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Updated: May 23, 2025
Evaluation of Left Ventricular Structure and Function using 3D Echocardiography
Published on: October 28, 2020
Complementary classification of hypertrophic cardiomyopathy using unsupervised cluster analysis on left ventricular
Dandan Sun1,2, Xingyu Fang1,2, Yuzhu Zhang1,2
1Department of Ultrasound, The People's Hospital of China Medical University, The People's Hospital of Liaoning Province, Shenyang, 110067, China.
Insights
Researchers identified two hypertrophic cardiomyopathy (HCM) subtypes based on left ventricular function. Subtype 1 HCM patients showed impaired function and higher atrial fibrillation risk, aiding personalized treatment for hypertrophic cardiomyopathy.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Imaging
Background:
- Current hypertrophic cardiomyopathy (HCM) classification relies on hypertrophy site and outflow tract obstruction.
- A functional classification could improve risk stratification and management for HCM patients.
Purpose of the Study:
- To develop a complementary classification for hypertrophic cardiomyopathy (HCM) based on left ventricular (LV) function.
- To identify distinct HCM subtypes with varying cardiovascular risks and inform individualized treatment strategies.
Main Methods:
- Utilized multi-dimensional echocardiographic parameters (conventional, TDI, STE) in 266 HCM patients and 169 healthy controls.
- Employed principal component analysis and unsupervised cluster analysis to define HCM subtypes based on LV function.
- Compared clinical variables and evaluated prognosis, specifically atrial fibrillation risk, between identified subtypes.
Main Results:
- Two HCM subtypes were identified: Subtype 1 (n=123) and Subtype 2 (n=143).
- Both subtypes exhibited impaired LV diastolic and systolic function compared to controls, with greater decline in Subtype 1.
- Subtype 1 HCM showed distinct functional characteristics (e.g., increased strain, decreased untwist rate) and a significantly higher risk of atrial fibrillation (HR: 4.34).
Conclusions:
- Stratified HCM patients into two functional subtypes with differential diastolic and systolic performance.
- Subtype 1 HCM is associated with poorer cardiac function and increased susceptibility to atrial fibrillation.
- This functional classification offers a potential tool for targeted management of hypertrophic cardiomyopathy.
Abstract:
Contemporary classification of hypertrophic cardiomyopathy (HCM) was mainly based on the site of myocardial hypertrophy and left ventricular outflow tract obstruction. A complementary classification based on left ventricular function could provide a powerful tool to identify individuals with high risk of adverse cardiovascular outcomes and guide individualized managements. Multi-dimensional echocardiographic parameters of left ventricular function derived from conventional echocardiography, tissue Doppler imaging, and speckle tracking echocardiography were obtained in 266 HCM patients and 169 healthy controls (HCs). According to these parameters, HCM subtypes were calculated by principal component analysis and unsupervised cluster analysis. Variables of different groups were compared. The prognosis between HCM subtypes were evaluated. There were two HCM subtypes generated, subtype 1 HCMs (n = 123) and subtype 2 HCMs (n = 143). Compared to HCs, left ventricular diastolic and systolic function were significantly declined to varying degrees in both subtype 1 HCMs and subtype 2 HCMs, especially in subtype 1 HCMs (all P value < 0.001). Subtype 1 HCMs characterized as increased LAVI and E/E', decreased mean E' and untwist rate, increased global and segmental longitudinal strains, circumferential strains and radial strains, decreased rotation degree, twist degree, and twist rate, in comparison with subtype 2 HCMs (all P value < 0.001). Notably, subtype 1 HCMs were more susceptible to adverse prognosis of atrial fibrillation (HR: 4.34; 95% CI 1.08-17.53; P value: 0.039). Collectively, we stratified HCM patients into two subtypes with different diastolic and systolic performance and risk of atrial fibrillation. This complementary classification might eventually help to target management of HCM patients who would benefit most.
