Impact of cardiovascular magnetic resonance assessment of ejection fraction on eligibility for implantable cardioverter defibrillators
Bibliographic record
Abstract
To determine whether cardiovascular magnetic resonance (CMR) for left ventricular ejection fraction (LVEF) assessment changes implantable cardioverter defibrillator (ICD) eligibility when compared with echocardiography. A markedly reduced LVEF is considered an indication for ICD placement for the primary prevention of sudden cardiac death. However, despite strict LVEF criteria, most guidelines do not specify the technique by which LVEF should be measured. The study population consisted of patients referred for LVEF measurement by CMR, for consideration of ICD implantation, who also underwent echocardiography within 30 days of the CMR. LVEF was assessed on echocardiography using Simpson’s biplane method. LVEF was determined from CMR based on manual planimetry of SSFP cine images of contiguous left ventricular short axis slices. CMR and echocardiography derived LVEFs were reported by two independent blinded observers. Forty-nine (49) eligible patients were identified (10 female, mean age 61 +/- 15 years, 24 with ischemic etiology) who underwent CMR between March 20, 2007 and Aug 12, 2010. The median number of days between CMR and echo was 3 (IQR 1 to 10 days). The mean LVEF by CMR and echo was 31 +/- 15 %, and 34 +/- 15%, respectively, (p =0.009), with a correlation coefficient (r) between the two of 0.86. Using Bland Altman analysis, the mean difference (CMR - echo) was - 3.1 % with limits of agreement of - 18 to 12 %. CMR resulted in reclassification regarding ICD eligibility in 10 (20 %) patients using an LVEF threshold of 35 %, and 8 (16 %) using an LVEF threshold of 30 %. Tables 1 and 2 . In this cohort of patients being considered for ICD implantation, echocardiography systematically over-estimated LVEF. Using strict LVEF criteria, CMR changed the eligibility for ICD in a substantial proportion of patients, with, in most cases, CMR determining that the patient was ICD eligible when they were not based on echocardiography.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.016 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.001 |
| 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".