Author + information
- Brian D. Powell, MD∗ ()
- ↵∗Cardiovascular Division, Sanger Heart & Vascular Institute, 1001 Blythe Boulevard, Suite 300, Charlotte, North Carolina 28203
I appreciate the comments by Dr. Gasparini, and I agree with them. Regarding implantable cardioverter-defibrillator (ICD) programming in our study, one-half of the patients in the ALTITUDE Survival by Rhythm Study (1) were taken from the ALTITUDE REDUCES (Real World Evaluation of Dual-Zone ICD and CRT-D Programming Compared to Single-Zone Programming) study (2) population in which patients were retrospectively evaluated for incidence of shocks and mortality based on ICD programming. The annual incidence of shocks and pre-shock mortality were highest in patients programmed with single-zone ventricular fibrillation ≤170 beats/min (20.1% of patients received shocks; 2.5% mortality) or dual-zone ventricular tachycardia (VT) ≤170 beats/min (12.3% of patients received shocks; 2.0% mortality). The lowest annual incidence of shocks (5.5%) and pre-shock mortality (1.0%) was in the group programmed with dual-zone VT ≥200 beats/min. Because it was a retrospective study, we cannot know with certainty if the higher mortality in the groups with a lower programmed VT or ventricular fibrillation zone was related to ICD programming or if these patients were programmed with lower zones because of previous episodes of slower ventricular arrhythmias. Whether or not inappropriate antitachycardia pacing increases mortality is not completely known at this time. However, programming higher detection rates for primary prevention ICDs and/or using ICD discriminators to avoid inappropriate shocks and antitachycardia pacing seems appropriate based on recent studies.
- American College of Cardiology Foundation