Scope and Contents
The collection includes engineering logbooks, drawings, operator manuals, correspondence, photographs, sales brochures and catalogs, biographical information about the engineering staff who worked on the monitor, patents and trademarks, and marketing and sales materials documenting the development of the Holter Monitor, a portable device for continuously monitoring heart activity.
The records document the successful collaboration of an independent inventor and a manufacturing firm to identify problems, develop solutions and bring to market diagnostic technologies. Bruce Del Mar's role as an innovator and collaborator with Holter is especially important, because Del Mar's work spurred the development of an entire diagnostic industry. In addition, the records also chronicle how "Holter technology" was affected by progressive technological innovations in the industry, as vacuum tubes were replaced by transistors, as microprocessors gave way to microchips and circuit boards, and as analog recordings were replaced by digital formats.
Documenting manufacturing developments (highs and lows) and marketing considerations is an important element in better understanding the invention process. Del Mar Avionics was the first to design and manufacture instrumentation for long-term monitoring of the human heart for the medical profession. Today, Holter Monitors continue to be an important diagnostic tool for monitoring the health of the heart.
Series 1, Historical Background, 1951-2010 and undated, consists of biographical materials for Bruce Del Mar, founder of Del Mar Avionics, company histories, copies of the Del Mar Avionics newsletter Pacemaker, employee information, newspaper clippings and ephemera, and photographs of some employees. The employee information contains a 1979 handbook, explaining company policies and the benefits of employment with Del Mar Avionics and a 1951 memo detailing overtime working hours for women, presumably from Douglas Aircraft, where Bruce Del Mar was employed.
Series 2, Del Mar Avionics Engineering, 1958-1976, is divided into three subseries, Subseries 1, Correspondence, 1965-1976; Subseries 2, Reports, 1964-1969; and Subseries 3, Drawings, 1958-1968. The documentation consists primarily of correspondence from the engineering department, 1965 to 1976, related to the development, design, budgeting, testing, and marketing of the Holter Monitor. The majority of the documentation is correspondence and is written by engineering staff members, but also included are quotation requests, trip reports, and technical reports. Correspondence between Holter and Del Mar about the development of the Holter Minotor is in Series 6. The drawings, 1958-1968, include six drawings (22" x 34" or smaller) for Avionics Research Products projects (panel assembly, chassis assembly, and battery chargers for model 602), and Electromation Company (degausser single coil).
Series 3, Patents and Trademarks, 1965-2002 and undated, consists of copies of patents by Norman J. Holter, W.E. Mills, and W.E. Thornton, Cliff Sanctuary. and Isaac Raymond Cherry related to the development of the Holter Monitor. Also included are lists of United States patents issued to Del Mar Avionics employees, as well as lists of registered trademarks and activities for Del Mar Avionics and copies of trademarks issued to the company.
Series 4, Product Literature, 1968-2010 and undated, consists of product literature for Del Mar Avionics products and some of its competitors. The product literature for Del Mar Avionics is arranged chronologically by model number, and the competitor literature is arranged alphabetically. All of the product literature is related to medical instrumentation with the exception of the Hydra Set, a precision load positioner which is the only product Del Mar Avionics sells today.
Series 5, Sales, 1967-1985, consists of price lists, price catalogs (both domestic and international) and sales objectives for medical instrumentation sold by Del Mar Avionics.
Series 6, Holter Monitor Materials, 1958-2005 and undated, is divided into three subseries, Subseries 1, Background Materials, 1958-2005 and undated; Subseries 2, Model 445, 1974-1978; and Subseries 3, Model 660, 1967-1978 and undated, and consists of materials documenting the relationship between Norman J. Holter, an inventor, and Del Mar Avionics.
Holter and Wilford R. Glassock were issued United States Patent 3,215,136 on November 2, 1965 for the Electrocardiographic Means. Dr. Eliot Corday introduced Holter to Bruce Del Mar, founder of the Del Mar Avionics Corporation in Irvine, California. Del Mar engineers developed the "electrocardiocorder" for clinical use, producing a commercially viable monitor which came to be known as the Holter Monitor Test. Further refinements led to the creation of a "minimonitor" in 1968 which was described by Holter as being the "size of a cigarette package." Commercial production of the Holter minimonitor, AVSEP, Jr., began in 1969. The Holter Research Foundation ultimately sold exclusive rights to their patents to Del Mar Engineering Laboratories.
The materials include biographical materials about Norman J. Holter, journal articles about the Holter Monitor, correspondence, engineering notebooks, a licensing agreement, product literature, reports, price lists, catalogs, operating manuals and specific information about the Dynamic Del Mar Avionics ElectroCardioCorder (Model 445), 1977, and the ElectroCardioScanner (Model 660), 1971. Both models were developed by Del Mar's medical device manufacturing staff. The licensing agreement and correspondence detail in chronological order the relationship between Norman Holter and Del Mar Avionics, specifically president Bruce Del Mar, in the rapid commercial marketing and development of Holter's electrocardiorecorder. Although Holter assigned exclusive rights to his patent to Del Mar Avionics, he was involved in the design and development process, albeit from a distance. The engineering staff at Del Mar kept Holter informed, and it is clear that Holter regularly visited the company.
The engineering notebooks relate to the models 445 and 660. The notebooks were maintained by engineering staff members D. Anderson, N. Mohammedi, Ray Cherry and Fike. The notebooks are handwritten, although in some instances memos and other information have been inserted. For example, N. Mohammedi's notebook documenting Model 445 contains black-and-white prints, magnetic tape samples, and recorder tape (EKG graph paper) samples with data from the monitor. The notebooks are bound and paginated, and individual pages are stamped sequentially.
Series 7, Slides, circa 1990s, consists of color slides used for presentations by Del Mar Avionics staff to discuss and promote the marketing of the Holter Monitor.