STENOSIS SEVERITY AND THE OCCURRENCE OF VENTRICULAR ECTOPIC ACTIVITY DURING ACUTE CORONARY-OCCLUSION DURING BALLOON ANGIOPLASTY

To elucidate the incidence and determinants of early ventricular arrhy thmias (VA) during acute coronary occlusion, continuous electrocardiog raphic, heart race, and blood pressure recordings were performed in 15 2 patients during standardized balloon occlusions of significant (50% to 95%) coronary artery stenoses, A control group of 13 patients with chronic total occlusion of a coronary artery was also studied, None of them developed VA during balloon inflation in the preexisting total o cclusion of the Balloon occlusion of a coronary artery was associated with occurrence of ventricular ectopy in 18 patients (VA group, 12%). The VA group had milder stenosis severity (72% vs 81%, p <0.01) than t he rest of the patients, and none of them had visible collaterals to t he occluded vessel. The VA group also had ST-segment deviations more o ften (p <0.05) during occlusion than patients with no VA, Occlusion of the left anterior descending artery caused VA more often (p <0.05) th an occlusion of the left circumflex or right coronary artery, No clini cal or hemodynamic variable or medication was associated with the occu rrence of VA, In stepwise logistic regression analysis, the only signi ficant predictors of ventricular ectopic activity were the stenosis se verity and the anterior site of coronary occlusion, Even a nonstenotic plaque can be so fragile that it is prone to rupture, The present fin dings suggest that such an occlusion may result in electrical instabil ity more easily than occlusion of a more advanced coronary lesion.