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Ischaemic heart disease
Classification & external resources

ICD-10	I20.-I25.
ICD-9	410-414
DiseasesDB	8695
eMedicine	med/1568
MeSH	D017202

Ischaemic or ischemic heart disease (IHD), or myocardial ischemia, is a disease characterized by reduced blood supply to the heart muscle, usually due to coronary artery disease (atherosclerosis of the coronary arteries). Its risk increases with age, smoking, hypercholesterolemia (high cholesterol levels), diabetes, 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 tests (cardiac markers), cardiac stress testing 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.

Contents 1 Atherosclerosis 1.1 Risk Factors 2 Blood supply of the heart 2.1 LM 2.2 LAD 2.3 LCX 2.4 RCA 2.5 PDA 3 Ischaemia and Infarction 3.1 Stable Angina 3.2 Acute Coronary Syndrome 3.2.1 Unstable Angina 3.2.2 Non STEMI 3.2.3 STEMI 4 Symptoms 5 Differential Diagnosis 6 Investigations 6.1 Serial ECGs 6.1.1 Localising Lesions 6.2 Chest Xray 6.3 Cardiac Enzymes 6.4 Urea and electrolytes 6.5 Coagulation profile 7 Treatment 7.1 Acute Treatment 7.1.1 Thrombolysis 7.1.2 Percutaneous intervention 7.1.2.1 Angiogram 7.1.2.2 Angioplasty 7.1.2.3 Stent Insertion 7.1.3 Coronary Artery Bypass Grafting 7.2 Treatment in short term post AMI 7.3 Treatment in longer term post AMI

The usual cause for narrowing of coronary arteries is atherosclerosis, an inflammatory process affecting arteries caused by diabetes, smoking, high cholesterol, genetic factors and several other causes.

Atherosclerosis results in the formation of fatty, inflamed plaques within the artery wall containing cholesterol, macrophages, smooth muscle cells and many other inflammatory products. These plaques may grow to narrow the artery completely.

If the plaque ruptures for one reason or another, those inflammatory products and cholesterol will be released locally, causing the rapid formation of a clot. If this occurs, total blockage of the artery may result, leading to acute myocardial infarction (a heart attack).

• Hyperlipidaemia (high cholesterol and high fats in the blood)
• Smoking
• Hypertension (high blood pressure)
• Hyperglycaemia (high blood sugar due to poorly controlled diabetes or other causes)
• Systemic inflammation (as in vasculitis or connective tissue disease
• Advanced age
• Male gender
• Other genetic factors

There are several major vessels in the heart.

The left main artery gives rise to the LAD, LCX and several other vessels.

The left anterior descending artery supplies the anterior heart including the left ventricle.

The left circumflex artery supplies the posterior heart.

The right coronary artery supplies the right heart.

This vessel supplies the inferior and posterior heart.

The term ischaemia refers to a reduction in blood supply. This is a condition which, when prolonged, will lead to death of affected tissues. While there are often areas in the heart supplied by more than one coronary artery, significant narrowing or total blockage of an artery may result in a great loss of blood supply. If this occlusion (blockage) is complete, it can result in the infarction of the affected cardiac muscle. This is known as a heart attack or acute myocardial infarction.

This is caused by significant narrowing of a coronary artery by an atherosclerotic plaque. When the patient exercises or undergoes cardiac stress, blood supply to the affected muscle is very restricted, leading to pain and shortness of breath.

This syndrome of unstable cardiac pain runs a spectrum between unstable angina and STEMI (severe heart attack). It is caused by the rupture of an atherosclerotic plaque leading to thrombus (clot) formation and occlusion of the artery.

This is caused by minor occlusion of an artery by thrombus (clot). This is differentiated from the other two disease processes due to the lack of injury to cardiac muscle.

This is a less severe acute myocardial infarction caused by major (but partial) occlusion of an artery by thrombus. In this pattern, there is elevation of cardiac enzymes due to death of cardiac muscle, but the ECG does not show ST elevation which is pathognomic of complete occlusion of a major coronary artery.

