Cardiac monitor of resistive phenomena

We used the left ventricular pressure-derivative loop(PDL) to generate new ways to demonstrate peripheral vascular resistance(PVR) and reflection phenomena. The continuously regenerating (per heart beat) PDL is formed with the left ventricular pressure(PLV) on the Y-axis and its first derivative on the x-axis. The P, v was obtained with a catheter tip manometer in 565 runs in 13 canine experiments. The resistive variations were obtained pharmacologically with norepinephrine and nitroprusside, and mechanically with obstructions at different sites on major vessels and aorta. Major distal obstructive and high resistive states elevated the right upper quadrant of the PDL and flattened the peak. High aortic obstructions also produced variable curlicues on the peak of the PDL. The initial post peak change and the height/angle of the left upper quadrant are sensitive indicators of normal and lowered PVR, and moderate indicators of elevated PVR. | The PDL is a new, practical, and effective cardiac monitor of vascular resistive phenomena. Support received from the Bromstedt, Leach, and Miklos Group Funds.