Original The role of early cardiac resynchronization therapy implantation in dilated cardiomyopathy patients with narrow QRS carrying lamin A/C mutation

Background: Dilated cardiomyopathy (DCM) caused by Lamin A/C gene (LMNA) mutation is complicated with atrioventricular conduction disturbances, malignant ventricular arrhythmias and progressive severe heart failure. Objective: We hypothesized that early cardiac resynchronization therapy (CRT) implantation in LMNA mutation carriers with an established indication for pacemaker or implantable cardioverter defibrillator (ICD), may preserve ejection fraction, and delay disease progression to end stage heart failure. Methods: We compared the primary outcomes: time to heart transplantation, death due to end stage heart failure or ventricular tachycardia (VT) ablation and secondary outcomes: change in left ventricular ejection fraction (EF) and ventricular arrhythmia burden between LMNA DCM patients in the early CRT and non-CRT groups. Results: Of ten LMNA DCM patients (age 51 +/- 10 years, QRS 96 +/- 14 msec, EF 55 +/- 7%) with indication for pacemaker or ICD implantation, five underwent early CRT-D implantation. After 7.2 +/- 4 years, three patients (60%) in the non-CRT group reached the primary outcome, compared to no patients in the CRT group (P=0.046). Four patients in non-CRT group (80%) experienced sustained ventricular tachycardia or received appropriate ICD shock compared to 1 patient (20%) in the CRT group (P=0.058). LMNA patients without early CRT had a higher burden of VPC/24 h in 12-lead holter (median 2352 vs 185, P=0.09). Echocardiography showed statistically lower LVEF in the non-CRT group compared to CRT group [(32 +/- 15)% vs (61 +/- 4)%, 95% CI: 32.97-61.03, P=0.016]. Conclusion: Early CRT implantation in LMNA cardiomyopathy patients, with an indication for pacemaker or ICD, may reduce heart failure deterioration and life-threatening heart failure complications.