Cardiac remodeling in patients with atrial fibrillation reversing bradycardia-induced cardiomyopathy: A case report.

Background: Bradycardia-induced cardiomyopathy (BIC), which is a disease resulting from bradycardia, is characterized by cardiac chamber enlargement and diminished cardiac function. The correction of bradycardia can allow for significant improvements in both cardiac function and structure; however, this disease has been infrequently documented. In this case, we conducted a longitudinal follow-up of a patient who had been enduring BIC for more than 40 years to heighten awareness and prompt timely diagnosis and rational intervention.

Case Summary: A woman who presented with postactivity fatigue and dyspnea was diagnosed with bradycardia at the age of 7. Since she had no obvious symptoms, she did not receive any treatment to improve her bradycardia during the 42-year follow-up, except for the implantation of a temporary pacemaker during labor induction surgery. As time progressed, the patient's heart gradually expanded due to her low ventricular rate, and she was diagnosed with BIC. In 2014, the patient developed atrial fibrillation, her ventricular rate gradually increased, and her heart shape gradually returned to normal. This report describes the cardiac morphological changes caused by the heart rate changes in BIC patients older than 40 years, introduces another possible outcome of BIC, and emphasizes the importance of early intervention in treating BIC.

Conclusion: BIC can induce atrial fibrillation, causing an increased ventricular rate and leading to positive cardiac remodeling.