December 13, 2005 — This is the first study designed to look at the relation between patient outcomes and physicians'/hospitals' volume of cardioverter-defibrillator implantation to determine whether implantation should be limited to physicians with high procedural volume.

Defibrillation, or shock, can be the only way to stop certain heart arrhythmias, or irregular heartbeats, before they kill. If the heart beats too quickly, the chambers, or ventricles, will not have enough time to fill with blood and pump blood to the rest of the body, which can cause death. For people at high risk for the deadliest forms of arrhythmias – called ventricular tachycardia and ventricu­lar fibrillation – an internal “shocking” device may be the best protection against sudden cardiac arrest (SCA).