Foulkes SJ; College of Health Sciences, University of Alberta, Canada;
Moura-Ferreira S; Milani M; Bekhuis Y; et al

Journal of Cardiac Failure. 32(10):1715-1726, 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, VO2peak) hemodynamic responses, and peripheral oxygen
extraction (a-vO2diff).

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
VO2peak, a-vO2diff, 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 VO2peak (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-vO2diff, mean
pulmonary artery pressure or the mean pulmonary artery pressure/CO slope.

CONCLUSIONS: Patients with HFpEF and AFPersist have a lower VO2peak
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