Myocardial work in systemic right ventricle: new insights on right ventricular adaptation to systolic flow

Abstract

Abstract Background Myocardial work (MW) is an innovative tool, which combines global longitudinal analysis with non-invasively assessed ventricular pressure to provide a measure of ventricular performance. This technique has recently been used in subpulmonary right ventricle (spRV), but it has not yet been studied in systemic right ventricle (sRV). Methods and Results MW indexes were obtained from ventricular pressure–strain loops in 48 patients with sRV (32 transposition of the great arteries following atrial switch repair and 16 congenitally corrected transposition of the great arteries; mean age 38.5±10years; 56% male) and in 20 healthy volunteers, as a control group of spRV. Echocardiographic parameters and global longitudinal strain(GLS) analysis demonstrated impaired systolic function in the sRV group (TAPSE: 12.3±3mm, S wave:6.9±2cm/s, fractional area change:29[23-35]% , GLS: -13.4±3%, RV septum GLS: -12±4%, RV free-wall GLS: -14.8±4%). Accordingly, MW indexes were below normal reference values reported for the left ventricle (global work index (GWI): 1056±331 mmHg%; global constructive work (GCW): 1490±269 mmHg%); and global wasted work (GWW) and global work efficiency (GWE) were mildly increased (245.5±162mmHg% and 87±9%, respectively). In addition, sRV free-wall contributed more than the septum to the global performance (GWI septum 879±318, free-wall 1241±412 mmHg%, p<0.0001; GCW septum 1348±287, free-wall 1626±377 mmHg%, p<0.0001). Notably, segmental pressure–strain loops demonstrated higher wasted work values in dyssynchronous segments (figure). As shown in Table1, MW indexes of performance were significantly higher in sRV compared to spRV (spRV GWI:349.3±99mmHg%; p<0.0001; spRV GCW: 451.1±104mmHg%; p<0.0001), likely reflecting sRV adaptation to increased afterload. However, as a response to chronic exposure to systemic pressure, a significant raise of both GWW and GWE in sRV compared to spRV was found (spRV GWW:43.1±22mmHg%, p<0.0001; spRV GWE:92.4±4,p=0.0005). Conclusion Assessment of MW in patients with a sRV is feasible and may provide additional data on ventricular global and segmental performance and efficiency, reflecting sRV adaptation to systemic loading.Table 1