Influence of Aging on Level and Layer-Specific Left Ventricular Longitudinal Strain in Subjects Without Structural Heart Disease
Bibliographic record
Abstract
Values for level- (apical, mid, and basal) and layer-based (endocardial, mid-myocardial, and epicardial) left ventricular (LV) longitudinal strain across age are scarce. The present study evaluates the effect of aging on level- and layer-specific LV longitudinal strain in subjects without structural heart disease. A total of 408 subjects (mean age 58 years [range 16 to 91]; 49% men) were evaluated retrospectively. Subjects were divided into equal groups based on age and gender. Subjects with evidence of structural heart disease or arrhythmias were excluded. Mean LV ejection fraction was 62 ± 6.2%. A gradual increase in magnitude of level LV longitudinal strain was observed from basal to mid and apical levels (-16.7 ± 2.1%, -18.8 ± 2.0%, -22.6 ± 3.8%; p <0.001, respectively). Across age groups, there was a borderline significant decrease in magnitude of basal longitudinal strain in older subjects, whereas the magnitude in the apical level significantly increased. On layer-based analysis, the magnitude of longitudinal strain increased from epicardium to endocardium across all age groups. On multivariable analysis, only diabetes mellitus was associated with more impaired longitudinal strain in the endocardium, and male gender was associated with more impaired longitudinal strain at the epicardium layer. In conclusion, with increasing age, the magnitude of LV longitudinal strain at the basal level declines while the apical LV longitudinal strain increases. In contrast, layer-specific LV longitudinal strain remains unchanged with aging. The presence of diabetes mellitus modulated the effect of age on the LV endocardial layer, and male gender was associated with more impaired longitudinal strain at the epicardial layer.
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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".