Repeatability of standard transthoracic echocardiographic measurements in horses.

OBJECTIVES: To assess the repeatability of commonly employed transthoracic echocardiographic measurements in standing horses.
DESIGN: Thirteen healthy 3- to 4-year-old fit Standardbred geldings with a mean weight of 411 (SEM +/- 10) kg were studied. The horses' environment, feeding and management regimens were standardised. All measurements were performed by the same investigator at the same time every day for three consecutive days. PROCEDURES: Standard transthoracic measurements were made on all horses. Each measurement was performed over three consecutive cardiac cycles on 1 day and all measurements were performed over 3 consecutive days. Summary statistics of each day were then compared using an analysis of variance with times as a repeated measures factor. Statistical significance was set at P < 0.05.
RESULTS: Many of the standard echocardiographic measurements used to derive quantitative and functional information about the equine heart have a low intra-observer variability.