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Left Atrial Reservoir Strain Improves Sudden Cardiac Death Risk Stratification in Hypertrophic Cardiomyopathy
Soongu Kwak1, Younghyun Kang2, Jihoon Kim3
1Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea; Cardiovascular Center, Seoul National University Hospital, Seoul, Republic of Korea.
Insights
Left atrial reservoir strain (LARS) effectively predicts sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). Integrating LARS improves risk stratification for low-to-intermediate risk HCM patients, enhancing preventive strategies.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Biomedical Engineering
Background:
- Sudden cardiac death (SCD) risk scores in hypertrophic cardiomyopathy (HCM) have limited predictive power for high-risk individuals.
- Left atrial reservoir strain (LARS) is a novel echocardiographic parameter with potential prognostic value.
Purpose of the Study:
- To evaluate the prognostic significance of LARS for SCD-related events in HCM patients.
- To assess the utility of LARS in refining risk stratification for SCD in HCM.
Main Methods:
- Retrospective cohort study of 1,761 HCM patients.
- Analysis of SCD-related events (SCD, aborted SCD, appropriate ICD shocks).
- Machine learning (SHAP) and Cox regression used to determine LARS prognostic value, especially in low-to-intermediate risk groups (HCM Risk-SCD score <6%).
Main Results:
- Decreased LARS (<21%) independently predicted higher SCD-related event risk (aHR 5.01).
- LARS was the top predictor identified by SHAP analysis.
- Adding LARS to the HCM Risk-SCD score significantly improved risk discrimination in low-to-intermediate risk patients (AUC 0.73 vs. 0.63).
Conclusions:
- LARS is an independent predictor of SCD-related events in HCM.
- LARS effectively stratifies risk in HCM patients initially classified as low-to-intermediate risk.
- Incorporating LARS into existing risk scores may enhance SCD prevention strategies.
Background:
Current risk scores for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) have limited ability to identify high-risk subgroups. We aimed to investigate the prognostic value of left atrial reservoir strain (LARS) for SCD-related events and its utility for risk stratification.
Methods:
This retrospective cohort study included 1,761 patients with HCM from 2 referral centers. The primary outcome was SCD-related events, including SCD, aborted SCD, and appropriate implantable cardioverter-defibrillator shocks. Explainable machine learning approaches were used to explore the importance of LARS and identify a clinically relevant threshold. The prognostic value of LARS was evaluated using Cox regression analyses, particularly among patients classified as low-to-intermediate risk (HCM Risk-SCD score <6%).
Results:
During a median follow-up of 6.8 years (interquartile range, 3.0-10.7 years), 69 (3.9%) SCD-related events occurred. Decreased LARS was independently associated with a higher risk of SCD-related events (per 1% decrease; adjusted HR, 1.11; 95% CI, 1.07-1.15; P < .001). SHapley Additive exPlanation analysis identified LARS as the top-ranked predictor and a clinically relevant threshold of <21%. LARS <21% was significantly associated with a higher risk of SCD-related events (adjusted HR, 5.01; 95% CI, 2.77-9.03; P < .001), even among patients without atrial fibrillation. Adding LARS to the HCM Risk-SCD score significantly improved risk discrimination in the low-to-intermediate risk population (5-year time-dependent area under the receiver operating characteristic curve [AUC], 0.73 vs 0.63; P = .005). Among low-to-intermediate risk patients, LARS <21% was associated with a significantly higher risk of SCD-related events (adjusted HR, 6.13; 95% CI, 3.13-12.03; P < .001), whereas the original low- and intermediate-risk categories showed limited risk discrimination.
Conclusions:
LARS was an independent predictor of SCD-related events and effectively stratified risk among patients classified as low-to-intermediate risk by the HCM Risk-SCD score. Integrating LARS into the HCM Risk-SCD score may enhance risk stratification and guide preventive strategies.
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