359 Invasive Validation of 'The Oh Factor' – a Simple, One-step Algorithm for Determining Left Ventricular Filling Pressure in All Patients. - Tomlinson, S.; Burstow, D.; Chan, J.; Anderson, B.; Edwards, N.; Chamberlain, R.; Appadurai, V.; Scalia, G. (Heart, Lung & Circulation, 2020)