Perinatal Cardiac Functional Adaptation in Hypoplastic Left Heart Syndrome: A Longitudinal Analysis
Bibliographic record
Abstract
Background The perinatal transition is characterized by acute changes in cardiac loading. Compared with normal newborn combined cardiac output (CCO), single right ventricular (RV) output of neonates with hypoplastic left heart syndrome (HLHS) is markedly greater. The aim of this study was to examine the mechanisms of cardiac adaptation that facilitate this perinatal transition from late fetal to early neonatal life in HLHS. Methods Prospectively recruited pregnancies complicated by fetal HLHS ( n = 35) and healthy control subjects (Ctrl; n = 17) underwent serial echocardiography in late gestation (38 ± 1 weeks) and 6, 24, and 48 hours after birth. Cardiac function was assessed using conventional, Doppler tissue, and speckle-tracking echocardiography. Results Term fetuses with HLHS had RV output comparable with Ctrl CCO via higher stroke volume. Compared with both left ventricular and RV indices of Ctrl, they exhibited globular and dilated right ventricles with reduced relative wall thickness (0.40 ± 0.08 vs 0.49 ± 0.10, P < .01), increased Tei index′ (HLHS vs Ctrl left ventricle/Ctrl right ventricle: sphericity index, 0.9 ± 0.25 vs 0.5 ± 0.10/0.6 ± 0.11; RV area index, 28 ± 6 vs 15 ± 3/17 ± 5 cm 2 /m 2 ; Tei index′, 0.65 ± 0.11 vs 0.43 ± 0.07/0.45 ± 0.09; P < .0001 for all). Neonates with HLHS generated elevated RV cardiac output compared with Ctrl CCO via higher heart rate and stroke volume, with further RV dilatation, increased longitudinal systolic strain at 48 hours (−17 ± 4% vs −14 ± 3%/ 14 ± 5%) with reduced circumferential and rotational myocardial deformation and altered diastolic function. Neonates with HLHS also demonstrated right atrial enlargement with increased longitudinal strain: 6 hours (33 ± 12% vs 26 ± 6%), 24 hours (37 ± 15% vs 26 ± 13%), and 48 hours (38 ± 11% vs 24 ± 13%) ( P < .0001). Conclusions Term fetuses with HLHS exhibit altered RV geometry and RV systolic and diastolic functional parameters. After birth, further alterations in these cardiac parameters likely reflect adaptation to acutely altered RV loading from increasing cardiac output and pulmonary artery flow demands.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".