Abstract: A gas-enriched fluid is provided by the combination of a first fluid, such as a patient's blood, with a second gas-supersaturated fluid, such as an oxygen supersaturated fluid. In this example, a catheter assembly includes a portion that receives the patient's blood from a pump and that receives the oxygen supersaturated fluid from an appropriate fluid source. The oxygen supersaturated fluid is advantageously combined with the blood in an area of laminar flow, and then this gas-enriched fluid is delivered to the patient through an appropriate lumen coupled to the portion of the catheter assembly.

Abstract: A method for regulating the heart rate of a patient comprises inserting into a blood vessel of the patient a catheter having an electrode assembly at its distal end. The electrode assembly comprises a generally circular main region that is generally transverse to the axis of the catheter and on which is mounted at least one electrode. The catheter is directed to an intravascular location wherein the at least one electrode on the electrode assembly is adjacent a selected cardiac sympathetic or parasympathetic nerve. The at least one electrode is stabilized at the intravascular location. A stimulus is delivered through the at least one electrode, the stimulus selected to stimulate the adjacent sympathetic or parasympathetic nerve to thereby cause a regulation of the patient's heart rate.

Abstract: A catheter particularly suitable for bipolar mapping and ablating comprises an elongated flexible body having a distal region and at least one lumen extending therethrough. A tip electrode is mounted on the distal region. The tip electrode has an exposed distal region having an outer diameter, a recessed central region having an outer surface proximal to the exposed distal region, and a proximal region having an outer diameter and an outer surface proximal to the central region. The recessed central region has an outer diameter less than the outer diameters of the exposed distal region and the proximal region. The central region and the proximal region are provided with an electrically insulating and thermally conductive layer over at least a portion of their outer surfaces. A ring electrode is mounted on the recessed central region. The ring electrode has an outer diameter less than the outer diameters of the exposed distal region and the proximal region.

Abstract: A gas-enriched fluid is provided by the combination of a first fluid, such as a patient's blood, with a second gas-supersaturated fluid, such as an oxygen supersaturated fluid. In this example, a catheter assembly includes a portion that receives the patient's blood from a pump and that receives the oxygen supersaturated fluid from an appropriate fluid source. The oxygen supersaturated fluid is advantageously combined with the blood in an area of laminar flow, and then this gas-enriched fluid is delivered to the patient through an appropriate lumen coupled to the portion of the catheter assembly.