electrocardiogram (ECG)

ECG at rest at heart rate 60 per minute.

electrocardiogram (ECG)

a recording of the electrical activity of the heart muscle during the cardiac cycle, as transmitted to electrodes placed at specific sites on the chest. The normal heart produces a waveform which consists of five deflections known as PQRST, relating to consecutive events in the atria and ventricles. ambulatory ECG (Holter monitoring) recording over 24 h to detect any transient ischaemia or arrhythmias; the person continues with their normal activities, keeping a record of their time and nature. exercise (stress) ECG may be performed during increasing levels of exertion, such as on a treadmill, to detect any abnormalities caused by physical stress. Used for the diagnosis or prognosis of heart disease or to monitor cardiac rehabilitation. In sport, used primarily as a simple and inexpensive screening tool for potential causes of sudden death; ECG is recorded continuously during treadmill and cycle ergometer fitness testing.