Hemodynamic deterioration during ICD implant: Predictors of high-risk patients

Defibrillation threshold (DFT) testing during implantation of the cardioverter defibrillator is associated with hemodynamic deterioration and pump failure in many patients. We investigated the influence of DFT testing on cardiac function intraoperatively using a balloon-tipped catheter. In 13 consecutive patients with a nonthoracotomy approach, a mean of 3.4 ± 1.4 episodes of ventricular fibrillation were induced with an overall ischemic time of 87 ± 54 seconds. At the end of DFT testing, patients with a left ventricular ejection fraction (EF) of <30% had significant impairment of cardiac index (1.6 ± 0.5 L/min/m² after testing vs 2.2 ± 0.6 L/min/m² before the procedure). One patient with severely comprised ventricular function needed prolonged positive inotropic support. The left ventricular function of patients with a preoperative EF ≥ 30%, however, was not changed (2.2 ± 0.5 L/min/m² after testing and 2.2 ± 0.5 L/min/m² before testing). The two groups did not differ with respect to the number of testing episodes, ischemic time, or DFT. Thus patients with a low preoperative EF (<30%) are threatened by a severe left ventricular deterioration during ICD implantation. Close hemodynamic monitoring with a balloon-tipped catheter is recommended in these patients.