HEMODYNAMIC DETERIORATION DURING ICD IMPLANT - PREDICTORS OF HIGH-RISK PATIENTS

Defibrillation threshold (DFT) testing during implantation of the card ioverter defibrillator is associated with hemodynamic deterioration an d pump failure in many patients. We investigated the influence of DFT testing on cardiac function intraoperatively using a balloon-tipped ca theter. In 13 consecutive patients with a nonthoracotomy approach, a m ean of 3.4 +/- 1.4 episodes of ventricular fibrillation were induced w ith an overall ischemic time of 87 +/- 54 seconds. At the end of DFT t esting, patients with a left ventricular ejection fraction (EF) of < 3 0% had significant impairment of cardiac index (1.6 +/- 0.5 L/min/m(2) after testing vs 2.2 +/- 0.6 L/min/m(2) before the procedure). One pa tient with severely comprised ventricular function needed prolonged po sitive inotropic support. The left ventricular function of patients wi th a preoperative EF greater than or equal to 30%, however, was not ch anged (2.2 +/- 0.5 L/min/m(2) after testing and 2.2 +/- 0.5 L/min/m(2) before testing). The two groups did not differ with respect to the nu mber of testing episodes, ischemic time, or DFT. Thus patients with a low preoperative EF (< 30%) are threatened by a severe left ventricula r deterioration during ICD implantation. Close hemodynamic monitoring with a balloon-tipped catheter is recommended in these patients.