Background-In a correlative functional/histopathologic study, we investigated the regional deformation characteristics of both chronic nontransmural and transmural infarctions before and after a dobutamine challenge. Methods and Results-After stenosing copper-coated stent implantation to produce circumflex artery endothelial proliferation, 18 pigs were followed up for 5 weeks. Posteuthanasia histology showed 10 to have a nontransmural and 8 a transmural infarction. Eight nonstented animals served as controls. Regional radial function was monitored by measuring ultrasound-derived peak systolic strain rates (SR SYS ) and systolic strains (⑀ SYS ) (1) before stent implantation and (2) at 5 weeks, at baseline (bs) and during an incremental dobutamine infusion. In controls, dobutamine induced a linear increase in SR SYS (dobutamine: bs, 4.8Ϯ0.4 s
The identification of an acute increase in regional wall thickness in a reperfused infarct zone by cardiac ultrasound following primary PTCA might be used in patients to both identify successful infarct reperfusion and to monitor the presence, extent and resolution of the oedema associated with reperfusion injury.
Abstract-Ischemic heart disease is a leading cause of chronic heart failure. Hibernation (ie, a chronic reduction of myocardial contractility distal to a severe coronary stenosis and reversible on revascularization) is an important contributing factor. The underlying cellular mechanisms remain however poorly understood. In young pigs (nϭ13, ISCH), an acquired coronary stenosis Ͼ90% (4 to 6 weeks) resulted in the development of hibernating myocardium. Single cardiac myocytes from the ISCH area were compared with cells from the same area obtained from matched normal pigs (nϭ12, CTRL). Myocytes from ISCH were larger than from CTRL. In field stimulation, unloaded cell shortening was reduced and slower in ISCH; relaxation was not significantly different.
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