Prevalence of diastolic dysfunction in patients with unexplained left ventricular hypertrophy consistent with a hypertrophic cardiomyopathy phenotype

Background

Diastolic dysfunction is a key determinant of symptoms and disease severity in hypertrophic cardiomyopathy (HCM). However, its prevalence and echocardiographic correlates in patients with unexplained left ventricular hypertrophy (LVH) consistent with an HCM phenotype remain insufficiently defined.

Purpose

To determine the prevalence of diastolic dysfunction using ASE/EACVI criteria and to evaluate its association with biomarkers and cardiac remodeling in patients with unexplained LVH consistent with an HCM phenotype.

Methods

A total of 193 patients with unexplained LVH consistent with an HCM phenotype were included. Unexplained LVH was defined as a left ventricular wall thickness ≥15 mm not attributable to loading conditions, or >13 mm in individuals with a genotype-positive first-degree relative.

Diastolic function was classified according to 2016 ASE/EACVI recommendations as normal, indeterminate, or diastolic dysfunction. Clinical variables, NT-proBNP levels, and comprehensive echocardiographic parameters including left atrial volumes and strain were compared across groups.

Results

According to ASE/EACVI criteria, 51.8% of patients (n=100) had normal diastolic function, 29.0% (n=56) had indeterminate diastolic function, and 19.2% (n=37) had overt diastolic dysfunction (Table 1).

Worsening diastolic function was associated with a stepwise increase in NT-proBNP levels (p<0.001) and progressive left atrial structural and functional remodeling, including reduced left atrial emptying fraction and impaired reservoir, conduit, and contractile strain (all p<0.001).

Patients with diastolic dysfunction were older and exhibited greater myocardial hypertrophy and impaired relaxation parameters. RV strain parameters showed mild but statistically significant differences without a consistent stepwise pattern, suggesting limited clinical relevance. Although GLS differed significantly across groups, the absolute magnitude of impairment was modest, consistent with early systolic involvement accompanying progressive diastolic deterioration.

Conclusion

In patients with unexplained LVH consistent with an HCM phenotype, approximately one-fifth exhibit overt diastolic dysfunction, while nearly half demonstrate abnormal or indeterminate diastolic function patterns. Diastolic dysfunction is closely linked to elevated NT-proBNP levels and advanced left atrial structural and functional remodeling, reflecting phenotypic disease severity rather than genetic status alone. These findings support the routine use of guideline-based diastolic function assessment for phenotypic risk stratification in patients with unexplained LVH.For image description, please refer to the figure legend and surrounding text.