The determination of volume of right ventricular casts using a conductance catheter

Conductance catheters were used to assess the volume of right ventricular models made from post-mortem casts. Models were made from silastic rubber and filled with saline. The correlation between volume assessed by conductance catheter and real volume was investigated as saline was withdrawn from, and injected into, five models. The mean regression between real and conductance-derived volume was 1.05 (SE 0.04 mean R2 0.94 SE 0.02) with Y-intercept -0.25 ml SE 1.72. Parallel wall conductance was assessed through the tricuspid orifice sealed with human tricuspid tissue, or left open, and found to be negligible. There was no difference between volumes measured by a catheter through either the pulmonary or tricuspid orifice. We conclude that conductance catheters are suitable for the assessment of right ventricular volume, despite the complex geometry.