Myocardial Ischemia & Angina

What is myocardial ischemia?

Heart muscle gets too little oxygen. It happens when oxygen supply cannot meet the heart's metabolic needs.

What causes myocardial ischemia?

Oxygen demand exceeds oxygen supply. Reduced coronary flow or increased workload can create this imbalance.

What is myocardial infarction (MI)?

Irreversible death of heart muscle. It develops when ischemia lasts long enough to permanently damage cells.

How can prolonged ischemia cause MI?

Long-term oxygen loss kills heart cells. Without oxygen, heart cells cannot maintain normal energy production.

Why does lactic acid build up during ischemia?

Cells switch to anaerobic metabolism. Oxygen shortage forces cells to produce energy without enough oxygen.

How does atherosclerosis cause ischemia?

Plaque narrows coronary arteries. Less blood can pass through the narrowed artery to the myocardium.

What is coronary thrombosis?

A clot blocks coronary blood flow. The clot may partly or completely obstruct the artery.

What is coronary vasospasm?

Sudden narrowing of a coronary artery. The narrowed vessel temporarily delivers less oxygen to heart muscle.

Which angina is linked to vasospasm?

Prinzmetal's angina. Its underlying mechanism is temporary coronary artery constriction.

How can anemia cause ischemia?

Blood carries less oxygen. Low hemoglobin reduces oxygen delivery even if blood flow is normal.

What is microvascular ischemia?

Small coronary vessels cannot supply enough blood. Large coronary arteries may appear

What is angina pectoris?

Chest discomfort caused by myocardial ischemia. It is a symptom of ischemia, not necessarily tissue death.

What is stable angina?

Predictable chest pain, often with exertion. It usually improves when oxygen demand falls.

What usually relieves stable angina?

Rest or nitroglycerin. Both reduce the oxygen supply-demand mismatch.

What is unstable angina?

New, worsening, or unpredictable chest pain. It may occur at rest and is not reliably relieved by rest.

Why is unstable angina an emergency?

It may progress to MI. It signals a potentially dangerous reduction in coronary blood flow.

What is microvascular angina?

Angina from small coronary vessel dysfunction. It involves dysfunction of small coronary vessels.

Does angina alone cause myocardial necrosis?

No. MI causes irreversible cell death. Necrosis distinguishes MI from angina without infarction.

What does high-sensitivity troponin detect?

Myocardial injury. It is released when cardiac muscle cells are damaged.

What does hs-CRP indicate?(high-sensitivity C-reactive protein)

Inflammation. It is not specific enough to diagnose a heart attack.

What does an ECG measure?

Heart electrical activity. It helps detect ischemic changes and abnormal rhythms.

What can coronary angiography show?

Narrowed or blocked coronary arteries. The images show where coronary blood flow is restricted.

What are four goals of angina treatment?

Relieve pain; improve oxygen supply; reduce demand; prevent MI. Treatment aims to correct the oxygen supply-demand imbalance.

What do nitrates do?

Dilate blood vessels and reduce heart workload. Vasodilation can improve symptoms and decrease oxygen demand.

What does aspirin do?

Reduces platelet aggregation. This helps prevent growth of platelet-rich clots.

When may oxygen be given for angina?

When oxygen saturation is low. Supplemental oxygen is not automatically needed for every patient.

What is CABG?

Surgery that bypasses blocked coronary arteries. A graft carries blood around an obstructed coronary segment.

Is ischemia always irreversible?

No. It may improve if blood flow returns. Restoring flow early may prevent permanent cell death.