LMNA–RELATED DILATED CARDIOMYOPATHY PRESENTING WITH REGIONAL WALL AKINESIS AND TRANSMURAL LATE GADOLINIUM ENHANCEMENT

A 26–year–old girl was admitted at hospital in December 2022 for a syncopal episode. She referred fatigue and dyspnea in the last 2 months. EKG was markedly abnormal showing peripheral low voltages, poor R wave progression in prechordial leads, negative T waves V4–V6, DII, DIII and aVF, fragmented QRS (Fig.1). Echo showed moderately dilated left ventricle (LV) with apical akinesia and apical aneurysm (no thrombi) and hypo–akinesia and hyperechoic appearance of the middle segments of the infero–posterior and lateral wall (Fig.2a). EF was 38%. There was no family history for sudden cardiac death and cardiomyopathy. Creatine kinase and neurological examination were normal. The diagnostic work–up included: myocardial scintigraphy which showed fixed tracer uptake deficit at apical and posterolateral levels (Fig.2b); cardiac magnetic resonance (CMR): apical aneurysm with extended late gadolinium enhancement (LGE) due to fibrosis, focally transmural, on the left ventricle’s midapical and infero–lateral thinned–hypokinetic myocardial walls (Fig.3a, 3b); Coronary angiography showed no stenosis. Due to myocardial aneurysm in absence of CAD, Chagas disease was excluded. We performed LV endomyocardial biopsy which showed cardiomyopathic changes and replacement fibrosis. Due to fibrosis extension, complex ventricular extrasystoles detected on monitoring and syncope, ICD was implanted. Finally genetic testing showed c.1621C>Tp.Arg541Cys LMNA pathogenetic mutation leading to the diagnosis of LMNA–related LV cardiomyopathy, with extensive fibrosis in multiple areas of left ventricle including the apical segments at a very young age. Patients with LMNA mutation-related heart disease are characterized by conduction abnormalities, ventricular tachyarrhythmias (VA) and high risk of sudden cardiac death with mildly impaired systolic function, often without chamber dilation. About 88% LMNA– cardiomyopathy have typical myocardial fibrosis, predominantly in the mid-myocardium of the basal septum. However, our patient and previous reported cases with the same p.R541 LMNA mutation presents with a specific phenotype including regional LV akinesis, segmental transmural LGE, significant LV dilatation and systolic dysfunction and VA without conduction abnormality. Of note, EKG shows normal A–V conduction but low voltage and negative T waves in precordial and inferior leads. These features are not typical for LMNA–disease and underline the phenotypic variability of cardiomyopathies.