This is the most severe category of ACS, caused by total occlusion of a major coronary artery. There is elevation of cardiac enzymes and severe ECG changes including ST elevation.

Cardiac ischaemia and infarction cause chest pain which is typically described as central, crushing and may radiate down the left arm and into the jaw. Patients may feel distressed, very sweaty, cold and short of breath. They may also get palpitations. In addition they may get chest pain or shortness of breath when lying flat or while asleep.

• Pulmonary Embolism
• Gastro-oesophageal reflux disease
• Gastritis and Peptic Ulcer Disease
• Aortic Dissection

Typical signs on ECG of ACS are: ST elevation (indicative of STEMI), ST depression, T wave inversion, Q waves (in old or evolving infarction). There may additionally be sinus tachycardia (fast heart rate), arrhythmias including ventricular fibrillation, ventricular tachycardia and heart block.

It is possible to work out roughly which area of the heart is affected by an ACS/AMI by looking at a pathological ECG. A rough guide is as follows:

Wall Affected	Leads Showing ST Segment Elevation	Leads Showing Reciprocal ST Segment Depression	Suspected Culprit Artery
Septal	V1, V2	None	Left Anterior Descending (LAD)
Anterior	V3, V4	None	Left Anterior Descending (LAD)
Anteroseptal	V1, V2, V3, V4	None	Left Anterior Descending (LAD)
Anterolateral	V3, V4, V5, V6, I, aVL	II, III, aVF	Left Anterior Descending (LAD), Circumflex (LCX), or Obtuse Marginal
Extensive anterior (Sometimes called Anteroseptal with Lateral extension)	V1,V2,V3, V4, V5, V6, I, aVL	II, III, aVF	Left main coronary artery (LCA)
Inferior	II, III, aVF	I, aVL	Right Coronary Artery (RCA) or Circumflex (LCX)
Lateral	I, aVL, V5, V6	II, III, aVF	Circumflex (LCX) or Obtuse Marginal
Posterior (Usually associated with Inferior or Lateral but can be isolated)	V7, V8, V9	V1,V2,V3, V4	Posterior Descending (PDA) (branch of the RCA or Circumflex (LCX))
Right ventricular (Usually associated with Inferior)	II, III, aVF, V1, V4R	I, aVL	Right Coronary Artery (RCA)

This may show acute pulmonary oedema, a complication of acute left heart failure, or suggest a different diagnosis.

These include cardiac-specific creatine kinase and troponin. Troponin is more specific but CK peak may be more indicative of actual cardiac damage. These may be falsely elevated in other conditions such as renal failure.

As a baseline investigation to see if there is associated acute renal failure, and also as a pre-angiogram workup.

Standard testing pre-thrombolysis and pre-angiogram.

• Aspirin (an antiplatelet agent) is routinely administered to most or all patients with an acute coronary syndrome or first presentation of angina.
• Oxygen is applied to increase oxygen delivery to affected heart muscle.
• Anginine/GTN, nitric oxide vasodilator drugs are used to peripherally vasodilate and thus reduce cardiac work. This eases stable angina as well as the pain of ACS.
• Cardiac monitoring and monitoring of blood pressure and heart rate- people with myocardial infarction are at much higher risk of life threatening arrhythmias.
• Urgent thrombolysis or angiogram/angioplasty/stent insertion in STEMI (aim for within 30-60 mins post onset of symptoms)
• Anticoagulation with enoxaparin, heparin infusion or similar anticoagulant in NSTEMI
• Correction of electrolyte abnormalities. Serum potassium is usually kept above 4.0 and magnesium above 1.0 as prophylaxis against life threatening tachyarrhythmias.
• Treatment of high or low blood pressure, treatment of hyper and hypovolaemia.
• Admission to coronary care unit.

