Abstract 13893: Relationship Between Exercise Function and Noninvasive Indices of Right Ventricular Function in Patients With Biventricular Circulation and Systemic Right Ventricles
Introduction: In patients (pts) with systemic RVs in a biventricular circulation, both exercise capacity (EC) and RV function often deteriorate over time. However, the relationship between these two phenomena is undefined, in part due to the complex anatomy of the RV and difficulty in assessing RV function using non-invasive imaging. The purpose of this study was to examine the relationship between EC and RV function and to determine which noninvasive imaging parameters are the best correlates of EC.
Methods: Pts with a biventricular circulation and systemic RV (physiologically corrected-TGA or D-TGA after atrial switch) who underwent cardiopulmonary exercise testing (CPX) from 2002-2013 and noninvasive imaging (cardiac magnetic resonance [CMR] and/or echocardiography [echo]) within 1 year of CPX were identified. Pts with non-cardiac comorbidities that might affect EC or those with clinically significant events between CPX and imaging studies were excluded. Regression analysis was used to evaluate the relationship between %predicted peak VO2 (%VO2) and the noninvasive indices (Tei index, mean dP/dt during isovolumetric contraction [dP/dtic], TAPSE, fractional area change and CMR-derived RV volumes and EF).
Results: We identified 159 studies (mean age 30.4 y, 57% male, 73% D-TGA) meeting the inclusion criteria. A weak, but statistically significant correlation between %VO2 and RVEF (r=0.29, p=0.0004, n=145) and RV end systolic volume (r=-0.25, p=0.003, n=143) was found. Significant correlations between %VO2 and echo parameters were not found. When analyses were limited to pts without additional hemodynamically significant lesions, the correlation between RVEF and % VO2 strengthened (r=0.36, p=0.0002, n=102) and weak correlations emerged between the Tei Index (r=-0.30, p=0.04, n=49), dP/dtic (r=0.27, p=0.06, n=49) and %VO2. On multivariate analysis, RVEF was the only statistically significant correlate of %VO2.
Conclusion: In pts with systemic RVs in a biventricular circulation, CMR-derived RVEF is the best correlate of %VO2. Echo indices of ventricular function correlate poorly with %VO2. Our data also suggest that additional factors, beyond RV size and function, contribute significantly to the poor EC commonly encountered in these pts.
- © 2013 by American Heart Association, Inc.