Electrocardiogram (ECG)

Definition

An electrocardiogram (ECG) is a medical test that measures the electrical activity of the heart over a period of time. It is used to detect and diagnose various heart conditions.

5 Must Know Facts For Your Next Test

1. An ECG measures the voltage differences generated by the heart's electrical activity using electrodes placed on the skin.
2. The standard ECG consists of 12 leads, providing different views of the heart's electrical activity.
3. The P wave represents atrial depolarization, while the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization.
4. Ohm's Law ($V = IR$) is applicable in understanding how voltage (V), current (I), and resistance (R) relate in an ECG circuit.
5. Electrodes used in an ECG are conductive materials that convert ionic current from the body into electronic current for measurement.

Review Questions

• What physiological process does the P wave represent on an ECG?
• How does Ohm's Law apply to interpreting an electrocardiogram?
• What role do electrodes play in recording an ECG?

Related terms

Depolarization: A change in a cell's membrane potential making it more positive, which is crucial for initiating muscle contractions.

Ohm's Law: $V = IR$: The relationship among voltage (V), current (I), and resistance (R).

Electrode: A device that conducts electricity and is used to connect with a nonmetallic part of a circuit, such as biological tissue.