June Cheng Baron1, Jessica Scott2, Ben Esch2, Kelvin Chow1, Ian Paterson3, Mark Haykowsky4, Richard Thompson1
1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada; 2Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, BC, Canada; 3Division of Cardiology, University of Alberta, Edmonton, AB, Canada; 4Physical Therapy, University of Alberta, Edmonton, AB, Canada
Cardiac performance is modulated in part by ventricular preload, which is determined largely by venous return to the heart and ventricular compliance. We illustrate control of preload using a custom MRI-compatible lower body negative pressure chamber to control venous return. Using standard cines, phase contrast and tissue tagging we measured ventricular volumes, hemodynamics and tissue mechanics at atmospheric (control) and -30 mmHg lower-body pressure (unloading similar to standing). We found significant changes in end-diastolic volumes, stroke volume, blood velocities, intraventricular pressure gradients, torsion and tissue velocity and strain rates, showing effective control of loading in a comprehensive cardiac MRI exam.