Overview
A pressure trace is a function of simulation time, scenario, channel, rhythm, rate and respiratory state. Atrial and pulmonary reference contours use piecewise smooth interpolation; ventricular and arterial functions add their own systolic, relaxation and runoff behavior.
The waveforms are designed to make physiological relationships readable. Their exact shape, frequency content and transient response are not recorded catheter data or a complete fluid-filled catheter/vascular impedance simulation.
Atrial contours
RA and wedge contours combine a, c and v waves with x and y descents. The engine removes coordinated atrial contraction when appropriate and adjusts atrial timing for dissociation or conduction block. Wedge has a modeled transport delay of 0.12 cardiac cycles.
MR increases the wedge v wave; TR enlarges the RA systolic wave and alters the x descent. MS/TS amplify atrial contraction when present and slow emptying. Tamponade blunts the RA y descent; constriction/restriction retain prominent early emptying. Contours are recentered around their intended reference mean before later respiratory/treatment modifications.
Ventricular contours
RV pressure has a rapid systolic rise, low-pressure relaxation and an end-diastolic level distinct from its minimum. Constriction/restriction introduce a rapid early diastolic dip followed by a plateau. LV pressure follows the pullback model, including filling pressure, outflow gradients, rate and contractility.
Beat strength, ectopy, pauses, pacing and respiratory loading change the actual pressure function. Ventricular systolic pressure must be compatible with the corresponding arterial pressure during ejection; low-flow or supported states are not merely rescaled normal loops.
Arterial and PA contours
PA systolic/diastolic endpoints are solved from the desired mean and pulse contour. The mean is based on contour integration, not universally (systolic + 2 × diastolic)/3. Pulmonic regurgitation uses faster diastolic runoff and a different contour.
Aortic/arterial pressure includes systolic ejection, diastolic runoff and valve-specific features: a slow upstroke in AS, widened runoff in chronic AR, and spike-and-dome behavior in HOCM. Low flow narrows pulse amplitude. During continuous support, dedicated arterial reservoir functions replace the ordinary ejection contour.
Which number is which
Mean pressure is a time average. A v-wave peak is not mean LA pressure; ventricular minimum is not EDP; aortic peak and LV peak need not occur together. Mouseover explanations use channel and event timing, so an annotation is an explanation of this synthetic segment rather than an independent diagnosis.
References & further reading
