Left ventricular mechanics after arterial switch operation: a speckle-tracking echocardiography study

Area of Science:

• Cardiology
• Pediatric Cardiac Surgery
• Cardiovascular Imaging

Background:

• Arterial switch operation (ASO) is standard for dextro-transposition of the great arteries (d-TGA).
• Patients undergoing ASO may exhibit reduced exercise capacity and myocardial perfusion defects, despite normal systolic function on standard echocardiography.
• Speckle-tracking echocardiography (STE) can detect subclinical myocardial abnormalities.

Purpose of the Study:

• To evaluate left ventricular (LV) systolic myocardial deformation and torsion in asymptomatic ASO patients using STE.
• To identify potential subclinical myocardial dysfunction in patients with normal LV ejection fraction post-ASO.

Main Methods:

• Sixty-two asymptomatic patients who underwent ASO for d-TGA (mean age 8.5 years) with normal LV ejection fraction (≥55%) were studied.
• Thirty-one age- and sex-matched healthy controls were included for comparison.
• Speckle-tracking echocardiography (STE) was used to assess LV longitudinal and circumferential strain, and LV torsion.

Main Results:

• ASO patients showed significantly reduced global LV longitudinal strain compared to controls (-19.2% vs. -22.7%, P<0.0001).
• Impaired longitudinal deformation was noted in the anterior and septal walls.
• Global circumferential strain and LV torsion were comparable between ASO patients and controls.

Conclusions:

• A significant reduction in longitudinal myocardial deformation, correlated with age at surgery, was observed in asymptomatic ASO patients with normal LV ejection fraction.
• Findings suggest the benefit of early surgical repair (≤7 days) for d-TGA.
• Continued monitoring of ventricular function using STE is recommended for post-ASO patients.