A leadless implantable cardioverter defibrillator (5) for treatment of sudden cardiac death includes a controller and at least one remote module. The defibrillator does not require transvenous/vascular access for intracardiac lead placement. The controller is leadless and uses subcutaneous tissue in proximity of the chest and abdomen for both sensing and defibrillation. The controller and one or more remote sensors sense a need for defibrillation and wireless communicate with the controller. The controller and one of the sensors discharge a synchronized defibrillation pulse to the surrounding subcutaneous tissue in proximity to the heart.