Letter from the Editor

In Recognition of the Contributions by Pablo Denes, MD

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

The origin of much of what we do in the electrophysiology (EP) laboratory has been forgotten. For example, it is now common for people to refer to an AH “jump” when describing the abrupt increase in the AH interval with an increasingly premature atrial extrastimulus at the induction of typical atrioventricular (AV) nodal reentry. However, where does this understanding of the mechanism of AV nodal reentry come from?
In 1973, Dr. Pablo Denes published the first report in the EP lab of discontinuous AV nodal conduction curves in two patients with paroxysmal supraventricular tachycardia.1 He was working at the time at the University of Illinois Medical School in Chicago with another pioneer in EP, Dr. Ken Rosen (it is notable that the publication refers to their affiliations as being with the Abraham Lincoln School of Medicine of the University of the Illinois College of Medicine). The classic, original figure of a discontinuous A1-A2/A2H2 conduction curve in one of the patients is shown in Figure 1. “These results provide the first electrophysiological demonstration of dual A-V nodal pathways in patients with normal P-R interval and PSVT, as manifest by dual A-V nodal conduction times and refractory periods. Antegrade failure of the fast pathway with subsequent availability for retrograde conduction could allow A-V nodal reentry. These findings provide a basis for reentrance in some patients with reentrant PSVT.”
In only seven years (between 1973 and 1980), Drs. Denes and Rosen published 77 research papers together. That is nearly one paper every month. Unfortunately, Dr. Rosen died suddenly at age 44. In total, Dr. Denes has published over 200 articles covering topics such as the mechanisms behind participation of fast and slow AV nodal pathways in patients with WPW, perpetuation of rate-dependent aberration, bifascicular conduction block, the “gap” phenomenon, and signal-averaged electrocardiography. He has done so in collaboration with many other pioneers in the field of EP, including Drs. Alfred Pick and Richard Kehoe.
Giving over 200 lectures during his career, Dr. Denes is an international leader in electrophysiology and a legend in Chicago. He has left his indelible mark at four different major academic medical centers in the city. After attending medical school at the University of Buenos Aires in Argentina and completing his residency at the Washington Hospital Center, he finished his cardiology fellowship in 1972 at the University of Chicago, where he also served as an instructor of medicine. From 1972-1978, he practiced electrophysiology at the University of Illinois in Chicago. Dr. Denes then spent the next decade at Rush University Medical Center in Chicago. After a brief stint as Chief of Cardiology at the St. Paul-Ramsey Hospital and Medical Center in Minnesota, he returned to Chicago as Chief of Cardiology at Michael Reese Hospital in Chicago from 1994-1999. Now shuttered, Michael Reese was once the leading cardiovascular center in Chicago. He then joined the faculty at Northwestern, where he took care of countless patients with heart rhythm disorders, taught the pearls of EP to students, residents, and fellows, and for a time, ran the EP consult service.
Last month, Dr. Denes announced his retirement from patient care at Northwestern Memorial Hospital, where he has been a member of the faculty for nearly 20 years. Senior faculty members are often credited for serving as mentors to trainees and junior faculty members, but Dr. Denes has gone beyond mentorship. He has not always been available professionally as a resource for difficult cases and research ideas, but he has been available personally as an interested listener, a source of institutional memory, a navigator of politics, and a provider of personal advice. Pablo has also given back to the community. He worked for a year in Ecuador as a volunteer cardiologist, has been quietly caring for patients at the local free clinic, and received the Northwestern Medicine Faculty Foundation’s Award for Community Service in 2011.
So, the next time someone refers to a “jump” to the slow pathway, remember the original publication of a discontinuous AH curve by Dr. Pablo Denes in 1973. Dr. Denes embodies the qualities that all academic physicians should strive for. As he “jumps” into retirement, may Dr. Denes enjoy every well-deserved millisecond.


  1. Denes P, Wu D, Dhingra RC, Chuquimia R, Rosen KM. Demonstration of dual A-V nodal pathways in patients with paroxysmal supraventricular tachycardia. Circulation. 1973;48:549-555.