Abstract 13214: Arrhythmic Burden After Bruton's Tyrosine Kinase Inhibitor Initiation and Major Cardiovascular Events

Abstract

Background: Bruton’s tyrosine kinase inhibitors (BTKi) have dramatic efficacy against B cell malignancies. BTKi’s also cause cardiotoxic arrhythmias, including atrial fibrillation (AF) and ventricular arrhythmias (VA). Yet, the true burden and long term effects of arrhythmias after BTKi therapy are unknown. Research Question: In patients with suspected BTKi related arrhythmias, what is the relative AF burden? Does it prognosticate future events? Methods: Leveraging a cohort of consecutive B cell malignancy patients initiated on BTKi from 2009-2020, we identified patients with available ambulatory rhythm monitors. The primary outcome was AF burden after BTKi initiation. Secondary outcomes included VA burden, conduction blocks, and other arrhythmias of probable or definite BTKi association. Observed incident AF rates and burden with next generation BTKi’s were compared to ibrutinib. Multivariable regression and survival analysis were used to define factors associated with AF related hospitalizations and major adverse cardiac events (MACE), as well as the relationship between AF burden and mortality. Outcomes were stratified by high (≥5%) vs low (<5%) AF burden. Results: Of 890 BTKi treated patients, 98 wore ambulatory rhythm monitors, including 38 on next generation BTKi’s [age 67.7 years, 24.2% prior AF]. Median duration BTKi use was 34 months. Among next generation BTKi treated patients, 8.7% developed incident AF compared to 25.5% with ibrutinib ( P =0.048). Ten patients (26.3%) developed symptomatic or >1% PVCs, at a mean burden of 7.1% compared to eight patients (13.3%) with mean burden 9.4% on ibrutinib. In a multivariable model accounting for traditional CV risk factors, prior AF associated with increased post BTKi AF burden. In follow up, high AF burden associated with increased MACE (HR 3.49, P =0.001) and mortality (HR 3.2, P =0.002); Figure . Conclusions: In BTKi treated patients, cardiotoxic AF burden prognosticates future MACE and mortality.