title: Actuarial incidence and pattern of occurrence of shocks following implantation of the automatic implantable cardioverter defibrillator.
abstract: The actuarial incidence and pattern of occurrence of shocks were analyzed in 65 patients after implantation of the automatic implantable cardioverter defibrillator. During a mean follow-up of 25 +/- 21 months only one patient died suddenly, and this patient had a nonfunctioning device at the time of death. The long-term actuarial risk of death from any cause in the patients who received appropriate shocks was not significantly different than for the entire group. The 1- and 4-year cumulative risk of receiving any shock was 51 +/- 7% and 81 +/- 11%; of receiving an appropriate shock was 33 +/- 7% and 64 +/- 10%; of receiving a spurious shock was 17 +/- 5% and 21 +/- 6%; and of receiving an "indeterminate" shock was 19 +/- 6% and 52 +/- 10%. In 14 patients who were followed for 24 months without receiving an appropriate shock, the actuarial risk of receiving an appropriate shock was 29 +/- 14% during the next 24 months. The mean number of shocks delivered during appropriate episodes was 1.6 +/- 0.9, which was significantly lower than the mean of 4.0 +/- 2.0 shocks during spurious episodes (P less than 0.02). The mean number of shocks during indeterminate episodes was 1.7 +/- 1.5. Our data confirms the efficacy of the implantable defibrillator in preventing sudden death. The majority of patients with this device receive appropriate shocks during long-term follow-up, and the cumulative incidence of appropriate shocks increases steadily for at least 4 years. In contrast, the cumulative incidence of spurious shocks plateaus at about 12 months. Our data suggests that many "indeterminate" shocks actually appear to be appropriate.
authors: Division of Cardiology, Medical College of Pennsylvania, Allegheny General Hospital, Pittsburgh 15212.
authors: R N
authors: RN
authors: Fogoros
authors: J J
authors: JJ
authors: Elson
authors: C A
authors: CA
authors: Bonnet
mesh_terms: D000206:Actuarial Analysis; D000328:Adult; D000368:Aged; D003645:Death, Sudden; D004554:Electric Countershock / Q000295:instrumentation*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013610:Tachycardia / Q000628:therapy*; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000628:therapy*