PATTERN OF CORONARY-ARTERY DISEASE IN PATIENTS WITH VENTRICULAR-TACHYCARDIA AND FIBRILLATION EXPOSED BY EXERCISE-INDUCED ISCHEMIA

The majority of patients with serious exercise-induced ventricular arr hythmias have extensive coronary artery disease. These arrhythmias dev elop, however, only in a minority of patients with angina pectoris. Th e purpose of the present study was therefore to investigate whether th ese arrhythmia patients are characterized by any specific ''arrhythmog enic'' pattern of coronary artery disease. Among 1100 consecutive pati ents undergoing coronary artery bypass grafting, 30 (2.7%) patients ha d ventricular tachycardia or fibrillation during preoperative exercise testing. For each of these patients, two matched controls with angina pectoris but no ventricular arrhythmia were selected. All patients un derwent angiocardiography by standard techniques. The recordings were blinded and interpreted in random order by an experienced invasive car diologist. Significant stenosis (greater than or equal to 50%) of the main left coronary artery was found in 27% of the case patients compar ed to 12% of the matched controls (p = 0.069, two-tailed t test); prox imal left anterior descending artery stenoses were more frequent in th e arrhythmia patients. Although stenosis greater than or equal to 75% was only moderately more frequent in the case patients, the difference was highly significant for stenosis greater than or equal to 95%, whi ch was seen in 47% of the case patients compared to 22% of the control s (p = 0.015). The difference was even more pronounced for the combina tion of main left coronary artery stenosis and/or high-grade stenosis (greater than or equal to 95%) of the left anterior descending artery. This pattern was seen in 60% of the case patients compared to 28% of the matched controls (p = 0.004). In addition, concurrent stenosis of the right coronary artery was seen in 14 (47%) of these case patients compared to 12 (20%) in the matched controls (p = 0.009). These result s suggest that exercise-induced ventricular tachycardia and fibrillati on are associated with a specific arrhythmogenic pattern of coronary a rtery obstruction consisting of the main left coronary artery or the p roximal left anterior descending artery. The additional effect of conc urrent right coronary artery involvement may be through an impaired co llateral supply to the left anterior descending territory.