ADVANCES IN IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR THERAPY

The use of implantable defibrillation systems in patients with cardiac arrest has resulted in lower mortality than expected from studies of similar patients not receiving defibrillators. Nonthoracotomy lead sys tems have led to a decrease in operative mortality and lowered the cos t of defibrillator implantation, but these systems have a higher energ y requirement for defibrillation than do epicardial ones. The recent i ntroduction of single-lead systems and bipolar defibrillation pulses h as simplified nonthoracotomy defibrillator implantation and improved d efibrillation efficiency. A prototype unipolar, single-lead pectoral i mplant defibrillation system is described that may significantly impro ve the reliability, safety, and cost effectiveness of nonthoracotomy d efibrillators. This and other improved nonthoracotomy systems may expa nd the indications for defibrillator implantation to prophylactic use in high-risk patients who have not yet experienced life-threatening ve ntricular arrhythmias.