Figure 13.

Case 5: R-SVC draining into the LA. Cardiac catheterization diagram with oxygen saturations and chamber pressures. The oxygen saturations and chamber pressures (mm Hg) of each chamber of the heart as determined by cardiac catheterization are represented in this diagram. Atrial chamber pressures are presented in terms of the atrial waveform, and ventricular pressures are presented in terms of systole and diastole. The left-to-right shunt appears insignificant, as blood in the RA is not significantly more oxygenated (80%) than blood returning from the systemic circulation (79%). This was confirmed by determination of the Qp:Qs as 1.2:1, leading to the conclusion that the right-to-left shunt was dominant in this patient. a, a-wave pressure; FiO2, fraction inspired oxygen; m, mean pressure; v, v-wave pressure.