Microvoltages

Microvoltages. Note! The p-waves are of normal amplitude.

Another example of (extreme) microvoltages.

Microvoltages are present when the QRS amplitude (the sum of the negative and positive parts) does not exceed 0.5 mV in any of the limb leads or 1.0mV in any of the chest leads. Causes of microvoltages:

• Cardiomyopathy, especially infiltrative cardiomyopathy, such as in amyloidosis
• Increased resistance between the skin and the electrodes: pneumothorax, obesity, pericardal effusion / tamponade, pleural effusion
• Myocarditis / pericarditis
• Heart transplantation, especially with chronic rejection
• Wrong ECG settings (e.g. sensitivity at 5 mm/mV instead of 10 mm/mV)