Electrocardiographic pattern of ischaemia T-wave abnormalities

We will remind here (Bayes de Luna, 1999) the characteristics of a normal T wave with respect to its morphology and voltage, including situations as vagal overdrive, where a higher-than-normal T wave may be recorded, as well as the leads where the T wave may be observed in normal conditions, flattened or negative. 

This pattern is recorded when a delay in cellular repolarisation exists in a certain area of myocardium related with a diminished blood perfusion to this 

Firstly, we will refer to cases presenting with a narrow QRS. Thereafter (see Electrocardiographic 

If the delay is subepicardial or even transmural (see The concept of ECG patterns of ischaemia, injury and necrosis ) (p. 20). this delay of repolarisation without change of shape of TAP generates a flattened or negative T wave. 

In isolated perfused heart of different animals Janse (1982) demonstrated that ischaemia induced by the occlusion of a coronary artery produces a shortening of repolarisation in the ischaemic area during a very early and brief phase (expressed by a shortening of the TAP in this area). Nevertheless, after this very early phase, a delay in repolarisation (TAP) can be observed in the same area (Cinca et al.1980 Surawicz, 1996). Other authors have demonstrated that, when the myocardium is cooled down - equivalent to an ischaemia - the affected area (subendocardium or subepicardium) shows from the beginning a lengthening of the TAP in the cooled area (Burnes et al, 2001). 

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

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