What does a vertical representation of 10 small squares on an EKG measure?

On an electrocardiogram (EKG or ECG), the vertical axis measures voltage, while the horizontal axis measures time. Each small square on the EKG paper typically represents 0.1 mV (millivolts) in voltage. Since there are 10 small squares making up a full vertical representation, this translates to a total of 1 millivolt (0.1 mV multiplied by 10 squares).

Understanding this measurement is essential for interpreting the amplitude of the EKG waves, such as P waves, QRS complexes, and T waves, which can provide vital information regarding cardiac activity and health. Therefore, a vertical representation of 10 small squares accurately measures 1 millivolt, ensuring proper assessment of the electrical activity of the heart.