RESPONSES OF HEART-RATE-VARIABILITY TO CORONARY-OCCLUSION DURING CORONARY ANGIOPLASTY

Signs of sympathetic activation are frequent during the early hours of anterior wall acute myocardial infarction, whereas parasympathetic re flexes predominate in inferior wall acute myocardial infarction. To as sess the immediate autonomic responses to acute coronary occlusion, th e high-frequency power and root-mean-square successive difference, fre quency and time domain measures of heart rate (HR) variability were an alyzed in 73 cases of significant (50 to 95%) coronary artery stenosis immediately before and during balloon occlusion (mean 99 seconds). Th e range of non-specific changes was formed on the basis of a control g roup with no ischemia during dilatations of 16 totally occluded corona ry arteries. Balloon occlusion of the left anterior descending artery (n = 35) caused an abnormal increase in the measures of HR variability as a sign of vagal activation in 8 patients (23%), and a significant decrease in HR variability in 4 (11%). Occlusion of the left circumfle x artery (n = 19) caused an increase in HR variability in 5 patients ( 26%), and a decrease in 2 (11%). Right coronary artery occlusion (n = 19) caused an increase in HR variability in 5 patients (26%) and a dec rease in 4 (21%). Thus, coronary occlusion causes immediate changes in HR variability in greater than one third of patients with coronary ar tery disease. The direction of these initial HR variability changes ca nnot be predicted by the site of coronary occlusion.