Left, but not right, ventricular status determines heart failure in adults with Ebstein anomaly - A case-control study based on magnetic resonance

Background: Ebstein anomaly (EA) is a congenital heart defect affecting the right heart. Heart failure (HF) is a significant complication in adults with EA. It may result not only from the right ventricle (RV), but also from the left ventricle (LV) abnormalities. We evaluate the size and function of both ventricles in patients with EA in cardiac magnetic resonance (CMR); to assess their association with the clinical markers of HF. Methods: Study group: 37 unoperated adults with EA (mean age 43.0 +/- 14.4y, 21[56.8%] males). Controls: 25 volunteers (mean age 39.9 +/- 10.9y, 15[60%] males). Study protocol included: CMR [ejection fraction (EF), end-diastolic (EDVind) and stroke volumes (SVind) indexed by body surface area]; cardiopulmonary test (peak VO2, %peak VO2, VE/VCO2 slope). Results: Size and systolic function of LV were reduced comparing to the controls [LVEDVind (ml/m2): 63.7(range 38.7-94.2) vs. 79.3(48.7-105.1), p < 0.001; LV SVind (ml/m2): 35.8(22.9-55.1) vs. 49.2(37.8-71.7), p < 0.0001; LVEF(%): 58.3(34-70.5) vs. 62.0(52.0-77.0), p = 0.009]. RV was enlarged comparing to the controls [RVEDVind (ml/m2): 124.3(52.8-378.9) vs. 83.0(64.0-102.0), p < 0.0001) with impaired systolic function (RV SVind (ml/m2): 22.7(11.1-74.1) vs. 48.0(37.8-71.7), p < 0.0001; RVEF(%): 38.0(21.0-66.1) vs. 59.0 (49.0-69.0), p < 0.0001). A significant correlation was found between LVEDVind vs. peakVO2 (r = 0.52, p = 0.001); LV SVind vs. peakVO2 (r = 0.47,p = 0.005). There was no correlation between the right ventricular status and exercise capacity. Conclusions: In adults with Ebstein anomaly the size of left ventricle is reduced, right ventricle is enlarged; the function of both is impaired. Abnormal exercise capacity is associated with left ventricular status. Ventricular interdependence probably plays a role in heart failure pathomechanism.