2026Arrhythmias & devicesHeart failure210 patients

MAPIT-CRT

Therapy group: Cardiac resynchronization therapy · Therapy: 4D cardiac MRI-guided lead placement vs standard

4D cardiac MRI-guided ventricular lead placement was feasible and safe and produced greater ejection fraction improvement at 6 months, without differences in mortality or heart failure hospitalization.

Published in Circ Arrhythm Electrophysiol (2026)

Question: Does placing the left and right ventricular leads using a cardiac MRI-derived 4D digital heart model improve response to cardiac resynchronization therapy compared with standard lead placement?
Design: Randomized multicenter trial at 7 Canadian sites, with masking per the registry. 202 participants were analyzed (the registry reports 210 enrolled).
Population: Adults with NYHA class II to IV heart failure on optimal medical therapy, LV ejection fraction ≤35%, and QRS duration ≥120 ms.
Intervention: LV and RV lead placement at the locations recommended by the 4DPcmr model through a web application. The recommendation combines regional scar distribution and burden, maximal regional delay in LV peak systolic strain, and maximal interlead distance.
Control: Standard LV and RV lead placement.
Primary outcome: Increase in LV ejection fraction of ≥5% at 6 months.
Results: The primary end point was reached in 69 of 105 guided participants (65.7%) versus 50 of 96 controls (52.1%); risk ratio 1.80 (95% CI 1.02-3.17; P=0.04). Absolute LV ejection fraction gains were 10.8% versus 5.8% (P=0.01).
Safety: No differences in adverse outcomes or procedural times between the arms.
Conclusion: 4DPcmr-guided lead placement was feasible and safe, and was associated with greater LV ejection fraction improvement at 6 months than standard placement.
Why it matters: It suggests that individualizing implant sites according to scar and mechanical dyssynchrony may improve resynchronization response without complicating the procedure. A benefit on hard clinical outcomes was not demonstrated in this trial.

Card generated automatically with AI from the abstract of the original publication and the trial registry; every figure was checked against those sources. It may contain errors: verify the data at the source before using it for clinical decisions.

Generated on October 14, 2026

Sources

Original publication on PubMed (PMID 41446931) ↗4D Digital Heart Model-Guided Left and Right Ventricular Lead Placement for Cardiac Resynchronization Therapy: Results of MAPIT-CRT Trial.
Journal article (DOI) ↗
ClinicalTrials.gov record (NCT01640769) ↗

Videos explaining it

Heart Rhythm TV Update: The MAPIT-CRT Randomized Clinical Trial

HRS · Heart Rhythm TV ↗4:01Video page

Source: Heart Rhythm TV · YouTube
Date: 26 Apr 2025
Audio: English
Subtitles: MultilingualYouTube
Audio transl.: Unconfirmed · check ⚙YouTube

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Podcasts explaining it

Episode 17: The MAPIT-CRT Randomized Clinical Trial
HRS · Heart Rhythm TV Podcast ↗4 minEpisode page
Source
HRS · Apple Podcasts
Date
1 May 2025
Audio
English
Translation
TextGoogle Chrome
Audio transl.
None

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