RESUMO
BACKGROUND: Arrhythmogenic left ventricular cardiomyopathy (ALVC) is characterized by fibrofatty myocardial replacement evidenced on cardiac magnetic resonance (CMR) by late gadolinium enhancement (LGE) mainly involving subepicardium. The study aimed to describe the layer-specific strain (LSS) echocardiography phenotype of ALVC and to compare it to LGE features. METHODS: All consecutive ALVC pathogenic genetic variant carriers and non-carrier relatives were reparted in four pre-specified groups (overt ALVC (Group 1), isolated LGE (Group 2), pathogenic genetic variant carrier without ALVC phenotype (Group 3), no genetic variant carrier (Group 4)) and explored accordingly by CMR and LSS echocardiography. RESULTS: Eighty-five individuals were included. Endocardial global longitudinal strain (GLS) (GLSendo)-Epicardial GLS (GLSepi) gradient was predominantly altered in Group 1 illustrating transmural strain alteration in overt ALVC (3.8 ± 1.1 in Group 1, 4.3 ± 2.2 in Group 2, 5.2 ± 1.2 in Group 3, 5.4 ± 1.6 in Group 4, p=0.0017), whereas GLSepi was predominantly impaired in Group 2 (GLSendo, GLSepi = 15.0 ± 4.1%, 11.2 ± 3.3% respectively in Group 1, 20.5 ± 2.8%, 16.2 ± 5.5% in Group 2, 23.4 ± 3.3%, 18.2 ± 2.7% in Group 3, 24.6 ± 2.8%, 19.2 ± 1.9% in Group 4, all p<0.0001). GLSepi was able to detect subepicardial LGE in genetic variant carriers without overt ALVC with an area under curve (AUC) of 0.84 (0.73;0.95). However, segmental epicardial and endocardial strain behaved similarly and showed comparable diagnostic values for segmental LGE detection (AUC 0.72 (CI 0.69-0.76) and 0.73 (CI 0.70-0.76) respectively, p =0.4). CONCLUSION: LSS alteration in ALVC progresses from epicardium to endocardium along with disease severity. Irrespective of LSS analysis, that did not provide incremental diagnostic value for the detection and localization of LGE, strain echocardiography was shown to be a potential surrogate marker of LGE, including in apparently healthy individuals with isolated LV fibrosis.