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 two 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 (IQR: 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<0.001). SHAP 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<0.001), 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 AUC 0.73 vs. 0.63, p=0.005). 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<0.001), 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.
S. Kwak, Younghyun Kang, Ji-Hyun Kim et al.· Journal of the American Soci...· 0 citations
BACKGROUND
Atrial fibrillation (AF) is pervasive and an independent driver of stroke and death in hypertrophic cardiomyopathy (HCM). Despite guideline recommendations for AF surveillance, effective risk stratification remains elusive, and the hemodynamic and functional states of the left atrium (LA) preceding AF onset remain poorly characterized.
OBJECTIVES
We aimed to delineate the hemodynamic and functional states of the LA in HCM, derive a novel LA staging system, and evaluate its prognostic performance for new-onset atrial fibrillation (NOAF).
METHODS
This multicenter retrospective study included consecutive HCM patients with normal left ventricular systolic function from January 2007 to February 2024 at 2 academic referral centers. Patients with valvular heart disease or prior AF were excluded. Patients were categorized by combining the presence of elevated LA pressure (hemodynamic load) and LA contractile strain (intrinsic LA function): stage 1 (normal LA pressure and function), stage 2 (relative contractile augmentation for a given LA pressure), stage 3 (loss of relative contractile augmentation despite elevated LA pressure), stage 4 (elevated LA pressure with decreased LA contractile strain), and isolated LA contractile dysfunction. The primary outcome was NOAF. External validation was conducted in an independent HCM cohort.
RESULTS
Of 1,856 patients screened, 705 were eligible (mean age 57.6 ± 13.0 years, 30.1% female). During a median follow-up of 7.5 years (Q1-Q3: 3.6-11.0 years), NOAF occurred in 101. The staging system was independently associated with a significant, stepwise increase in the risk of NOAF (adjusted HR: 1.83 per increment; 95% CI: 1.42-2.37; P < 0.001) and conferred incremental predictive value beyond established risk models (CHARGE-AF and HCM-AF). Consistent results were demonstrated in 1-year landmark and competing-risk analyses, as well as in an external validation cohort (n = 425; age 59.7 ± 13.5 years, 33.9% female). Importantly, serial echocardiography performed in 217 patients 4 to 6 years after baseline revealed a predominantly unidirectional evolution of the proposed LA stage, with most patients remaining stable (39.6%) or progressing to higher stages or AF (43.8%).
CONCLUSIONS
The proposed LA staging framework offers mechanistic insights into how the LA adapts to progressive diastolic dysfunction in HCM. It is associated with a graded risk of NOAF and may help tailor AF surveillance strategies.
Jaehyun Lim, I. Hwang, Ji-Hyun Kim et al.· Journal of the American Coll...· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
