title: Conductance-echocardiography correlation during changes in left ventricular volume.
abstract: Conductance (COND) measurements of left ventricular volume, satisfactory under steady state conditions, may be altered by extraneous factors during complex experiments or cardiac surgery. A reference technique is needed to detect changes in the COND-left ventricular volume relationship. This technique should indicate when recalibration of COND is needed. Accordingly, we assessed the relationship between left ventricular COND and the area of left ventricular short-axis cross section (SACS) by two-dimensional echocardiography during vena caval occlusion. Thirteen anesthetized pigs underwent a median sternotomy and insertion of a COND catheter. Two-dimensional echocardiography and COND were displayed and recorded simultaneously on a digital video monitor. Data were analyzed at end-diastole during the filling phase after vena caval occlusion, because the quality of two-dimensional echocardiography was better during recovery. Results demonstrated a linear relationship between left ventricular COND and SACS at end-diastole, with a positive slope. Correlation coefficients ranged from 0.88 to 1.0 and averaged 0.96 +/- 0.01 (SE). The overall mean relationship was (SACS) = 0.40 (COND) - 17. It is concluded that SACS by two-dimensional echocardiography can be employed to confirm COND measurements of left ventricular end-diastolic volume during laboratory experiments or cardiac surgery. Stability of the SACS-COND relationship indicates that COND calibration is valid. Changes in the SACS-COND relationship would require recalibration of COND. Data markedly deviating from a linear SACS-COND relation reflect experimental error and should be discarded.
authors.affiliation: Department of Surgery, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Cabreriza
authors.forename: M M
authors.initials: MM
authors.lastname: Amirhamzeh
authors.forename: C X
authors.initials: CX
authors.lastname: Jia
authors.forename: H M
authors.initials: HM
authors.lastname: Spotnitz
mesh_terms: D000818:Animals; D003971:Diastole / Q000502:physiology; D004452:Echocardiography; D004553:Electric Conductivity; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*