Sources and Magnitude of Variation of Echocardiographic Measurements in Normal Standardbred Horses

Abstract

The purpose of this study was to assess the intraobserver variation of various echocardiographic measures in standardbred trotters. Serial echocardiographic examinations were carried out on eight standardbred mares by one ultrasonographer for 5 separate days. During each examination, five nonconsecutive cardiac cycles (frames) were recorded and an average obtained for each individual measure. Various echocardiographic measures were obtained by use of two-dimensional (2-D), M-mode, color flow Doppler and pulsed wave Doppler echocardiography. The total variation in the echocardiographic measurements was split into three levels: the variation between horses, the day-to-day variation within individual horses, and finally the variation within horse on the same day of examination (intercardiac cycle variation). The intraclass correlation coefficient (ICC) was calculated for each measure. The ICC represents the variability of the measurements because of differences between the horses. In general the 2-D, M-mode and color flow Doppler measures had higher ICC values (ICC from 0.63 to 0.95) than the pulsed wave Doppler measures (ICC from 0.24 to 0.46), and the former measures were more repeatable than the pulsed wave measures. Exceptions to that were left ventricular free wall in diastole, the pulmonary artery in systole and the left ventricular mass, which all had low repeatability (ICC from 0.22 to 0.49). The results were used to calculate the relative differences that must be detected to diagnose a statistically significant change between two measurements in an individual horse. Differences from 4.2% to 21.8% must be achieved to document significant changes between serial measurements. A general tendency is that the color flow and pulsed wave Doppler measures require a larger relative difference (11.4-21.8%) between the measures to point out statistically significant cardiac changes than the 2-D and M-mode measures (4.2-13.9%).

Echocardiographic measurements of cardiac dimensions in normal Standardbred racehorses

“…Although several studies report measurements of cardiac dimensions for different breeds of horses, 3,7,8,17,19,20 reference ranges for some of the cardiac parameters measured in other breeds are not available for Standardbred racehorses. 2,4,5,10,11,18,21 The aim of the present study was to develop additional echocardiographic reference standards in a population of 30 healthy Standardbred racehorses in training, identify important influences of weight, age, or sex on these 14 parameters, and compare these data with those previously reported.…”

“…By using these guidelines, normal reference ranges for cardiac dimensions of National Hunt horses, 8 Thoroughbreds, 17 Standardbreds, 5,10,11,18 small ponies, large ponies and Warmbloods 19 have been reported. Although several studies report measurements of cardiac dimensions for different breeds of horses, 3,7,8,17,19,20 reference ranges for some of the cardiac parameters measured in other breeds are not available for Standardbred racehorses.…”

Estabelecimento de índices ecocardiográficos de cavalos de polo

“…Este resultado coincidiu com os achados de Long et al (1992) para um grupo de cavalos de caça (National Hunt horse), Bakos et al (2002) para cavalos trotadores e Young et al (2005) em Puro Sangue Inglês de corrida. Por outro lado, Buhl et al (2004) evidenciaram forte correlação entre o tamanho do DIVE e peso corporal, já Zucca et al (2008) observaram, embora com fraca correlação, diferença estatística do peso corporal em relação ao DIVEd, DIVEs, PLVEs e AO, sendo que ambos os autores estudaram cavalos trotadores.…”

“…Rovira & Muñoz (2009) encontraram diferenças estatísticas para as dimensões cardíacas (PLVE, DIVE, AO, SIV) ao comparar diferentes faixas etárias de potros Lusitanos. Buhl et al (2004) que repetiram quatro vezes as mensurações das dimensões cardíaca em cavalos jovens, durante seis meses, encontraram um significante alargamento cardíaco em cavalos trotadores entre dois e três anos e meio de idade. Sendo assim, Buhl et al (2005) sugeriram que se deve sempre levar em consideração a idade ao se avaliar ecocardiograficamente cavalos jovens.…”

“…Além disso, para Young (1999) o treinamento de corrida aumentou a espessura de parede e da massa do ventrículo esquerdo como um todo. Para Buhl et al (2004), a contratilidade ventricular esquerda em repouso avaliada através da fração de encurtamento, diminuiu após seis meses de treinamento em equinos jovens. Finalmente, Young (2003) e Young et al (2005) verificaram a existência de correlação positiva entre o tamanho do ventrículo esquerdo, função sistólica, e o progresso do desempenho atlético em cavalos de corrida.…”