Myocardial Infarction

Besides cardiac arrhythmias, myocardial infarction (MI) represents the most important subject in electrocardiography, because of the high prevalence and severity of the disease. Forty to fifty percent of acute and previous MIs can be recognized in the electrocardiogram (ECG) by typical ST elevation and/or pathologic Q waves, many cases with combined infarctions or with right bundle-branch block (RBBB) included. Another 20% of MIs are detectable by complex ECG patterns (with bundle-branch block or fascicular blocks) and special ECG patterns (e.g., the so-called non-Q wave infarction or new not significant Q waves).

Since the introduction of urgent percutaneous transluminal coronary angioplasty (PTCA) and fibrinolysis, accurate diagnosis of acute MI (AMI) has become more important than ever. It is therefore also necessary to recognize atypical infarction patterns and to consider the differential diagnosis of the Q wave, ST elevation, and T wave.