Relationship Between QT Interval and Outcome in Low‐Flow Low‐Gradient Aortic Stenosis With Low Left Ventricular Ejection Fraction
Bibliographic record
Abstract
Background QT interval has been shown to be associated with cardiovascular events. There is no data regarding the association between QT interval and left ventricular ( LV ) function and prognosis in patients with low LV ejection fraction ( LVEF ), low‐flow, low‐gradient aortic stenosis ( LF ‐ LG AS ). We aimed to examine the relationship between corrected QT interval ( QT c ) and LV function and outcome in these patients. Methods and Results Ninety‐three patients (73±10 years; 74% men) with LF ‐ LG AS (mean gradient <40 mm Hg and indexed aortic valve area ≤0.6 cm 2 /m 2 ) and reduced LVEF (≤40%) were prospectively included in this analysis and 63 of them underwent aortic valve replacement within 3 months following inclusion. Prolonged QT c was defined as QT c >450 ms in men and >470 ms in women. LV global longitudinal strain was measured by speckle tracking and expressed in absolute value |%|. QT c correlated with the following: global longitudinal strain ( r =−0.40, P =0.005), LVEF ( r =−0.27, P =0.02), stroke volume ( r =−0.35, P =0.007), and B‐type natriuretic peptide ( r =0.45, P =0.0006). During a median follow‐up of 2.0 years, 49 patients died. Prolonged QT c was associated with a 2‐fold increase in all‐cause mortality (hazard ratio=2.05; P =0.01) and cardiovascular mortality (hazard ratio=1.89; P =0.04). In multivariable analysis adjusted for Euro SCORE , aortic valve replacement, previous myocardial infarction, LVEF , and ß‐blocker medication, prolonged QT c was independently associated with all‐cause mortality (hazard ratio=2.56; P =0.008) and cardiovascular mortality (hazard ratio=2.50; P =0.02). Conclusions In patients with LF ‐ LG AS and reduced LVEF , longer QT c interval was associated with worse LV function and increased risk of death. Assessment of QT c may provide a simple and inexpensive tool to enhance risk stratification in LF ‐ LG AS patients. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 01835028.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".