A system for the on-line acquisition, visualization, and analysis of pressure-area loops

Transesophageal echocardiography is a widely accepted technique for the assessment of left ventricular (LV) function in the operating room, intensive care unit, and cardiac catheterization suite. Not only do the images generated by these systems provide the observer with dynamic views of currently ongoing cardiac mechanics, but the computed LV area values obtained by the automated border detection system can be converted to an analog signal and then used to generate pressure-area loops if LV pressure is measured simultaneously. The intraventricular area has been shown to correlate closely with intraventricular volume and to vary proportionately. Therefore, it can be substituted for volume to generate pressure-area loops that display equivalent behavior to external perturbations as pressure-volume loops. Visualization of these waveforms and the values extracted from them, along with the associated hemodynamic values, provide valuable insight into ventricular function and heart-lung interactions. This paper describes a system that was designed and developed to acquire, display, store, and analyze pressure-area loops in addition to other associated hemodynamic signals of interest.