Cardiovascular magnetic resonance feature-tracking strain characterization across phenotypic spectrum of danon disease

To characterize atrial and ventricular strain across the phenotypic spectrum of Danon disease (DD) and explore their relationships with left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE) extent. This retrospective case-control study included 27 DD patients (median age 17 [range 10-50] years; 15 males) and 32 healthy controls. Cardiac magnetic resonance (CMR) imaging was performed at 3-T with cine and LGE. Structural, functional, and LGE parameters were assessed. Kruskal-Wallis H test with Dunn's test and Bonferroni correction was used for intergroup comparisons; Mann-Whitney U or t-test for two-group comparisons; Spearman's correlation; and receiver operating characteristic (ROC) analysis were used. Left atrial (LA) and right atrial (RA) strain were impaired across all DD subgroups versus controls, with LA strain impairment evident even in the hypertrophic cardiomyopathy (HCM) subgroup with preserved LVEF. LV global longitudinal strain (LV-GLS) was reduced across all subgroups, whereas global circumferential strain (GCS) and global radial strain (GRS) impairment were confined to hypertrophic and dilated cardiomyopathy (HCM-DCM) and dilated cardiomyopathy (DCM) subgroups. Mid-ventricular longitudinal strain was relatively preserved (P = 0.062). LGE extent correlated with GRS (all P < 0.01). Left atrial conduit strain rate (LASRe) demonstrated the best diagnostic performance (area under the curve [AUC] = 0.981; sensitivity 88.9%, specificity 100%). CMR feature-tracking revealed phenotype-specific bi-atrial and biventricular strain abnormalities in DD. Atrial strain impairment was detectable even in HCM with preserved LVEF, suggesting early mechanical dysfunction. LASRe showed promising discrimination and warrants validation. HCM-DCM may represent a possible transitional phenotype; longitudinal validation is required.