Acute changes on atrial function during progressive exercise in patients with heart failure with mildly-reduced ejection fraction. A case-control study

Background: the aim of this study was to assess acute changes on left atrial (LA) function a during a progressive exercise in patients with heart failure with mid-range ejection fraction (HFmrEF) in comparison to healthy controls (HS). Methods: twenty patients with established HFmrEF were compared with 10 HS, age-matched controls. All subiects performed a stepwise exercise test on cyclette. Echocardiography was performed at baseline, during submaximal effort, at peak of exercise, and after 5 minutes of recovery. Results: HS obtained an higher value of METs at peak exercise than HFmrEF (7.4 vs 5.6; between group p 0.002). Heart rate and systolic blood pressure presented a greater increase in the HS group than in HFmrEF (between-groups p 0.006 and p 0.003 respectively). In the HFmrEF group peak atrial longitudinal strain (PALS), and conduit strain were both increased at submaximal exercise (p<0.05 for both versus baseline) and remained constant at peak exercise. Peak atrial contraction strain (PACS) did not show significant changes during the exercise. In the control group PALS and PACS increased significantly at submaximal level (p<0.05 for both versus baseline) but PALS returned near baseline values at peak exercise; conduit strain decreased progressively during the exercise in HS. Stroke volume (SV) increased in both groups at submaximal exercise; at peak exercise SV remained constant in the HFmrEF while it decreased in controls (between-groups p 0.002). Conclusions: Patient with HFmrEF, show a proper increase of LA reservoir function during incremental exercise that contributes to maintain SV throughout the exercise.