Late development of intractable ventricular tachycardia after acute myocardial infarction

Four cases are reported in which medically refractory and ultimately fatal ventricular tachycardia developed relatively late during hospital convalescence from acute myocardial infarction. All 4 had tachycardia refractory to combinations of antiarrhythmic agents, and they required almost continuous ventricular defibrillation. Mechanical circulatory assistance (Avco intra aortic balloon pumping) proved ineffective in controlling the recurrent arrhythmias. Emergency cardiac catheterization performed in 3 patients and postmortem examination in the fourth patient demonstrated the following: complete occlusion of the left anterior descending coronary artery near its origin and diffuse circumflex obstruction; extensive myocardial infarction involving two thirds of the anterior wall; and ventricular ejection fractions of less than 25%. Emergency surgery also proved ineffective in 2 patients. These findings suggest that recurrent ventricular tachycardia developing late in the course of recovery from an acute myocardial infarction is an ominous prognostic sign in patients such as these. Mechanical circulatory assistance in combination with various antiarrhythmic agents appears to be of little benefit in controlling this type of ventricular arrhythmia.