Exacerbation of ventricular arrhythmias during the postoperative period after implantation of an automatic defibrillator

The postoperative course of 68 consecutive patients treated with an implantable defibrillator during the period from 1982 through 1990 was studied. In 46 patients (group 1), no concomitant surgery was performed during the implantation. In 22 patients (group 2), concomitant surgery (coronary artery bypass [n = 12], valve replacement [n = 3] or arrhythmia surgery [n = 7]) was performed. All patients in group 1 were clinically stable before surgery, receiving an antiarrhythmic regimen chosen by serial drug testings. The same regimen was continued postoperatively. Eight of the 46 patients in group 1 whose condition had been stable in the hospital for 19 ± 25 days preoperatively developed multiple episodes of sustained ventricular tachycardia 4 ± 9 days after implantation while receiving the same antiarrhythmic regimen. Although the exacerbation was transient in some patients, six required different antiarrhythmic therapy and one eventually died. Two additional patients had frequent and prolonged episodes of nonsustained ventricular tachycardia that could trigger the defibrillator, requiring changes in the antiarrhythmic regimen. Another patient had progressive cardiac failure and died on day 5. A marked (sevenfold) increase in asymptomatic ventricular arrhythmias was noted in 42% of the remaining 35 patients. In group 2 (combined surgery), one patient developed refractory ventricular tachycardia 3 days postoperatively and died on that day. Three patients developed frequent nonsustained ventricular tachycardia postoperatively, requiring changes in the antiarrhythmic regimen. The overall surgical mortality rate was 4.4% (4.3% in group 1 and 4.5% in group 2) and was due to refractory ventricular tachycardia in two patients and cardiac failure in one. Thus, during the postoperative period after defibrillator implantation, exacerbation of ventricular arrhythmias was common. The exacerbation was clinically significant in many patients and included multiple episodes of sustained ventricular tachycardia (with eventual death in some patients) or frequent prolonged nonsustained ventricular tachycardia that could trigger the defibrillator. A sevenfold asymptomatic increase in ventricular ectopic activity was noted in 42% of the remaining clinically stable patients. The long-term effect of the exacerbation is unknown.