Abstract 4141378: Comparative Analysis of Hemodynamic Parameters in Heart Failure with Preserved Ejection Fraction Patients with and without Atrial Fibrillation Undergoing Exercise Right Heart Catheterization

Introduction: Atrial fibrillation (AF) is common in patients with heart failure with preserved ejection fraction (HFpEF) and is associated with higher mortality. This study aims to compare hemodynamic parameters between HFpEF patients with and without AF to better understand the impact of AF on cardiac function in this population. Method: Patients from the Johns Hopkins HFpEF Clinic who underwent exercise right heart catheterization (July 2014 - May 2024) were included. They were categorized into two groups based on ECG findings of AF before catheterization: HFpEF-AF versus HFpEF-NonAF. Continuous variables were assessed for normal distribution using the Shapiro-Wilk test. Group differences were explored using one-way ANOVA or the Mann-Whitney U test. ANCOVA was performed to account for major confounders. Results: Sixty-six HFpEF patients were enrolled: 44 HFpEF-NonAF (66.7%) and 22 HFpEF-AF (33.3%). HFpEF-AF group was older (72.09 vs. 63.63 years, p < .001) and had more males (54.5% vs. 27.3%, p = 0.03). No significant differences were observed in other baseline characteristics between the two groups. More patients in the HFpEF-NonAF group reached higher stages compared to the HFpEF-AF group, indicating poorer performance in the AF group (Figure A). There were no significant differences between the groups at early stages or peak exercise regarding mean pulmonary artery pressure, mean pulmonary capillary wedge pressure, pulmonary vascular resistance, and heart rate. However, significant differences were observed in terms of cardiac output (CO) at baseline (5.81 vs. 4.77, p = 0.035) and during exercise (8.9 vs. 7, p = 0.019), and cardiac index (CI) during peak exercise (4.14 vs. 2.90, p < 0.001) between the two groups (Figures B-F). A negative correlation between age, CO, and CI within the AF subgroup was observed. ANCOVA analysis showed HFpEF-AF patients have lower CI at peak exercise even after adjusting for age. Discussion: The study reveals that in HFpEF patients, those with AF exhibit significantly lower cardiac output and cardiac index during exercise compared to those without AF, despite similar pulmonary pressures. These findings underscore the importance of rhythm control strategy for AF in HFpEF patients.