ANTIARRHYTHMIC EFFECT OF REPEATED CORONARY-OCCLUSION DURING BALLOON ANGIOPLASTY

Objectives. The purpose of the present study was to assess whether bri ef, repeated coronary artery occlusions during balloon angioplasty pro tect against ischemia-induced ventricular ectopy. Background. Most sud den cardiac deaths are caused by fatal ventricular arrhythmias precipi tated by early myocardial ischemia of acute coronary occlusion. In ani mals, a preceding 3- to 5-min coronary occlusion protects against mali gnant ventricular arrhythmias during a subsequent prolonged coronary o cclusion. Whether such an antiarrhythmic effect caused by ischemic pre conditioning occurs in humans is not known. Methods. To assess the eff ects of a preceding, brief vessel occlusion-reperfusion cycle on the o ccurrence of ventricular ectopy, continuous electrocardiographic, hear t rate and blood pressure recordings were performed in 156 patients be fore and during two identical balloon occlusions of a coronary artery (mean 111 s) separated by a 5-min equilibration period. Results. The o ccluded vessel was the left anterior descending coronary artery in 94 patients, the left circumflex branch in 29 patients and the right coro nary artery in 33 patients. Balloon occlusion of a coronary artery cau sed ventricular ectopy in 24 patients. The incidence of ventricular ec topy was higher during the first occlusion than during the second occl usion (21 patients [13.5%] vs. 11 patients [7%], p = 0.02). In 13 pati ents, ventricular ectopy was observed only during the first occlusion; in 8 patients during both occlusions; and in 3 patients only during t he second occlusion. Bigeminal or repetitive ectopic beats were observ ed in eight patients during the first coronary occlusion and in four p atients during the second occlusion. Atrial premature beats occurred d uring the first occlusion in three patients, but in none of the patien ts during the second occlusion. The 24 patients with ventricular ectop y during coronary occlusion had milder stenosis than the rest of the p atients (mean [+/-SD] 74 +/- 12% vs. 81 +/- 12%, p = 0.01). The 13 pat ients with ventricular ectopy only during the first occlusion did not, however, differ significantly with respect to any clinical or angiogr aphic features from the rest of the patients with ventricular ectopy. There were no significant differences in the signs of myocardial ische mia or hemodynamic variables between the sequential occlusions. Conclu sions. A preceding, short vessel occlusion-reperfusion cycle seems to increase the electrical stability of ischemic myocardium. (C)1997 by t he American College of Cardiology.