Infarction evolving

Besides establishing the diagnosis of ischemic stroke, DWI also offers the capability of measuring the approximate age of infarcts. The apparent diffusion coefficient (ADC) of water, a measure of diffusion that can be derived easily from DWI images, follows a typical sequence of changes in evolving infarcts. °" ADC... 

Magnetic resonance imaging (MRI) of the head will reveal areas of ischemia earlier and with better resolution than a CT scan. Some types of imaging can reveal an evolving infarct within minutes. 

E. Therapeutic response Activase, and other thrombolytic agents, used in a timely manner during an evolving myocardial infarction, decrease mortality and improve left ventricular function. Resolution of chest pain, resolution of baseline EKG changes, reduced total creatine phospho-kinase (CPK) release, and preserved left ventricular function are evidence of cardiac reperfusion. Activase, administered within the first 3 hours of ischemic stroke onset, has been shown to improve recovery. 

A 73-year-old man with a history of breathlessness, cough, and weight loss had some ill-defined peripheral shadow in the upper zones of a chest X-ray. He had fiberoptic bronchoscopy with cocaine and lidocaine and 5 minutes later became distressed, with dyspnea, chest pain, and tachycardia. Electrocardiography showed an evolving anterior myocardial infarction. Coronary angiography showed a stenosis of less than 25% in the proximal left anterior descending artery with coronary artery spasm. He made an uneventful recovery. 

Cognitive or visual field defects may have to be assumed in drowsy patients. Deviation of the eyes towards the affected hemisphere is common but recovers in a few days. A large hematoma may cause midUne shift, transtentorial herniation and coma within 24-hours (Fig. 9.3). By contrast, these changes take two or three days to evolve with large infarcts as cerebral edema develops. 

Pretreatment CT showing hypodensity which could represent evolving infarct over three hours old mass effect or edema tumor, aneurysm or arteriovenous malformation... 

Fig. 7 (a) Diffusion-weighted MRI of a patient with laige middle cerebral artery stroke. There is involvement of the entire vessel territory with possibly some hemorrhage in the basal ganglia. The image was made within hours of the infarct and there is minimal compression of the ventricles, (b) CT days after the infarct shows the massive shift of the midUne structures away from the evolving mass lesion. Compression of the CSF outflow tracts causes the hydrocephalus with interstitial edema in the white matter adjacent to the ventricles... 

The acute coronary syndromes (ACS) are now classified on the basis of the ECG and plasma troponin measurements into (1) patients with ST elevation myocardial infarction (STEMI), (2) non-ST elevation myocardial infarction (non-STEMI, by ECG and a positive troponin test) and (3) unstable angina (by ECG and negative troponin test). The present account recognises that this is a rapidly evolving field, but therapeutic strategies are likely to evolve according to these forms of ACS. 

Garcia JH, Liu KF, Yoshida Y, Lian J, Chen S, del Zoppo GJ (1994) Influx of leukocytes and platelets in an evolving brain infarct (Wistar rat). Am J Pathol 144 188-199. 

Generally, the clinical presentation of myocardial ischaemia is the characteristic pain known as angina pectoris or some equivalents (e.g. dyspnoea), although sometimes ischaemia may be silent (see Silent ischaemia , p. 302). If the anginal pain is new or if it has increased with respect to previous discomfort (crescendo angina), this constitutes the clinical condition called acute coronary syndrome (ACS), which may evolve into myocardial infarction (MI) (see Section Acute coronary syndrome , p. 209). If the angina pain appears with exercise... 

First predominant subendocardial compromise occurs and then, transmural and homogeneous compromise ACS with ST-segment elevation evolving to Q-wave infarction or coronary spasm (Prinzmetal angina) ... 

Figure 4.17 Acute myocardial infarction with ST-segment elevation in II, III and VF and ST-segment depression in V1-V3. This pattern corresponds classically to an infarction involving inferior and posterior walls. Nowadays, this is the pattern of STE-ACS of inferolateral zone evolving to inferolateral infarction due to distal occlusion of a dominant RCA (ST-segment depression in I and V1-V3,...

In Figure 4.33B, C the involved myocardial area and the polar map of that area are shown. The involved segments are 3, 4, 9 and 10 and part of segments 14 and 15. These cases never evolve towards a right-ventricular infarction, since the branches perfusing the RV are proximal to the occlusion. 

Sgarbossa et al. (1996b 2001) have reported that in cases compatible with acute MI, a diagnosis of evolving infarction associated with a complete LBBB is supported by the following criteria... 

Figure 4.66 Above (A) Acute phase of evolving Q-wave myocardial infarction of anteroseptal zone. There is a huge ST-segment elevation, especially in I, VL and from V2 to V5, QRS >0.12 s and morphology of complete RBBB that was not present in previous ECG. (B) Twenty-four hours later RBBB have disappeared and subacute anterior extensive infarction becomes evident. There is ST-segment elevation from V1 to V4. The transient presence of new...

Currently, the CMR images with gadolinium injection have demonstrated in very elegant manner (Mahrholdt et al, 2005a, b) how, after coronary occlusion, a wavefront of infarction starts in the subendocardium and evolves to a transmural infarction. With this technique it has been defined that there are infarctions predominantly in the subendocardium or transmural but never subepicardial (Figures 1.5 and 8.6) (see p. 216). 

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