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Holter Monitoring
OHC uses Holter Monitoring to record every heartbeat for a 24 hour period.  The patient has 5 leads attached to their chest and wear the monitor for 24 hours.  At the end of 24 hours the patient returns to OHC to have the device remove.  Our trained technicians downloads the information into a computer and generates a printout of the 24 hour time period.  One of our cardiologists, then analyzes the data and reports their findings to the ordering physician or the patient during their next appointment.

The Aria recorder is state-of-the-art Holter monitoring made simple. No larger than a typical pager, it uses four leads to record three channels of patient data. Worn under the shirt in a chest pouch and can record up to 48 hours of full-fidelity ECG data without data compression.



14 Sep 2004 

History of Holter Monitoring

History of Holter Monitoring
A Review of Literature - By: R. Hal Gant

The first ambulatory electrocardiograms (AECG) were conducted by Jefferis (Jeff) Holter and Dr. W. R. Glasscock in 1961 using a heavy, complicated and cumbersome assortment of radio telemetry and tape recording equipment that allowed a limited range and time of measurement for human subjects.(1,2,3) Bruce Del Mar teamed up with Holter to develop and produce a smaller, lighter "Electrocardiocorder®" and high speed review technique that allowed a practical method to record and interpret long term AECGs of 24 or more hours.(4) Through the Holter monitoring technique, patients' ECGs are routinely recorded and analyzed during normal daily activity, even during sleep. High speed playback and computer assisted analysis provide the physician with valuable information regarding the electrical activity of the patient's heart that are especially useful for the determination of cardiac abnormalities, drug efficacy, pacemaker follow-up, Sudden Infant Death Syndrome (SIDS), differential diagnosis of patient symptoms and activity related cardiac changes.(5,6,7,8,9)

Although Holter's first efforts consisted of an 85 pound radio transmitter and a receiving device that required the same amount of analysis time as the time recorded, the first commercial AECG device manufactured in 1962 by Del Mar Engineering Laboratories under the name Avionics Research Products Corporation was much lighter and easier to use.(4) A large number of research and clinical findings were published immediately after the introduction of this technology to the medical community leading to wide spread acceptance of the technique by 1966. Del Mar Avionics continued to improve upon Holter's earlier concepts by miniaturizing portable tape recorders, speeding up and simplifying analysis techniques and increasing the number of channels that could be recorded and analyzed. Concerns regarding the volume of data, accuracy of analysis, operator dependency/fatigue and other technical considerations resulted in the development of computerized models for analysis of the ECG and summary report generation for physician interpretation.(4,11) Refinements to the recording technique include; three channel recording, timing track speed correlation, development of reusable cartridge tapes, utilization of standardized cassette tape, use of micro cassette recorders and tape; simultaneous recording of Electroencephalogram (EEG), Blood Pressure (BP) or gastric pH with ECG.(14) Augmentation of the analysis technique has included refinements in arrhythmia, ST, Pacemaker and heart rate variability analysis.(15,16,17,18) Signal Averaging techniques and high resolution analysis of the ECG signal have also been added to increase clinical utility of AECG.(12,13) Computerized analysis of the QT intervals of each normal beat is the latest innovation in the ever expanding use of Holter ECG data.(19,20)

Intended primarily for cardiac patients, the benefits of a portable recording device that is non-invasive and poses no risk to the patient are apparent. An LCD digital clock used in conjunction with a diary of the patient's activities and symptoms allows the technician to correlate cardiac activity with diary entries. A patient event button can also be utilized to mark the recording for symptom correlation. Originally designed using magnetic tape, recording limitations such as wow, flutter, tape head misalignment and mechanical malfunctions are eliminated with the use of a PCMCIA type II digital recorder which acquires 8-bit data on a Flash memory device. Digitized data is more quickly and accurately transferred to the analysis station and time searching of the data is more easily accomplished by the technician leading to an improved reproducibility of results. The recorder, cable and electrodes are arranged under the patient's clothing so that they are unobtrusive to the patient. The recorder can be worn by shoulder strap or waist belt in such a way that it will not interfere with normal motion and has been attached to athletes during strenuous activity.(6,7,10) It is estimated that more than 100,000 Del Mar Holter recorders have been, and still are, in service.