• Cardiac monitoring for >48 hours
• Introduction of (ideally): a statin cholesterol lowering agent such as atorvastatin, simvastatin or pravastatin; a cardioselective beta blocker antihypertensive such as carvedilol, metoprolol or bisoprolol; regular low dose aspirin or other antiplatelet agent such as clopidogrel; an ACE inhibitor such as perindopril, captopril, ramipril or lisinopril
• Treatment of cardiac arrhythmias
• Echocardiogram to assess extent of cardiac damage and effect on function
• Consideration of angiogram/angioplasty/stent insertion
• Consideration of coronary artery bypass surgery in multi-vessel disease

• Cardiac rehabilitation
• Reduction of risk factors - tighter glycaemic control, blood pressure control, cessation of smoking, reduction of cholesterol

v • d • e Circulatory system pathology (I, 390-459)
Hypertension	Hypertensive heart disease - Hypertensive nephropathy - Secondary hypertension (Renovascular hypertension)
Ischaemic heart disease	Angina pectoris (Prinzmetal's angina) - Myocardial infarction - Dressler's syndrome
Pulmonary circulation	Pulmonary embolism - Cor pulmonale
Pericardium	Pericarditis - Pericardial effusion - Cardiac tamponade
Endocardium/heart valves	Endocarditis - mitral valves (regurgitation, prolapse, stenosis) - aortic valves (stenosis, insufficiency) - pulmonary valves (stenosis, insufficiency) - tricuspid valves (stenosis, insufficiency)
Myocardium	Myocarditis - Cardiomyopathy (Dilated cardiomyopathy, Hypertrophic cardiomyopathy, Loeffler endocarditis, Restrictive cardiomyopathy) - Arrhythmogenic right ventricular dysplasia
Electrical conduction system of the heart	Heart block: AV block (First degree, Second degree, Third degree) - Bundle branch block (Left, Right) - Bifascicular block - Trifascicular block Pre-excitation syndrome (Wolff-Parkinson-White, Lown-Ganong-Levine) - Long QT syndrome - Adams-Stokes syndrome - Cardiac arrest - Sudden cardiac death Arrhythmia: Paroxysmal tachycardia (Supraventricular, AV nodal reentrant, Ventricular) - Atrial flutter - Atrial fibrillation - Ventricular fibrillation - Premature contraction (Atrial, Ventricular) - Ectopic pacemaker - Sick sinus syndrome
Other heart conditions	Heart failure - Cardiovascular disease - Cardiomegaly - Ventricular hypertrophy (Left, Right)
Cerebrovascular diseases	Intracranial hemorrhage/cerebral hemorrhage: Extra-axial hemorrhage (Epidural hemorrhage, Subdural hemorrhage, Subarachnoid hemorrhage) Intra-axial hematoma (Intraventricular hemorrhages, Intraparenchymal hemorrhage) - Anterior spinal artery syndrome - Binswanger's disease - Moyamoya disease
Arteries, arterioles and capillaries	Atherosclerosis (Renal artery stenosis) - Aortic dissection/Aortic aneurysm (Abdominal aortic aneurysm) - Aneurysm - Raynaud's phenomenon/Raynaud's disease - Buerger's disease - Vasculitis/Arteritis (Aortitis) - Intermittent claudication - Arteriovenous fistula - Hereditary hemorrhagic telangiectasia - Spider angioma
Veins, lymphatic vessels and lymph nodes	Thrombosis/Phlebitis/Thrombophlebitis (Deep vein thrombosis, May-Thurner syndrome, Portal vein thrombosis, Venous thrombosis, Budd-Chiari syndrome, Renal vein thrombosis, Paget-Schroetter disease) - Varicose veins / Portacaval anastomosis (Hemorrhoid, Esophageal varices, Varicocele, Gastric varices, Caput medusae) - Superior vena cava syndrome - Lymph (Lymphadenitis, Lymphedema, Lymphangitis)
Other	Hypotension (Orthostatic hypotension)
See also congenital (Q20-Q28, 745-747)