Right ventricular longitudinal strain but not right ventricular ejection fraction in hypertrophic cardiomyopathy associates with sarcomere positive status and adverse phenotypes
Bibliographic record
Abstract
Abstract Background Right ventricular (RV) dysfunction is a well-established prognostic marker in some cardiac diseases, yet its role in hypertrophic cardiomyopathy (HCM) remains under-investigated. Little is known about the impact of pathogenic or likely pathogenic sarcomeric variants on RV function. Objectives We set out to assess the prevalence of RV dysfunction among HCM patients and its association with sarcomeric variant status and markers of sudden cardiac death risk using data from a large prospective cardiac magnetic resonance (CMR) Registry of HCM - the National Heart, Lung, and Blood Institute (NHLBI) Hypertrophic Cardiomyopathy Registry (HCMR). Methods A total of 2,303 patients with hypertrophic cardiomyopathy (HCM) (mean age: 50 ± 11 years; 71.1% male) underwent comprehensive CMR imaging. Three-dimensional right ventricular (RV) longitudinal strain was assessed using cine CMR analysed with in-house feature-tracking software. Baseline genetic, demographic, serum biomarker, and clinical data were used for statistical analysis. Impaired strain was inferred from a reference HCM and control population and defined as 2SD from the control mean. Results 50 (2.2%) patients had impaired RV ejection fraction (RVEF) (< 47% in males, < 49% in females) compared to 501 (21.8%) patients with RV strain impairment (> -6.09%). Impaired RV strain was associated with more adverse phenotypes, higher LV mass index (89 ± 31 g/m2 vs 83 ± 25 g/m2, p = 0.002), increased maximal wall thickness (21.4 ± 5.3 mm vs 20.3 ± 4.6 mm, p < 0.0001), reduced LA contractile function (p < 0.0001), impaired LV global longitudinal strain (p < 0.0001) and higher late gadolinium enhancement (LGE) % (p <0.0001). Impaired RVEF was associated with male sex, lower LA contractile function, yet lower NT-proBNP and decreased maximal wall thickness (19.1 ± 5.9 mm vs 20.6 ± 4.8 mm, p = 0.002). A higher proportion of younger patients with impaired RV strain were sarcomere positive than sarcomere negative (p <0.0001, Fig 1.). Patients with concentric and reverse curvature morphology were more likely to have impaired RV strain (Fig 2.). RV strain, but not RVEF correlated with predicted risks of sudden cardiac death based on ESC HCM risk calculator and AHA risk calculator (p = 0.011). Elastic net regression (Fig 3.) revealed impaired RV strain was associated with larger ventricular volumes, greater extent of LGE, reduced RVEF, LV hypertrophy, impaired LA function, higher baseline Troponin T, and male sex. Conclusion Impaired RV strain is prevalent and associated with sarcomere positive status and more adverse HCM phenotypes in low-risk HCM. RV strain has the potential to be prognostically relevant in HCM risk stratification.Association of RV strain with Phenotype
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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 | 0.001 | 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) | 0.002 | 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".