Catheter systems include direction-sensitive, multi-polar tip electrode assemblies for electroporation-mediated therapy, electroporation-induced primary necrosis therapy and electric field-induced apoptosis therapy, including configurations for producing narrow, linear lesions as well as distributed, wide area lesions. A monitoring system for electroporation therapy includes a mechanism for delivering electrochromic dyes to a tissue site as well as a fiber optic arrangement to optically monitor the progress of the therapy as well as to confirm success post-therapy. A fiber optic temperature sensing electrode catheter includes a tip electrode having a cavity whose inner surface is impregnated or coated with thermochromic/thermotropic material that changes color with changes in temperature. An optic fiber/detector arrangement monitors the thermochromic or thermotropic materials, acquiring a light signal and generating an output signal indicative of the spectrum of the light signal. An analyzer determines an electrode temperature based on the detector output and predetermined spectrum versus temperature calibration data.