Spontaneous resolution of left bundle branch block and biventricular stimulation lead to reverse remodeling in dyssynchronopathy.

Left bundle branch block (LBBB) is considered a marker of underlying structural cardiac disease. To determine whether LBBB is cause or consequence of deterioration of left ventricular (LV) function is difficult as both are often diagnosed concomitantly. We discuss a patient where reversal of LBBB and subsequent normalization of LV function was observed after 2 different therapies, first after start of heart failure medication, and years later after implantation of a cardiac resynchronization device. This indicates that LBBB per se may result in the development of non-ischemic cardiomyopathy and that LBBB resolution can lead to reverse remodeling in dyssynchronopathy.