Polymorphous ventricular tachycardia associated with acute myocardial infarction

Abstract

During a 2.9-year period, 11 patients developed polymorphous ventricular tachycardia 1-13 days after acute anterior (seven patients) or inferior (four patients) myocardial infarction. None of the 11 patients had sinus bradycardia (mean heart rate, 90 +/- 23 beats/min), but three had a sinus pause immediately before the onset of polymorphous ventricular tachycardia. In all 11 patients, the QT interval and corrected QT interval (QTc) were normal or minimally prolonged (QT, 385 +/- 34 msec; QTc, 442 +/- 40 msec). None had significant hypokalemia (mean serum potassium concentration, 4.3 +/- 0.5 meq/l) or a grossly abnormal serum magnesium or calcium concentration (2.1 +/- 0.4 and 8.9 +/- 0.7 mg/dl, respectively).