Objectives Patients with Ebstein’s anomaly of the tricuspid valve (EA) are at risk of tachyarrhythmia, congestive heart failure and sudden cardiac death. We sought to determine the value of cardiovascular magnetic resonance (CMR) for predicting these outcomes.

Methods Seventy-nine consecutive adult patients (aged 37±15 years) with unrepaired EA underwent CMR and were followed prospectively for a median 3.4 (range 0.4-10.9) years for clinical outcomes, namely major adverse cardiovascular events (MACE: sustained ventricular tachycardia/heart failure hospital admission/cardiac transplantation/death) and first-onset atrial tachyarrhythmia (AT).

Results CMR-derived variables associated with MACE (n=6) were right ventricular (RV) or left ventricular (LV) ejection fraction (EF) (HR 2.06[95%CI 1.168-3.623],p=0.012 and HR 2.35[95%CI 1.348-4.082],p=0.003, respectively), LV stroke volume index (HR 2.82[95%CI 1.212-7.092],p=0.028) and cardiac index (HR 1.71[95%CI 1.002-1.366],p=0.037);all remained significant when tested solely for mortality. Prior history of AT (HR 11.16[95%CI 1.30-95.81],p=0.028) and NYHA-class >2 (HR 7.66[95%CI 1.54-38.20],p=0.013) were also associated with MACE; AT preceded all but one MACE events suggesting its potential role as an early marker of adverse outcome (p=0.011).
CMR variables associated with first-onset AT (n=17;21.5%) included RVEF (HR 1.55[95%CI 1.103-2.160],p=0.011)],total R/L volume index (HR 1.18[95%CI 1.06-1.32],p=0.002), RV/LV end diastolic volume ratio (HR 1.55[95%CI 1.14-2.10],p=0.005) and apical septal leaflet displacement/total LV septal length (HR 1.03[95%CI 1.00-1.07],p=0.041); the latter two combined enhanced risk prediction (HR 6.12[95% CI 1.67-22.56],p=0.007).

Conclusion CMR-derived indices carry prognostic information regarding MACE and first-onset AT amongst adults with unrepaired EA. CMR may be included in the periodic surveillance of these patients.