Modifying AV search hysteresis to increase AV delay extension to 100% significantly reduced the mean percentage of right ventricular pacing at 1 week from 41.4% to 14.7% (P<0.0001).
Observational (n=1,530)
Yes
Does extending AV delay by 100% using AV search hysteresis reduce the percentage of right ventricular pacing compared to a 50% extension in patients with dual-chamber ICDs?
Modifying AV search hysteresis to extend the AV delay by 100% dramatically reduces unnecessary right ventricular pacing in ICD recipients compared to a 50% extension.
Absolute Event Rate: 14.7% vs 41.4%
p-value: p=<0.0001
BACKGROUND: Unnecessary right ventricular (RV) pacing in patients with implantable cardioverter defibrillators (ICD) may adversely affect heart failure morbidity and total mortality. Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs (INTRINSIC RV) is a prospective, multicenter, randomized trial evaluating outcomes in ICD recipients programmed to single-chamber pacing (VVI) versus dual-chamber (DDDR) pacing with AV search hysteresis (AVSH). METHODS: Patients underwent ICD implant (for standard indications). The ICD was programmed to DDDR with AVSH regardless of any need for pacing. Rate-adaptive pacing was set at 60-130 ppm with dynamic AV delay from 200 to 90 ms. AVSH was programmed to search every 32 intervals and extend the AV delay by 50%. One week post-implant patients with ICDs were interrogated to assess the percentage of RV pacing with the expectation that most would have <20% RV pacing and would be randomized into INTRINSIC RV. Early analysis showed that targets for randomization were not met. AVSH parameters were modified under a protocol amendment to increase AV delay extension to 100%. We report findings related to this programming change based upon analyses of (nonrandomized) data pre- and post-amendment. RESULTS: Twenty-one percent of patients (n = 314) were enrolled pre-amendment and 79% (n = 1,216) were enrolled post-amendment. The mean percentage of RV pacing at the 1-week visit was 41.4 +/- 29.6% pre-amendment and 14.7 +/- 22.6% post-amendment (P < 0.0001). The proportion of patients eligible for randomization (RV pacing <20% at the 1-week visit) was 31.2% pre-amendment and 76.8% post-amendment (P < 0.0001). CONCLUSION: AVSH can dramatically reduce the percentage of RV pacing among ICD recipients.
Olshansky et al. (Wed,) conducted a observational in Patients with implantable cardioverter defibrillators (ICD) (n=1,530). AV search hysteresis with 100% AV delay extension vs. AV search hysteresis with 50% AV delay extension was evaluated on Mean percentage of right ventricular pacing at 1 week (p=<0.0001). Modifying AV search hysteresis to increase AV delay extension to 100% significantly reduced the mean percentage of right ventricular pacing at 1 week from 41.4% to 14.7% (P<0.0001).