Low voltage on the ECG is defined as a peak-to-peak QRS amplitude of less than 5 millimeters in the limb leads and/or less than 10 millimeters in the precordial leads.
Low voltage may be present in the following situations:
Chronic obstructive pulmonary disease, or COPD
Massive myocardial damage/infarction
Infiltrative/restrictive diseases such as amyloid cardiomyopathy
Note: If the gain indicated at the left of the ECG is turned down accidentally, the voltage will be falsely low (pseudo low voltage). The indicator should be set to 10 mm amplitude.
1. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric, 6e
2. Surawicz B, et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. Circulation. 2009; doi:10.1161/CIRCULATIONAHA.108.191095.