Hi, this is Eric Prystowski. Welcome to another segment of EP on EP. Now, I'm going to tell you from the start, this is a different segment. This is not actually an interview as I typically do, but I have had an opportunity to put together a bit of a history of our field of electrophysiology discoveries. It's going to go quick, but I'd like to make sure for some of the folks who haven't been around as long as I have, to make sure you understand some of the background of our field. So let's get started right now. The first slide shows you a picture of Eindhoven and Sir Thomas Lewis way before Heart Rhythm Society ever came about. And those folks are also followed by a long stream of investigators that you'll see on this slide that start from Kent, they move all the way up. This is really the road to the discovery of how to identify and then cure patients with WPW, and we'll come back to that later. In the beginning, when I started, and it's not the beginning, but in the beginning when I started in my training, if you look around the world, there were five major places that contributed an enormous amount to our understanding of electrophysiology. Over in Europe was the wonderful work going on by Dirk Doerr and Hein Wellens. We come to the United States, there's the famous laboratory on Staten Island directed by Anthony D'Amato, and then you had many people who left his lab and went elsewhere, Ken Rosen in Illinois, and you have Josephson in Philadelphia, and you have John Gallagher and Will Seeley in Duke. Now on this slide, on the right is Professor Wellens, Hein Wellens, who had many important discoveries in our field. This is one of his earlier papers before his bundle of recordings were done, showing you the role of premature beats to initiate tachycardia and the WPW syndrome, and you can see here one of the figures from that paper, a PAC blocks the pathway and starts reciprocating tachycardia. Then we move over to the important discovery from D'Amato's laboratory, first authored by Benjamin Sherlock, the first recording of a his bundle in man, and here you can see a figure from that paper showing you the his bundle. Also from that lab were some of the earlier works on the ability of programmed stem to induce arrhythmias and the importance of AV node delay. Here you can see a PAC getting conduction over a slow pathway and then tachycardia initiated. There's also the wonderful observation from Ken Rosen, who had many observations in the field. This one is a his bundle extra-systole, and you can see one of the earliest observations here is a his extra-systole causing prolongation in an XAH interval. Then Ken Rosen's lab and a bunch of investigators there really opened the door to our understanding of AV node reentry. Here's one of the first and early papers looking at dual AV node pathways. Here you can see in the lab initiating with a long AH interval in tachycardia, and then the classic curves that you've all grown to understand of a dual AV node physiology. We also then had important observations from an investigator called Rui Sung, who looked at the unusual or the so-called atypical variety of AV node reentry. Here you can see starting in his laboratory, the long RP tachycardia, and basically having an entry point coming out closer to the coronary sinus area. Now to my mentor and another person that I work with in my days at Duke, in the middle is Will Seeley, and the other side of me is Dr. John Gallagher, who was my mentor. Will Seeley was the first one who ever cut an accessory pathway. Here is the first paper, the case report of WPW surgery, and you can see it was an epicardial approach that was done here. And then there are many, many papers that came out from the Duke School. Here is one of the classic ones that really wrapped up this whole issue of mapping WPW before you took him to surgery. You can see Dr. Gallagher, first author, and here's one of the many figures from that paper showing you how to map retrograde, a right-sided pathway, a septal pathway, and a left-sided pathway. Other observations in this area came from a number of investigators, and really one of the most important investigators in our field is the late Masoud Akhtar, who made important observations on physiology, and this is a picture of him. And one of his, my favorite papers of his, showed the importance of having a retrograde block to start AV reentry in a lab. Let me show you the figure from his paper. On the A side, you can see a PVC has a retrograde hiss, and on B, you see when the retrograde hiss is gone and you don't block any AV node, you start tachycardia, an important observation that he made in the early days. If you've not read the paper, Total Excitation of the Heart, you have really missed one of the key papers in our field. Many important observations come directly from this wonderful paper by Dirk Doerr, published early on, and here is one of my favorite figures from that paper, and the reason you need to understand this is this is the Total Excitation of the Heart. If you look at the septum activation time, you realize it's somewhere around 50 milliseconds or so in humans. That observation led to many important other observations in our field. For example, Philippe Coumel, the so-called Coumel sign, who demonstrated in reciprocating tachycardia that a bundle branch block would change cycle length of tachycardia, and here's a figure from that paper. You see when you have a left bundle branch block and a left-sided pathway, the cycle length is longer than when you lose the left bundle, and again, that all has to do with the issue of including transeptal conduction. This was studied in much greater detail, and the reasons for this, through the Duke Group. This is one of several papers, an important one that was published by Charlie Kerr, and this is where this delta VA interval of greater than 30 milliseconds comes from to identify a left free wall