New Technique in Cardiac Catheterization: The Advantages of Multisensor Catheters.

Conventional methods of flow and pressure measurement restrict the evaluation of patients to a physiologic ″steady state″ . To follow continuous changes in aortic flow velocity and pressures at multiple sites without additional risk or invasion of the patient, special multisensor catheters were designed for right and left heart studies. Three matched Millar pressure sensors were mounted on a #7 USCI catheter so that pressures from the pulmonary artery, right ventricle and right atrium could be simultaneously recorded. Two identical pressure sensors and a Carolina electromagnetic flow velocity probe were used on a #8 USCI catheter so that aortic flow velocity could be obtained with left ventricular and aortic pressures. The high frequency response of each pressure sensor (flat to 12 KHz) allows the derivation of intracardiac phonocardiograms from multiple sites. Over 50 patients have been successfully studied using both catheters during rest, exercise, and a variety of physiologic and pharmacologic stimuli. Numerous advantages to such an approach include: Multiple high quality pressures, sound signals, and aortic flow velocity using routine catheterization maneuvers; the ability to follow instantaneous changes to a variety of stresses; and excellent data input suitable for computer analysis.