CARDIAC-OUTPUT IS NOT AFFECTED DURING INTRAOPERATIVE TESTING OF THE AUTOMATIC IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR

Introduction: Perioperative mortality of patients undergoing implantat ion of automatic implantable cardioverter defibrillators (ICDs) has be en reduced dramatically following the availibility of transvenous-subc utaneous defibrillation leads. However, patients with severely reduced left ventricular function show a substantial rate of nonsudden cardia c mortality within the first year. Whether repeated intraoperative ind uctions of ventricular tachycardia/fibrillation (VT/VF) during implant ation lead to hemodynamic deterioration and thus might contribute to d evelopment of end-stage heart failure in these patients is unknown. Th e purpose of the present study was to determine cardiac output and hem odynamic performance during transvenous-subcutaneous ICD implantation in patients with severe left ventricular dysfunction. Methods and Resu lts: In 11 patients with a left ventricular ejection fraction (EF) les s than or equal to 0.35, cardiac output was measured automatically wit h a combined continuous cardiac output/mixed venous oxygen saturation pulmonary artery catheter system. ICD implantation was performed durin g standardized general anesthesia. In the 11 patients (EF = 27 +/- 2% [mean +/- SEM]) a total of 95 episodes of VT/VF followed by defibrilla tion were induced (epsiodes per patient = 9 +/- 1; range 6 to 11). Car diac index was 2.2 +/- 0.2 L . min(-1). m(-2) after induction of anest hesia (before start of surgery), and 1.9 +/- 0.1 L . min(-1). m(-2) im mediately before first induction of VT/VF. After the last episode of V T/VF, cardiac index was 2.1 +/- 0.2 L . min(-1). m(-2). Cardiac index measured 1, 2, and 3 minutes after induction of VT/VF was not signific antly different when compared to the preinduction value during any epi sode of VT/VF induction. Similarly, stroke volume index was 39 +/- 5 m L . m(-2) immediately before first induction of VT/VF and 36 +/- 3 mL . m(-2) after the last episode of VT/VF (NS). At the end of surgery, h emodynamic parameters did not exhibit any significant difference when compared to the data obtained before start of ICD implantation and tes ting. Conclusion: Extensive defibrillation tests during transvenous-su bcutaneous ICD implantation in patients with severe left ventricular d ysfunction are not associated with acute deterioration of cardiac perf ormance.