A non-invasive system for assessment of left ventricular systolic mechanical performance

Previously developed systems of echocardiography with automatic border detection (Echo-ABD) to generate left ventricular (LV) pressure-area loops were not truly non-invasive: (i) pressures used were either invasive aortic/LV or raw peripheral arterial pressure waveforms uncorrected for wave propagation/reflection effects; (ii) preload reduction was achieved with vasodilator agents perhaps influencing ventricular performance indices. To overcome these problems, the authors combined Echo-ABD area measurement with (i) ascending aortic pressure waveforms derived from non-invasive finger pressure waveforms (FINAPRES) with a mathematical model of the upper limb that was tailored against each individual´s carotid tonometric pressure waveform to accurately match the aortic waveform, and (ii) preload reduction achieved with phase I of Valsalva manoeuvre (VM). This totally non-invasive method should be useful in assessing left ventricular systolic function in clinical settings