Prevalence and evolution of right ventricular dysfunction among different genetic backgrounds in dilated cardiomyopathy

Background: Titin (TTN)-related dilated cardiomyopathy (DCM) has a higher likelihood of left ventricular reverse remodelling compared with other genetic etiologies. No data regarding the evolution of right ventricular dysfunction (RVD) according to genetic background are available. Methods: Consecutive 104 DCM patients with confirmed pathogenic genetic variants (51 TTN-related DCM; 53 other genetic DCM) and a control group of 139 patients with negative genetic testing and available follow-up data at 12-24 months were analysed. RVD was defined as a right ventricular fractional area change (RVFAC) < 35%. The main study end point was the comparison of the evolution of RVD and the change of RVFAC throughout the follow-up according to etiology. A composite of all-cause mortality and heart transplantation was included as outcome measure. Results: At enrollment, RVD was present in 29.1% of genetically positive DCM without differences between genetic cohorts. At 14 months follow-up, 5.9% of TTN-related DCM patients vs 35.8% of other genetic DCM patients had residual RVD after treatment (P < 0.001). Accordingly, RVFAC significantly improved in the TTN-related DCM cohort and remained stably impaired in other genetic DCM patients. However, the evolution of RVD was similar between TTN-related DCM and patients without a genetic mutation. After adjusting for RVD at follow-up, no differences in the outcome measure were seen in the study cohorts. Conclusions: The evolution of RVD in DCM is heterogeneous in different genetic backgrounds. TTN-related DCM is associated with a higher chance of RVD recovery compared with other genetic etiologies.