The Effect of Cardiac Resynchronization Therapy on Left Ventricular Diastolic Function Assessed with Speckle-Tracking Echocardiography
Bibliographic record
Abstract
AIMS: Changes in left ventricular (LV) diastolic function after cardiac resynchronization therapy (CRT) in relation to LV reverse remodelling and heart failure aetiology have not been extensively characterized. The aims of the study were to evaluate changes in LV diastolic function with speckle-tracking echocardiography in relation to: (i) cardiac resynchronization therapy response (LV remodelling) and (ii) heart failure aetiology. METHODS AND RESULTS: A total of 192 heart failure patients undergoing CRT implantation were evaluated. Speckle-tracking echocardiography was performed before and 6 months after implantation and reliable analysis was obtained in 188 patients. Left ventricular diastolic function was assessed by measuring diastolic strain rate during the isovolumic relaxation period (SR(IVR)) and by calculating the ratio of peak transmitral E-wave to SR(IVR) (E/SR(IVR)). Changes in LV diastolic parameters were evaluated in responders and non-responders and in patients with ischaemic and non-ischaemic cardiomyopathy. Response to CRT was defined as ≥15% reduction in LV end-systolic volume at 6 months follow-up. One-hundred and nine patients (58%) were defined as responders. Significant improvements in LV diastolic performance were observed in responders with improvement in SR(IVR) (from 0.14 ± 0.08 to 0.18 ± 0.12 s(-1), P= 0.001) and E/SR(IVR) (from 834 ± 840 to 641 ± 612, P= 0.04). In addition, LV relaxation improved in patients with non-ischaemic aetiology (SR(IVR): from 0.15 ± 0.08 to 0.19 ± 0.13 s(-1), P= 0.004). In contrast, LV relaxation did not improve in non-responders and in patients with ischaemic heart disease. CONCLUSIONS: Novel diastolic strain rate indices are useful for evaluating changes in LV diastolic function after CRT. Improvement in diastolic function was only observed in responders to CRT and patients with non-ischaemic aetiology.
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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 | 0.002 |
| 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 | 0.000 |
| 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".