Is Beta-Blockade Useful in Heart Failure Patients with Atrial Fibrillation? An Analysis of Data from Two Previously Completed Prospective Trials

BACKGROUND: Beta-adrenergic blockade is of proven value in chronic heart failure. It is uncertain, however, if beta-blockade provides a similar degree of clinical benefit for heart failure patients with atrial fibrillation (AF) as those in sinus rhythm (SR). AIMS: To compare the effectiveness of beta blockade in patients with heart failure and AF. METHODS: Patients with chronic heart failure were randomized to treatment (double blind) with metoprolol 50 mg twice daily or carvedilol 25 mg twice daily in addition to standard therapy. Response was assessed after 12 weeks by a quality of life questionnaire, New York Heart Association class, exercise capacity (6-min walk test), radionucleotide ventriculography for LVEF, 2-D echocardiography measurement of left ventricular (LV) dimensions and diastolic filling and 24-h electrocardiograph monitoring to assess heart rate changes. RESULTS: Both beta-blockers produced significant improvements in LVEF in both the SR group: (+6+/-10% at 12-week, P<0.001) and the AF group: (+11+/-9% at 12-week, P<0.05). However, significant improvement in symptoms (P<0.001) and exercise capacity (P<0.001) were observed only in the SR group but not in the AF group despite a significant improvement in LVEF. CONCLUSION: Beta-blockers were effective in improving LV ejection fraction in chronic heart failure patients in either SR or AF but had less effect on symptoms and exercise capacity in those with AF.