Final answer:
An electrocardiogram (ECG) is a record of the heart's electrical activity. The 12 leads of a state-of-the-art ECG can provide valuable information about the heart, including regions of damaged tissue and subtle changes. ECG technology has advanced to the point where portable monitors can be used for continuous monitoring of heart activity.
Step-by-step explanation:
An electrocardiogram (ECG) is a record of the voltages created by the wave of depolarization and subsequent repolarization in the heart. Voltages between pairs of electrodes placed on the chest are vector components of the voltage wave on the heart. Standard ECGs have 12 or more electrodes and can provide a wealth of information about the heart.
The 12 leads of a state-of-the-art ECG can detect regions of damaged heart tissue, called infarcts, and subtle changes due to slight or gradual damage to the heart. By comparing a recent ECG to an older one, healthcare professionals can monitor changes in the heart's electrical activity and diagnose heart conditions.
ECG technology has advanced to the point where portable ECG monitors can be incorporated into wearable devices and other small objects, allowing for continuous monitoring of heart activity.