T waves in lead

Disequilibrium in the eleetrolyte balanee ean provide diagnostic clues. For example, hyperkalemia causes tail T-waves in leads II, III, V2 to V4, when the potassium balance exceeds 5.5 mmol/1. In conjunction, the amphtude of the P wave is reduced and QRS is widened. Hyperkalemia is usually present when the amphtude of the T-wave is higher than that of the R-wave. With increasing potassium concentration, P-waves widen and eventually disappear. Accentuated hyperkalemia results in asystole. 

Anginal pain is not intense and/or repetitive, and the ECG is normal with no changes in the follow-up or with flattened or mildly negative T wave in leads with dominant R wave. Sometimes, small Q waves of necrosis or mildly ST-segment... 

Nikus KC, Eskola MJ, Virtanen VK. ST-depression with negative T waves in leads V4-V5 - a marker of severe coronary artery disease in non-ST elevation acute coronary syndrome a prospective study of angina at rest, with troponin, clinical, electrocardiographic and angiographic correlation. Ann Noninvasive Electrocardiol 2004 9 207. 

Figure 3.27 T amplitude by age in lead I, each curve corresponding to the indicated percentile level ( = mean). T waves in lead I are small, absent, or even negative, shortly after birth and their amplitude Increases gradually, reaching a plateau by age 3-6 months, and stays little changed until adolescence.

This 12-lead ECG shows characteristic changes of LB6B. All leads have prolonged QRS complexes. In lead V, note the QS wave pattern. In lead Ve. note the slurred R wave and T-wave inversion. The elevated ST segments and upright T waves in leads and... 

Figure 3.8 Morphologies of taller than normal T wave in patients with ischaemic heart disease. (A) T wave very tall not preceded by rectified ST segment This morphology is frequently observed in a transitory form in case of Prinzmetal angina (Figure 8.44). (B) A tall T wave, very symmetric and with previous rectified ST segment completely abnormal for V2 lead, which may be frequently observed in a hyperacute phase of an ACS with ST-segment...

Figure 3.10 (A) ECG with a typical pattern of chronic subepicardial ischaemia in the leads facing the inferior wall (negative T wave in II, III and VF) and the lateral wall (positive peaked T wave in V1-V2). There is a necrosis in the same area in which a QR complex in II, III and VF and an RS complex in V1 are recorded. (B) Horizontal axial...

Figures 3.18 and 3.19 show the evolution of two Mis from the acute phase with a huge ST-segment elevation until the appearance of Q wave of necrosis and negative T wave of subepicardial ischaemia. In Figure 3.20, a patient with chronic MI of inferior wall presents in the same ECG a different grade of ECG pattern of subepicardial ischaemia (negative and deep T wave in inferior leads, tall and positive T wave in right precordial leads as a mirror pattern and flat T wave in V6).

Figure 3.23 A patient with unstable angina (NSTE-ACS) with new, flattened or slightly negative T wave in various leads.

Figure 3.35 Four sets of leads with basal ECG (left) and after pacemaker implantation in the RV (right) in a patient without ischaemic heart disease. Note the negative T wave in sinus rhythm complexes after implantation due to cardiac memory phenomenon. Characteristically, in case...

Figure 3.40 (A) Acute phase of an infarction in a patient symmetrical T wave in III (mixed pattern of repolarisation with complete left bundle branch block. Note the clear abnormality) leads to the suspicion of associated...

Figure 3.41 Symmetric negative T wave (see leads I and V5) in a patient with hypertension and intermittent complete left bundle branch block, who presents symmetric T wave when the LBBB disappears after a...

It should be reminded (Bayes de Luna, 1999) that the T wave in the normal ECG is positive because the surface ECG leads face the head of the vector of repolarisation. That goes from the area with less physiological flow (theoretically ischaemic), the subendocardium, to the area with more physiological flow, the subepicardium. 

ST-segment depression in all the leads except VR and V1, with maximal ST-segment depression in V3-V5. As the injury vector faces more VR than V1 the ST-segment elevation in VR > V1. (B) Typical ECG of LMT critical subocclusion. The ST-segment depression is higher than 6 mm in V3-V5 and there is not evident final positive T wave in V4-V5. 

Figure 4.53 Arrhythmogenic right ventricular dysplasia (ARVD). Note the image of atypical right bundle branch block, negative T wave in the V1-V4 leads, and premature ventricular complexes of the right ventricle. QRS duration...

V4-V5) It is accompanied by a positive T wave in V3-V5. In this case the culprit artery is in general proximal LAD occlusion (Table 8.1B Nikus, Eskola and Virtanen, 2004). Characteristically, as happens in exercise testing, the ST-segment depression is not usually present as the most evident changes in leads with rS morphology (V1-V2). 

Figure 4.59 (A) The ECG of a patient with ACS and the ECG typical of tight but incomplete occlusion of the left main coronary artery (see coronary angiography) (B) in the presence at basal state of important and circumferential subendocardial ischaemia. There is ST-segment depression in more than eight leads and clear ST-segment elevation in VR. Note that the maximum depression occurs in V3-V4 without final positive T wave in V4-V5.

May be 2-3 vessel disease but usually with 1 culprit artery. More frequently in leads with dominant R wave. Cases of worst prognosis present ST depression in V4-V6 and in FP leads, with negative T wave in V4-V6. 

Figure 8.3 Atypical patterns of STE-ACS. (A) Tall and positive T wave in V1-V2. Hyperacute phase of LAD occlusion. (B) Deep and negative T wave in V1-V4-V5. Impending STE-ACS or reperfusion pattern after treatment. New occlusion may appear. (C) ST-segment depression in V1-V2 clearly greater than ST-segment elevation in inferior/lateral leads due to LCX occlusion.

Therefore the presence of negative and deep T wave in precordial leads, especially in VI- VI, is usually the expression of evolutive phase of STE-ACS that occurs when the LAD occlusion is opened (reperfusion ECG sign). However, in some cases may herald, especially if the angina pain is recurrent, a new occlusion with the appearance of pseudonormal T wave and occasionally a new ST-segment elevation (Figures 8.3B and 8.9). 

A) tall and/or wide T waves in inferior leads (B) abnormal ST-segment elevation, with no changes of the final part of QRS (C) important ST-segment elevation and distortion of the final part of QRS. (2) The three types of repolarisation... 

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