Impact of Atrial Fibrillation on Hemodynamics, Oxygen Consumption, and Its Fick Determinants in Patients With Heart Failure With Preserved Ejection Fraction.

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.