Myocardial dysfunction in the periinfarct and remote regions following anterior infarction in rats quantified by 2D radial strain echocardiography: An observational cohort study

<p>Abstract</p> <p>Background</p> <p>Heart failure from adverse ventricular remodeling follows myocardial infarction, but the contribution of periinfarct and remote myocardium to the development of cardiomyopathy remains poorly defined. 2D strain echocardiography (2DSE) is a novel and sensitive tool to measure regional myocardial mechanics. The aim is to quantify radial strain in infarcted (I), periinfarct (PI) and remote (R) myocardial regions acutely and chronically following anterior infarction in rats.</p> <p>Methods</p> <p>The left anterior coronary artery of male Sprague-Dawley rats (270–370 g) were occluded for 20–30 minutes and 2DSE was performed in the acute setting (n = 10; baseline and 60 minutes post-reperfusion) and in the chronic setting (n = 14; baseline, 1, 3 and 6 weeks). Using software, radial strain was measured in the mid-ventricle in short axis view. The ventricle was divided into 3 regions: I (anteroseptum, anterior and anterolateral), PI – (inferoseptum and inferolateral) and R – (inferior). Infarct size was measured using triphenyl tetrazolium chloride in the acute group.</p> <p>Results</p> <p>Following infarct, adverse remodeling occurred with progressive increase in left ventricular size, mass and reduced fractional shortening within 6 weeks. Radial strain decreased not only in the infarct but also in the periinfarct and remote regions acutely and chronically (I, PI, R, change vs. baseline, 60 minutes -32.7 ± 8.7, -17.4 ± 9.4, -13.5 ± 11.6%; 6 weeks -24.4 ± 8.2, -17.7 ± 8.3, -15.2 ± 8.4% respectively, all p < 0.05). Reduced radial strain in periinfarct and remote regions occurred despite minimal or absent necrosis (area of necrosis I, PI, R: 48.8 ± 23, 5.1 ± 6.6, 0 ± 0%, p < 0.001 vs. I).</p> <p>Conclusion</p> <p>Following left anterior coronary occlusion, radial strain decreased at 60 minutes and up to 6 weeks in the periinfarct and remote regions, similar to the reduction in the infarct region. This demonstrates early and chronic myopathic process in periinfarct and remote regions following myocardial infarction that may be an under recognized but important contributor to adverse left ventricular remodeling and progression to ischemic cardiomyopathy.</p

Left ventricular remodeling in the acute (A, C, E) and chronic group (B, D, F)

A and B. There is significant reduction in fractional shortening following ischemia-reperfusion and persists up to 6 weeks. C and D. There is a trend towards increased end systolic dimension 60 minutes following ischemia. There is progressive dilation of the left ventricle from 1–6 weeks. E and F. The estimated left ventricular mass increased at 3 weeks and progressed at 6 weeks. (LVIDd-left ventricular internal diameter in diastole, LVIDs-left ventricular internal diameter in systole).<p><b>Copyright information:</b></p><p>Taken from "Myocardial dysfunction in the periinfarct and remote regions following anterior infarction in rats quantified by 2D radial strain echocardiography: An observational cohort study"</p><p>http://www.cardiovascularultrasound.com/content/6/1/17</p><p>Cardiovascular Ultrasound 2008;6():17-17.</p><p>Published online 29 Apr 2008</p><p>PMCID:PMC2397379.</p><p></p

Correlation between infarct region and periinfarct region radial strain (A) and remote region (B) in the chronic group

There is significant correlation between radial strain in the infarct region and those in the periinfarct and remote regions.<p><b>Copyright information:</b></p><p>Taken from "Myocardial dysfunction in the periinfarct and remote regions following anterior infarction in rats quantified by 2D radial strain echocardiography: An observational cohort study"</p><p>http://www.cardiovascularultrasound.com/content/6/1/17</p><p>Cardiovascular Ultrasound 2008;6():17-17.</p><p>Published online 29 Apr 2008</p><p>PMCID:PMC2397379.</p><p></p