The T waves
Let’s talk about T waves.
The T wave represents typically ventricular repolarization and it is considered the most labile wave on the EKG surface.
Normal T wave
✅ Morphology: Asymmetric.
✅ Amplitude: ≤6 mm in limb leads and ≤10 mm in precordial leads.
Normal T wave
Tall upright (peacked) T wave
Tall upright T waves are usually characterized by tall and peaked shape.
✅ Amplitude: >6 mm in limb leads and >10 mm in precordial leads.
Causes: Hyperkalemia, hyperacute MI, normal variant, prinzmetal angina, aortic stenosis, LVH, RVH, others.
Peaked T wave
Notched T wave
Possible causes: May be caused by morphological changes in the cardiomyocytes' action potential waveforms. Another causes include: Drugs (such as Dofetilide, Quinidine, Ranolazine, Verapamil), long QT syndrome, athletes, others.
Notched T wave
Inverted T wave
Causes: Myocardial ischemia (acute or chronic), MI, BBB, hypertrophic cardiomyopathy, PE, raised intracranial pressure, persistent juvenile T wave, normal finding in children, LVH, RVH, others.
Isolated T wave inversion in lead III can be a normal variant.
Inverted T wave
Biphasic T wave
✅ Biphasic T wave can be with "terminal positivity (down-up)" or "terminal negativity (up-down)".
Causes: Myocardial ischemia, hypokalemia, reperfusion phase, others.
If biphasic T wave with terminal negativity is present in V2-V3, consider Wellens type I.
Biphasic T wave
Giant Inverted T wave
✅ Morphology: Giant and symmetrical.
✅ Amplitude: ≥10 mm.
Causes: Severe ischemia, pheochromocytoma, electroconvulsive therapy, brain bleed, cocaine abuse, post-pacemaker syndrome, apical hypertrophic cardiomyopathy, others.
Giant Inverted T wave
Hyperacute T wave
Hyperacute T wave have been reported in association with acute myocardial ischemia due to critical stenosis or occlusion of a coronary artery that may occur in the very early phases of myocardial infarction within the 30 minutes of onset of symptoms.
Hyperacute T wave
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