Low voltage is defined as peak-to-peak QRS amplitude of < 5 mm in the limb leads and/or < 10 mm in the precordial leads. Low voltage may be present in the following situations:

1) Obesity
2) COPD
3) Pericardial effusion
4) Severe hypothyroidism
5) Subcutaneous emphysema
6) Massive myocardial damage/infarction
7) Infiltrative/restrictive diseases (such as amyloid cardiomyopathy)

Note: If the gain indicated at the left of the ECG is turned down accidently, the voltage will be falsely low (pseudo-low voltage). The indicator should be set to 10 mm amplitude.