A case of fulminant acute myocarditis mimicking ST-segment elevation myocardial infarction complicated by complete atrioventricular block

The clinical presentation of myocarditis varies widely and can rapidly change or deteriorate, manifesting with symptoms similar to ST-segment elevation myocardial infarction, such as decreased cardiac output, reduced contractility, sinus node dysfunction, atrioventricular (AV) and bundle branch blocks, and various arrhythmias. A previously healthy 50-year-old woman presented with symptoms of an upper respiratory infection followed by acute cardiogenic shock and complete AV block. An electrocardiogram (ECG) showed pathological Q waves and ST-segment elevation, raising suspicion for acute myocardial infarction. However, coronary angiography revealed normal coronary arteries. Following temporary pacemaker insertion and conservative management, her cardiac function recovered. However, right bundle branch block remained as a sequela. In patients presenting with symptoms and ECG findings suggestive of acute myocardial infarction but with normal coronary arteries, fulminant myocarditis must be included in the differential diagnosis. With active life-sustaining treatment, favorable outcomes can be achieved.