Heart Rate <i>per se</i> Impacts Cardiac Function in Patients with Systolic Heart Failure and Pacing: A Pilot Study
Bibliographic record
Abstract
AIMS: This study was designed to compare the specific effects of two heart rates (HR), 55 and 75 b.p.m., in patients with heart failure (HF). METHODS AND RESULTS: Patients with chronic HF, left ventricular ejection fraction (LVEF) </= 35%, and a pacemaker with >90% of paced QRS, were included in a randomized cross-over trial of two 3-month periods where pacing rate was set at either 55 or 75 b.p.m. At the end of each period, patients were examined and radionuclide ventriculography, echocardiography, and blood sampling were performed for centralized and blinded analysis. Two patients did not complete the study because of early worsening while paced at 75 b.p.m. Twelve patients completed the study. Compared with 75 b.p.m., pacing at 55 b.p.m. was associated with a higher LVEF [+4.7% (2.6-6.7), P < 0.001], lower B-type natriuretic peptide levels [-91 pg/mL (-148 to -33), P < 0.01], lower systolic pulmonary artery pressure (41 +/- 10 vs. 47 +/- 10 mmHg, P = 0.02) and lower NYHA (New York Heart Association) class (2.2 +/- 0.6 vs. 2.6 +/- 0.5, P = 0.03). The baseline pacing rate prior to inclusion had no effect on results. CONCLUSION: HR per se may impact cardiac function and low HR might be beneficial in patients with systolic HF compared with intermediate HR.
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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 | 0.002 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".