ABSTRACT
PURPOSE: Patients with severe cardiomyopathy often have chronotropic incompetence, which is predominantly managed by activating rate-adaptive pacing in patients implanted with an implantable cardioverter-defibrillator (ICD) capable of atrial pacing. The purpose of this study was to determine predictors of rate-adaptive pacing activation, the cumulative incidence of activation, and the association of rate-adaptive pacing activation with subsequent clinical outcomes in an ICD population. METHODS: The authors evaluated 228 patients implanted with an ICD between 2011 and 2015. Multivariable logistic regression was used to evaluate predictors of rate-adaptive pacing activation. Cox proportional-hazards regression was used to examine associations of rate-adaptive pacing activation and clinical outcomes. RESULTS: Rate-adaptive pacing was turned on in 38.5% (n = 88) of patients during follow-up. Several statistically significant predictors of rate-adaptive pacing activation were found, particularly previous atrial fibrillation (odds ratio [OR] = 8.27, 95% confidence interval [CI] = 2.96-23.06, p < 0.001), previous myocardial infarction (OR = 4.17, 95% CI = 1.38-12.58, p = 0.01), and non-ischemic cardiomyopathy (OR = 3.83, 95% CI = 1.22-12.00, p = 0.02). In multivariable adjusted analyses, rate-adaptive pacing activation within 30 days of implantation was not associated with the risk of device therapy for tachyarrhythmias (hazard ratio [HR] = 1.52, 95% CI = 0.71-3.28, p = 0.29), atrial fibrillation (HR = 1.42, 95% CI = 0.71-2.87, p = 0.32), HF re-admission (HR = 1.39, 95% CI = 0.80-2.43, p = 0.25), nor all-cause mortality (HR = 2.34, 95% CI = 0.80-6.84, p = 0.12). CONCLUSIONS: During follow-up, more than one in three HF patients implanted with an ICD developed the need for rate-adaptive pacing. Atrial fibrillation, prior myocardial infarction, and non-ischemic cardiomyopathy were statistically significant baseline clinical predictors of rate-adaptive pacing activation. Rate-adaptive pacing activation was not associated with subsequent adverse clinical outcomes.