BACKGROUND Coronary microvascular resistance during maximal hyperemia is generally assumed to be unaffected by percutaneous coronary interventions (PCIs). We assessed a velocity-based index of hyperemic microvascular resistance (h-MR(v)) by using prototypes of a novel, dual-sensor (Doppler velocity and pressure)-equipped guidewire before and after PCI to test this hypothesis. METHODS AND RESU...

The discharge characteristics of mechanoreceptors located in the left superior vena cava were determined in an in vitro preparation developed from the rat. Two classes of receptors with afferent fibers in the vagus were identified on the basis of their response to steps of pressure. Slowly adapting receptors (n = 18) discharged as long as pressure was above threshold and exhibited a biphasic de...

This study attempted to evaluate the relative roles of vessel distensibility and vessel recruitment in the changes in pulmonary blood volume induced by changes in pulmonary intravascular pressure. Pulmonary blood volume was determined by a double-injection indicator-dilution technique in eight anesthetized open-chest dogs with a right and left ventricular bypass which allowed independent contro...