Final answer:
An electrocardiogram (ECG or EKG) records the electrical activity of the heart, showing depolarization and repolarization through features such as the P wave, QRS complex, and T wave.
Step-by-step explanation:
An electrocardiogram (ECG or EKG) is a graphic recording of the electrical activity of the heart, including its depolarization and repolarization phases. The ECG captures voltage differences between pairs of electrodes placed on the chest, which are vector components of the electrical activity. This test is crucial for assessing heart muscle function and diagnosing potential heart problems.
The ECG strip displays several important features: the P wave, which represents atrial depolarization; the QRS complex reflecting ventricular depolarization; and the T wave, corresponding to ventricular repolarization. Subtle changes in the ECG can also detect infarcts—regions of damaged heart tissue. Continuous ECG monitoring through devices like the Holter monitor can capture heart electrical activity over extended periods, offering a detailed picture of heart function.