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. Such a recording is called a Signal Averaged ECG (SAECG). The ARVD taskforce has published a document with recommended settings to record an SAECG in ARVD.

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

References

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1. simson pmid=7249291
2. Breithardt pmid=2007727

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