Low ECG voltage
Definition
- QRS < 5 mm in limb leads, or
- QRS < 10 mm in chest leads
Causes
- Low electrical power within the heart (e.g. hypothyroidism)
- Poor electrical conduction within the heart (e.g. sarcoid or scar tissue)
- Poor conduction of signal from the heart to the ECG lead (e.g. obesity, COPD, pericardial effusion)
- Low voltage + tachycardia = pericardial effusion until proven otherwise