Quantitative echocardiographic [corrected] evaluation of mitral endocardiosis in dogs using ratio indices.

This study compares M-mode echocardiographic ratio indices (ERIs) in dogs with mitral regurgitation due to chronic valvular disease (CVD/MR) for their ability to discriminate and quantify associated echocardiographic changes. Weight-based M-mode ERIs were determined retrospectively for 2 groups of dogs, normal (n = 47) and CVD/MR (n = 176). The CVD/MR group was further subdivided into those with (CVD/MR B, n = 74) and without (CVD/MR A, n = 102) left-sided congestive heart failure (LCHF). ERIs were compared descriptively (summary statistics) and also by receiver-operator characteristic curve areas (ROCAs) for their ability to discriminate between groups. Univariate logistic regression (LR) models were used to estimate the odds ratio for each ERI as a predictor of the CVD/MR condition as well as to predict LCHF within the CVD/MR group. A novel ERI (wdeltaA), designed to express body size-normalized short-axis stroke area, was sensitive (90%) and specific (98%) to discriminate between normal and CVD/MR at a cutoff value of 1.8 standard deviations (wdeltaA = 2.1). Prediction of LCHF within the CVD/MR group was more problematic, but an ERI expressing left atrial size (wLA) showed 76% sensitivity and 81% specificity at a cutoff value of 5.2 standard deviations (wLA = 1.55). Ours was a descriptive study of echocardiographic patterns of pathology associated with CVD/ MR and determined which ERIs are sensitive and specific for CVD/MR and for LCHE ERIs normalize echocardiographic data for body size in dogs and are well-suited to quantitative descriptions and analysis.

M-mode echocardiographic ratio indices in normal dogs, cats, and horses: a novel quantitative method.

A novel method for quantitative echocardiographic interpretations is introduced based on the calculation of ratio indices in which each raw M-mode measurement is divided by the aortic root dimension (Ao). "Aorta-based" indices were calculated with the animal's measured aortic root dimension (Ao(m)) as the length standard. Conversely, "weight-based" indices employed an idealized estimate of aortic dimension (Ao(w)) with a weighted least squares linear regression against the cube root of body weight (Ao(w) = kW(1/3)). Use of these indices circumvented undesirable statistical characteristics inherent in linear regression of echocardiographic dimensions against body weight and, to a lesser extent, body surface area. Compared with the regressions, ratio indices resulted in substantial refinement of the predictive range for each M-mode measurement in dogs, particularly with decreasing body size. Weight-based indices outperformed aorta-based indices in this regard. To refine the predictive range, neither type of index was clearly advantageous in cats compared with the simple average method typically employed for that species. Several of the raw M-mode measurements, however, were correlated with body weight in cats and horses, indicating the need for an appropriate correction for body size in these species. The ratio index method was suitable for this purpose. Summary statistics derived from normal dogs (n = 53), cats (n = 32), and horses (n = 17) are presented for each index, including novel clinical indices calculated from area ratios. The latter were designed to represent body size-adjusted lett ventricular stroke area (ie, volume overload) and myocardial wall area (ie, hypertrophy).