Cardiac Magnetic Resonance Imaging Findings in Filamin C Variant-Associated Arrhythmogenic Left Ventricular Cardiomyopathy

A 28-year-old woman with a family history of dilated cardiomyopathy was found to have premature ventricular contractions on ECG during workplace screening. Transthoracic echocardiography revealed mild hypokinesis of the left ventricle (LV) despite normal morphology. Cardiac magnetic resonance imaging (CMR) revealed diffuse circumferential subepicardial late gadolinium enhancement (LGE) in the LV, the so-called “ring-like LGE,” as well as scattered patchy enhancement in the midmyocardial wall without subendocardial involvement. Multiparametric CMR revealed significant prolongation in native T1 (1,450 ms [normal, 1,230–1,250 ms]) and T2 (55.0 ms [normal, 40–45 ms]), which suggested diffuse myocardial edema. The myocardial extracellular volume fraction was elevated (44% [normal, 23–28%]), which reflected myocardial fibrosis (Figure). Endomyocardial biopsy revealed myocardial fibrosis and mild inflammatory cell infiltration. Genetic testing identified a filamin C gene variant (FLNC:c.2809C>T:p.Q937X), and the patient was eventually diagnosed with filamin C variant-associated arrhythmogenic LV cardiomyopathy (ALVC). The same variant was detected in her sister and father.

Figure.

Multiparametric cardiac magnetic resonance imaging including late gadolinium enhancement (LGE; arrows in A–C). Native T1 (D), extracellular volume (E), and T2 (F) maps.

Editorial p ????

In 2020, new diagnostic criteria (the Padua criteria) for arrhythmogenic cardiomyopathy (ACM), which include those for arrhythmogenic right ventricular cardiomyopathy and ALVC, were proposed.¹ In patients with ACM, ring-like LGE of ≥3 contiguous segments with subepicardial and/or mid-wall LGE in the same slice is associated with malignant arrhythmic events. Ring-like LGE is also the imaging phenotype of filamin C gene variants and is associated with a high risk of sudden death.²

Disclosures

K.T. is a member of Circulation Journal’s Editorial Team.

References

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• 2.   Augusto JB, Eiros R, Nakou E, Moura-Ferreira S, Treibel TA, Captur G, et al. Dilated cardiomyopathy and arrhythmogenic left ventricular cardiomyopathy: A comprehensive genotype-imaging phenotype study. Eur Heart J Cardiovasc Imaging 2020; 21: 326–336.