the present invention relates generally to medical devices ; in particular and without limitation , to unique electrodes and / or electrical lead assemblies for stimulating cardiac tissue , muscle tissue , neurological tissue , brain tissue and / or organ tissue ; to electrophysiology mapping and ablation catheters for monitoring and selectively altering physiologic conduction pathways ; and , wherein said electrodes , lead assemblies and catheters optionally include fluid irrigation conduit for providing therapeutic and / or performance enhancing materials to adjacent biological tissue , and wherein each said device is coupled to or incorporates nanostructure or materials therein . the present invention also provides methods for fabricating , deploying , and operating such medical devices .