The Right Ventricular Septum Presents the Optimum Site for Maximal Electrical Separation During Left Ventricular Pacing
Bibliographic record
Abstract
UNLABELLED: Cardiac resynchronization therapy (CRT) benefits selected heart failure (HF) patients. The optimal placement of the right ventricle (RV) lead during biventricular pacing has not been assessed. Greater electrical separation (ES) between left ventricle (LV) and RV leads has been associated with better clinical outcomes. The site of maximal electrical separation(MES) in the RV is unknown. METHODS: Prospective study of 50 CRT patients. The LV lead was placed in a postero-lateral branch of the coronary sinus. ES was recorded at 6 sites within the RV during LV pacing at 600 milliseconds cycle length (CL). The median ES was recorded with a roving deflectable catheter at the RV outflow tract (RVOT), high septum, inflow septum, mid-septum, apical septum and apex. RESULTS: Mean age was 67 ± 7 years, 39 were male (78%). Thirty had ischemic etiology (60%). Mean left ventricular ejection fraction (LVEF) was 25 ± 7%, QRS duration pre and post was 165 ± 26 milliseconds and 138.5 ± 15.6 milliseconds (P < 0.001). Mapping ES showed a difference between 20 and 50 milliseconds distributed across the RV in the majority of patients (40/49). However, 7 subjects demonstrated delay distribution of between 50 and 82 milliseconds. ES was significant greater in the RV mid-septum (161.2 ± 23.7 milliseconds) compared with RVOT (154.1 ± 20.8 milliseconds) and apex (148.0 ± 25.5 milliseconds; P < 0.001). The site of Maximal ES was most commonly found at the mid-septum (40 patients, 80%) and only rarely at the RVOT (5, 10%) and apex (5, 10%; P < 0.01). CONCLUSION: MES was observed most commonly at the RV septum and rarely at the RV apex. Better correction of electrical and mechanical dyssynchrony by CRT may be achieved by placing the RV lead in a site outside of the apex in the majority of patients. Clinical studies exploring RV septal pacing in CRT seem warranted.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".