Introduction:
Arterial switch operation (ASO) is the standard surgical procedure for transposition of the great arteries allowing a complete anatomical and physiological repair. In these patients the functional impact of myocardial perfusion on global and regional myocardial function has not been investigated. Stress echocardiography with visual myocardial assessment has been used to detect regional myocardial dysfunction. Studying LV mechanics using speckle-tracking echocardiography during exercise could provide more quantitative information. The aim of the study was to study the myocardial response to exercise in children after ASO using semi-supine cycle ergometry stress echocardiography (SSCE).
Materials and Methods:
Forty children after ASO and 29 age and gender matched controls were included. Median age was 14 years. A stepwise SSCE protocol was used. LV global longitudinal strain and circumferential strain was measured in all subjects at rest and at incremental heart rate.
Results:
Resting HR was similar between groups, peak HR was lower in the ASO group compared with controls (142 ±11 vs 157±14 bpm, p=0.0007). LV global longitudinal strain was lower at rest (19±2.3% vs. 21±2.5%, p=0.004) but not at peak exercise (22.7±5.6 % vs. 24±4.5 % p=0.2) in the ASO group compared to controls. No significant difference was found in LV global circumferential strain at rest (23.7±2.3% vs. 24±3.2 %, p=0.6) and peak exercise (28±2.6% vs. 27.9±4.1 %, p=0.9). Also when plotted versus heart rates the increase in longitudinal and circumferential strain values were not significantly different.
Conclusions:
These data show that circumferential and longitudinal myocardial deformation during exercise is preserved in children after ASO compared to controls. Earlier data obtained using Tissue Doppler in the same study cohort, showed a normal increase in systolic tissue Doppler velocities. These data suggest a preserved LV reserve during exercise in this patient cohort.
Adenosine stress myocardial perfusion scintigraphy in pediatric patients after arterial switch operation
