Relationship between Exercise Parameters and Noninvasive Indices of Right Ventricular Function in Patients with Biventricular Circulation and Systemic Right Ventricle

OBJECTIVES: In patients with systemic right ventricles (RVs) in a biventricular circulation, exercise capacity and RV function often deteriorate over time and echocardiographic assessment of systemic RV function is difficult. The purpose of this study was to examine the relationship between exercise capacity and RV function and to determine which noninvasive imaging parameters correlate most closely with exercise capacity. DESIGN: Patients with a systemic RV (D-loop transposition of the great arteries [TGA] after atrial switch procedure or physiologically "corrected" TGA) who underwent cardiopulmonary exercise testing (CPX) and noninvasive imaging (cardiac magnetic resonance [CMR] and echocardiography [echo]) within 1 year of CPX were identified. Regression analysis was used to evaluate the relationship between exercise variables and noninvasive indices of ventricular function. RESULTS: We identified 92 patients with 149 encounters (mean age 31.0 years, 61% men, 70% D-loop TGA) meeting inclusion criteria. Statistically significant correlations between % predicted peak oxygen uptake (%pVO2 ) and RV ejection fraction (EF) (r = 0.29, P = .0007), indexed RV end-systolic volume (r = -0.25, P = .002), and Tei index (r = -0.22, P = .03) were found. In patients without additional hemodynamically significant lesions, the correlations between %pVO2 and RV EF (r = 0.37, P = .0007) and the Tei index (r = -0.28, P = .03) strengthened and a correlation emerged between %pVO2 and dP/dtic (r = 0.31, P = .007). On multivariable analysis, Tei index was the only statistically significant correlate of %pVO2 (P = .04). CONCLUSIONS: In patients with systemic RVs in a biventricular circulation, CMR-derived RVEF and echo-derived Tei index correlate with %pVO2 . On multivariable analysis, the Tei index was the strongest predictor of peak %pVO2 response.