Beta-blocker use and incidence of new atrial fibrillation or flutter requiring therapy in post-septal myectomy hypertrophic cardiomyopathy patients

• Published in: Journal of cardiac failure 2024-09, Vol.30, p.S8-S8
• Main Authors: Kim, Morris, Elman, Miriam, Paas, Mason, Volk, Hailey, Butzner, Michael, Sanghai, Saket, Masri, Ahmad
• Format: Article
• Language: English
• ISSN: 1071-9164
• DOI: 10.1016/j.cardfail.2024.08.009

Atrial fibrillation and atrial flutter (AF/AFL) are common arrhythmias in hypertrophic cardiomyopathy (HCM) and are associated with ongoing adverse remodeling. Septal myectomy (SM) is a commonly offered surgery in patients with symptomatic obstructive HCM. Beta blockers (BB) are frequently prescribed post-SM even in the absence of left ventricular outflow tract obstruction (LVOTO). BB have been shown to be detrimental in heart failure with preserved ejection fraction. The impact of BB on the incidence of new AF/AFL requiring treatment is unknown. This study investigated whether BB use post-SM were associated with decreased rates of new AF/AFL requiring treatment and/or intervention. Healthcare claims from the Symphony Health database between 2016-2021 were used to define a cohort of 3,532 patients with obstructive HCM with no known history of AF/AFL who underwent SM. The first chronological claim for SM was used as the index procedure and the first 30 days post SM was assigned as a blanking period. Primary endpoint was development of new AF/AFL beyond 30 days post-SM which required an intervention (cardioversion, ablation, anti-arrhythmics, anti-coagulants). Detailed BB use data were gathered using pharmacy claims and were categorized into continuous use, never use, and discontinuations. Multivariable extended Cox models adjusted for 19 variables selected a priori were constructed. During a median follow up period of 2.2 (0.6, 3.9) years, 606 (17.2%) patients developed AF/AFL and 2,637 (74.7%) patients used beta blockers at any point during the follow up period (Table 1). Patients who used BB during the follow-up period had higher rates of new AF/AFL compared to those who never used BB (unadjusted HR 2.05, 95% CI 1.67, 2.56; P