The recorded ECG is analyzed at a work station or, "scanner," that allows technician overview and computer assisted analysis of both the wave shapes and rate/rhythm of the signals.(8) The first commercially available systems could only record 10 hours and playback speed was limited to 60 times faster than real time. Today, 48 hour Holter recordings are common and playback speed is in excess of 500 times real time. Detection and quantification of cardiac anomalies is performed simultaneously with the documentation of the patient's ECG in the process referred to as, "scanning." Documentation of cardiac abnormalities allows the physician to interpret the Holter recording in an effort to further understand the patient's increased risk for sudden death or response to treatment. By providing a global assessment and examples of ECG from the recording period, the physician has a better picture of the patient's electrocardiographic activity during their normal daily routine.


1. Holter, N.J.: Historical Background and Development of Ambulatory Monitoring: The Nature of Research, in Jacobsen, N.K., and Yarnall, S.R. (eds.): Ambulatory ECG Monitoring, Seattle, Wash.: MCSA, 1976; pp. 1-9.
2. Holter, N.J.: New method for heart studies continuous electrocardiography of active subjects, Science 1961; 134:1214-20.
3. Gilson, J.S., Holter, N.J., and Glasscock, W.R.: Continuous ambulant electrocardiograms and their analysis: Clinical observations using the electrocardiocorder and AVSEP analyzer, Am. J. Cardiol. 1964; 14:204-17.
4. Corday, E.: Historical Vignette Celebrating the 30th Anniversary of Diagnostic Ambulatory Electrocardiographic Monitoring and Data Reduction Systems, JACC 1991; 17:286-92.
5. Knoebel, S.B., Fisch, C., et.al.: ACC/AHA Task Force Report Guidelines for ambulatory electrocardiography: J. Amb Mon. 1989; 2:4:313-328.
6. Canete, D.R., Sol, J., et.al.: The Honolulu Holter Marathon Study, John A. Burns School of Medicine, Honolulu, Hawaii: 1975
7. Tzivoni, D., Benhorin, J.: Holter Recording During Treadmill Testing in Assessing Myocardial Ischemic Changes: Am J. Card. 1985; 55:1200-1203.
8. Corday, E., Lang, T.: Accuracy of data reduction systems for diagnosis and quantification of arrhythmias: Am. J. Card. 1975;35:927-28.
9. Kennedy, H.L.: Ambulatory Electrocardiography including Holter Recording Technology: Philadelphia, Lea & Febiger, 1980.
10. Horner, S.L.: Ambulatory Electrocardiography Applications and Techniques: J.B. Lippincot Company.
11. DiBianco, R., Katz, R.J. et. al.: Evaluation of Technician Audiovisual Scanning of Ambulatory Electrocardiographic Recordings Utilizing the Rapid Oscillographic Printout Technique of Validation: Clin. Card. 1982:5,39-45.
12. Henkin R., Caref E.B., Kelen G.J., El-Sherif N.: A Comparitive Analysis of Commerical Signal-Averaged Electrocardiogram Devices. In: High Resolution Electrocardiography. El-Sherif and Turitto (EDS.) Futura Publisher. 1991:pp. 173-185.
13. Kelen, G, Henkin, R.: Correlation Between the Signal-Averaged Electrocardiogram from Holter Tapes and from Real-Time Recordings. Amer Jour of Card. 1989; pp. 1321-1325.
14. McCall, V.R.: fully Automated Indirect Blood Pressure Measurement Techniques and Clinical Applications. 1987 © DMA.
15. Salerno, D.M., Granrud, G, et. al.: Accuracy of Commercial 24-Hour Electrocardiogram Analyzers for Quantitation of Total and Repetitive Ventricular Arrhythmias. Am J. Card. 1987; 60:1299-1305.
16. Hammill, S.C.: Evaluation of a Holter System to Record ST-Segment Changes. J. Electrocard. 1987; Supplemental Issue-Oct.
17. Kennedy, H., Wiens, R.D.: Ambulatory (Holter) electrocardiography and myocardial ischemia. St. Louis University School of Medicine; 1988.
18. Van Gelder, L.M., El Gamal, M.I.H.: Undersensing in VVI-Pacemakers Detected by Holter Monitoring. PACE 1988;11:1507-1511.
19. Baranowski, R., Poawska, W., Rydlewska-Sadowska, W.: Day to day reproducibility of beat by beat Holter QT analysis. Abstract for National Institute of Cardiology, Warsaw, Poland.
20. Bent, T. J., et al: Reproducibility of QT Dynamics in Healthy Subjects. Abstract for University of Copenhagen, Copenhagen, Denmark.