An implantable cardiac defibrillation/cardioversion electrode. The electrode is elongated and comprises a distal active region and a proximal lead region. Conductive discharge and insulative materials occupy distinct surfaces along the length of the active region. The active region is preformed to adopt a planar spiral patch configuration under relaxed conditions. Additional flexible preformed insulative and conductive discharge wings are provided to attach to the corresponding surfaces of the active region. A method of implantation of the spiral patch is disclosed for deployment by straightening the electrode and introducing the same through an opening that approximates the cross section of the straightened electrode.