Right Atrial and Right Ventricular Strain in Dilated Cardiomyopathy vs. Healthy Population Controls: A Comparative CMR Analysis from Two Large Population Cohorts

Background: CMR strain imaging is increasingly applied in the functional characterization of dilated cardiomyopathy (DCM). While left-sided strain has been well described and evaluated, large healthy volunteer reference data for right atrial (RA) and right ventricular (RV) strain are limited, complicating clinical interpretation. We therefore aimed for the generation of normal RA and RV strain values in cardiovascular (CV) disease–free individuals and the comparison to patients with DCM from a population-based registry using standardized imaging and post-processing protocols.

Methods: Data sets of 162 patients with non-ischemic DCM from the German Centre for Cardiovascular Research (DZHK) nationwide multicenter databank with standardized clinical and imaging protocols were enrolled. Normal reference data were obtained from 400 cardiovascular disease–free participants of the MRI sub-study of the population-based KORA (Cooperative Health Research in the Region of Augsburg) cohort. All participants underwent 1.5T or 3T CMR. RA reservoir strain (RA-RS), RA longitudinal strain (RA-LS), RV radial strain (RV-RS), RV longitudinal strain (RV-LS), and RV circumferential strain (RV-CS) were measured using feature tracking (cvi42, Circle CVI). Group differences were assessed by multivariable linear regression adjusted for age and sex.

Results: Reference values from controls were RA-RS 50.5%, RA-LS 20.0%, RV-RS 24.9%, RV-LS 21.6%, and RV-CS 14.3%.
In patients with DCM, all strain parameters were significantly reduced: RA-RS 40.8% (−9.7), RA-LS 15.4% (−4.6), RV-RS 16.1% (−8.8), RV-LS 17.8% (−3.8), and RV-CS 9.2% (−5.1) (all p< 0.001). The largest absolute age- and sex- adjusted differences were revealed for RA-RS (β=9.7%; 95%CI: -13.5 to -4.7, p< 0.001) and RV-RS (β=-8.8%; 95%CI: -10.3 to -6.2, p< 0.001). The largest relative impairments were observed for RV-CS (-36%) and RV-RS (-35%).

Conclusion: These results provide robust, population-based reference data for right heart strain and demonstrate the value of CMR-derived strain for detecting early right heart dysfunction in cardiomyopathy. Such reference values may improve diagnostic precision and refine clinical decision-making in DCM.

Comparison of Right Heart Strain Parameters Between DCM Patients and Healthy Controls

Strain Parameter	DCM Group mean % (SD)	Control Group mean % (SD)	Relative Difference	Absolute Difference	P-value
RA-RS	40.8 (25.0)	50.5 (21.5)	-19%	-10%	< 0.001
RA-LS	15.4 (11.7)	20.0 (5.3)	-23%	-5%	< 0.001
RV-RS	16.1 (11.0)	24.9 (10.5)	-35%	-9%	< 0.001
RV-LS	17.8 (9.0)	21.6 (4.6)	-18%	-4%	< 0.001
RV-CS	9.2 (6.4)	14.3 (3.8)	-36%	-5%	< 0.001

Forest plot of multivariable regression results showing adjusted differences in right atrial (RA) and right ventricular (RV) strain parameters between DCM patients and controls.