Magnetic Resonance Imaging Based Risk Stratification for Defibrillator Implantation in Heart Failure Patients Requiring Cardiac Resynchronisation Therapy (MADURAI CRT)

This is a single centre, prospective, randomized study in which patients with LB-NICM, LVEF ≤35% and heart failure despite guideline directed medical therapy (GDMT) will be included. CMR with gadolinium contrast will be performed to risk categorize the patient into low-risk or high risk based on presence of scar. Low risk patients (without scar ?<5%) will be randomized in 1:1 fashion to receive either LBBP without defibrillator or traditional CRT-D with biventricular pacing. LBBP will be performed by premature ventricular complex guided approach with 3830 selectsecure lead and C315His sheath in the proximal interventricular septum 1.5-2 cm distal to His bundle. LBB capture will be confirmed as per standard criteria. If LBBP lead implantation is unsuccessful, a coronary sinus lead will be placed to achieve biventricular pacing. In patients randomized to BiV-ICD, left ventricular lead will be placed in the postero-lateral branch of the coronary sinus with Q-LV duration of >90ms. If coronary sinus lead placement is unsuccessful, a LBBP lead will be implanted. The defibrillator lead will deployed in the right ventricular apical septum.