pathway versus, for example, a septal pathway, and of course, the same one of the right bundle branch on the right side. These may seem like, why would you bother, but in the early days, our job was to take people to the OR, and you needed to know where a pathway was before you opened someone's chest and did surgery. I understand in the ablation era that it's not quite at the same level of importance, but it's still important. We actually got into this. I used the physiology of this transeptal conduction, working with my friend George Klein in a paper published by Bill Miles from our lab, looking at the whole idea of a pre-excitation index. Our thinking was, if we had a catheter in the right ventricle, and we could get into a circuit early, then that would mean it's probably right-sided. If we had to go across the septum, using that same physiology published by Durer, then it would take longer, and you can see this is where that pre-excitation index comes from, and if you were greater than 75 milliseconds, it means you were on the left side of the heart. Then comes other observations in our field, the classic paper by George Klein on risk stratification in WPW. This is that graph that he published back in 79, or 80, where it shows the shortest pre-excited RR interval is important to figure out who's at risk for sudden death. We then move over to ventricular tachycardia. There were so many observations from Dr. Josephson's lab. This is just one showing you the importance of these pre-systolic slow conduction to let you know where to go surgically initially, and now with ablation. The gentleman that I'm with in this picture is Dr. Al Waldo, again, made many important observations, but the key for clinicians, in my opinion, is his observations on entrainment. Here's that paper that Al Waldo published, and you can go read the paper yourself and you'll see he goes through his rules of entrainment, which has been a mainstay for electrophysiologists dealing with macro-reentry tachycardias. Coming along to add to that important observation is Bill Stevenson, who did work showing you the idea of concealed entrainment. Here's a picture, a figure from one of his papers, showing you what it was like if you were in an isthmus, still building on the observations of Al Waldo. In the same area of VT and cardiac arrest, we come to the very important paper published by Jeremy Ruskin in the New England Journal, showing you that people who had cardiac arrest often had a substrate problem and could be induced into sustained VT in the laboratory, but most importantly is the observation of Michel Mirowski, many years of work, and finally brought to fruition when he published his initial observation on the use of an implantable defibrillator to prevent sudden death in human beings. Now we move to ablation, classic paper by Mel Scheinman, looking at AV junctional ablation, and here is a figure from his paper, John Gallagher, also published early in this area. It's interesting that I was studying a patient in my lab, and I noticed something that I thought was actually an atrial hyssian pathway, which I'd never seen before, and then the catheter probably bumped the pathway, and I realized that I was actually recording an accessory pathway. Dr. Jackman had been in my lab just a couple years before this, but I looked at this as an interesting curio, and luckily for the field, Dr. Jackman did not, because Sonny Jackman went on to investigate this whole area of identifying accessory pathways, and then from that, he went and showed us that we could go ahead and ablate these pathways. Very important observation, moved the whole field of WPW non-pharmacologic treatment out of the OR and into our laboratories. And then Fred Marotti, in a paper first authored by Hugh Calkins, his lab showed that there was a way to do this in a very efficient manner. He showed us that you could study these people and ablate them all at the same time. It really changed the way that we all approach this. Sonny Jackman went on to also look at the patients with AV node re-entry, and here is his paper showing you how to find the right site to ablate AV node re-entry and cure those patients. We move into the area of atrial fibrillation. We have to look at the landmark studies from Jimmy Cox. This is the Mays procedure, and notice on the left side of the heart, there's a big black box around the pulmonary veins. Now, he was developing this based on the concept of multiple wavelet theory from Gordon Moe, but part of his procedure, and I'm sure it's what made it very effective, was he blocked off the pulmonary veins, which changed our entire approach to this. In the laboratory was a seminal observation from Michel Hassegger in Bordeaux, when he showed us that actually the pulmonary veins were the source of many patients' problems with atrial fibrillation. Here is a figure from that paper where you can see that the pulmonary vein potential start atrial fibrillation. There are so many people in our field who have added to this whole area of atrial fibrillation ablation, too numerous to identify. The ones listed on here, in my opinion, have made some very, very important observations from Xian Chen's lab with right atrial sources, Hans Kottkamp looking at atrial myopathies, Frank Markslinsky with trigger ablations, Nasir Maroosh was looking at the substrate with imaging techniques, Sanjeev Narayan investigating rotors, Andrea Natale, a whole series of important observations, Doug Packer with the CABANA trial, and David Wilber also with a series of important observations. Where's the future? For me, the future is going to be non-invasive mapping and zapping the arrhythmia foci from inside the heart. I think this is where we're headed. I hope we get there soon, and it's been a wonderful ride.

electrophysiology discoveries

Wolff-Parkinson-White syndrome

His bundle recordings

AV node reentry

accessory pathways