title: Validation of admittance computed left ventricular volumes against real-time three-dimensional echocardiography in the porcine heart.
abstract: The admittance and Wei's equation is a new technique for ventricular volumetry to determine pressure-volume relations that addresses traditional conductance-related issues of parallel conductance and field correction factor. These issues with conductance have prevented researchers from obtaining real-time absolute ventricular volumes. Moreover, the time-consuming steps involved in processing conductance catheter data warrant the need for a better catheter-based technique for ventricular volumetry. We aimed to compare the accuracy of left ventricular (LV) volumetry between the new admittance catheterization technique and transoesophageal real-time three-dimensional echocardiography (RT3DE) in a large-animal model. Eight anaesthetized pigs were used. A 7 French admittance catheter was positioned in the LV via the right carotid artery. The catheter was connected to an admittance control unit (ADVantage; Transonic Scisense Inc.), and data were recorded on a four-channel acquisition system (FA404; iWorx Systems). Admittance catheterization data and transoesophageal RT3DE (X7-2; Philips) data were simultaneously obtained with the animal ventilated, under neuromuscular blockade and monitored in baseline conditions and during dobutamine infusion. Left ventricular volumes measured from admittance catheterization (Labscribe; iWorx Systems) and RT3DE (Qlab; Philips) were compared. In a subset of four animals, admittance volumes were compared with those obtained from traditional conductance catheterization (MPVS Ultra; Millar Instruments). Of 37 sets of measurements compared, admittance- and RT3DE-derived LV volumes and ejection fractions at baseline and in the presence of dobutamine exhibited general agreement, with mean percentage intermethod differences of 10% for end-diastolic volumes, 14% for end-systolic volumes and 9% for ejection fraction; the respective intermethod differences between admittance and conductance in eight data sets compared were 11, 11 and 12%. Admittance volumes were generally higher than those obtained by RT3DE, especially among the larger ventricles. It is concluded that it is feasible to derive pressure-volume relations using admittance catheterization in large animals. This study demonstrated agreements between admittance and RT3DE to within 10-14% mean intermethod difference in the estimation of LV volumes. Further investigation will be required to examine the accuracy of volumes in largest ventricles, where intermethod divergence is greatest.
authors: Division of Cardiology, University of Nebraska Medical Center, Omaha, NE 68114, USA. skutty@unmc.edu
authors: Shelby
authors: S
authors: Kutty
authors: Anil T
authors: AT
authors: Kottam
authors: Asif
authors: A
authors: Padiyath
authors: Keshore R
authors: KR
authors: Bidasee
authors: Ling
authors: L
authors: Li
authors: Shunji
authors: S
authors: Gao
authors: Juefei
authors: J
authors: Wu
authors: John
authors: J
authors: Lof
authors: David A
authors: DA
authors: Danford
authors: Titus
authors: T
authors: Kuehne
mesh_terms: D000818:Animals; D002306:Cardiac Volume / Q000187:drug effects / Q000502:physiology*; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology; D002404:Catheterization / Q000379:methods*; D057785:Catheters; D004280:Dobutamine / Q000494:pharmacology; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology; D013552:Swine; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*
chemical_list: D004280:Dobutamine