433 A PRO-ARRHYTHMIC DOUBLE HIT


 A 42-year-old man went to the emergency room complaining about dyspnea and palpitations. He reported an episode of atrial fibrillation (AF) with symptoms of dizziness 8 years before. He had a family history of ischemic cardiopathy, his father has suffered from AF since a young age.Acute course: The ECG revealed AF at high ventricular frequency. The echocardiography demonstrated mild reduction of the left ventricular function (EF 45%) with diffuse hypokinesis, and mitral valve prolapse (MVP) with mild mitral regurgitation. The blood tests showed a troponin peak of 750 ng/L (n.v. 0–34 ng/L). The suspect was acute coronary syndrome. Thus, he was treated with dual antiplatet therapy and low doses of beta-blockers, and he underwent coronarography, which demonstrated no significant lesions. So, after a transesophageal echocardiography that excluded thrombosis, and a loading dose of amiodarone, a successful electrical cardioversion was performed. The discharge diagnosis was AF with mild left ventricular disfunction. Three months later: He came back to the emergency room because of suffering some days of progressive epigastric and retrosternal pain radiating to the shoulders. The ECG and the echocardiography were unchanged, the troponin-I values were 79 ng/L-74 ng/L. Therefore, he underwent cardiac magnetic resonance (CMR), which showed normal biventricular dimensions and function (LVEF 64%, LVEDV 80 ml/mq), MVP with mitral annular disjunction (MAD) and curling of the infero-lateral basal wall (Figure A). The native T1, T2 and ECV values were increased, and there was a wide left ventricular subepicardial late gadolinium enhancement (LGE). The conclusion was MVP and active myocarditis. Moreover, he underwent endomyocardial biopsy that revealed focal lymphocytic infiltration, PCRs for common cardiotropic viruses or bacteria were negative. Six months later: The basal ECG was characterized by low QRS voltages in limb leads (Figure B). The CMR revealed a wide left ventricular non-ischemic fibrosis with a ring-like pattern (Figure C). The 24-hours Holter ECG showed premature ventricular beats with a right bundle branch block/superior and inferior axis morphology (Figure D), in keeping with MVP. The next step was the genetic testing that resulted positive for a Filamin-C (FLNC) mutation associated with cardiomyopathy. The final diagnosis was “Hot-phase of Left Ventricular Arrhythmogenic Cardiomyopathy (ACM), MVP and paroxysmal AF”. Discussion: The ACM is a rare hereditary heart muscle disease, and the “hot phase” represents its uncommon clinical presentation. Mutations in FLNC gene could be involved in the pathogenesis of ACM. Moreover, there are few cases in literature about the correlation between FLNC mutations and MVP. FLNC mutation may be a cross-sectional substrate for both these pro-arrhythmic conditions.