178 ARRHYTHMIC STORM IN ATTR WILD TYPE AMYLOIDOSIS: AN UNUSUAL COMBINATION

Cardiac amyloidosis (CA) is characterized by extracellular protein fibril deposition in the myocardium leading to restrictive heart failure. Both atrial and ventricular arrhythmias are common in CA. Study have shown up to one half of patients with CA die suddenly. However, the most common cause of sudden death has been historically through to be secondary electromechanical dissociation rather than a lethal ventricular arrhythmia. We present the case of a 84 years old man, with a history of hypertension, dyslipidaemia, and prior smoking. In June 2020 the patient was admitted to the emergency room of our hospital due to an episode of hemodynamically unstable sustained ventricular tachycardia (SVT). The patient underwent electrical cardioversion with restoration of sinus rhythm. An echocardiogram that showed a slightly reduced ejection fraction (FE = 45%), severe concentric hypertrophy, grade 3 diastolic dysfunction with high pressures in the left ventricular (LV) cavity, and a reduced GLS (-13.8%) with a typical apical-sparing aspect. A cardiac magnetic resonance (Fig.1). was performed showing a diffuse area of LGE with a subepicardial pattern involving left ventricular and atrial segments, compatible with myocardial storage disease. In order to complete the diagnostic workout, we performed a bone scintigraphy (Fig.2). (Positive for CA, with Perugini score grade 2), a genetic test (negative for hATTR-CA mutations) and free light chain in serum (negative for AL-CA). The patient was discharged at home after ICD implantation in secondary prevention and prescribed appropriate heart failure therapy. In May 2022 the patient was readmitted in emergency room for dyspnea during an arrhythmic storm characterized by several SVTs and ICD interventions, and atrial fibrillation (FA). After stabilization of clinical parameters, the patient was hospitalized in our ward. We optimized medical therapy with metaprololo 100 mg 1 cp BID, cordarone 600 mg ev and mexiletina 200 mg cp BID. During the hospitalization we succeeded in reducing SVT burden. However, ventricular PVCs and slow SVT remained. For this reason, we decided to perform an electrophysiological study (EPS) followed by catheter ablation. The EPS found two low voltage areas (Fig.3). The first were found under the aortic valve; the second was an area of dense scar and fragmented potentials along the basal-posterior wall. After ablation of the first area we succeeded in removing clinical PVCs. During the ablation of the second area the procedure was complicated by ventricular fibrillation that required advanced life support and many electrical shocks. The patient was discharged at home in absence of further episodes of SVTs with optimized therapy At a three moths follow up no arrhythmic events were recorded.