Hyperacute T Waves

Hyperacute T waves are broad, symmetric T waves that are very large (in compared to the QRS complex). The ratio for T wave:QRS complex that is concerning for hyperacute T waves is >0.36. They are found in the earliest stages of a OMI and precede ST elevation. T waves with high amplitude but without being broad or symmetric are not considered hyperacute T waves.

Note that these are different from the peaked T waves of hyperkalemia, which are thin and pointy. Note also the ratio of T wave amplitude to QRS amplitude is quite high (14/6 in V3; much greater than 0.36)

Peaked T waves of hyperkalemia

These T waves are of normal variant. Note that they are somewhat tall for the QRS complexes (they would meet the ratio), but they are quite asymmetric and not very broad. This would be difficult to interpret in the setting of concerning chest pain, however.

Examples:

Hyperacute T waves in the anterior leads with some ST elevation.

Loss of Precordial T Wave Balance

This is a form of hyperacute T waves where the T waves in the precordial leads are larger than the T wave in V6, as one would expect the voltage of the T wave in V6 to be the highest.

Pseudonormalization

Pseudonormalization is a form of hyperacute T waves that appear to be normal T waves but represent ischemia (usually an OMI). They occur when a patient's prior EKG has T wave inversions and then the patient develops an occlusion. The T wave has to overcome the inversion and become upright. It appears similar to a normal T wave, but is a form of 'large/hyperacute' T waves because it also overcomes the inversion. This is most commonly seen or identified in patients who present with a Wellen's syndrome pattern of having had ischemia that reperfused prior to evaluation, so their initial EKG shows T wave inversions typical of reperfusion. They then develop pseudonormalization of the T waves when they have re-occlusion.