Figure 6

Chamber Pressure-Volume Relationships. Pressure-volume (P-V) relationships in the four chambers for control (no effusion), 900 ml effusion, and 1000 ml effusion. The RA pressure-volume loop is particularly altered with effusion, with a delayed and reduced x-descent, flattened y-descent, elevated pressure, and greater emptying. The left atrium displays similar characteristics to a lesser degree. P-V ventricular loops demonstrate chamber compression and show increasingly reduced stroke output and higher diastolic pressures. Atrial contraction causes a dip in pericardial pressure, drawing down RV pressure as well which causes a notching effect in the diastolic portion of the RV loop.