LEFT-VENTRICULAR INTRAMYOCARDIAL PRESSURE DETERMINATION USING 2 DIFFERENT SOLID-STATE MICROMANOMETRIC PRESSURE SENSORS

Intramyocardial tissue pressure can influence distribution of ventricu lar blood flow and dynamics during the cardiac cycle. Left ventricular ventral wall subepicardial and subendocardial tissue pressures were m easured simultaneously using two different types of solid-state microm anometers (5F Millar model SPR-230 and Konigsberg Instruments model P1 9 pressure transducers) and compared with left ventricular cavity pres sure. Systolic pressures recorded by Millar and Konigsberg transducers were similar when the sensor surfaces faced the left ventricular cavi ty either in the endocardium or epicardium. Diastolic pressures in the epicardium were higher than left ventricular cavity pressure. When Mi llar and Konigsberg transducers were placed in the epicardium, with th e pressure sensors facing epicardially, the output signal of the Milla r transducer was out of phase with the signal of the Konigsberg transd ucer and left ventricular chamber pressure outputs. Results indicate t hat output signals for intramyocardial pressures vary depending on the direction of the Millar or Konigsberg pressure sensor in the left ven tricular wall. Thus, pressure output signals vary depending on configu ration of the sensor surface, relative flexibility of the connecting c ables, and orientation of the sensor surface with respect to left vent ricular anatomy.