Several trials demonstrated that a long detection interval and a high-rate cutoff reduced implantable cardioverter-defibrillator (ICD) therapy in primary prevention patients. However, only a few data are available for secondary prevention (SP) patients. The aim of this study was to evaluate whether these ICD programming would be effective in reducing ICD therapies in SP patients. We enrolled 65 SP patients under ICD or cardiac resynchronization therapy with the defibrillator programmed with the same setting (conventional setting). During follow-up, we changed detection rates in each zone; cycle length (CL) ≤400 to ≤370 ms for ventricular tachycardia (VT) zone, CL ≤350 to ≤320 ms for fast VT zone, CL ≤300 to ≤270 ms for ventricular fibrillation (VF) zone, and number of intervals to detect ventricular tachyarrhythmia in VF zone: 12-24. We retrospectively compared the incidences of ICD therapies, syncope, and hospitalization due to slow VT under the detection rate between both settings. Median follow-up periods were 5.0 (interquartile range 2.5-7.8) and 2.5 years (interquartile range 2.3-2.7) in conventional and strategic settings, respectively. The incidence of appropriate ATP and shock significantly decreased in strategic setting (conventional and strategic settings: 21.2 and 4.8 ATPs per year, respectively, OR 0.18, 95 % CI 0.06-0.54, p = 0.002, 26.1 and 7.8 shocks per year, respectively, OR 0.29, 95 % CI 0.09-0.88, p = 0.03). The incidence of overall inappropriate therapy significantly decreased (conventional and strategic settings: 17.6 and 2.8 therapies per year, respectively, OR 0.14, 95 % CI 0.05-0.44, p = 0.01). The incidence of syncope and slow VT was not significantly different between both settings. In conclusion, ICD programming-combined long detection interval with high-rate cutoff was effective in reducing appropriate shock and inappropriate therapy without increasing the incidence of syncope and slow VT in SP patients.
Keywords: High-rate cutoff; Implantable cardioverter-defibrillator; Long detection interval; Secondary prevention; Shock reduction.