The incidence and morphology of ischaemic ventricular tachycardia.

Ventricular arrhythmias are a frequent cause of sudden death in patients with coronary artery disease. The incidence and relationship of ventricular tachycardia to periods of myocardial ischaemia in these patients has not been fully investigated. Ambulatory ST-segment monitoring was performed in 100 consecutive patients with chest pain, of whom 74 had significant coronary artery disease. Recordings were analysed for ST-segment changes and episodes of ventricular tachycardia (greater than 3 beats, rate greater than 100 beats min-1). None of the 26 patients with normal coronary arteries, one of the 22 patients (4.5%) with single vessel disease, one of the 22 patients (4.5%) with double vessel disease and four of the 30 patients (13%) with triple vessel disease, had episodes of non-sustained ventricular tachycardia. Four of these six patients had episodes of reversible ST-segment change but ventricular tachycardia was related to these episodes in only two patients. These two patients had multiple episodes of tachycardia which occurred after the onset of ST-segment change and terminated before the ST-segment returned to baseline; they occurred in clusters with a mean of 12 episodes in each cluster. ST-segment change did not follow episodes of ventricular tachycardia in any patient. The number of ventricular complexes in each episode varied between three and 24 beats and were uniform in three of the six patients. The mean heart rate before the onset of tachycardia was 79 +/- 8 beats per minute and the rate of tachycardia had a mean of 170 +/- 34 beats a minute. Less than 10% of the episodes had a prematurity index of less than 1.(ABSTRACT TRUNCATED AT 250 WORDS)