Recurrent Ventricular Tachycardia

The objective of this study is to determine if there is a meaningful benefit to using the sedative medication dexmedetomidine in the acute treatment of patients with recurrent ventricular arrhythmias, known as electrical storm. This will be a multi-centre, double-blinded, placebo-controlled, randomized trial. Patients with electrical storm will be randomized to receive 48 to 72 hours of dexmedetomidine or placebo as part of their initial treatment in an intensive care unit.

This is a multicenter, prospective, parallel, randomized controlled trial to test for non-inferiority with an ILAM-guided VT ablation compared to conventional voltage- based ablation. The study has two treatment arms: conventional voltage mapping and ablation (control arm). In the investigational arm, the ablation strategy is guided by ILAM to target deceleration zones, blinded to voltage mapping. In the control arm, ablation will be performed to extensively ablate all low voltage regions (\<1.5mV) during sinus rhythm, right ventricular (RV) pacing, or left ventricular (LV) pacing, with discretionary use of pacemapping and activation mapping. In both arms, mapping with be performed with a multielectrode catheter (HD Grid) and ablation will be performed using an irrigated tip catheter (FlexAbility SE or Tactiflex catheters). In the control armonly voltage mapping displays will be utilized (blinded to functional ILAM and fractionation). High density mapping with automated last deflection annotation (Ensite X) will be performed in all patients randomized to ILAM approach during either sinus rhythm or RV pacing.