Abstract 15871: Implantable Cardioverter Defibrillator Therapy and Mortality
Background: Several publications have demonstrated an association between mortality and ICD shocks, both appropriate and inappropriate. The objective of this study was to analyze the association of both ATP and shock ICD therapy, appropriate and inappropriate, using data from the OMNI study.
Methods: Predictors of mortality were analyzed in patients from the OMNI ICD observational study. Baseline characteristics associated with mortality were determined using a stepwise proportional hazards regression model. Differences in all-cause mortality among patients with either 1) no treated VT/VF episodes, 2) only ATP treated episodes, 3) ≥1 episode with a shock but ≤1 shock delivered for all episodes, or 4) multi-shocked episodes (MSE) were evaluated. Separate analyses were conducted for patients with only appropriately detected episodes and for patients with only inappropriately detected episodes. In each analysis, comparisons were made with reference to patients having no detected episodes.
Results: The OMNI study included 2255 patients implanted with either a Single Chamber ICD (n=322), Dual Chamber ICD (n=1087), or CRT-D (n=846). Most patients were male (73%) having a primary prevention indication for device implant (84%). Average follow-up was 39 ± 19 months (range 0.4 to 63.1 months). There were 470 deaths (21%). Mortality risk by group is shown in the table below. One hundred and eighty patients had both appropriate and inappropriate shocks.
Conclusions: Patients who received only inappropriate ICD therapy, regardless of the type of therapy, were at no increased risk of mortality. For patients with only appropriate therapy, the risk of mortality increased with increased electrical energy to terminate the tachycardia, ranked from ATP as the least energy, to MSE as the most energy. It is unknown if ventricular arrhythmia complexity as indicated by terminating therapy is a marker for increased mortality or if mortality rises due to the impact of shock delivery.
- © 2013 by American Heart Association, Inc.