Sabine Ernst (lead electrophysiology research/consultant cardiologist, Royal Brompton and Harefield Hospital, London, UK and associate lead for Cardiac Imaging in the Biomedical Research Unit of the Royal Brompton Hospital) set up the first magnetic navigation catheter ablation laboratory in Europe and is also credited with becoming the first operator in the world to perform a truly remote catheter ablation in 2003. Ernst is currently focusing on finding solutions for patients with congenital heart disease and has successfully applied remote magnetic navigation in this patient cohort. She is also interested in the role of the autonomic nervous system to explore completely novel strategies of electrophysiology (EP) interventions.
When did you first decide you wanted a career in medicine?
When I finished school I was unsure of what I wanted to study, but I was determined to follow my older siblings to university. My older sister had a PhD in Germanistik (German studies) and my older brother was an engineer who also went on to get his PhD, while my other brother studied economics. I definitely wanted to do my own thing and was torn between medicine and law so I checked out what the prerequisites for medicine were and found out about the entry exam Medizinertest (Medical test). I had chosen mathematics and French as my major subjects for my final school exams (“Abitur”) and had only continued to do physics in my final two school years, but I was good in 3D visualisation and other tasks so I finally went for it in my final school year. In combination with the estimated grade of my Abitur, I was confident that I would be eligible for a place; however, when the results finally came out, I was among the top 10% in my country, which guaranteed me a place. However, I was not sure if I would be happy with this and, therefore, worked in a little hospital in my home town to gain some experience. Eventually, I enrolled at the University of Ulm, Ulm, Germany, in the autumn of 1990 and in retrospect enjoyed every second of the time I spent in medical school. I had some fantastic professors and made a lot of very good friends. I also was very fortunate that one of my cousins was practising as a general practitioner in a village close to Ulm, which allowed me to join him in his surgery to learn the real-life of medicine with lots of hands-on experience.
Why did you choose cardiology and EP?
Through my love for anatomy, I had gotten in contact with a young professor of anatomy who recommended an eager gastroenterologist who had just returned from a fellowship at UCLA. He was looking for students interested in inflammatory bowel disease and I went on to become the first student to do a medical thesis under his supervision. But when it came to securing a permanent position in the department, after three years of experimental work in parallel to med school, one of my best (male) friends was selected. Being massively disappointed and somewhat disheartened (had I not done everything possible, including winning a grant from the Deutsche Akademischer Austausch Dienst, to allow performing radio-immunoassays as part of my thesis at UCLA?), I decided to choose something completely different such that I never would have to encounter these people that let me down again. During one of my placements in a specialist surgery (“Facharztpraxis”), I had an outstanding experience with Dr Henning Nissen who introduced me to echocardiography, 12-lead electrocardiograms (ECGs) and the like. After a successful resuscitation in the surgery and a really fantastic 30 days, Nissen gave me a Braunwald “Internal Medicine” edition which is now one of the books in my possession that I am immensely proud of. This first glance into cardiology made me choose it as a specialty after the gastroenterology disaster. I looked up all the cardiology departments in Germany and directly applied at my 10 favorite cities. One of them was Hamburg and I applied at the University of Eppendorf. The German hospital address book that the university library had at the time listed Prof Karl-Heinz Kuck as the interim chief of the service so I addressed my application to him, not knowing of course that he had just moved to St Georg General Hospital in Hamburg. When St Georg Hospital contacted me to see if I was still interested in the job, I responded positively. When I finally interviewed with Prof Kuck (on my own initiative), he asked me if I was interested in more basic research or rather clinical research. My frustrations with some of my experiments during my thesis made me respond instantly that I would be far more interested in clinical research. So I landed myself in the EP group in St Georg, not knowing anything about it at all, but with a great enthusiasm for ECGs and a love for anything challenging, 3D and computer-driven.
Who were your mentors and what wisdom did they impart to you?
When I joined St Georg, I was amazed at the opportunities of invasive EP and got hooked on the chance to cure patients of potentially life-threatening arrhythmias. My greatest mentor there was without any doubt Karl-Heinz Kuck. His enthusiasm, energy and enormous ability to concentrate, persist and finally solve even the most difficult invasive situations have left an unerasable stamp on me. Of course, there were many more, like Joachim Hebe, who allowed me to assist him in paediatric and congenital patients. I seemed to make a positive difference and he began, after some initial hesitations, to ask me to help either at the electroanatomical mapping system or to run the sedation of the patients. Feifan Ouyang explained every concept in EP to me and helped me, especially in the first few years when we were both relatively new. I learned how to read tracings from him and we were a great team, writing and analysing data together. Michael Schlueter showed me how to programme databases and write concise abstracts and manuscripts and most importantly, he critically reviewed my presentations for large congresses and his attention to detail was key for me to be finally confident when presenting our data of AF ablation to the world. “Surviving” the in-house rehearsal made the real abstract presentation looks like a child’s play!
