Introduction: Arrhythmogenic right ventricular car-diomyopathy (ARVC) is an important cause of malignant ventricular arrhythmias in young population. The diagnosis of ARVC can be difficult, and sometimes belated, as it requires the meeting of structural, histo-logical, genetic and electrocardiographic criteria. The treatment of the disease is pharmacological, but it can include the implantation of devices such as implantable cardioverter-defibrillator (ICD), and also complex in-terventions – substrate ablation.

Case presentation: We present the case of a 60 years old woman with sudden onset of palpitations, with a duration of hours, recurrent episodes since December 2018, without syncope. The patient has no significant history of disease, nor history of sudden cardiac death in family. At the emergency department she is sta-ble hemodynamic, with no signs of heart failure. The electrocardiogram shows initially sinus rhythm with negative T waves in V1-V3, isolated premature ventri-cular contractions (PVC) with BRS-like morphology, transition in V4. Afterwards sustained ventricular ta-chycardia (VT) is recorded, self-limiting, with good hemodynamic stability, morphology similar to PVCs, highly suggestive for origin at the apex of right ventri-cle. At the admission in the intensive care unit (ICU) the patient repeats sustained VT chemically converted into sinus rhythm. The echocardiography shows nor-mal left ventricular function, but it is seen hypokinesia of the free wall of the right ventricle and a diameter of the right ventricular outflow tract (RVOT) of 37 mm from parasternal short axis view. Moreover, a coronary angiogram is performed that shows normal coronary arteries. In conclusion, the patient reunites the diagnostic criteria for ARVC – one echocardiographic major criterium and two electrocardiographic major criteria (repolari-zation abnormalities and arrhythmias). Treatment with betablocker and amiodarone is started. Furthermore, the patient has class IIa indication for ICD implant, pro-cedure that is done without complications. 2 months following the initial hospital admission the patient co-mes for 3 ICD shocks in 24 hours. The ICD interrogation shows numerous episodes of monomorphic VT, most of them stopped by antitachycardia pacing and 3 of them correctly treated by shock, thus meeting the criteria for electrical storm. Given all of the above the patient is proposed for endocardial substrate ablation. The procedure is done with the help of an electroana-tomical mapping system. Dilated right ventricle is do-cumented, with scars at RVOT and an extensive scar at the right ventricular free wall. Late potentials are detec-ted in both scars, especially in the right ventricular free wall. Radiofrequency catheter ablation is performed at the late potentials area and at the upper limit of the ri-ght ventricular free wall scar. No VT is inducible at the end of the procedure. At the follow up at 1 month and 2 months the patient is free of symptoms, with no new arrhythmia recorded at the ICD interrogation.

Particularity: The case shows the importance of a de-tailed echocardiographic evaluation for patients with ventricular arrhythmias, because the typical manifes-tations of ARVC can be late, and they require a highly degree of suspicion for establishing a correct diagno-sis. Substrate ablation for VT represents a good way in reduction the number of ventricular arrhythmias in patients with ARVC, with recurrent episodes of TV or shocks, despite the antiarrhythmic treatment. Moreo-ver, substrate ablation represents an important option of treatment in patients who can’t tolerate antiarrhythmic drugs or refuse to take it. Despite the considerable rate of recurrence of ventricular arrhythmia after the ablation, the use of this method of treatment is associa-ted with a better survival free of arrhythmia.