Transmyocardial laser treatment reduces ischemia-induced ventricular fibrillation during the early phase (1a) after coronary artery occlusion in openchest anesthetized pigs

Introduction. It has previously been shown that transmyocardial. revascular ization with laser (TMR) prior to coronary artery occlusion decreases the o ccurrence of ischemia-induced arrhythmias. The aim of the present study was to determine the effects of TMR on ventricular fibrillation and other arrh ythmias during the early Cia) and late phase (Ib) of ischemia in pigs. Methods. In six pigs TMR was performed in the anterior wall of the left ven tricle 60 minutes prior to occlusion of the proximal LAD. Six other pigs we re subjected to coronary occlusion without preceding TMR and served as cont rols. Results. During the 30 min period with LAD occlusion ventricular fibrillati on occurred 22 times in 5 of 6 control animals (20 episodes in phase la, 2 in phase Ib), whereas none of the animals subjected to TMR prior to the cor onary artery occlusion developed ventricular fibrillation (p<0.01). The tot al number of premature beats per animal was lower during the early phase (l a) after LAD occlusion in the TMR group than in the control group (18+/-13 vs 248+/-82, p<0.05). Conclusions, TMR prior to occlusion of LAD reduced the occurrence of early phase (la) ischemia-induced ventricular fibrillation and premature beats. T his anti-fibrillatory effect might explain the improved survival observed i n. experimental studies after TMR prior to coronary artery occlusion found by others.