XI. T Wave
Abnormalities
INTRODUCTION:The T wave is the most labile wave in the ECG. T wave changes
including low-amplitude T waves and abnormally inverted T waves
may be the result of many cardiac and non-cardiac conditions. The normal T wave
is usually in the same direction as the QRS except in the right precordial leads
(see V2 below). Also, the normal T wave is asymmetric with the first half
moving more slowly than the second half. In the normal ECG (see below) the T
wave is always upright in leads I, II, V3-6, and always inverted in lead aVR.
The other leads are variable depending on the direction of the QRS and the age
of the patient.
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Differential Diagnosis of T Wave Inversion
Q wave and non-Q wave MI (e.g., evolving anteroseptal MI):
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Myocardial ischemia
Subacute or old pericarditis
Myocarditis
Myocardial contusion (from trauma)
CNS
disease causing long QT interval (especially subarrachnoid hemorrhage; see
below):
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Idiopathic apical hypertrophy (a rare form of hypertrophic
cardiomyopathy)
Mitral
valve prolapse
Digoxin effect
RVH
and LVH with "strain" (see below: T wave inversion in leads aVL, V4-6 in LVH)
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