Left Atrial Strain and Function in Pediatric Hypertrophic Cardiomyopathy

Area of Science:

• Cardiology
• Pediatric Cardiology
• Echocardiography

Background:

• Left atrial (LA) strain and dysfunction are early indicators of diastolic dysfunction and are linked to reduced exercise capacity in adults with hypertrophic cardiomyopathy (HCM).
• Limited research exists on assessing LA mechanics in pediatric HCM patients.
• This study aimed to evaluate LA strain and function in pediatric HCM patients with (P+) and without (G+P-) ventricular hypertrophy and correlate findings with exercise stress test results.

Purpose of the Study:

• To assess left atrial (LA) strain and function in pediatric patients with hypertrophic cardiomyopathy (HCM).
• To compare LA mechanics between pediatric HCM patients with (phenotype positive [P+]) and without (genotype positive, phenotype negative [G+P-]) ventricular hypertrophy.
• To evaluate the correlation between LA function and exercise stress test parameters in pediatric HCM.

Main Methods:

• Retrospective analysis of 78 children (3-25 years) with HCM (46 P+, 32 G+P-) and 20 healthy controls.
• Phasic LA volumetric analysis to compute LA conduit, reservoir, and pump function.
• Speckle-tracking echocardiography for LA reservoir strain (LASr) and LA contractile strain measurement; exercise test data collected within 12 months.

Main Results:

• Patients with P+ HCM exhibited significantly lower LA conduit function (36% vs 48%) and LA reservoir function (137% vs 180%) compared to G+P- patients.
• LA contractile function did not differ significantly between the groups (31% vs 32%).
• P+ HCM patients showed reduced four-chamber LASr (29% vs 41%), two-chamber LASr (30% vs 41%), average LASr (29% vs 42%), and LA contractile strain (9% vs 12%) compared to G+P- patients. LA conduit function weakly correlated with aerobic capacity (r=0.42, P=0.019) in patients who underwent stress testing.

Conclusions:

• Children with P+ HCM demonstrate impaired LA function, detectable through both volumetric and strain analyses.
• Altered LA mechanics in pediatric HCM are associated with reduced exercise capacity.
• This study provides a basis for evaluating novel LA parameters in pediatric HCM and suggests the need for larger longitudinal studies to determine clinical significance.