Cardiac resynchronisation therapy for reversal of new-onset left bundle branch block and heart failure after surgical aortic valve replacement.

Left bundle branch block (LBBB) is not an uncommon complication following both surgical aortic valve replacement and transcatheter aortic valve implantation. LBBB can cause interventricular and intraventricular dyssynchrony that can lead to development of heart failure as demonstrated by a decline in left ventricular ejection fraction (LVEF). It is known that change in QRS duration has significant correlation with change in LVEF. In a study involving 202 consecutive patients with no baseline ventricular conduction disturbances or previous permanent pacemaker implantation who underwent transcatheter aortic valve replacement (TAVR) with a balloon-expandable valve, it was found that around 30% of patients develop new LBBB.