Abstract 4142619: Implications of Rate Limiting Medications in Patients with Atrial Fibrillation and Heart Failure with Preserved Ejection Fraction

Introduction: Concerns have been raised regarding the potential adverse effect of beta-blockers particularly in limiting chronotropic response in Heart failure with preserved ejection fraction (HFpEF) patients. While beta-blockers are commonly used in Atrial fibrillation (AF) management, their effect in patients with both AF and HFpEF remains uncertain. Methods: In patients undergoing AF ablation, invasive left atrial (LA) hemodynamic measurements were obtained at rest and following 500mL fluid challenge. Patients with HFpEF (baseline mean LA pressure >15 mmHg) and preclinical HFpEF (baseline mean LA pressure <15 mmHg, increasing to >15 mmHg post-fluid challenge) were included for analysis. Two subgroups were identified based on the use of rate-limiting medications (RLM) at the time of recruitment. The validated AF Severity Scale (AFSS) and Minnesota Living with Heart Failure questionnaire (MLHFQ) were utilised to assess AF and HFpEF symptoms respectively. Baseline Pro-BNP level and cardiopulmonary exercise test were also performed. Results: Of the 88 patients (mean age 65.1 ± 10.8 years, 64% males) included for analysis, 63.6% had clinical HFpEF and 36.4% had preclinical HFpEF. Patients on RLM (79.5%) and not on RLM (20.5%) had similar baseline characteristics including age ( p =0.53) sex ( p =0.24) type of AF ( p =0.43) and pacemaker implantation ( p =1.0). Treatment with beta-blockers did not significantly affect quality of life as measured by the AFSS ( p =0.77) reported global wellbeing ( p =0.51) or exercise capacity as assessed by maximum heart rate at peak exercise ( p =0.75) and peak oxygen consumption (VO2ml/kg.min) ( p =0.65). Additionally, there were no differences between groups in self-reported heart failure (HF) symptoms as measured by the MLHFQ ( p =0.69) or in mean Pro-BNP levels ( p =0.63). Results were consistent when groups matched for age and sex. Conclusions: While there is some apprehension regarding the use of RLM in patients with HFpEF, in this observational study, there was no difference in exercise capacity, quality of life, HF symptoms or biomarkers between those using RLM and those not.