Reduced occurrence of appropriate therapy for ventricular arrhythmias after beta-blocker uptitration following implant of a primary prevention CRT-defibrillator.

Background: Absence of beta-blocker use independently predicts appropriate therapy. Following cardiac resynchronisation therapy (CRT) implant, reverse remodelling and protection against bradycardia allows for beta-blocker dose uptitration. The differential dosing effects on the occurrence of a first episode of appropriate therapy in primary prevention CRT-defibrillator (CRT-D) patients remains unstudied.Methods and Results: Changes in beta-blocker dose following CRT-D in consecutive primary prevention patients implanted between 2008 and 2015 were retrospectively studied. Beta-blocker dose was expressed as percent of target dose. Uptitration of beta-blocker dose following implant was calculated as the change in percent of target dose between implant and 6-months follow-up. Results from a prospectively maintained database of all device analysis were used to determine the occurrence of appropriate therapy. A total of 162 patients (68 ± 8 years) were studied. One hundred and ten (68%) patients underwent uptitration (mean 47 ± 19% in target dose) and 52 (32%) remained on a stable beta-blocker dose. During 37 ± 22 months follow-up, the cumulative percent of appropriate therapy was 31% in patient receiving no-uptitration versus 10% in the uptitrated patients (p < 0.001). After correction for known predictors of appropriate therapy, uptitration was independently associated with an OR = 0.263 (CI = 0.103-0.675; p = 0.001) for the occurrence of appropriate therapy. Every 1%-increase in target dose for beta-blocker associated with a significant lower risk for appropriate therapy, OR = 0.982 (CI = 0.965-0.999; p = 0.042).Conclusion: Following implantation of a primary prevention CRT-D, uptitration of beta-blockers associated with a reduced occurrence of a first episode of appropriate therapy for ventricular arrhythmias. An inverse dose-response effect was seen between beta-blocker dose and appropriate therapy.