Abstract: A catheter includes a cryoablation tip with an electrically-driven ablation assembly for heating tissue. The cryoablation tip may be implemented with a cooling chamber through which a controllably injected coolant circulates to lower the tip temperature, and having an RF electrode at its distal end. The RF electrode may be operated to warm cryogenically-cooled tissue, or the coolant may be controlled to conductively cool the tissue in coordination with an RF treatment regimen, allowing greater versatility of operation and enhancing the lesion size, speed or placement of multi-lesion treatment or single lesion re-treatment cycles. In one embodiment a microwave energy source operates at a frequency to extend beyond the thermal conduction depth, or to penetrate the cryogenic ice ball and be absorbed in tissue beyond an ice boundary, thus extending the depth and/or width of a single treatment locus.

Abstract: An iontophoretic material is provided that uses controlled electrical current derived from two dissimilar galvanic materials to drive oligodynamic metal ions into solution to kill microorganisms on and near the material. Iontophoretic structures or material associated with a medical device are partially or completely covered with one or more covering layers that alter physical, mechanical, chemical, or biological properties of the device and/or the iontophoretic material. In addition to being partially coated or completely enveloped by iontophoretic material or structures, all or a portion of a medical device can be integrated with, impregnated by, or fabricated from an iontophoretic material.