Exploring difference in atrioventricular valve opening times to predict elevated left atrial pressure - a novel approach to left atrial pressure quantification on cardiovascular MRI

Background The ratio of the transmitral early inflow velocity (E wave) and the tissue Doppler mitral annular velocity (e’ wave) can be used to measure left atrial pressure on the echocardiographic examination. An elevated E/e’ (>15) on echo Doppler is an established measure of elevated LAP. Unlike echo, cardiac MRI (CMR) has no non-invasive measure of LAP. Normally both the atrioventricular valves open simultaneously or the tricuspid valve opens earlier than the mitral valve due to a very short rightsided isovolumic relaxation time (IVRT). Elevated LAP shortens the left sided IVRT and therefore causes the mitral valve to open earlier than expected. Also, elevated LAP indirectly leads to elevation of right heart pressures causing lengthening of the tricuspid valve isovolumic relaxation time resulting in delayed tricuspid valve opening. We investigate the role of using the time differential of mitral and tricuspid opening as novel parameter of LAP measurement on CMR.