How is voltage measured on an EKG?
In millimeters
In seconds
In milliseconds
In millivolts
The correct answer and explanation is:
The correct answer is In millivolts.
Voltage on an EKG (electrocardiogram) is measured in millivolts (mV). The EKG records the electrical activity of the heart by detecting the tiny electrical impulses generated by the depolarization and repolarization of heart muscle cells. These electrical signals are very small, so they are expressed in millivolts, which is one-thousandth of a volt.
The EKG machine converts the electrical activity picked up by electrodes placed on the skin into graphical tracings on paper or a digital screen. The vertical axis of the EKG graph represents the voltage, which corresponds to the strength of the electrical signal. Each small square on the vertical axis usually represents 0.1 millivolt. By measuring the height of the waves in millivolts, clinicians can assess the heart’s electrical activity, identify abnormalities, and diagnose conditions like arrhythmias, ischemia, or electrolyte imbalances.
The horizontal axis on the EKG graph shows time, measured in seconds or milliseconds. This allows the timing of electrical events to be analyzed, such as the duration of the P wave, QRS complex, and QT interval. The time intervals help evaluate how well the electrical impulses travel through the heart.
In summary, while time intervals on an EKG are measured in seconds or milliseconds, the voltage of the electrical signals recorded is measured in millivolts. Understanding this distinction is important for interpreting the amplitude and timing of the heart’s electrical activity accurately.