Very Late Continued Reverse Remodelling After Cardiac Resynchronization Therapy in Patients With Extreme Left Ventricular Dilatation.

Response to cardiac resynchronization therapy (CRT) varies greatly among patients. We present 2 patients with severe heart failure symptoms (New York Heart Association class IV) and extreme initial left ventricular (LV) dilatation (LV end-diastolic diameter of 92 mm and 80 mm, respectively) and severe functional mitral regurgitation who underwent CRT device implantation. Long-term follow-up showed late (≥ 4 years) normalization of LV ejection fraction (LVEF), LV dimensions, and functional status. In a subgroup of patients with nonischemic dilated cardiomyopathy and complete left bundle branch block, late continued LV reverse remodelling may lead to normalization of LV volumes and LVEF and significant improvement in functional class.