In-hospital Stellate Ganglion Block for Arrhythmic Storm

Inclusion Criteria: * age ≥ 18 years, * presence of arrhythmic storm defined as more than three sustained ventricular arrhythmias in 24 hours refractory to the standard medical treatment. Exclusion Criteria: * A previous history of cardiac sympathicectomy * Having a neck judged unsuitable for the procedure (previous neck surgery, previous burns, presence of large scars, thyroid goiter) Both the two approaches present in literature and commonly used for this technique are allowed for the study: * The "anatomical" approach which consist in the identification of the Chassaignac's tubercle that represents the point of needle insertion * The "echo-guided" approach Regardless to the approach (anatomical or echo-guided) the doctor will be able to choose, according to the clinical characteristics of the patients, whether to perform a single shot injection of anesthetic or a continuous infusion of anesthetic. In the second case a catheter will be left in place and connected to an infusion pump.