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T-wave amplitude

Column: t_amplitude_mv · Unit: mV (in your signal's units) · Measured on: every lead, then averaged

In one sentence: the T wave is the rounded bump after the main spike, made by the lower chambers recharging; its amplitude is how tall that bump is above the baseline.

Everyday picture

After every pump stroke the lower chambers reset, like a spring winding back up. The T wave is that reset. In most leads it is a gentle, upright hill, smaller than the main spike. Its height and direction change with the body's salt balance (especially potassium), with the oxygen supply to the heart muscle, and with the size of the heart.

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What to notice:

  • Typical: an upright hill that rises slowly and falls a bit faster.
  • Upside down (inverted): normal in a few leads (for example aVR), but in most leads doctors take note. It can follow reduced blood supply or a thickened heart wall.
  • Tall and peaked: one classic cause is too much potassium in the blood.
  • Flat: can follow low potassium or some medicines.

What's typical

T-wave height (lead II, rough guide) Plain meaning
below 0 mV upside down (inverted)
0–0.1 mV flat
about 0.1–0.5 mV typical
above 0.5 mV tall

T waves are naturally taller in the chest leads (V2–V4), so ranges depend on the lead. ECGEN-Eval averages over all leads, which is fine for comparing real and synthetic sets measured the same way.

Why it matters for synthetic ECGs

The T wave is low and wide, so generators that focus on the sharp QRS may shrink, flatten or even flip it. Matching the distribution of T heights is a simple check that the model learned the recharge part of the beat, not just the spike.

How ECGEN-Eval measures it

For every lead:

  1. The baseline of each beat is the median level from 40 ms to 10 ms before the QRS onset (the flat PR segment).
  2. The T peak is the point furthest from the baseline between 80 ms after the end of the QRS and the end of the T wave. It keeps its sign, so an inverted T wave gives a negative value.
  3. T amplitude = T-peak level − baseline, median over beats. The summary averages the leads.

Works with or without NeuroKit2. Against GE 12SL (average over the 12 leads): r 0.96 (validation).

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