A transatrial intravascular temperature management catheter , with first and second heat exchange segments separated from each other wherein the first heat exchange segment being positionable in the inferior vena cava of a patient without blocking the inferior vena cava such that blood can flow past the first heat exchange segment; the second heat exchange segment being positionable in the superior vena cava of the patient when the lower heat exchange segment is located in the inferior vena cava; without blocking the superior vena cava such that blood can flow past the second heat exchange segment; a connecting segment connecting the heat exchange segments and located in the right atrium of the patient when the first heat exchange segment is located in the inferior vena cava and the second heat exchange segment is located in the superior vena cava with neither heat exchange segment extending into the atrium and only the connecting segment being located in the atrium, working fluid being circulatable through the heat exchange segments and the connecting segment to and from a heat exchange system external to the patient, the heat exchange system establishing a temperature of the working fluid at least in part based on a signal representing patient temperature, the connecting segment being configured as an elongated tube with a supply and a return lumen for the second heat exchange segment , the connecting segment being smaller in diameter than the heat exchange segments so as to minimize the risk of the connecting segment contacting the right atrium; and a temperature sensor on the catheter distal to the second heat exchange segment providing the signal representing patient temperature. the first heat exchange segment being positionable in the inferior vena cava of a patient without blocking the inferior vena cava such that blood can flow past the first heat exchange segment; the second heat exchange segment being positionable in the superior vena cava of the patient when the lower heat exchange segment is located in the inferior vena cava; without blocking the superior vena cava such that blood can flow past the second heat exchange segment; a connecting segment connecting the heat exchange segments and located in the right atrium of the patient when the first heat exchange segment is located in the inferior vena cava and the second heat exchange segment is located in the superior vena cava with neither heat exchange segment extending into the atrium and only the connecting segment being located in the atrium, working fluid being circulatable through the heat exchange segments and the connecting segment to and from a heat exchange system external to the patient, the heat exchange system establishing a temperature of the working fluid at least in part based on a signal representing patient temperature, the connecting segment being configured as an elongated tube with a supply and a return lumen for the second heat exchange segment , the connecting segment being smaller in diameter than the heat exchange segments so as to minimize the risk of the connecting segment contacting the right atrium; and a temperature sensor on the catheter distal to the second heat exchange segment providing the signal representing patient temperature. <EOS>