Summary
Highlights
Myocardial Infarction (MI) is another term for a heart attack. The word "myocardial" refers to the heart muscle, and "infarction" means an area of dead or dying tissue due to lack of oxygen and blood. Therefore, an MI signifies that the heart muscle is dying from a lack of oxygen.
The heart muscle requires oxygen to function. An MI occurs when the coronary arteries become blocked, often due to plaque buildup (a collection of cholesterol and cells). This plaque can either excessively narrow the vessels or break off and block main arteries, leading to the heart muscle not receiving enough oxygen and starting to die.
Key risk factors for MI include a history of coronary artery disease, high cholesterol (contributing to plaque buildup), high blood pressure (damaging vessels and causing narrowing), a family history of heart conditions, stress, and smoking.
Common symptoms of MI include crushing chest pain (often described as an elephant sitting on the chest), left arm pain, shortness of breath, sweating (diaphoresis), pallor, nausea, and vomiting. It's crucial to note that women may present with different, often atypical, symptoms like fatigue, shoulder discomfort, and heartburn, which can be easily overlooked.
MI is diagnosed through an electrocardiogram (EKG) and troponin levels. There are two types: STEMI (ST-elevation MI), indicating a total occlusion and showing an ST elevation on an EKG, and Non-STEMI (non-ST-elevation MI), indicating restricted but not completely stopped blood flow, often due to partial occlusions. Elevated troponin levels, a protein released when the heart muscle is injured, also confirm an MI.
Immediate treatment often follows the MONA mnemonic (Morphine, Oxygen, Nitroglycerin, Aspirin). Morphine reduces cardiac workload and pain, oxygen addresses deprivation, nitroglycerin vasodilation, and aspirin prevents platelet aggregation. Thrombolytics (clot busters like alteplase, reteplase, streptokinase) are then used to break down the occlusion and restore blood flow.
Further treatments include cardiac catheterization (angioplasty with or without stent placement) to widen narrowed vessels, and Coronary Artery Bypass Graft (CABG), or open-heart surgery, to bypass blocked vessels. Medications such as heparin (to prevent blockages), nitroglycerin (to open vessels), beta-blockers (to reduce heart's workload), and calcium channel blockers (to relax the heart) are also prescribed.
Preventing MI involves modifying risk factors: quitting smoking, adopting a low-fat and low-sodium diet, increasing exercise, and regularly taking prescribed medications for high blood pressure (antihypertensives) and high cholesterol (anti-hyperlipidemics like statins). These measures help prevent plaque buildup and reduce the risk of a heart attack.