Electrical dysfunction occurs in more than 90% of patients with myocardial infarction. Electrical dysfunction, which usually leads to death in the first 72 hours, includes tachycardia (from any source) with a sufficiently high heart rate, capable of reducing cardiac output and lowering blood pressure, an atrioventricular block of the Mobitz II type (2 degrees) or complete (grade 3), ventricular tachycardia (VT) and ventricular fibrillation (VF).