Effects of ß-blocker therapy on exercise oscillatory ventilation in reduced ejection fraction heart failure patients: A case series study

Background: Exercise oscillatory ventilation (EOV) is an abnormal breathing pattern that occurs in similar to 20% of patients with heart failure (HF) and is associated with poor prognosis and exercise intolerance. ss-blockers (ss b) are prescribed for most HF patients; however, their effect on EOV remains unclear. We evaluated the effect of ss b on EOV in HF patients with reduced ejection fraction (HFrEF). Methods: Fifteen patients diagnosed with HF, ejection fraction < 45%, aged from 18 to 65 years, were included before starting ss b therapy. Patients underwent clinical evaluation, cardiopulmonary exercise testing, echocardiography, laboratory exams (norepinephrine levels, B type natriuretic peptide) at baseline and after ss b therapy optimized for six months. Presence of exercise oscillatory breathing was determined by two experienced observers who were blinded to the moment of the test (pre or post). Results: Fifteen patients (1 female), aged 49.5 +/- 2.5 years, with HFrEF, NYHA I-III enrolled in the study. The etiologies of the HFrEF were idiopathic (n = 8) and hypertensive (n = 7). LVEF increased after ss b therapy from 25.9 +/- 2.5% to 33 +/- 2.6%, P = 0.02; peak VO2 did not significantly change (21.8 +/- 1.7 vs 24.7 +/- 1.9, P = 0.4); VE/VCO2 slope changed from 32.1 +/- 10.6-27.5 +/- 9.1, P = 0.03. Before ss b initiation, nine patients (60%) had EOV, but only two (13%) did after optimized therapy. McNemar test was used to evaluate the significance of the association between the two moments (P = 0.02). Conclusion: In patients with HF, medical therapy with ss b can reverse EOV. This may explain why these patients experience symptom improvement after ss b therapy.

Automated summary

This study indicates that in patients with HF, medical therapy with beta blockers can reverse exercise oscillatory ventilation (EOV), helping to improve symptoms and exercise capacity.