Ischaemia patterns

Fine PEM (1995). Variation in protection by BCG implications of and for heterologous immunity. Lancet 346 1339-1345 Gorter JW for the Stroke Prevention in Reversible Ischaemia Trial (SPIRIT) and European Atrial Fibrillation Trial (EAFT) Groups (1999). Major bleeding during anticoagulation after cerebral ischaemia patterns and risk factors. Neurology 53 1319-1327... 

In some cases of coronary artery spasm of just a few seconds duration, the reversible subendocardial ischaemia pattern may be the unique electrocardiographic change recorded. Sometimes, while passing from one pattern to another (from a posi-... 

Figure 3.9 In case that in basal state a certain degree of ischaemia with subendocardial predominance exists too mild to produce clear ECG changes, an increase of active ischaemia still with subendocardial predominance will produce an ST-segment depression (subendocardial injury pattern) (A). If as a consequence of ischaemia there is a delay in repolarisation predominating in subepicardium or being transmural, a flattened or negative T wave appears in leads with, but also without, predominant R wave (B-1) (subepicardial ischaemia pattern). The latter pattern is...

Only few detailed analyses of the intracellular events following epithelial injury have been performed using cells from the airways, and most mechanistic work has concentrated on pre-necrotic and necrotic processes in epitheUal cells of renal origin (Trump etal., 1980, 1981 Trump and Berezesky, 1984). Collectively these studies, which have employed a wide range of stimuli to evoke cellular injury (ischaemia, metabolic poisons, chaotropic agents and ionophores), suggest that similar patterns of intracellular events accompany injury evoked by the different stimuli. 

PART I Electrocardiographic patterns of ischaemia, injury and infarction... 

In case of ACS with ST-segment elevation (STE-ACS), the ECG patterns of ischaemia (subendocardial), injury (transmural) and usually necrosis appear in a sequential way (see Figures 3.7 and 8.5). In the case of exercise angina, the ECG pattern of subendocardial injury is the most frequently found (see Figures 3.9A and 4.57). 

The concept of the electrocardiographic patterns of ischaemia, injury and necrosis (Sodi Pallares, 1956,1968 Cabrera, 1966)... 

The electrocardiographic pattern or necrosis (see p. 129, Figures 2.1(4) and 5.3) is characterised by the occurrence of abnormal (pathological) Q wave (see explanation in Electrophysiological mechanisms of Q wave of necrosis p. 130 and Figure 5.3). Today we know that in many cases of MI, this pattern is not present (non-Q-wave infarction). Tissue necrosis is the highest degree of clinical ischaemia. 

The electrocardiographic patterns of ischaemia, injury and necrosis are of greatest importance in the diagnosis and prognosis of IHD. They are recorded in different leads as direct patterns, according to the affected zone. On the other hand, they may also be recorded in opposite leads as mirror patterns ... 

When we affirm in daily clinical practice that a patient s ECG shows an electrocardiographic pattern of ischaemia, injury or infarction, it does not mean that we can establish a diagnosis of IHD. The same patterns can be found in other clinical situations as well. In fact, the recording of sequential changes of a certain electrocardiographic pattern... 

Table 2.1 Acute and chronic ischemic heart disease relationship between degree of ventricular wall involvement and electrocardiographic pattern of ischaemia, injury and necrosis.

Location of ECG patterns due to clinical ischaemia classical classification... 

In acute phase, usually the ECG shows at the same time patterns of injury, ischaemia and even necrosis, and in chronic phase there are frequently Q waves and abnormal T waves. These different ECG patterns are not present exactly in the same leads, because although the areas of infarction, injury and ischaemia often coincide, they are not usually identical and especially the injury pattern (ST-segment deviations) in acute phase is present in more leads than is the necrosis pattern (Q wave or equivalent) in chronic phase. 

Therefore, in clinical practice, the same correlation Q waves of necrosis in ECG leads and necrotic areas is used to locate injured areas (ST changes) or ischaemic ones (T-wave changes), although, very often in the acute phase, the ECG patterns of ischaemia and injury are usually visible in more leads than the ECG pattern of necrosis. However, in the chronic phase, the ECG pattern of injury usually... 

The same pattern (STf in VR) in case of an NSTE-ACS with ST-segment depression in many leads suggests the incomplete occlusion of the left main trunk (LMT) (Yamaji et al, 2001) or its equivalent (very proximal LAD occlusion + LCX) in patients with previous subendocardial ischaemia (Figures 4.59-4.61). 

CHAPTER 3 Electrocardiographic pattern of ischaemia T-wave abnormalities 31... 

Figure 3.3 Left Recordings in case of experimental occlusion of LAD coronary artery in a dog with open heart. (A) Control. (B) ECG pattern of ischaemia (negative T wave). (C) ECG pattern of injury (ST-segment elevation).

ECG pattern for subepicardialischaemia) or symmetric and usually taller-than-normal T wave with QTc prolongation (ECG pattern of subendocardial ischaemia) located in different leads according to the corresponding affected zone - anteroseptal or inferolateral (see Experimental point of view -below - and Figure 3.5). 

The ECG pattern of subepicardial ischaemia, is more consequence of previous ischaemia than due to the presence of active ischaemia. On the contrary, the ECG pattern of predominant subendocardial ischaemia (symmetric and usually taller-than-normal positive T wave accompanied by rectified ST segment and prolongation of QTc interval) represents the first ECG change induced by active ischaemia (Figure 3.7). 

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