Myocardial Infarction (MI)

Myocardial infarction usually caused by occlusive thrombus or prolonged vasospasm in a coronary artery.

History and Physical Exams:

• Acute onset substernal chest pain that is described as pressure or tightness and radiate to the left arm, neck, or jaw
• Shortness of breath, diaphoresis, light-headedness, nausea, vomiting, anxiety, syncope
• Tachycardia, bradycardia, arrhythmias, new mitral regurgitation, hypotension, pulmonary edema, and ventricular fibrillation
• Sudden death from a lethal arrhythmia (ventricle fibrillation)
• Clinically silent MIs in elderly, diabetic, postmenopausal and postorthopic heart transplant patients

Diagnosis

• ST-segment elevation or new LBBB on ECG
• ECG changes: peaked T waves, ST-segment elevation, Q wave, T-wave inversion, ST-segment normalization, T-wave normalization
• Inferior MI : ST-segment elevation in leads II, III, and aVF
• Anterior MI : ST-segment elevation in leads V1-V4
• Lateral MI : ST-segment elevation in leads I, aVL, and V5-V6
• Serial cardiac enzymes: troponin and CK-MB.

Treatments:

1. Acute treatments is Morphine, Oxygen, Nitroglyserin sublingualy, Aspirin, and IV beta-blocker.
2. Glycoprotein
3. Heparinization, angiography and revascularization
4. Consider thrombolysis with tPA, urokinase, or streptokinase
5. PTCA
6. CABG - Coronary Artery Bypass Graft (for depressed ventricular function, unable to PTCA, stenosis of left main, and triple-vessel disease)
7. Long term treatments: ASA, beta-blocker, ACEIs, and statins
8. Dietary changes and exercises