The use of strain, strain rate, and displacement by 2D speckle tracking for assessment of systolic left ventricular function in goats: applicability and influence of general anesthesia

Abstract

BackgroundAssessment of left ventricular (LV) systolic function can be achieved by conventional echocardiographic methods, but quantification of contractility, regional myocardial function, and ventricular synchrony is challenging. The goal of this study was to investigate the applicability of two-dimensional speckle tracking (2DST) to characterize segmental and global wall motion for assessment of LV function and LV synchrony in healthy goats. We aimed to describe the techniques, report normal values of a variety of 2DST indices, and determine the influence of general anesthesia.MethodsProspective study on 22 healthy female Saanen goats (3.7 ± 1.1 y, 60.2 ± 10.5 kg [mean ± SD]). All goats underwent two transthoracic echocardiographic examinations, the first standing and unsedated and the second 7.4 ± 3.5 days later during isoflurane anesthesia and positioned in sternal recumbency. Data analyses were performed offline, blinded, and in random order. Left ventricular longitudinal, radial and circumferential strain and strain rate as well as longitudinal and radial displacement were measured using 2DST methods. Summary statistics were generated and differences of 2DST variables between myocardial segments and treatments (i.e., awake vs. anesthetized) were assessed statistically (alpha level=0.05).ResultsEchocardiographic analyses by 2DST were feasible in all goats and at both time points. Longitudinal systolic strain, strain rate and displacement followed a gradient from apex to base. Absolute systolic strain was generally lower and strain rate was higher in awake goats compared to anesthetized goats. Circumferential and radial indices did not consistently follow a segmental pattern. Generally, peak strain occurred later in anesthetized goats compared to awake goats. General anesthesia did not significantly influence LV synchrony.Conclusions2SDT is a valid method for non-invasive characterization of LV wall motion in awake and anesthetized goats. The results of this study add to the understanding of LV mechanical function, aid in the diagnosis of global and segmental LV systolic dysfunction, and will be useful for future cardiovascular studies in this species. However, effects of anesthesia and species-specific characteristics should be considered when goats are used as animal models for human disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12947-015-0005-8) contains supplementary material, which is available to authorized users.

Two-dimensional speckle tracking echocardiography in goats: repeatability, variability, and validation of the technique using an exercise test and an experimentally induced acute ischemic cardiomyopathy.

“…Another major limitation of the study was the choice of recorded image orientation for 2DST analysis. Analyses were performed only on short axis views of the LV, while short axis and long axis views were used in humans, dogs, horses and in the previous study in goats [3,20,23,29,36]. In humans, the apical 4-chambers long axis view is often used for colour flow and pulsed wave Doppler echocardiography, for tissue Doppler imaging, and for acquisition of myocardial longitudinal strain [2,36].…”

Two-dimensional speckle tracking echocardiography in goats: repeatability, variability, and validation of the technique using an exercise test and an experimentally induced acute ischemic cardiomyopathy.

“…The use of 2DST has been described in several domestic animals species such as dogs [14], horses [15,16], pigs [17], sheep [18], calves [19] and goats [20]. This technique has been recommended to assess LV function in small animals with several cardiac diseases, like chronic mitral valve regurgitation in dogs [21].…”

“…In horses, this technique was successfully applied to detect myocardial injuries occurring with various myopathies [22,23]. In goats, the 2DST technique has been demonstrated to be feasible in standing position and under general anaesthesia [20] but, to the best of the authors' knowledge, neither repeatability studies of the technique, nor 2DST measurements in 4 exercising animals or in animals with cardiac disease have been reported in goats.…”

“…Another major limitation of the study was the choice of recorded image orientation for 2DST analysis. Analyses were performed only on short axis views of the LV, while short axis and long axis views were used in humans, dogs, horses and in the previous study in goats [3,20,23,29,36]. In humans, the apical 4-chambers long axis view is often used for colour flow and pulsed wave Doppler echocardiography, for tissue Doppler imaging, and for acquisition of myocardial longitudinal strain [2,36].…”

Two-Dimensional Speckle Tracking for Quantitative Right Ventricular Wall Motion Analysis in Horses Affected by Equine Asthma

“…It is also valuable in cardiac resynchronization therapy (D'Andrea et al, 2007;Shi et al, 2009), diagnosis of arrhythmogenic right ventricular cardiomyopathy (Teske et al, 2009) and other systemic diseases secondarily affecting right heart function (Kosmala et al, 2007;Lindqvist et al, 2006;Matias et al, 2009). In veterinary medicine, speckle tracking has been used so far to evaluate left ventricular function in dogs (Chetboul et al, 2007b), horses (Schwarzwald et al, 2009a) and goats (Berli et al, 2015). In dogs, it was shown that the left ventricular contractility is impaired and the speckle tracking parameters were changed in dogs with cardiomyopathy (Chetboul et al, 2007a).…”