Inclusion Criteria:  arrhythmic storm <24 hours before inclusion:  3 or more episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) terminated by external or internal shock, or incessant VT lasting >30 minutes, or very frequent nonsustained or sustained VT leading to hemodynamic instability with the need of escalation of the therapy clinical indication for LBGS based on the judgment of the physician, independent of the study  Exclusion Criteria:  known allergy to bupivacaine prior LBGS performed <7 days before the study known reversible provoking trigger of the arrhythmias ventricular arrhythmias triggered by premature ectopic beats during bradycardia hemodynamically tolerated idiopathic VT in patients without structural heart disease