Global Longitudinal Strain and Strain Rate Imaging for Assessment of Systemic Right Ventricular Function

Abstract

Background - We determined the usefulness of novel 2-dimensional strain indices, based on speckle tracking imaging, for assessment of systemic right ventricular (RV) function after atrial switch operation for transposition of the great arteries. Methods - Twenty-six patients, aged 21.0±3.6 years at 19.9±3.2 years after atrial switch operation, and 27 age-matched controls were studied. Two-dimensional imaging at the 4 chamber view was obtained with tracing of the entire RV endocardial border. The RV global longitudinal strain (GLS) and GLS rate were derived using an automated software (EchoPAC, GE Medical) (fig), and correlated with tissue Doppler-derived RV isovolumic acceleration (IVA), and, in patient cohort, with cardiac magnetic resonance-derived RV ejection fraction. Results - Intraobserver and interobserver variability for measurement of GLS from 20 studies were 0.06±1.93% and 0.24±1.77% respectively. Compared with controls, patients had lower RV GLS (17.1±1.9% vs 26.3 ±2.9%, p<0.001), reduced GLS rate (0.78 ±0.11/s vs 1.33 ±0.23/s, p <0.001), lower RV IVA (1.10 ±0.36 m/s2vs 1.56 ±0.53 m/s2, p=0.001), and increased RV myocardial performance index (0.52±0.09 vs 0.38 ±0.09, p=0.001). Both RV GLS and GLS rate correlated positively with RV IVA (r=0.43, p<0.001 and r=0.46, p<0.001, respectively), and negatively with RV myocardial performance index (r=−0.65, p<0.001 and r=−0.57, p<0.001 respectively). In patients, GLS rate correlated positively with RV ejection fraction (r=0.62, p=0.001). Conclusion - Two-dimensional RV GLS and GLS rate are novel indices potentially useful for assessment of systemic RV function.