Right ventricular long axis strain-validation of a novel parameter in non-ischemic dilated cardiomyopathy using standard cardiac magnetic resonance imaging.

PURPOSE: Right ventricular longitudinal axis strain (RV-LAS) is a simple measure of RV longitudinal function. The purpose of this study was the evaluation of its diagnostic performance in non-ischemic dilated cardiomyopathy (NIDCM) and the determination of reference values in controls.

METHODS

217 NIDCM patients and 200 healthy controls were analysed retrospectively regarding the diagnostic performance of RV-LAS using receiver operating characteristic curves in comparison with RV ejection fraction (RVEF), tricuspid annular plane systolic excursion (TAPSE) and global longitudinal strain (RV-GLS). Hereby, four different approaches were evaluated to assess RV-LAS based on different reference points. RV-LAS LVapex/mid was defined as the change in distance between the LV apex and the middle of a line connecting the origins of the tricuspidal valve leaflets in systole and diastole. The ethical approval was obtained in all participants.

RESULTS

NIDCM and controls were 48 years in mean. Controls were equally gender distributed, while the proportion of men with NIDCM was higher with 77%. Among the four approaches RV-LAS LVapex/mid provided the highest diagnostic performance for discrimination between NIDCM and controls (AUC=0.94). Of all RV functional parameters RV-LAS LVapex/mid preformed significantly better than RVEF (delta AUC=0.05; p=0.003), TAPSE (delta AUC=0.23; p<0.0001) and RV-GLS (delta AUC=0.31; p<0.0001). A significant correlation was found between RV-LAS LVapex/mid and RVEF (r=-0.65; p<0.0001). The reference mean values for RV-LAS LVapex/mid were -17.4±3.5 for men and -18.5±3.7 for women.

CONCLUSION

RV-LAS showed better diagnostic accuracy for RV dysfunction than RVEF, TAPSE and RV-GLS. Furthermore, it has a rapid accessibility and low intra- and interobserver variability.