1) QRS complex in I+II+III <15 mm
- or -
2) QRS complex in V1+2+3 <30 mm
Low voltage is either a 'weak battery' or there is something dampening the current reaching your leads.
Intrinsic low voltage:
- Infiltrative disease
- End stage cardiomyopathy
- Severe hypothyroidism
- Pericardial effusion
- Pleural effusion
If the low voltage is new, consider new onset severe hypothyroidism, pericardial or pleural effusions.