Influence of load changes on tricuspid inflow

In healthy subjects, the right ventricular filling pattern estimated from tricuspid valve inflow is highly load-dependent. This can be clearly demonstrated by changes of Doppler inflow tracings recorded during tidal breathing at rest. The aim of our study was to test the magnitude of tricuspid inflow changes during more pronounced load changes induced by specific maneuvers. In 31 apparently healthy subjects (16 men and 15 women, mean age 36+/-16 years) we recorded pulsed Doppler tracings of tricuspid inflow during forced inspiration, elevation of lower extremities (increased preload) and handgrip exercise (increased afterload). The obtained values were compared with end-expiratory phase of tidal breathing at rest. We found a significantly larger increase in the early and late filling velocities (for E and A p<0.001) under the conditions of increasing preload (elevation of legs) and less pronounced, but still significant changes with isometric exercise (for E p<0.001 and for A p<0.01). We conclude that the right ventricular filling pattern in healthy humans is highly load-sensitive and for this reason the effect of any intervention (e.g. pharmacological) must be studied under strict and well-defined resting conditions.