Low Voltage ECG Review

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:

  1. Obesity
  2. Chronic obstructive pulmonary disease, or 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 accidentally, the voltage will be falsely low (pseudo low voltage). The indicator should be set to 10 mm amplitude.

ECG Examples:

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.