Purpose To explore the prognostic value of cardiac magnetic resonance (MR) imaging in predicting postoperative cardiac death in patients with severe functional tricuspid regurgitation (TR). Materials and Methods This study was approved by the institutional review board, and written informed consent was obtained from all patients. Prospectively collected data included cardiac MR images, New York Heart Association (NYHA) functional class, a comprehensive laboratory test, and clinical events over the follow-up period in 75 consecutive patients (61 women and 14 men; mean age ± standard deviation, 59 years ± 9) undergoing corrective surgery for severe functional TR. Cox proportional hazards models were used to assess the association between cardiac MR parameters and outcomes. Results During a median follow-up period of 57 months (range, 21-82 months), cardiac mortality and all-cause mortality were 17.3% and 26.7%, respectively, with a surgical mortality of 6.7%. Cardiac death risk was lower with a higher right ventricular (RV) ejection fraction (EF) on cardiac MR images (hazard ratio per 5% higher EF = 0.790, P = .048). By adjusting for confounding variables, RV EF remained a significant predictor for cardiac death (P < .05) and major postoperative cardiac events (P < .05). The area under the receiver operating characteristic curve (AUC) confirmed the incremental role of RV EF on cardiac MR images in the prediction of postoperative cardiac death (AUC, 0.681-0.771; P = .041) and major postoperative cardiac events (AUC, 0.660-0.745; P = .044) on top of NYHA class. RV end-systolic volume index was also independently associated with these outcomes but failed to increase the AUC significantly. Conclusion Preoperative assessment of cardiac MR imaging-based RV EF provides independent and incremental prognostic information in patients undergoing corrective surgery for severe functional TR. (©) RSNA, 2016 Online supplemental material is available for this article.