STEMI, Non-STEMI and Unstable Angina: How to Tell Them Apart

Once symptoms begin, the earliest ST elevation can appear on ECG within 15 to 30 minutes. This ST elevation persists if there is complete occlusion of the artery, and can still be present up to 48 hours later. If blood flow is restored spontaneously, whether from medicines or other reasons, the ST elevation resolves; otherwise it persists until the artery is reopened.

Mortality in ST-elevation MI can be quite high if the patient is not treated properly, up to 30 to 50%, which is why adequate and timely treatment matters so much. Cardiac echo, alongside ECG and cardiac enzymes, is very important and can pick up early signs of heart damage; it is now one of the first-line investigations at tertiary care hospitals in suspected cases.

Cardiac echo is important and is now done routinely, alongside cardiac enzymes and ECG, in suspected cases of heart attack at every tertiary care hospital where it is available. In summary, once ischemic heart disease is confirmed, every patient is loaded with aspirin (325 mg) along with clopidogrel (300 mg), prasugrel (60 mg) or ticagrelor (180 mg), a statin (atorvastatin or rosuvastatin, 40 to 80 mg), a beta blocker if blood pressure and heart rate allow, and glyceryl trinitrate for pain relief alongside oxygen. From there, ST-elevation MI patients receive heparin ahead of primary angioplasty, or are thrombolyzed if angioplasty is unavailable; non-ST-elevation MI and unstable angina patients are managed medically with low molecular weight heparin or fondaparinux instead of thrombolysis, and are escalated to coronary angiography and angioplasty or bypass surgery if they are high-risk or not improving.

Myocardial bridging can cause chest pain and can act as a risk factor. The initial approach is medical management with beta blockers, calcium channel blockers or nitrates. If the patient's chest pain continues despite medication, the next step is bypass surgery rather than angioplasty, since angioplasty is not successful in a bridged segment of artery.

Aspirin, clopidogrel, statins and beta blockers are all safe in pregnancy and can be used without hesitation. Low molecular weight heparin is also safe. ACE inhibitors should not be given, and thrombolysis is contraindicated outright in pregnant patients; these patients should instead be referred for primary angioplasty. The mother's life takes priority, though the fetal risk should be explained to the family before proceeding.

Both present with chest pain and similar ECG changes, but troponin is elevated in non-STEMI and normal in unstable angina.

No. Thrombolysis is reserved for ST-elevation MI or new-onset left bundle branch block. Non-STEMI and unstable angina are managed medically with heparin or low molecular weight heparin instead.