Scott Buzby , 2025-05-08 13:51:00
Key takeaways:
- 4D model-guided cardiac resynchronization lead placement improved left ventricular function vs. standard care.
- Quality of life and physical function were not significantly different between the groups.
A 4D imaging, MRI-guided approach to lead placement for cardiac resynchronization therapy was not only feasible and safe but demonstrated significant improvement in left ventricular function vs. standard care, a speaker reported.
The results of the multicenter MAPIT-CRT trial were presented at Heart Rhythm 2025.
Derek S. Chew
“CRT reduces morbidity and mortality in select patients with heart failure; however, despite our traditional selection criteria, including wide QRS, NYHA class II to IV as well as low ejection fraction, a substantial proportion of people don’t respond to CRT,” Derek S. Chew, MD, MSc, cardiac electrophysiologist at Libin Cardiovascular Institute, University of Calgary, Alberta, Canada, said during the presentation. “The reasons for CRT response are multifactorial, but could be broadly divided into preprocedural factors, which include bundle branch morphology, QRS with the etiology of cardiomyopathy, ischemic vs. nonischemic and the presence of [right ventricle] dysfunction. Intraprocedural as well as postprocedural determinants include percentage biventricular pacing, [atrioventricular] delays and the device programming itself and offsets.”
The aim of the study was to assess whether a web-based MRI navigation tool for LV and RV lead placement during CRT implant would improve response to CRT for adult patients with LVEF less than 35%, QRS of 120 milliseconds or more and NYHA class II to IV who were on optimal HF medical therapy.
Utilizing MRI data, the web-based application conducted a 4D myocardial deformation analysis and provided algorithmic selection of optimal LV and RV lead targets based on the lowest regional late gadolinium enhancement scar burden, greatest mechanical delay and greatest inter-lead distance.
Overall, 210 patients undergoing CRT implant at seven sites in Canada were randomly assigned to standard care or MRI-guided CRT implant (median age, 69 years; 31% women; 45% with ischemic etiology).
The primary endpoint was a 5% or more improvement in LVEF at 6-month follow-up. The secondary exploratory endpoints included all-cause death, HF hospitalization, ventricular arrhythmia and quality of life assessed using EQ-5D and Minnesota Living with Heart Failure questionnaire scores at 12 months.
At 6 months, a greater proportion of patients assigned to MRI-guided CRT implant had LVEF improvement of 5% or more compared with standard care (65.7% vs. 51.6%; OR = 1.8; 95% CI, 1.02-3.17; P = .04).
Chew and colleagues reported that 4D model-guided CRT implant was associated with a median 5.2-point increase in LVEF vs. standard care (95% CI, 1.1-9.3; P = .01).
The researchers reported no significant difference between the two groups for any of the secondary endpoints as well as change in 6-minute walk test.
“This 4D modeling approach to CRT implantation is feasible, safe and facilitates personalized delivery of both LV and RV leads. The big advantage to this technique is that it requires no technical complexity. It’s a web-based app. There are no intraprocedural fusion image overlays required. This can be done using routine cardiac MRI data, and the process has been improved where automated model preparation is now available through an AI pipeline,” Chew said during the presentation. “The 4D phenomics-guided CRT approach resulted in significantly greater ejection fraction improvement vs. standard care.”
During a discussion after the presentation, Yong-Mei Cha, MD, cardiac electrophysiologist and director of cardiac device services at Mayo Clinic, said: “4D MRI-guided LV lead placement is a useful technology to enhance CRT outcomes, with a greater LVEF improvement compared with standard CRT in patients with severe HFrEF left bundle branch block and on optimal guideline-directed medical therapy. Further analysis may provide insight on MRI-guided best lead location and the actual lead location because of the limitation of the [coronary sinus] anatomy. The audience will look forward to the potential long-term comparative outcomes from the study.”
Sources/Disclosures
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Chew DS, et al. Late-breaking clinical trials and science: Randomized clinical trials. Presented at: Heart Rhythm 2025; April 24-27, 2025; San Diego.
Disclosures:
Cha reports receiving grant support from Medtronic. Chew reports serving as an independent contractor for UIT Limited Partnership, an entity of the University of Calgary.
