Right ventricular longitudinal strain on CMR predicts ventricular arrhythmias and mortality in cardiac sarcoidosis.

Background: Right ventricular (RV) dysfunction and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) are associated with ventricular arrhythmias (VA) and mortality in cardiac sarcoidosis (CS). However, image resolution limits the detection of RV LGE. Global longitudinal RV strain (RVS) correlates to RV scar on electroanatomical mapping and RV function. Objective: We evaluated the association between RVS on CMR and VA/death (combined-primary-endpoint (CPE)) in patients with CS. Methods: RVS and RV LGE on MRI were retrospectively compared to variables known to predict outcomes in 66 patients with CS. Outcomes were obtained from electronic medical records and implantable cardioverter defibrillator (ICD) interrogations over median [IQR] 3.7[1.7, 6.3] years. Cox proportional hazard models were used to evaluate survival. Harrell's C-statistic was used to compare variables in risk prediction models. Results: 62.1 % of patients were male, with a mean age [SD] of 52.3 [9.6] years and left ventricular ejection fraction (LVEF) of 51.1[17.5]%. 9 patients with the primary endpoint were more likely to be Caucasian (p = 0.01) with prior VAs (p = 0.002), be on anti-arrhythmic drugs (p = 0.001) with an ICD (p = 0.002). In multivariable analyses adjusted for age, race, and history of VA, RVS (1.18 [1.05-1.31], p = 0.004), RV EDVI (1.08[1.01, 1.14], p = 0.02), and LV LGE (1.07[1.00, 1.13], p = 0.04) predicted the CPE. Risk prediction models including RVS (Cstatistic 0.94), outperformed those including RV and LV LGE (0.89-0.92). Conclusion: RVS on CMR was the best predictor of VA and mortality in CS.