Validation of the Conductance Catheter Method to Evaluate Dynamics of a Biomechanical Heart

The conductance catheter method has been applied to evaluate dynamics of a heart cycle. Its validation for the functional analysis of Biomechanical Hearts (BMH), autologous muscular blood pumps with a stabilizing pumping chamber, has not yet been reported. In a test apparatus, a fluid filled pumping chamber of a BMH was hydraulically compressed by a moving piston. Volume shift was measured simultaneously by a conductance catheter and by a movement analyzer as control with variation of catheter’s electrical field, the pumping chamber’s surrounding conductivity and the piston velocity. For all these conditions, no significant influence on the measurement accuracy was observed (p>0.4,p>0.33,p>0.18). Volumes measured by both methods showed a maximum relative error of 6.1±0.4% (R=0.99). Peak flows however demonstrated a remarkably high relative error up to 48% (R=0.955). Aberrations in peak flows as well as in volumes may be compensated by computed calibration formulae. The conductance catheter method offers a valuable tool for the evaluation of Biomechanical Heart dynamic properties. (160 W).