Hypertrophic cardiomyopathies encompass a heterogeneous group. Atrial strain is becoming increasingly valuable in detecting and quantifying early functional alterations in atrial function in these cardiomyopathies. This atrial deformation can provide previously unknown insights into atrial function and its modifications induced by various etiologies. However, their effects on atrial function and stiffness (Left Atrial Stiffness) have been poorly explored.

We aimed to explore specific alterations in atrial function in hypertrophic cardiomyopathies by evaluating atrial stiffness (LAS/(E/Ea) among different types of left ventricular hypertrophy (LVH). The ultimate goal is to predict the underlying etiology of LVH on cardiac ultrasound through this atrial stiffness.

Our retrospective observational cohort study, conducted at the University Hospital Center of Caen-Normandy from 2020 to 2023 (n=142 patients), focused on adult patients with confirmed etiology of a LVH (LVH≥12mm on ultrasound), including genetic mutation for Fabry disease, sarcomeric hypertrophic cardiomyopathy, cardiac amyloidosis (Any type of amyloidosis, treated or not) or hypertensive cardiomyopathy. Demographic characteristics and biological characteristics were collected. Transthoracic echocardiographic assessments were conducted using ASE/EACVI guidelines (Philips EPIQ®). Atrial strain was retrospectively measured using PHILIPS® QLAB software. 52% of cardiac amyloidosis were in atrial fibrillation, 13% for sarcomeric hypertrophic cardiomyopathy. Statistical analysis (Kruskal-Wallis and Dunn's test) was performed (software R v4) to assess significant differences between groups. ROC curves were generated to differentiate etiologies of LVH.

Significant differences in Left Atrial Stiffness were observed among the groups (Fig. 1). Sarcomeric hypertrophic cardiomyopathy showing an average stiffness of 2.84±2.0, amyloidosis 0.99±0.85, hypertensive cardiomyopathy 3.5±1.4, Fabry disease 2.37±1.68 (P≤0.001). ROC curve analysis for amyloidosis indicated excellent sensitivity and specificity for LAS/(E/Ea)≤1.108 (sensitivity ≈ 89%, specificity ≈ 87%, AUC=0.922).

The presence of left ventricular hypertrophy with atrial stiffness value (LAS/(E/Ea) less than 1.108) appears to be one of the most sensitive and specific indicators of cardiac amyloidosis.