Infarction defining

Defined as worsening (in intensity or frequency) angina attacks, sudden-onset angina at rest, and angina lasting more than 15 min. As these may herald myocardial infarction, they require urgent medical attention. 

However, the real promise of CTP lies not in its ability to detect acute stroke, but in its ability, like that of MRP, to distinguish between infarct core and the ischemic penumbra. CTP produces maps of the same perfusion parameters that are generated by MRP, and CTP maps are interpreted in a similar manner, with one important exception with CTP, DWI images are usually not available to identify the infarct core. Therefore, CBV maps are usually used to define the infarct core. Tissue that appears normal in CBV maps, but abnormal in CBF or MTT maps, is taken to represent the ischemic penumbra. 

Hypertension is the most common cardiovascular disease in fact, nearly 25% of adults in the U.S. are considered hypertensive. Hypertension is defined as a consistent elevation in blood pressure such that systolic/diastolic pressures are >140/90 mmHg. Over time, chronic hypertension can cause pathological changes in the vasculature and in the heart. As a result, hypertensive patients are at increased risk for atherosclerosis, aneurysm, stroke, myocardial infarction, heart failure, and kidney failure. There are several categories of antihypertensive agents ... 

It is important to realize, that diseases such as myocardial infarction or type 2 diabetes represent a heterogeneous group of several distinct subphenotypes definable by clinical or biochemical characteristics. Thus, contradictory findings in pharmacogenomic studies may only not be the consequence of a lack of a major isolated gene effect (of the gene variant studied) and chance findings, but also be caused by the variability in the mix of distinct clinical phenotypes hidden beneath a common characterization such as type 2 diabetes and modulated by differences in the environment between studies. 

Ventricular tachycardia (VT) is defined by three or more repetitive PVCs occurring at a rate greater than 100 beats/min. It occurs most commonly in acute myocardial infarction (MI) other causes are severe electrolyte abnormalities (e.g., hypokalemia), hypoxemia, and digitalis toxicity. The chronic recurrent form is almost always associated with underlying organic heart disease (e.g., idiopathic dilated cardiomyopathy or remote MI with left ventricular [LV] aneurysm). 

The zone at risk is defined differently from the infarct area and from viability as the area of reduced flow reserve by dipyridamole stress perfusion imaging rather than by rest perfusion imaging. The physiologic basis for this approach is the well documented observation that resting coronary flow may be normal with up to 85% stenosis consequently, rest imaging may not define the correct size of zone at risk, as illustrated by the example below. 

Schmidt M, Voth E, Schneider CA, Theissen P, Wagner R, Baer FM et al. F-18-FDG uptake is a reliable pre-dictory of functional recovery of akinetic but viable infarct regions as defined by magnetic resonance imaging before and after revascularization. Magn Reson Imaging 2004 22 229-236... 

Among these 76 patients, 109 bare-coronary stents were deployed in 103 de novo lesions in an equal number of major native epicardial vessels. Patients with in-stent restenosis, bifurcation lesions, vein graft lesions, lesion length of >0.20 mm, acute myocardial infarction in the previous 72 hours, poor left ventricular function (ejection fraction <35%), renal failure defined as creatinine concentration of >2 mg, or under immunosuppressive treatment were excluded from the study. 

In 1997, Condado et al. was the first to investigate the effectiveness of ICB after PTCA in human coronary arteries. Twenty-one patients who underwent PTCA for unstable angina received ICB (gamma radiation) for prevention of restenosis, Immediate and six-month follow-up revealed improved freedom from major adverse cardiac event (MACE) defined as death, myocardial infarction or target lesion revascularization compared with several previously completed balloon angioplasty trials (20), More importantly, this trial demonstrated that ICB was a feasible technique for the prevention of restenosis without any unexpected acute complications in humans. 

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