Single Right Ventricles Have Impaired Systolic and Diastolic Function Compared to Those of Left Ventricular Morphology

Abstract

Differences in single right ventricle (SRV) and single left ventricles (SLV) function are poorly described, although myocardial dysfunction is an important risk factor for morbidity and mortality. The aims of this study were to compare function between patients with SRVs and those with SLVs using newer echocardiographic techniques and to determine differences across staged palliation. In this cross-sectional study comparing 30 patients with SRVs and 30 with SLVs of similar ages (2.5 ± 1.7 vs 2.6 ± 1.6 years), patients were matched for surgical stage (20 pre-bidirectional cavopulmonary anastomosis, 20 pre-Fontan, and 20 post-Fontan patients). Circumferential and longitudinal strain, strain rate (SR), early diastolic SR, postsystolic strain index, and myocardial dyssynchrony index were measured. Comparisons between SRV and SLV parameters were made as a whole group and by subanalysis at each surgical stage. Patients with SRVs had reduced systolic SRs (circumferential: -1.0%/sec vs -1.2%/sec, P= .01; longitudinal: -1.1%/sec vs -1.3%/sec, P= .002), reduced early diastolic SRs (circumferential: 1.4%/sec vs 1.9%/sec, P= .03; longitudinal: 1.6%/sec vs 2.2%/sec, P= .001), and increased circumferential postsystolic strain indexes (8% vs 0%, P < .0001). Subanalysis at each surgical stage showed that the greatest disparity in systolic parameters occurred before bidirectional cavopulmonary anastomosis (longitudinal SR, P= .009; postsystolic strain index, P= .005) and that parity was regained after the Fontan procedure, while traditional diastolic parameters (E velocity, P= .004; E/E' ratio, P= .0003) were reduced in patients with SRVs after the Fontan procedure. The SRV has reduced contractility and diastolic function compared with the SLV. Ventricular systolic performance in patients with SRVs was poorest before bidirectional cavopulmonary anastomosis, while differences in diastolic function were more prominent after Fontan completion.