The Total Right/Left-Volume-Index: A New and Simplified Cardiac Magnetic Resonance Measure to Evaluate the Severity of Ebstein's Anomaly of the Tricuspid Valve: A Comparison with Heart Failure Markers from Various Modalities
Background—The classification of clinical severity of Ebstein's Anomaly (EA) still remains a challenge. The aim of this study was to focus on the interaction of the pathologically altered right heart with the anatomically -supposedly- normal left heart and to derive from cardiac magnetic resonance (CMR) a simple imaging measure for the clinical severity of EA.
Methods and Results—Twenty-five patients at a mean age of 26 ± 14 years with unrepaired EA were examined in a prospective study. Disease severity was classified using CMR volumes and functional measurements in comparison with heart failure markers from clinical data, Electrocardiography, laboratory and cardiopulmonary exercise testing and echocardiography. All exams were completed within 24 hours. A Total Right/Left-Volume-Index was defined from end diastolic volume measurements in CMR: Total R/L-Volume-Index = (RA+aRV+fRV)÷(LA+LV). Mean Total R/L-Volume-Index was 2.6 ± 1.7 [normal values: 1.1 ± 0.1]. This new Total R/L-Volume-Index correlated with almost all clinically employed biomarkers of heart failure: BNP (r=0.691,p=0.0003), QRS (r=0.432,p=0.039), peak VO2/kg (r=-0.479,p=0.024), VE/VCO2 (r=0.426,p=0.048), the severity of tricuspid regurgitation (r=0.692,p=0.009), tricuspid valve offset (r=0.583,p=0.004) and TAPSE (r=0.554,p=0.006). Previously described severity indices ((RA+aRV)/(fRV+LA+LV)) and fRV/LV EDV corresponded only to some parameters.
Conclusions—In patients with EA, the easily acquired index of right sided to left sided heart volumes from CMR correlated well with established heart failure markers. Our data suggest that the Total R/L-Volume-Index should be used as a new and simplified CMR measure, allowing more accurate assessment of disease severity than previously described scoring systems.
- Received November 21, 2013.
- Accepted April 25, 2014.