Late potentials

Late potentials are thought to be caused by early afterdepolarizations of cells in the right ventricle (in ARVD). Their amplitude is often too small to show up on a normal ECG. However, when multiple QRS recordings (typically 250 consecutive QRS complexes) are averaged, random noise is filtered out and late potentials can show up.

Criteria for late potentials on a signal averaged ECG
* filtered QRS duration > 114ms RMS voltage in the terminal 40ms < 20 µV low amplitude singal (LAS) duration > 38ms Noise should be minimal with a standard deviation of the TP segment of < 1 µV