Adenosine preconditioning reduces both pre and postischemic arrhythmias in human myocardium.

Abstract Introduction. Consistently, clinical series record supraventricular tachyarrhythmias in approximately 30% of patients following coronary artery bypass surgery (CABG). Ischemic preconditioning and adenosine preconditioning (Ado-PC) decrease postischemia/reperfusion (I/R) myocardial stunning, infarct size, and pharmacologically induced arrhythmias in all species including man. We hypothesized that adenosine preconditioning would decrease spontaneous pre- and postischemic atrial arrhythmias in human myocardium. The purposes of this study were to determine the effect of in vivo and in vitro Ado-PC on atrial arrhythmias. Methods. Human atrial trabeculae were harvested from CABG patients, placed in organ baths, and paced (1 Hz). Developed force (DF) was recorded during simulated I/R (30/45 min). Prior to I/R, trabeculae were treated with Ado (125 μM) for 5 min ( in vitro ), or patients were treated with Ado (12 mg iv) 5 min ( in vivo ) prior to harvest of trabeculae. Contraction frequency >4 Hz (defined as atrial tachyarrhythmias) was recorded in all groups pre- and postischemia. Results. Control trabeculae exhibited increased tachyarrhythmias pre- and postischemia. In vivo and in vitro Ado -PC suppressed both pre- and postischemic arrhythmias. Conclusions. Adenosine preconditioning suppresses the frequency of pre- and postischemic tachyarrhythmias against an ischemia/reperfusion insult in human myocardium. This antiarrhythmic effect occurs with both in vitro and in vivo administration of adenosine. Preconditioning with adenosine prior to elective ischemia/reperfusion is a prmising strategy of reducing spontaneous atrial arrhythmias in patients undergoing myocardial revascularization.