Microvoltations
thumb|Microvoltages. Note the normal amplitude of the p waves. thumb|Another example of (extreme) microvoltations.
- microvoltations
- The QRS amplitute (i.e. the sum of the postive and negative parts) in the limb leads does not exceed 0.5 mV (5 mm) OR is no more than 1.0 mV (1 cm) in the chest leads.
Possibe causes of microvoltations:
- Cardiomyopathy, especially infiltrative cardiomyopathy, such as in amyloidosis
- Increased resistance between the heart and the electrodes: pneumothorax, obesesity, pericardial fluid / tamponade, pleural effusion
- Myocarditis / pericarditis
- Heart tranplantation, especially during acute or chronic rejection
- Wrong settings on the ECG apparatus (sensitivity should be at 10 mm/mV)