118. Chronic coronary syndromes (stable angina pectoris, silent myocardial ischemia, ischemic cardiomyopathy) - etiology, pathogenesis, clinical manifestations.

Chronic coronary syndromes (stable angina pectoris, silent myocardial ischemia, ischemic cardiomyopathy) – etiology, pathogenesis, and clinical manifestations.

Chronic coronary syndromes represent chronic forms of myocardial ischemia resulting from stable atherosclerotic plaques, where myocardial oxygen supply is repeatedly insufficient to meet demand but without acute plaque rupture and thrombosis.

Etiology

Primary cause

Atherosclerosis of coronary arteries (most common).

Contributing factors

Endothelial dysfunction.

Coronary microvascular disease.

Fixed coronary artery stenoses.

Risk factors

Same as for atherosclerosis and ischemic heart disease:

• Age, male sex, family history.
• Hyperlipidemia.
• Hypertension.
• Diabetes mellitus.
• Smoking.
• Obesity, metabolic syndrome.

Pathogenesis

Stable plaque characteristics

Thick fibrous cap, small lipid core.

Less prone to rupture but can cause fixed narrowing.

Mechanism of ischemia

1. Fixed luminal narrowing → blood flow adequate at rest but insufficient during increased demand (exercise, stress).
2. Imbalance between oxygen supply and myocardial demand → transient, reversible ischemia.
3. Repeated or prolonged episodes → progressive myocyte loss and fibrosis → ventricular dysfunction.

Clinical manifestations

1. 1 Stable angina pectoris

Episodic chest pain:

• Triggered by exertion or emotional stress.
• Relieved by rest or nitroglycerin.

Pain characteristics:

• Substernal pressure or tightness.
• May radiate to left arm, neck, jaw, or back.

Associated symptoms:

• Dyspnea, sweating, fatigue.

1. 2 Silent myocardial ischemia

Asymptomatic episodes of myocardial ischemia, detected only by:

• ECG changes (ST depression, T wave inversion).
• Stress testing.

Common in:

• Diabetics (due to autonomic neuropathy).
• Elderly.

Clinical relevance: Can lead to unnoticed myocardial damage and sudden death.

1. 3 Ischemic cardiomyopathy

Chronic ischemia-induced diffuse myocardial fibrosis.

Clinical features:

• Progressive heart failure symptoms:
• Dyspnea on exertion → at rest.
• Orthopnea, paroxysmal nocturnal dyspnea.
• Fatigue, weakness.
• Peripheral signs:
• Edema.
• Hepatomegaly.
• Jugular venous distension.

Arrhythmias and sudden cardiac death can also occur.