Withdrawal of Heart Failure Treatment Patients With Non-ischemic Cardiomyopathy Who Have Been Super-responders to Cardiac Resynchronization Therapy.

Inclusion Criteria: * Diagnosis of non-ischemic cardiomyopathy * LBBB already present at the time of first diagnosis of LV dysfunction * Negative genetic test * Cardiac MRI with no evidence of late gadolinium enhancement (LGE at RV insertion points is acceptable) * Carrier of a resynchronization device (ICD or pacemaker, with LV epicardial pacing form a cardiac vein or left bundle area pacing), pacing percentage \>95% and paced QRS \<140 ms * Device indication: LVEF ≤35% and LBBB with QRS \>150 ms * LVEF ≥50% and normal indexed LV volumes on echocardiogram performed at least 6 months after CRT implantation * No heart failure decompensations (no hospitalizations or urgent/day hospital visits) since CRT implantation * No need for loop diuretic treatment * NYHA class I or II * NT-proBNP \<450 ng/L (or \<1000 ng/L in atrial fibrillation/flutter) * On neurohormonal therapy with at least two drugs Exclusion Criteria: * Family history of non-ischemic cardiomyopathy with LVEF \<50% in at least one first-degree relative * Severe valvular heart disease * History of sustained ventricular arrhythmia or treated by ICD * Need to maintain beta-blocker therapy for other arrhythmias * Hypertension not controlled with other medications * CRT devices implanted as an upgrade from prior pacemaker or ICD, where prior pacing percentage was \>20% * Clinical indication other than heart failure to maintain any of the neurohormonal treatment drugs (class I recommendation in ESC or ACC/AHA guidelines)