4D Digital Heart Model–Guided Left and Right Ventricular Lead Placement for Cardiac Resynchronization Therapy: Results of MAPIT-CRT Trial
Bibliographic record
Abstract
BACKGROUND: Suboptimal left ventricular (LV) and right ventricular lead positioning has been associated with a lesser response to cardiac resynchronization therapy. The MAPIT-CRT (MRI Allocation of Pacing Targets in Cardiac Resynchronization Therapy) randomized controlled trial evaluated a novel, cardiac magnetic resonance–generated 4-dimensional phenomics cardiac magnetic resonance imaging (4DPcmr) lead placement strategy. METHODS: A total of 202 participants with New York Heart Association class II to IV heart failure on optimal medical therapy, LV ejection fraction ≤35%, and QRS duration ≥120 ms were analyzed from 7 Canadian sites. Participants were randomized to 4DPcmr-guided lead placement using a web-based application or standard lead placement. 4DPcmr-recommended LV and right ventricular (RV) lead locations were generated using the combined consideration of (1) regional scar distribution and burden, (2) maximal regional delay in LV peak systolic strain, and (3) maximal interlead distance. RESULTS: The primary end point, an increase in LV ejection fraction ≥5% at 6 months, was reached in 69 of 105 4DPcmr-guided participants (65.7%) versus 50 of 96 control participants (52.1%; risk ratio, 1.80 [95% CI, 1.02–3.17]; P =0.04). The absolute increases in LV ejection fraction observed for the respective study arms were 10.8% versus 5.8% ( P =0.01). No differences were identified in the secondary end points of all-cause mortality or heart failure hospitalization at 12 months, rate of adverse outcomes, or procedural times between the 2 study arms. CONCLUSIONS: 4DPcmr-guided LV/RV cardiac resynchronization therapy lead implantation using a practical web application was clinically feasible, safe, and was associated with greater LV ejection fraction improvement at 6 months versus standard of care with no increase in procedural times or complications. REGISTRATION: URL: https://clinicaltrials.gov/study/NCT01640769 ; Unique identifier: NCT01640769.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".