The Vitatron implantable transvenous leads are designed to be used with pulse generators as part of a cardiac pacing system. When the tri-cuspid valvular disease is present, the use of a transvenous ventricular lead is contraindicated. In patients with mechanical tri-cuspid heart valves, use of endocardial ventricular leads is contraindicated. The use of a passive fixation atrial lead may be contraindicated in the absence of a right atrial appendage. Do not use steroid-eluting leads in patients who use a single dose of 1.0 mg dexamethasone sodium phosphate. An implanted lead forms a direct, low-resistance current path to the myocardium. It is important to use only battery-powered equipment during lead implantation and testing to protect against fibrillation caused by alternating currents.