USEFULNESS OF ELECTROPHYSIOLOGIC STUDIES FOR NEW-ONSET SUSTAINED VENTRICULAR TACHYARRHYTHMIAS SHORTLY AFTER CORONARY-ARTERY BYPASS-GRAFTING

We retrospectively studied a group of 17 patients who developed life-threatening ventricular tachyarrhythmias shortly after coronary artery bypass grafting. The initial clinical event was sustained monomorphic ventricular tachycardia (VT) in 15 and ventricular fibrillation (VF) in 2, occurring at an average of 3.6 days postoperatively. All patients underwent electrophysiologic testing, with sustained monomorphic tachyarrhythmias inducible in 7. Three early deaths occurred after this initial evaluation. Among the 9 survivors with non-sustained, nonclinical or noninducible VT, 4 received no antiarrhythmic therapy and remained free of recurrence, whereas of the 5 that received drugs, implantable defibrillators, or both, 2 had spontaneous recurrence. For the surviving subgroup with inducible monomorphic VT, serial drug testing culminated in maintenance therapy with class IA agents or amiodarone, whereas defibrillators were also implanted in 3 patients. Overall, recurrence of life-threatening tachyarrhythmias beyond the immediate postoperative period was seen in 40% of patients with monomorphic clinical tachycardias and inducible sustained monomorphic VT. Ventricular tachyarrhythmias appearing shortly after cardiac surgery demonstrate significant chronicity and resistance to antiarrhythmic drug therapy, while statistically significant predictors of inducibility or their recurrence remain undefined.