P-39/ CO-05 : Two different spectrums of Arrhythmogenic cardiomyopathy

posted Jan 26, 2017, 8:30 AM by sourav ghosh

Deepak Tewari1Hermohander S Isser2Praloy Chakraborty2Sudheer Arava3
(1) V.V.V. College for Women, Virudhunagar, India (2) Vardhman Mahavir Medical College (VMMC) and Safdarjang Hospital, New Delhi, India (3) All India Institute of Medical Science New Delhi, India

Background: Although classically known as ARVC/ARVD, Arrhythmogenic cardiomyopathy can affect both ventricles, RV only and rarely LV only. We present two cases of different spectrum, one of the common types (biventricular type) and another rare type (Left dominant type).
Patients and Methods: 
Case 1: 64 years female patient presented with VT of RV origin. Echocardiography documented LVEF=50%. Coronary angiography was normal. Contrast enhanced cardiac MRI showed mild biventricular dysfunction and late gadolinium enhancement (LGE) distributed in both ventricles. Endomyocardial Biopsy(EMB) shoed fibro fatty changes and myocyte loss.
Case 2: 45 years male presented with VT from LV. Echocardiography and coronary angiography was normal. CMRI showed normal biventricular function with patchy LGE involving LV and IVS. EMB from IVS showed shoed fibro fatty changes and myocyte loss. A diagnosis of left dominant Arrhythmogenic cardiomyopathy (LDAC) was made. The individual showed a variation in TMEM 43 gene (p.Thr277Ser).
Discussion: Arrhythmogenic cardiomyopathy is a rare form of inherited cardiomyopathy characterized by fibro fatty replacement and myocyte loss. It presents with ventricular arrhythmias with or without features of ventricular dysfunction. The commonest form involves the free wall of right ventricle and known as ARVC/D however in later stage in affects the LV also. Isolated involvement of LV is rare and occurs in less than 5% cases. The disease is caused by mutation in desmosomal genes. TMEM 43 is is a highly conserved inner nuclear membrane (INM) protein. It has been hypothesized that mutant TMEM43 protein would disrupt structure and function of desmocollin-2, desmoglein-2, desmoplakin, and junctional plakoglobin, leading to Arrhythmogenic cardiomyopathy.