Ambulatory (Holter) electrocardiography technology.

Ambulatory ECG is an evolutionary cardiovascular discipline with regard to both its clinical applications and technology. With the technologic advances of the past decade, powerful personal computers have expanded the traditional clinical role of ambulatory ECG examination for cardiac arrhythmias to detection of ST-segment changes, heart-rate variability, QT interval measurement, and the signal-averaged ECG. These expanded clinical applications increase the practicality of a 24-hour ambulatory ECG on an individual cardiac disease patient and make the 24-hour ambulatory ECG one of the most cost-effective cardiovascular diagnostic tests when used properly. The current clinical developments make valid ST-segment detection and quantitation readily available and heart-rate variability an easily applied investigative tool to a wide spectrum of diseases. Automatic QT interval measurements and signal averaging of ambulatory ECG are just technologically emerging and can be expected to develop more in the near future.