Description of the Two-Dimensional Layer-Specific Strain Echocardiography Phenotype of Arrhythmogenic Left Ventricular Cardiomyopathy

Abstract

Arrhythmogenic left ventricular cardiomyopathy (ALVC) is characterized by fibrofatty myocardial replacement demonstrated on cardiac magnetic resonance by late gadolinium enhancement (LGE) mainly involving the subepicardium. The aims of this study were to describe the layer-specific strain (LSS) echocardiography phenotype of ALVC and to compare it with LGE features. All consecutive ALVC pathogenic genetic variant carriers and noncarrier relatives were separated into four prespecified groups (overt ALVC [group 1], isolated LGE [group 2], pathogenic genetic variant carrier without ALVC phenotype [group 3], and no genetic variant carrier [group 4]) and studied accordingly using cardiac magnetic resonance and LSS echocardiography. Eighty-five individuals were included. Endocardial global longitudinal strain (GLS)-epicardial GLS (GLSepi) gradient was altered predominantly 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, and 5.4±1.6 in group 4; P=.0017), whereas GLSepi was impaired predominantly in group 2 (endocardial GLS and GLSepi were 15.0±4.1% and 11.2±3.3%, respectively, in group 1; 20.5±2.8% and 16.2±5.5% in group 2; 23.4±3.3% and 18.2±2.7% in group 3; and 24.6±2.8% and 19.2±1.9% in group 4; P<.0001 for all). GLSepi was able to detect subepicardial LGE in genetic variant carriers without overt ALVC with an area under curve of 0.84 (95% CI, 0.73-0.95). However, segmental epicardial and endocardial strain behaved similarly and showed comparable diagnostic values for segmental LGE detection (areas under the curve, 0.72; [95% CI, 0.69-0.76] and 0.73 [95% CI, 0.70-0.76], respectively, P=.40). LSS alteration in ALVC progresses from the epicardium to the endocardium along with disease severity. Irrespective of LSS analysis, which 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.