart's ability to respond to external stress in a controlled clinical environment....
s may be used to induce both symptoms and detect changes by way of electrocardiography (using an ECG), echocardiography
Echocardiography
An echocardiogram, often referred to in the medical community as a cardiac ECHO or simply an ECHO, is a sonogram of the heart . Also known as a cardiac ultrasound, it uses standard ultrasound techniques to image two-dimensional slices of the heart...
(using ultrasound
Medical ultrasonography
Diagnostic sonography is an ultrasound-based diagnostic imaging technique used for visualizing subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions...
of the heart) or scintigraphy
Scintigraphy
Scintigraphy is a form of diagnostic test used in nuclear medicine, wherein radioisotopes are taken internally, and the emitted radiation is captured by external detectors to form two-dimensional images...
(using uptake of radionuclide
Radionuclide
A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...
by the heart muscle). If part of the heart seems to receive an insufficient blood supply, coronary angiography
Coronary catheterization
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional purposes....
may be used to identify stenosis
Stenosis
A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....
of the coronary arteries and suitability for angioplasty
Angioplasty
Angioplasty is the technique of mechanically widening a narrowed or obstructed blood vessel, the latter typically being a result of atherosclerosis. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is passed into the narrowed locations and then inflated to a fixed size...
or bypass surgery
Coronary artery bypass surgery
Coronary artery bypass surgery, also coronary artery bypass graft surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease...
.
Acute chest pain
Diagnosis of acute coronary syndromeAcute coronary syndrome
Acute coronary syndrome is usually one of three diseases involving the coronary arteries: ST elevation myocardial infarction , non ST elevation myocardial infarction , or unstable angina ....
generally takes place in the emergency department
Emergency department
An emergency department , also known as accident & emergency , emergency room , emergency ward , or casualty department is a medical treatment facility specialising in acute care of patients who present without prior appointment, either by their own means or by ambulance...
, where ECGs may be performed sequentially to identify "evolving changes" (indicating ongoing damage to the heart muscle). Diagnosis is clear-cut if ECGs show elevation of the "ST segment", which in the context of severe typical chest pain is strongly indicative of an acute myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
(MI); this is termed a STEMI (ST-elevation MI), and is treated as an emergency with either urgent coronary angiography
Coronary catheterization
A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional purposes....
and percutaneous coronary intervention
Percutaneous coronary intervention
Percutaneous coronary intervention , commonly known as coronary angioplasty or simply angioplasty, is one therapeutic procedure used to treat the stenotic coronary arteries of the heart found in coronary heart disease. These stenotic segments are due to the build up of cholesterol-laden plaques...
(angioplasty with or without stent
Stent
In the technical vocabulary of medicine, a stent is an artificial 'tube' inserted into a natural passage/conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow...
insertion) or with thrombolysis
Thrombolysis
Thrombolysis is the breakdown of blood clots by pharmacological means. It is colloquially referred to as clot busting for this reason...
("clot buster" medication), whichever is available. In the absence of ST-segment elevation, heart damage is detected by cardiac markers (blood tests that identify heart muscle damage). If there is evidence of damage (infarction
Infarction
In medicine, infarction refers to tissue death that is caused by a local lack of oxygen due to obstruction of the tissue's blood supply. The resulting lesion is referred to as an infarct.-Causes:...
), the chest pain is attributed to a "non-ST elevation MI" (NSTEMI). If there is no evidence of damage, the term "unstable angina" is used. This process usually necessitates admission to hospital, and close observation on a coronary care unit
Coronary care unit
A coronary care unit is a hospital ward specialized in the care of patients with heart attacks, unstable angina, Cardiac dysrhythmia and various other cardiac conditions that require continuous monitoring and treatment.-Characteristics:...
for possible complications (such as cardiac arrhythmias - irregularities in the heart rate).
Depending on the risk assessment, stress testing or angiography may be used to identify and treat coronary artery disease in patients who have had an NSTEMI or unstable angina.
Heart failure
In patients with heart failure, stress testing or coronary angiography may be performed to identify and treat underlying coronary artery disease.Pathogenesis
The disease process underlying most ischaemic heart disease is atherosclerosisAtherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
of the coronary arteries. The arteries become "furred up" by fat-rich deposits in the vessel wall (plaques).
Stable angina is due to inability to supply the myocardium (heart muscle) with sufficient blood in situations of increased demand for oxygen, such as exertion.
Unstable angina, STEMI and NSTEMI are attributed to "plaque rupture", where one of the plaques gets weakened, develops a tear, and forms an adherent blood clot
Thrombus
A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...
that either obstructs blood flow or floats further down the blood vessel, causing obstruction there.
Prevention
Various treatments are offered in people deemed to be at high risk of coronary artery disease. These include control of cholesterol levels in those with known high cholesterol, smoking cessationSmoking cessation
Smoking cessation is the process of discontinuing the practice of inhaling a smoked substance. This article focuses exclusively on cessation of tobacco smoking; however, the methods described may apply to cessation of smoking other substances that can be difficult to stop using due to the...
, and control of high blood pressure.
Management
In stable IHD, antianginalAntianginal
An antianginal is any drug used in the treatment of angina pectoris, a symptom of ischaemic heart disease.-Nitrates:Nitrates cause vasodilation of the venous capacitance vessels by stimulating the endothelium-derived relaxing factor...
drugs may be used to reduce the rate of occurrence and severity of angina attacks. Treatments for acute coronary syndrome and established coronary artery disease is discussed above in "diagnosis". Revascularization for acute coronary syndrome has a significant mortality benefit. Recent evidence suggests that revascularization for stable ischaemic heart disease may also confer a mortality benefit over medical therapy alone.
Treatment of coronary artery disease includes addressing "modifiable" risk factors. This includes suppression of cholesterol (usually with statin
Statin
Statins are a class of drugs used to lower cholesterol levels by inhibiting the enzyme HMG-CoA reductase, which plays a central role in the production of cholesterol in the liver. Increased cholesterol levels have been associated with cardiovascular diseases, and statins are therefore used in the...
s), even in those with statistically normal cholesterol levels, control of blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
, blood sugar
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
s (if diabetic), regular exercise and a healthy diet. Smokers are encouraged to stop smoking.