Rhythmic complications seem common after left ventricular (LV) assist device (LVAD), especially in the early phase of implantation (<30 days). We sought to identify the incidence and risk factors of arrhythmic storm (AS) occuring after Heart Mate^® 2 device (HM2, Thoratec Corporation, Plesanton, CA, USA) implantation. All patients with HM2 implanted in our institution were included. All clinical and ultrasound data were restrospectively collected. Each patient was regurlarly followed until the end of data collection in April 2015. From January 2008 to December 2014, forty-three patients (39 male, 57±11 yo) with severe myocardiopathy (LV Ejection Fraction of 20±5%), mainly ischemic (74%), in bridge to cardiac transplantation (72%), were included. Before implantation, 20 had ICD (16 for prophylaxic indication) and 13 had a prior history of sustained ventricular tachycardia (VT). The overall mortality rate was 60% with a mean follow-up of 18±18 months. 12 patients experienced AS in the first 30 days after implantation, with a median delay of 9±8 days. Early AS often occured in heavier patients (81 vs 69kgs, p<0.05) or with larger body surface area (1.99 vs 1.81m2, p<0.01), in patients with prior sustained VT (50% vs 22%, p=0.08) or long-term treated by betablocker therapy (75% vs 45%, p=0.09). The cardiomyopathy etiology, the indication of assistance or the emergy of implantation were not associated with early AS, as an AS occuring just prior LVAD implantation (11 patients). No AS occured under a Betablocker therapy. VT ablation was performed in 10 patients under assistance. The substrate of VT was not related to HM2 cannula. Arrhythmic storm are frequent (28%) in the early period of HM II implantation.