787 A CASE OF LEFT-DOMINANT ARRHYTHMOGENIC CARDIOMYOPATHY
Authors: Pietro Spissu Paolo Marco , Maiani Silvia , Pittau Roberta , Montisci Roberta 
Published: December 2022

The case we present involves a 45-years-old male patient who presented to the Emergency Department of our Hospital complaining of epigastric increasing pain associated with nausea and vomiting since the previous afternoon. During night patient had a syncopal episode after having had the feeling of pounding heart at the moment he was having a diarrheal bowel movement. Blood test showed no HS-Troponin nor D-dimer increase. Consultant cardiologist decided to test patient with an exercise test that showed polymorphic ventricular ectopic beats thus leading to hospitalization in our Cardiology Unit.

Here patient was asymptomatic and hemodynamically stable during the whole period. He underwent an echocardiography showing no abnormal findings. For this reason, our team decided to perform a Cardiac Magnetic Resonance that showed LGE at subepicardial level in mid-apical segment of inferior wall and apical segment of interventricular septum. What's more, “India ink artifact” as of intramyocardial adipose infiltration was evident.

Not having made a final diagnosis we decided to implant a Loop Recorder and asked patient to wear a wearable cardiac defibrillator. Genetic testing was also ordered to search for common mutations involved in Arrhythmogenic cardiomyopathy. At discharge, a therapy with metoprolol 50 mg twice per day was prescribed.

Two months later, the result of genetics confirmed the diagnosis of Arrhythmogenic Cardiomyopathy with left ventricular involvement and the patient entered our Unit to undergo Implantable Cardioverter-Defibrillator (ICD) positioning for primary prevention of sudden cardiac death (SCD).

Arrhythmogenic Cardiomyopathy (AC) is a genetic heart muscle disorder whose main pathological feature is normal myocardial tissue replacement by fibrofatty scar tissue and clinical presentation with life-threatening ventricular arrhythmias associated or not with global or regional ventricular systolic dysfunction. Although it was firstly described a predominant right ventricle involvement, nowadays it is known the existence of biventricular and even left-dominant phenotype. Prevalence is estimated between 1:1000 and 1:5000. AC occurs all over the world but has an increased prevalence in Northeastern Italy area. Pathologically fibrofatty tissue replacement begins from the subepicardial layers of myocardium towards subendocardial to become transmural.

Diagnosis is made following a scoring system firstly created in 1994, then revised in 2010 and again in 2020, when the so-called Padua criteria were proposed. They are divided in 6 different categories: morpho-functional ventricular abnormalities, structural myocardial abnormalities, repolarization and depolarization abnormalities, ventricular arrhythmias, genetics. Demonstration of mutation in left-dominant AC related genes is mandatory for diagnosis because clinical and imaging features are not specific for this condition.

Our case demonstrates a challenging diagnosis of left-dominant AC with a perfect example of Padua criteria implementation, because our patient had structural myocardial abnormalities as LGE by CMR plus had a positive molecular genetic testing.