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

Study of MRI-guided choices for pacing devices in heart failure

Age
18 years or above
Gender
All
participants needed
114
Locations
6
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Brief description of study

This randomized study aimed to compare the efficacy of LBBP without defibrillator vs biventricular pacing with defibrillator (BiV-ICD/CRT-D) in patients with LB-NICM and left ventricular ejection fraction (LVEF) ≤35% risk categorized by CMR imaging.

Detailed description of study

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 ?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.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Non Ischemic Cardiomyopathy
  • Age: 18 years or above
  • Gender: All

Inclusion Criteria:

  1. Patients with age ≥18 years
  2. Typical left bundle branch block as defined by Strauss criteria with LVEF ≤35%
  3. Heart failure symptoms despite guideline directed medical therapy (GDMT)

Exclusion Criteria:

  1. Patients with angiographic evidence of significant coronary artery disease requiring revascularisation. In patients with significant CAD, LVEF will be re-assessed 3 months after revascularisation to decide about CRT
  2. Patients with associated uncorrected congenital or valvular heart disease
  3. Expected life-expectance of <12 months due to associated comorbidities
  4. Patients with contrast allergy
  5. Baseline non-LBBB morphology
  6. Renal dysfunction which limits the acquisition of CMR with contrast
  7. Pregnant or lactating women
  8. Patients who are unable to comply with study protocol

The purpose of this research study is to learn whether one type of heart pacing treatment works as well as another in adults with heart failure who have a typical left bundle branch block and a weak pumping heart (left ventricular ejection fraction of 35% or less), despite guideline-directed medicines. The study uses a heart MRI scan with contrast dye to sort people into lower-risk or higher-risk groups based on whether there is heart muscle scarring.

Participants will have a cardiac MRI scan with gadolinium contrast dye to look for scar in the heart muscle. Based on the scan, participants will be placed into a low-risk group (no scar) or a high-risk group (scar present). Participants in the low-risk group will receive a pacing device without a defibrillator lead, using left bundle branch pacing. Participants in the high-risk group will receive biventricular pacing with a defibrillator. If placing a lead through the coronary sinus is not successful, a left bundle branch pacing lead will be implanted instead. For participants who receive a defibrillator lead, it will be placed in the right ventricle near the tip of the heart (apical septum).

Who can participate:
Adults with heart failure may be able to participate if they:

  • Are age 18 years or older
  • Have typical left bundle branch block and a left ventricular ejection fraction of 35% or less
  • Have heart failure symptoms despite guideline-directed medical therapy

Updated on 28 Aug 2026. Study ID: MADURAI CRT

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