What Causes a Myocardial Infarction?
Dec 23, 2020
Source: Cainiu Health
Dr. Liu Shilei
Introduction
What causes myocardial infarction?
1. Coronary artery occlusion—severe atherosclerotic plaques in the coronary arteries or significant subintimal hemorrhage;
2. Sudden drop in cardiac output—caused by severe dehydration, shock, hemorrhage, arrhythmias, or certain surgical procedures;
3. Marked increase in myocardial oxygen and blood demand—such as during prolonged heavy physical exertion or episodes of intense emotional stress.
The primary cause of myocardial infarction (MI) is atherosclerotic plaque formation in the coronary arteries, leading to luminal narrowing. On this basis of stenosis, triggering factors can destabilize the plaque, causing rupture, subsequent hemorrhage, and intraluminal thrombus formation—ultimately resulting in acute coronary occlusion and myocardial infarction. So, what exactly causes myocardial infarction? Below is an explanation.
Causes of Myocardial Infarction
1. Coronary Artery Occlusion
If severe atherosclerotic plaques or extensive subintimal hemorrhage develop within the coronary arteries, intraluminal thrombosis may occur, resulting in complete vessel occlusion and triggering myocardial infarction.
2. Sudden Drop in Cardiac Output
Additionally, conditions such as severe dehydration, shock, hemorrhage, arrhythmias, or certain surgical procedures may cause an abrupt decline in cardiac output. This leads to markedly insufficient coronary perfusion—a common underlying cause of myocardial infarction.
3. Sudden Increase in Myocardial Oxygen and Blood Demand
Frequent heavy physical exertion or recurrent emotional stress can significantly increase left ventricular workload and markedly elevate catecholamine secretion, thereby increasing myocardial oxygen and blood demand. Furthermore, acute myocardial infarction may also result from coronary artery spasm, severe coronary embolism, inflammation, or congenital coronary anomalies.
Additional Information: Key Precautions for Myocardial Infarction Patients
1. Eat Small, Frequent Meals
Chew food thoroughly and eat slowly. Aim for three to five small meals daily—avoid overeating. Follow a low-sugar, low-salt, low-fat diet; minimize intake of stimulants such as tobacco and alcohol. Consume more fresh green vegetables and fruits. Also, restrict sodium intake: excessive sodium increases vascular sensitivity to vasoconstrictive substances, induces small arterial spasm, and elevates blood pressure.
2. Maintain Warmth
Under extreme cold or strong cold air exposure, coronary arteries may undergo spasm followed by secondary thrombosis, precipitating acute myocardial infarction. Rapid weather changes and low atmospheric pressure often provoke noticeable discomfort in patients with coronary artery disease.
3. Bath Water Temperature
Water temperature should approximate body temperature. Excessively hot water causes marked cutaneous vasodilation, diverting large volumes of blood to the skin surface and potentially inducing cerebral and cardiac ischemia. Bath duration should be brief; bathrooms are typically warm and poorly ventilated, increasing metabolic demand and risk of hypoxia and fatigue—especially dangerous for patients with coronary artery disease. Thus, patients with severe coronary artery disease should bathe only with assistance.
The above outlines the primary causes of myocardial infarction. We hope this information proves helpful.
