Low Voltages
QRS amplitude <5 mm in all limb leads; <10 mm in all chest leads, causes;
- Decreased muscle mass:
- Remote MIs; infiltrative processes (amyloidosis, hypothyroidisms)
- Increased tissue resistance or skin impedance:
- obesity; emphysema; pericardial effusion; anasarca; scleroderma
- most common cause in the ICU: fluid resuscitation, edema
- Unexplained low voltage: check amplification (r/o 5 mm/mV)