Measurement of left ventricular volume by dual-field conductance catheter in humans--comparison with single-field conductance catheter.

摘要

The single-field conductance (SF) method for continuous measurement of left ventricular (LV) volume has achieved widespread use. However, it has been shown theoretically that the ratio between the measured conductance and the actual volume varies between the different interelectrode segments of the catheter due to the convex shape of the equipotential planes at the apex and base. The dual-field conductance (DF) method has recently been introduced and reportedly provides a flatter equipotential plane within the LV. In 11 patients, we compared LV volume measured by biplane cineangiography with conductance volume by the SF and DF methods. Strong correlations were found for both the SF method (r = 0.98) and the DF method (r = 0.99). However, in comparison with the SF method, the DF method gave a regression line with a slope factor, alpha, that was closer to unity, and the intercept of the regression line was small (p < 0.01). The DF method gave a significantly greater segmental stroke volume (SV) in the apex and base than the SF method. The ratio of the DF segmental SV to the SF segmental SV in the apex increased in proportion to the end-diastolic volume (p < 0.05). In conclusion, the DF method may facilitate the accurate measurement of LV volume in the human heart.