Ventricular tachycardia in myocardial infarction: relation to heart rate and premature ventricular contractions

Analysis of monitored electrocardiograms, recorded in 77 patients during the first 48 hours following the onset of myocardial infarction, revealed 492 episodes of ventricular tachycardia with rates of 90-220 min-1. Characteristics of the ventricular tachycardia episodes were correlated with heart rate and with the rate and complexity of ventricular arrhythmias in the 10-min period preceding ventricular tachycardia. Ventricular tachycardia with rates of 140-180 min-1 and with a QS configuration was the most frequent event. The first ectopic complex of VT was R-on-T in only 17.2%. Sinus tachycardia was associated with significantly fewer episodes of VT with rates of 110-140 min-1 than when the sinus rate was normal. However episodes of ventricular tachycardia with rates of 181 to 220 beats min-1 were more frequent during sinus tachycardia. Analysis of the frequency of premature ventricular contractions in the 10-min period immediately preceding ventricular tachycardia revealed no premature ventricular contractions in 24.4% of cases. Multiple premature ventricular contractions with a frequency of greater than or equal to 5 min-1 were observed in 8.4% of cases, multifocal in 30.3%, couplets in 24% and early PVCs in 12.2%. In the minute before ventricular tachycardia, only 40.2% of cases displayed premature ventricular contractions. In that minute, complex premature ventricular contractions were distributed as follows: multifocal in 10%, couplets in 8.7% and early PVCs in 2.6% of cases. Out of the total of 492 runs of ventricular tachycardia, 5 cases (1%) resulted in ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)