Journal of cardiac failure,2026 Oct
- Objective: Atrial fibrillation (AF) is a common comorbidity in patients with heart failure with preserved ejection fraction (HFpEF) that contributes to increased morbidity and mortality. We sought to evaluate the impact of AF on key HFpEF features, including exercise tolerance (peak oxygen uptake, VO2 peak) hemodynamic responses, and peripheral oxygen extraction (a-vO2 diff).
- Methods: Patients referred to a multidsciplinary clinic for evaluation of unexplained dyspnea and diagnosed with HFpEF after a comprehensive clinical and hemodynamic evaluation were stratified on the basis of whether they were in persistent/permanent AF (AFPersist; n = 86), paroxysmal AF (AFParox; n = 328), or sinus rhythm (SR; n = 274). Cardiopulmonary exercise testing with simultaneous echocardiography was applied to assess the VO2 peak, a-vO2 diff, and exercise hemodynamics. Groups were compared using analysis of covariance with adjustment for age, sex, body mass index, and the presence of hypertension and diabetes.
- Results: Compared with patients in SR or with AFParox, patients with HFpEF and AFPersist had a lower VO2 peak (1.3-2.4 mL/kg/min lower, P < .001). This coincided with lower peak exercise cardiac output (CO, 0.6-1.2 L/min lower), secondary to a lesser stroke volume (14-17 mL lower, P < .001), and a smaller left ventricular end-diastolic volume (15-18 mL lower, P < .001) that tended to decrease during exercise. In contrast, there was no impact of AF status on peak exercise a-vO2 diff, mean pulmonary artery pressure or the mean pulmonary artery pressure/CO slope.
- Conclusions: Patients with HFpEF and AFPersist have a lower VO2 peak secondary to decreased CO, SV, and reduced end-diastolic volume reserve. Rhythm control strategies may therefore be pivotal in optimizing exercise performance and clinical outcomes in patients with HFpEF and AF.