Impact of pulmonary vein isolation on left bundle branch block following tachycardia-induced cardiomyopathy in a patient with persistent atrial fibrillation.

A 61-year-old man was referred to our hospital with exertional dyspnea. Electrocardiography showed atrial fibrillation (AF) with a heart rate of 116 bpm and left bundle branch block (LBBB). Chest radiography demonstrated pulmonary congestion and cardiomegaly with a cardiothoracic ratio of 57%. Transthoracic echocardiography revealed a severely reduced left ventricular systolic function (ejection fraction: 32%), suggesting tachycardia-induced cardiomyopathy (TIC) due to AF. Following treatment for congestive heart failure and complete isolation of each pulmonary vein, the LBBB disappeared, with a complete recovery of the cardiac systolic function. This report describes a case of transient reversible LBBB associated with systolic dysfunction treated with catheter ablation.