Low ECG voltage

  • QRS < 5 mm in limb leads, or
  • QRS < 10 mm in chest leads
  • From either low electrical power within the heart (e.g. hypothyroidism), or low conduction within the heart (e.g. sarcoid or scar tissue), or poor conduction from the heart to the ECG lead (e.g. obesity, COPD, pericardial effusion
  • Low voltage + tachycardia = pericardial effusion until proven otherwise

See Also