ISCHEMIC HEART DISEASE

ISCHEMIC HEART DISEASE

Ischemic heart disease (IHD) is the generic designation for a group of closely related syndromes resulting from ischemia – an imbalance between the supply and demand of the heart for oxygenated blood. Ischemia comprises not only insufficiency of oxygen (hypoxia, anoxia) but also reduced availability of nutrient substrates and inadequate removal of metabolites. Because coronary artery narrowing or obstruction owing to atherosclerosis underlies myocardial ischemia in the vast majority of cases, IHD is often termed coronary artery disease (CAD) or coronary heart disease (CHD).

The etiology and pathogenesis

Etiology of IHD is identical to the one of atherosclerosis and hypertension. Direct reasons of development of the myocardial infarctions are spasms of vessels, thrombosis or thromboembolism of coronary arteries of heart. Pathogenic factors (factors of risk) are:

1. Hyperlipidemia;
2. Arterial hypertension;
3. Steatosis;
4. Hypodynamia;
5. Smoking;
6. Impairments of tolerance to carbohydrates;
7. Diathesis;
8. Genetic predisposition;
9. Sex-binded.

Depending on the rate of development and ultimate of the arterial narrowing and the myocardial response, four ischemic syndromes may result:

1. Angina pectoris.
2. Myocardial infarction.
3. Sudden cardiac death.
4. Chronic ischemic heart disease.

Acute Ischemic Heart Disease (AIHD)

Angina pectoris

It is a symptom complex of IHD characterized by paroxysmal attacks of substernal or pericordial chest discomfort (variously described as constricting, squeezing, choking, or knife-like) caused by transient (15 sec. to 15 min.) myocardial ischemia that falls short of inducing the cellular necrosis that defines infarction.

There are three somewhat distinctive patterns of angina pectoris, differentiated on the basis of the provocation and severity of the pain:

1. Stable (typical) angina pectoris appears to be reduction of coronary perfusion to a critical level by chronic stenosing coronary atherosclerosis; this renders the heart vulnerable to further ischemia whenever there is increased demand, such as that produced by physical activity, emotional excitement, or any other cause of increased cardiac workload.
2. Prinzmetal’s variant refers to a pattern of episodic angina that occurs at rest and has been documented to be due to coronary artery spasm.

Unstable angina refers to a pattern of pain that occurs with progressively increasing frequency, is precipitated with progressively less effort, often occurs at rest, and tends to be of prolonged duration. This syndrome is sometimes referred to as preinfarction or acute coronary insufficiency. Unstable angina is induced by fissuri