An ECG data recorder based on RAM card technology

Having used transtelephonic monitoring, the author recognised that the telephone transmission aspects of ECG event monitoring are an unnecessary complication in routine patient diagnosis and management. In preference to setting up the required telephone answering facilities, many doctors advise their patients to return the device to the clinic once ECG recordings have been stored. The recordings are then reviewed at a time to suit both the doctor and the patient. The need for a means of collecting "a quantity of good quality" ECG records over a period of several weeks on patients who might find it difficult to transmit ECGs by telephone led the author to the Hertcard principle. The Hertcard recorder utilises a 64 Kbytes Static RAM Memory Card to store 12 episodes of EGG, each 32 seconds long. The patient either applies temporary electrodes to the wrists or wears semi-permanent electrodes on the chest. When symptoms occur, he or she presses a button and an episode of ECG is stored together with the time of day, the date and other recording circumstance data. Since many of the patients are elderly and not technically skilled it is of paramount importance that the recorder is very simple to use. This has been achieved by providing "one button operation" and displaying unambiguous messages on two LEDs and a four digit LCD. The only other controls required, time setting buttons, are concealed from the patient inside the battery compartment.