AMBULATORY ECG MONITOR

Typical Number in Hospital: 2

Cost Bands: 5

References: 3

Abnormalities of the ECG and heart rate may not show when the patient is being monitored in the clinic. At one time it was common to confine the patient to bed and watch the ECG tracing for a few days. Automatic monitors are now available which will recognize abnormalities in the cardiac rhythm.

A special type of automatic arrhythmia detector monitors the patient during his normal working day by means of a special cassette tape recorder which is carried by the patient under investigation. By suitable data compression mechanisms the whole 24 hours (approximately 100 000 heart beats) can be compressed on to one cassette and this is read through on the following day at high speed to identify the frequency and significance of fluctuations in the heart rhythm.

The whole apparatus consists of a number of special portable tape recorders complete with ECG leads and electrodes, and the arrhythmia analyser which is kept at the hospital. The analyser consists of a cassette playback mechanism and a small computer programmed to recognize variations in the heart rate, and possibly abnormalities of the ECG itself. Typically, the output would be a histogram of the heart rate over the 24 hours and the ability to reproduce small sections of the ECG waveform relating to unusual events.

The use of such apparatus is much more cost efficient than long-term monitoring in the coronary intensive care unit, and is also more likely to detect transitory problems because the patient is performing normal tasks.