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A retrospective study of the effect of cardioversion upon ejection fraction in people with atrial fibrillation and heart failure with systolic dysfunction

Aims To determine the effect of successful cardioversion upon ejection fraction in patients with left ventricular systolic dysfunction.

Methods: The pre-cardioversion and post-cardioversion echocardiogram results were compared for all patients with an ejection fraction <50% who remained in sinus rhythm for at least 12 weeks after cardioversion. The post-cardioversion echocardiogram was timed to be at least 12 weeks after cardioversion, and was included if the patient was in sinus rhythm during the echocardiogram. Student’s paired t-test was then used to compare the ejection fraction in these patients from before and after cardioversion.

Results: 142 patients satisfied the criteria of the study: 1) had a pre-cardioversion ejection fraction of less than 50%, 2) remained in sinus rhythm after 12 weeks, and 3) remained in sinus rhythm during the echocardiogram. 108 patients had echocardiograms before and after cardioversion, and 34 patients had not had echocardiograms, or had alternate device therapy. From these 108 patients, 50 had moderately impaired ejection fraction (greater than or equal to 40% and less than 50%), and 50 had a reduced ejection fraction (less than 40%) on the pre-cardioversion echocardiogram. The echocardiogram results were compared with Student’s paired t-test. The group including all patients with an ejection fraction less than 50% (n = 108) showed a mean improvement of 14.2% in ejection fraction (n = 108, 95% CI = 11.0% – 17.4%, p < 0.0001). The subgroup analysis of moderately reduced ejection fraction (HFmrEF) showed a mean improvement of 4.24% (n = 50, 95% CI = 0.3% – 8.2%, p = 0.03). The subgroup analysis of reduced ejection fraction (HFrEF) showed a mean improvement of 23.0% (n = 58, 95% CI = 19.4% – 26.6%, p < 0.0001).

Conclusion: The ejection fraction is the most studied predictor for morbidity and mortality in heart failure. Cardioversion, when successful, significantly improves the ejection fraction in patients with atrial fibrillation and heart failure with reduced ejection fraction. This benefit is more significant in patients with reduced ejection fraction. This may be due to restoration of the atrial contraction, or more favourable heart rate control.