Echocardiographic Speckle-Tracking Based Strain Imaging for Rapid Cardiovascular Phenotyping in Mice

Abstract

Rationale High-sensitivity in vivo phenotyping of cardiac function is essential for evaluating genes of interest and novel therapies in small animal models of cardiovascular disease. Transthoracic echocardiography is the principal method currently used for assessing cardiac structure and function; however, standard echocardiographic techniques are relatively insensitive to early or subtle changes in cardiac performance, particularly in mice. Objective To develop and validate an echocardiographic strain imaging methodology for sensitive and rapid cardiac phenotyping in small animal models. Methods and Results Herein, we describe a modified echocardiographic technique that utilizes speckle-tracking based strain analysis for the non-invasive evaluation of cardiac performance in adult mice. This method is found to be rapid, reproducible, and highly sensitive in assessing both regional and global left ventricular (LV) function. Compared to conventional echocardiographic measures of LV structure and function, peak longitudinal strain and strain rate were able to detect changes in adult mouse hearts at an earlier time point following myocardial infarction (post-MI) and predicted the later development of adverse LV remodeling. Moreover, speckle-tracking based strain analysis was able to clearly identify subtle improvement in LV function that occurred early in response to standard post-MI cardiac therapy. Conclusions Our results highlight the utility of speckle-tracking based strain imaging for detecting discrete functional alterations in mouse models of cardiovascular disease in an efficient and comprehensive manner. Echocardiography speckle-tracking based strain analysis represents a method for relatively high-throughput and sensitive cardiac phenotyping, particularly in evaluating emerging cardiac agents and therapies in mice.

Heart Rate Reduction With Ivabradine Protects Against Left Ventricular Remodeling by Attenuating Infarct Expansion and Preserving Remote‐Zone Contractile Function and Synchrony in a Mouse Model of Reperfused Myocardial Infarction

“…Baseline strain and strain rate values were in good agreement with previously published values using the same scanner model and analysis software 23. Global analyses revealed E || reductions from baseline to day 2 post‐MI of −17.8±0.5 to −11.8±0.6 in controls and −18.6±0.7 to −11.6±1.1 in the ivabradine group (34% and 37% reductions in the control and ivabradine groups, respectively; Figure 5A).…”

“…Longitudinal strain was chosen for strain analysis because it has been shown to be more sensitive and reliable than circumferential and radial strain for measuring LV function and has been demonstrated to have strong clinical relevance 23, 24, 25…”

Evaluation of Global and Regional Strain in Patients with Acute Coronary Syndrome without Previous Myocardial Infarction

“…Although ETT and cardiac scan have acceptable sensitivity and specificity, high rate of false positive and false negative results as well as their time-consuming nature causes them not to be an appropriate choice in emergency set. STE is a new non-invasive imaging technique that permits assessment of global and regional myocardial function independently from both cardiac translational movements and beam angle in a short time (1)(2)(3)(4)(5). STE is accepted as a diagnostic method in ACS cases for evaluation of myocardial wall motion at rest and during stress (12).…”

“…Speckle Tracking Echocardiography (STE) is a new non-invasive imaging technique that permits assessment of global and regional myocardial function independently from both cardiac translational movements and beam angle (1)(2)(3)(4). It is based on analysis of spatial displacement of spots during cardiac cycle and can capture myocardial deformation in 3 dimensions: radial, circumferential, and longitudinal.…”

“…It also offers a superseded way to evaluate strain and strain rate and can conquer many traditional problems related to angle-dependent methods. Before this technique, only Magnetic Resonance Imaging (MRI) provided a valid analysis of deformities in myocardium (1)(2)(3)(4)(5). Although this method was primarily introduced as an exclusive analyzer of Left Ventricular (LV) function, many papers have extended its usage to assessment of other chambers (2,4).…”