Influence of daily step count on improvement of left-ventricular ejection fraction in heart failure patients

F. Schymek (Bochum)¹, J. Wintrich (Homburg/Saar)², B. Sasko (Herne)³, I. El-Battrawy (Bochum)⁴, N. Hamdani (Bochum)⁵, A. Haghikia (Bochum)⁴, D. Bismpos (Herne)³, C. Ukena (Herne)^3
1Bochum, Deutschland; ²Universitätsklinikum des Saarlandes Innere Medizin III - Kardiologie, Angiologie und internistische Intensivmedizin Homburg/Saar, Deutschland; ³Marienhospital Herne, Klinikum der Ruhr-Universität Bochum Med. Klinik II, Kardiologie u. Angiologie Herne, Deutschland; ⁴Klinikum der Ruhr-Universität Bochum Medizinische Klinik II, Kardiologie Bochum, Deutschland; ⁵Kath. Klinikum Bochum Cellular Physiology Bochum, Deutschland

Background:
We investigated the prognostic role of objectively measured daily physical activity (step count) on left-ventricular ejection fraction (LVEF) improvement in heart failure (HF) patients.

Methods:
This registry study included patients newly diagnosed with HF who received a wearable cardioverter-defibrillator (WCD) because of a high risk of sudden cardiac death. LVEF was assessed by echocardiography before and after WCD treatment. Step count was recorded continuously by the WCD in 5-minute intervals and aggregated to the total number of steps per day for each patient. LVEF recovery was defined as a follow-up LVEF >35%. The association between daily step count and LVEF recovery was assessed using multivariable logistic regression adjusted for age, sex and ischemic aetiology.

Results:
In total, 142 patients were enrolled (63.1±12.5 years, 75% male). Indications for WCD prescription were newly diagnosed HF due to ischemic cardiomyopathy (51%) or non-ischemic / other cardiomyopathy (49%). At baseline, LVEF was severely reduced (28.5±5.9%). After a median WCD wear time of 83 days, LVEF improved to 36.1±12.2%, and a follow-up LVEF >35% was reached in 74 of 130 patients with follow-up echocardiography (57%). The median daily step count was markedly low at 3992 steps/day (IQR 2405–6141). Age was inversely correlated with daily step count (Pearson r=−0.30, p<0.001); even patients younger than 60 years remained relatively inactive (median 5641 steps/day, IQR 3615–7913). Patients who achieved LVEF recovery had a significantly higher daily step count than those who did not (median 4470 vs. 3284 steps/day; p=0.013). In multivariable analysis, a higher daily step count was independently associated with a greater likelihood of LVEF recovery (OR 1.17 per 1000 steps/day; 95% CI 1.01–1.34; p=0.032).

Conclusion:
In this newly diagnosed HF cohort, objectively measured daily step counts were low overall and decreased with advancing age. A higher daily step count was independently associated with a higher likelihood of LVEF recovery. These findings underline the potential importance of physical activity and cardiac rehabilitation in HF patients.