Abstract Body (Do not enter title and authors here): Background:
Hypertrophic cardiomyopathy (HCM) is a common genetic cardiac disorder with heterogeneous clinical expression. While global data on HCM phenotypes are available, there is a paucity of region-specific data from India.
Objectives:
To characterize the clinical and imaging profile of Indian patients with HCM and assess the correlation between STE-derived GLS, CMR-derived LGE, electrocardiographic abnormalities, indexed LV mass, and left atrial (LA) size.
Methods:
In this cross-sectional study, 150 adult HCM patients were prospectively enrolled at a tertiary care center in North India. All patients underwent clinical evaluation, 12-lead ECG, 24-hour Holter monitoring, transthoracic echocardiography including STE-derived GLS, and tissue Doppler imaging. CMR was performed in 74 patients. GLS and LGE were quantified using vendor-specific software. Indexed LV mass and LA diameter were recorded. Correlations were assessed using Spearman’s rank coefficient (ρ).
Results:
The mean age was 46.7 ± 13.8 years; 80% were male. Asymmetric septal hypertrophy was the most common phenotype (76%), with obstructive HCM in 53%. Mean indexed LV mass on CMR was 109.5 ± 22.6 g/m². Mean LA diameter was 38.4 ± 4.2 mm, significantly larger in patients with atrial fibrillation (41.2 ± 4.7 mm vs. 38.1 ± 4.0 mm; p = 0.02). STE-derived GLS was reduced (<–20%) in 89% of patients (mean GLS: –12.1% ± 4.1%). CMR revealed LGE in 92% of patients, with extensive fibrosis (LGE ≥15%) in 40.5%. Peak GLS showed a strong positive correlation with percent LGE (ρ = 0.739, p < 0.001), and was significantly lower in those with perfusion deficits (–9.8% vs. –12.2%, p = 0.04). Patients with extensive LGE had significantly higher indexed LV mass (116.4 ± 18.9 g/m² vs. 104.6 ± 22.4 g/m², p = 0.02). Modest inverse correlations were observed between GLS and tissue Doppler velocities (medial e′: ρ = –0.55; lateral e′: ρ = –0.60), and between LA diameter and medial e′ (ρ = –0.41, p < 0.001). GLS was not significantly associated with non-sustained ventricular tachycardia (NSVT, p = 0.18).
Conclusions:
Indian patients with HCM exhibit a high burden of myocardial fibrosis, enlarged left atria, and increased LV mass. STE-derived GLS correlates strongly with CMR-derived fibrosis, indexed LV mass, and diastolic dysfunction, suggesting its potential as a pragmatic surrogate for risk stratification in resource-limited settings. Larger multicenter studies are needed to validate these findings.