- age <18 years - pregnancy (to be excluded using serum betahcg in women of childbearing age) - signs of infection, eczema or psoriasis at the application site - active malignancy - implanted cardiac pacemaker, deficrillator or other active implanted electrical devices - patient unable to consent - heart rate <60/min - known vagal hypersensitivity - history of hemophilia

- age <18 years - pregnancy (to be excluded using serum betahcg in women of childbearing age) - signs of infection, eczema or psoriasis at the application site - active malignancy - implanted cardiac pacemaker, deficrillator or other active implanted electrical devices - patient unable to consent - heart rate <60/min - known vagal hypersensitivity - history of hemophilia