High Frequency Ultrasound Imaging Detects Cardiac Dyssynchrony in Noninfarcted Regions of the Murine Left Ventricle Late After Reperfused Myocardial Infarction

Abstract

Cardiac dyssynchrony in the left ventricles of murine hearts late (>= 28 days) after reperfused myocardial infarction (post-MI) was assessed using high frequency 30 MHz B-mode ultrasound imaging. Nine post-MI and six normal C57Bl/6 mice were studied in both short-and long-axis views. Regional time to peak displacement (T peak_d ) and time to peak strain (T peak_s ) were calculated in 36 sectors along the myocardial circumference; then their standard deviations (SD_T peak_d and SD_T peak_s ) were computed among non-infarcted myocardial regions for each mouse, and were compared between the normal and post-MI mouse groups with Student's t test. The comparison revealed that SD_T peak_d and SD_T peak_s were significantly larger in the post-MI hearts than in the normal hearts. The displacement uniformity ratio was determined to be 0.97±0.01 and 0.85±0.07 for radial and circumferential displacements in the normal hearts, respectively; and 0.59±0.17 and 0.64 ±0.24 in the post-MI hearts. In conclusion, this high resolution ultrasound image tracking method provides for the detection of cardiac dyssynchrony in the non-infarcted regions in the murine left ventricles late after MI by identifying the temporal and spatial disparity of regional myocardial contraction.

Prospective ECG-gated mouse cardiac imaging with a 34-MHz annular array transducer

“…These high frame rates facilitate visualization of high temporal resolution events in the cardiovascular system such as cardiac dyssynchrony [17] and regional contractile dysfunction [31]. At even higher frame rates, one can perform elastography of the mouse LV [32] and evaluate mechanical and electromechanical waves as they travel through the cardiac tissue [10].…”

“…Recently, HFU adult-mouse-cardiac-high-frame-rate imaging was implemented with a single-element transducer using an ECG-based, retrospective imaging approach [10], [16], [15], [17], and end-diastolic (EDS) and end-systolic (ESS) measurements were performed. In HFU retrospective imaging, a set of M-modes and an ECG waveform are acquired at each lateral position of the image.…”

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

“…The initial traces were corrected, as needed, to assure faithful tracking throughout the complete cardiac cycle. Each vertical LA view of the LV myocardium was divided into 6 standard anatomic segments for regional speckle‐tracking 26, 27. The mid‐anterior, apical‐anterior, and apical‐inferior wall segments were designated as the infarct region and the basal‐inferior and mid‐inferior wall segments were designated as the remote zone 23…”

Micro-ultrasound for preclinical imaging

“…[15 -19]). In the area of cardiovascular research see, for example [20][21][22][23], and in the area of cancer see, for example [24][25][26][27][28]. While single element systems have fared well in the market they suffer from serious limitations in depth of field, in their ability to provide functional maps of Doppler blood flow in real time, and in their ability to image contrast agents.…”