Disk-based, high-resolution ECG recorder for ambulatory monitoring

To meet the need for a higher fidelity electrocardiogram (ECG) recorder, the authors developed a unit that is programmable for various sampling rates and is capable of storing vast amounts of digital data without using data-distorting compression techniques. The Altair-DISC recorder has been developed for use in an ambulatory clinical environment. The Altair-DISC, which is the size of a conventional cassette recorder, utilizes a magnetic hard disk drive for data storage. The monitor´s operation is controlled by a microprocessor and data sampling by a crystal oscillator, which when combined with digital data storage eliminates timing variations, channel-to-channel skew, frequency response variations and other problems associated with cassette recorders. To demonstrate the benefits of the Altair-DISC recorder, a study was done to measure the heart rate variability of stimulated data recorded by an Altair-DISC recorder versus the data recorded by a Holter cassette tape recorder. From the histograms and tabulated results, the Altair-DISC recorder is clearly superior to tape recorders, when used for heart rate variability studies