Association between echocardiographic structural parameters and body weight in Wistar rats

// Silvio A. Oliveira-Junior 1, * , Paula F. Martinez 1, * , William Y.C. Fan 2, * , Bruno T. Nakatani 2, * , Luana U. Pagan 2, * , Carlos R. Padovani 3, * , Antonio C. Cicogna 2, * , Marina P. Okoshi 2, * , Katashi Okoshi 2, * 1 School of Physical Therapy, Federal University of Mato Grosso do Sul, Campo Grande, MS, Brazil 2 Botucatu Medical School, Sao Paulo State University, UNESP, Botucatu, SP, Brazil 3 Botucatu Biosciences Institute, Sao Paulo State University, UNESP, Botucatu, SP, Brazil * These authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation Correspondence to: Katashi Okoshi, email: katashi@fmb.unesp.br Keywords: development, physiological cardiac remodeling, rat, echocardiogram, cardiac structures Received: November 16, 2016      Accepted: January 26, 2017      Published: February 13, 2017 ABSTRACT Background: The association between echocardiographic structural parameters and body weight (BW) during rat development has been poorly addressed. We evaluated echocardiographic variables: left ventricular (LV) end-diastolic (LVDD) and end-systolic (LVSD) diameters, LV diastolic posterior wall thickness (PWT), left atrial diameter (LA), and aortic diameter (AO) in function of BW during development. Results/Materials and Methods: Male Wistar rats ( n = 328, BW: 302–702 g) were retrospectively used to construct regression models and 95% confidence intervals relating to cardiac structural parameters and BW. Adjusted indexes were significant to all relationships; the regression model for predicting LVDD (R2 = 0.678; p < 0.001) and AO (R2 = 0.567; p < 0.001) had the highest prediction coefficients and LA function the lowest prediction coefficient (R2 = 0.274; p < 0.01). These relationships underwent validation by performing echocardiograms on additional rats ( n = 43, BW: 300–600 g) and testing whether results were within confidence intervals of our regressions. Prediction models for AO and LA correctly allocated 38 (88.4%) and 39 rats (90.7%), respectively, within the 95% confidence intervals. Regression models for LVDD, LVSD, and PWT included 27 (62.7%), 30 (69.8%), and 19 (44.2%) animals, respectively, within the 95% confidence intervals. Conclusions: Increase in cardiac structures is associated with BW gain during rat growth. LA and AO can be correctly predicted using regression models; prediction of PWT and LV diameters is not accurate.