Abstract 9925: Association between Resting Heart Rate, Chronotropic Index and Long-term Outcomes in Patients with Heart Failure Receiving Beta-blocker Therapy. Data from the HF-ACTION Trial
Bibliographic record
Abstract
Aim s: To assess the association between resting heart rate (HR), chronotropic index (CI) and clinical outcomes in patients with chronic heart failure (HF) on optimized β-blocker therapy. Methods: We performed a sub-study in 1118 patients with chronic HF and reduced ejection fraction (EF <35%) who were enrolled in the HF-ACTION trial. We included patients in sinus rhythm who received a β-blocker and who performed an adequate symptom-limited maximum exercise test. Chronotropic Index was calculated as a percentage of predicted maximum HR reserve achieved, by using the equation (220-age) for estimating maximum HR. A sensitivity analysis using an equation estimating maximum HR for patients with HF taking β-blockers [(119 + (resting HR/2) - (age/2) - (5 * bike)] was also performed. Cox proportional hazards models were fit to assess the association between CI and clinical outcomes. Results: Median (25 th , 75 th percentiles) follow-up was 32 (21, 44) months. In a multivariable model including resting HR and CI as continuous variables, neither was associated with the primary outcome of all-cause mortality or hospitalization. However, in multivariable analysis, each 0.1 unit decrease in CI below 0.6 was associated with 17% increased risk of all-cause mortality (Hazard Ratio 1.17, 95% Confidence Interval 1.01-1.36; p=0.036) (figure), and 13% increased risk of cardiovascular mortality or HF hospitalization (Hazard ratio 1.13, 95% Confidence Interval 1.02-1.26; p=0.025). CI did not retain statistical significance when dichotomized at a value ≤0.62 as opposed to analysis of CI as a continuous variable. Sensitivity analysis showed a similar relationship between CI and outcomes. Conclusion: In patients with chronic HF receiving optimal medical therapy, a decrease in CI below 0.6 was associated with the risk of adverse clinical outcomes. These data support a strategy of including improved heart rate response to exercise, as a therapeutic target in the chronic HF population.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".