Biography

Born in Anrath, in the county of Kempen-Krefeld, Germany, Irnich received a Masters degree in Electrical Engineering at the Rhine-Westfalian Technical Institute (RWTH), Aachen, Germany in 1960 and remained in the Department of Theoretical Electrical Engineering for an additional eight years during which he wrote a doctoral thesis "Investigations on Noninvasive Blood Pressure Measuring Techniques", and received the Ph.D. in Electrical Engineering in 1968. Between 1968 and 1979 he was in charge of pacemaker patient care in the Department of Internal Medicine, a cardiology clinic at the RWTH, and established the first systematic pacemaker follow-up in Germany. At this time he wrote the "Habilitation Thesis", a prerequisite for professorship in Germany, on "Electrostimulation of the Heart" which was accepted in 1975. In 1979 he was appointed Professor of Biomedical Electronics at the Justus-Liebig-University Hospital in Giessen, Germany where he built the "Department of Medical Engineering". He retired from his academic position in April 1999.

Based on involvement with cardiac pacemakers, Irnich founded the "German Central Pacemaker Registry" in 1980 publishing detailed annual reports from 1982, based on the investigation of 3060 pacemakers removed from deceased pacemaker patients. He was able to ascertain that there are more pacemaker malfunctions in deceased than in living patients, suggesting the role of malfunction in patient mortality. In 1986 he became a "publicly appointed and sworn expert for electro-medical devices". In 1970 he designed an anti-tachycardia stimulator, used by a patient for more than 6 years and an effective early model active fixation lead for atrial and/or ventricular application which was successfully applied internationally in over 100,000 patients. In 1975 he published the theoretic concept of dual chamber pacing now designated as DDD and in 1988 described rate modulated AV delay and the theory of time-varying magnetic fields, formulating a theory of magnetostimulation (important for patients undergoing MRI).

Over the past 30 years he developed a theory of electrode optimization and has become especially knowledgeable concerning stimulation theory, redefining rheobase and chronaxie in terms which allowed stimulation threshold to be accurately calculable. He added to the theorem by optimizing defibrillation pulses and demonstrating that an exponential defibrillating pulse reaching rheobase should be truncated as that part of the pulse below rheobase is not useful and may be deleterious. He has long studied electromagnetic interference (EMI) relative to cardiac pacemakers and implantable defibrillators and described a discrimination method for superior interference suppression.

He is co-author of five books dealing with "Electrotherapy of the Heart", "A Contribution to the Safety of Implants", "Mobil Phones in Hospitals", "Introduction to Bioelectronics", and "Medical Technical Service Centers". He is author or co-author of more than 300 articles or letters to the editor in scientific journals and has been a Senior Editor of PACE (Pacing and Clinical Electrophysiology) since its founding in 1978.

Interview Excerpts

Temperature problems in early implantable pacemakers. (4:17 sec.; Real Audio)

Development of specific terms in EP: Rheobase and Chronaxie. (3:34 sec.; Real Audio)

Excerpted from this interview:
Interviewer: Seymour Furman, MD
Date: August 14, 1996
Place: Toronto, Ontario, Canada
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