Heart gate variability and occurrence of ventricular arrhythmias during balloon occlusion of a major coronary artery

Experimental studies suggest that autonomic mechanisms are important in the genesis of ischemia-induced malignant ventricular arrhythmias, but the rol e of the autonomic nervous system in human arrhythmogenesis is not well kno wn. To assess whether heart rate variability (HRV) predicts the occurrence of ventricular arrhythmias during acute coronary artery occlusion, we perfo rmed continuous electrocardiographic, heart rate, and blood pressure record ings before and during a 2-minute balloon occlusion of a stenotic coronary artery in 252 patients with no baseline ventricular premature complexes (VP Cs). The ranges of nonspecific responses in heart rate and blood pressure w ere determined by analyzing a control group of 19 patients with no ischemia during a 2-minute balloon inflation in a totally occluded coronary artery. Balloon occlusion of a coronary artery was stopped because of complex, i.e ., bigeminal or repetitive, VPCs in 14 patients, and solitary (<5) VPCs wer e observed in an additional 19 patients. During coronary occlusion, HRV inc reased (p <0.001) and heart rate decreased (p < 0.05) in patients with no V PCs, whereas an opposite tendency to reduction in HRV (p = 0.08) was observ ed in patients with complex VPCs. Complex VPCs were observed in 5 (42%) of the 12 patients with a significant coronary occlusion-induced decrease in H RV, in 7 (3.5%) of 200 patients with no change in HRV, but in none of the 4 0 patients with a significant increase in HRV (p <0.001). Baseline HRV did not predict the occurrence of VPCs during coronary occlusion. Logistic regr ession analysis identified the decrease in HRV (p <0.001) to be the only in dependent predictor of complex VPCs. In conclusion, coronary occlusion-indu ced increase in HRV seems to protect against occurrence of complex ventricu lar arrhythmias during the early phase of abrupt coronary occlusion, sugges ting that vagal activation may modify the outcome of acute coronary events in patients with coronary artery disease. (C) 1999 by Excerpta Medico, Inc.