Real-world behavior of CRT pacing using the AdaptivCRT algorithm on patient outcomes: Effect on mortality and atrial fibrillation incidence

Abstract

Background: The AdaptivCRT (aCRT) algorithm continuously adjusts cardiac resynchronization therapy (CRT) according to intrinsic atrioventricular conduction, providing synchronized left ventricular pacing in patients with normal PR interval and adaptive BiV pacing in patients with prolonged PR interval. Previous analyses demonstrated an association between aCRT and clinical benefit. We evaluated the incidence of patient mortality and atrial fibrillation (AF) with aCRT compared with standard CRT in a real-world population.

Methods and results: Patients enrolled in the Medtronic Personalized CRT Registry and implanted with a CRT from 2013-2018 were divided into aCRT ON or standard CRT groups based upon device-stored data. A Frailty survival model was used to evaluate the potential survival benefit of aCRT, accounting for patient heterogeneity and center variability. Daily AF burden and first device-detected AF episodes of various durations were recorded by the device during follow-up. A total of 1814 CRT patients with no reported long-standing AF history at implant were included. Mean follow-up time was 26.1 ± 16.5 months and 1162 patients (64.1%) had aCRT ON. Patient survival probability at 36 months was 88.3% for aCRT ON and 83.7% for standard CRT (covariate-adjusted hazard ratio [HR] = 0.71, 95% CI: 0.53-0.96, P = .028). Mean AF burden during follow-up was consistently lower in aCRT ON patients compared with standard CRT. At 36 months, the probability of AF was lower in patients with aCRT ON, regardless of which AF definition threshold was applied (6 minutes-30 days, all P < .001).

Conclusion: Use of the AdaptivCRT algorithm was associated with improved patient survival and lower incidence of AF in a real-world, prospective, nonrandomized registry.

Trial registration: ClinicalTrials.gov NCT01524276.

Keywords: AV conduction; atrial fibrillation; cardiac resynchronization therapy; heart failure; optimized pacing; synchronized pacing.

Figure 1

A, Patient Survival for aCRT vs standard CRT. Curves reflect unadjusted Kaplan‐Meier estimates of cumulative survival probability in patients programmed to aCRT (blue line) and standard CRT (red line) through 36 months follow‐up. Unadjusted hazard ratio derived from data through 36 months for each cohort using Frailty survival regression models. B, Patient survival stratified by percent LV pacing (LVP). Curves reflect unadjusted Kaplan‐Meier estimates of cumulative survival probability among aCRT patients and standard CRT patients (red line). aCRT patients were stratified by percent LV pacing (≥50% [blue line] and less than 50% [green line]). CRT, cardiac resynchronization therapy; HR, hazard ratio; LV, left ventricular

Figure 2

Mortality subgroup analysis hazard ratio forest plot. Risk of mortality through 36 months postimplant comparing aCRT and standard CRT. The vertical solid line corresponds to equal risk. The vertical dashed line represents the hazard ratio from the full comparison. The horizontal solid lines represent the 95% confidence intervals for the hazard ratios. AV, atrioventricular; CAD, coronary artery disease; CRT, cardiac resynchronization therapy; LBBB, left bundle branch block; LVEF, left ventricular ejection fraction; LVP, left ventricular pacing; NYHA, New York Heart Association

Figure 3

A, Daily AF burden summary. Average daily AF burden summary in 6‐month time periods comparing aCRT (blue bars) with standard CRT (red bars). Error bars reflect the standard deviation. B, Incidence of AF burden of 5.5 hours or longer. Curves reflect unadjusted Kaplan‐Meier estimates of cumulative incidence of developing daily AF burden of 5.5 hours or longer in patients programmed to aCRT (blue line) and standard CRT (red line) through 36‐month follow‐up. Unadjusted hazard ratio derived from data through 36 months for each cohort using Frailty survival regression models. AF, atrial fibrillation; CRT, cardiac resynchronization therapy; HR, hazard ratio. *P < .05, t test

Figure 4

Incidence of AF episode of 48 hours or longer. Curves reflect unadjusted Kaplan‐Meier estimates of cumulative incidence of developing 48 hours of AF in patients programmed to aCRT (blue line) and standard CRT (red line) through 36‐month follow‐up. Unadjusted hazard ratio derived from data through 36 months for each cohort using Frailty survival regression models. AF, atrial fibrillation; CRT, cardiac resynchronization therapy; HR, hazard ratio