Speckle Tracking Echocardiography Detects Strain Changes in Murine Heart during Acute Ischemia Perfusion

Myocardial infarction (MI) is the leading cause of mortality and morbidity worldwide. Rapid loss of cardiomyocytes induced by MI and subsequent reperfusion results in remodeling of left ventricular (LV) cardiac architecture to support the contractile functioning of the heart. The functioning of such a remodeled heart subsequently leads to a heart failure. Though global strain measurements are considered to be an index to characterize heart function, the prognosis of an imminent heart failure needs better understanding for providing adequate treatment. This is because, vital measurement parameters such as the ejection fraction (EF), LV end-systolic stroke volume remains within normal limits and hence, measurement of LV global function remains insufficient. 2D-Speckle tracking echocardiography (STE) is a novel method for determining both globular and regional strain and strain rate. The principle used in STE is the measurement of distance between 2 stable patterns or “speckles” on a 2D echocardiographic image of a LV segment during a cardiac cycle.The aims of our study were to measure regional myocardial strain and strain rate in both the radial (Sr) and longitudinal (Sl) (MI) and (MI+MSC) hearts using STE to detect changes in LV wall deformation within hours after MI. MI was performed by ligation of the left coronary artery for 90 minutes followed by reperfusion for 24 hours. The mean strain values for the radial strain at the post.apex were measured at MI (5.65±1.36 %), MI+MSC (17.87±2.93 %), and at the Ant apex it was measured at MI (6.69±1.36%) and MI+MSC (15.56±2.92%). The longitudinal strain for the post apex at MI (-8.40±3.44 %) MI+MSC (-11.65±2.33 %) & ant apex at MI (-4.79±0.57 1/s) and MI+MSC (-5.67±1.29 1/s). Overall, our data demonstrated an increase in strain and strain rate measures with the introduction of stem cells when compared to a sham & a MI group with no stem cells. The presence of stem cells altered the strain and strain rate values in a positive manner.