What is your biggest motivation for working in EP?
I still thoroughly enjoy every day I spend in an EP lab and these two days are usually the highlight of my week. The ability to solve complex arrhythmia cases, applying the best techniques that ultimately result in a positive outcome for a patient, gives me a personal gratification that is unparalleled. Seeing the patient and possibly the relatives later in follow-up and witnessing their gratitude is an opportunity that not so many specialities in medicine have. This is normally reserved for colleagues from surgical disciplines, but invasive cardiology allows for a similar experience. I simply love the challenge of a novel experience in every procedure. I have elected to treat not only the typical AF cases, but I have built a strong reputation for complex congenital heart disease patients or patients with ventricular or previously failed ablation procedures when I joined the Royal Brompton Hospital, nearly 10 years ago. This assures that I am never bored and even enjoy the occasional “simple” case. Using novel technologies such as new ablation energies, remote navigation or novel 3D mapping and navigation systems is another perk that fuels my passion for EP more than any other field in cardiology. There is still so much to learn and we are barely scratching the surface of our understanding of why and how cardiac arrhythmias occur. My recent research interest focuses on the role of the autonomic nervous system and this field is again unchartered territory which allows me to explore completely novel strategies of EP interventions.
What skills are required to be an electrophysiologist?
An electrophysiologist must have a good 3D understanding and realise that everything happens in the actual heart of the patient, then all 12-lead ECG findings just “jump” into place. Detailed knowledge of cardiac anatomy is also extremely relevant, which led me to collaborate on a book for cardiac anatomy with Prof Yen Ho. Finally, persistence and stamina are necessary to continue to follow one’s dream in the presence of adversity.
A good hand-eye coordination is helpful, but there are now several systems that would allow even non-manual gifted colleagues to perform invasive procedures—some of the most famous EP physicians are also not “hands positive”. EP is only successful if the arrhythmia is fully understood, getting the catheter at the correctly identified position is a trivial task compared to finding the correct diagnosis. And of course, there is absolutely nothing that would make EP a male specialty. Every single aspect can easily be handled by a woman—even the lead apron as I have been reminded many times.
In your view, what has been the most important development in electrophysiology during your career?
The most dramatic game-changer in EP happened just before I started my training. The introduction of 3D electroanatomical mapping systems allowed a combination of the findings of 12-lead ECGs to be transferred to the invasive EP procedure; a task that so far only a handful of experts had applied using fluoroscopy only. EP had stayed a niche discipline and electrophysiologists were a rare breed of people who were ready to spend many hours of their life finding the insertion of an accessory pathway on a grey X-ray picture. When I joined the EP group in St Georg, I was immediately exposed to the CARTO system (Biosense Webster) and my natural affinity to computers made me jump at the opportunity. My whole understanding was from day one based on the 3D maps and I frequently had to ask which X-ray projection we were looking at. Once I was allowed to move the catheters, I instantly concentrated on the 3D map rather than on the X-ray picture.
You set up the first magnetic navigation catheter ablation laboratory in Europe and performed the first remote-controlled catheter ablation procedure in the world; could you tell us about these experiences?
I was initially intrigued but equally scared to be given this opportunity. Of course, I wanted to succeed but also felt the heavy responsibility that comes with performing the first-in-man procedure. So in order to prepare and to familiarise myself with all the options of the remote navigation system, I trained a lot on a phantom so I was confident that I was in total control of the catheter. One inadvertent move of the catheter (or the patient for the same matter) could potentially result in a catastrophe, so I tried to think through every possibility. We planned a step-wise approach with right-sided supraventricular arrhythmias first and got permission to proceed from the ethics committee. If I would have created any complication, then this would have possibly been the end of all the hard work and time that I had invested. Besides that, a lot of my colleagues would have jumped at the opportunity to take over, so I worked very hard to avoid any slip-up. In the end, I managed to work in “my” magnetic lab for over five years without a single tamponade, performing more than 500 procedures in the final years.
From your experience, where have you seen the best results with the use of magnetic navigation catheter ablation?
Patients with congenital heart disease with difficult-to-reach target chambers are the ones who benefit the most from the use of remote magnetic navigation. The alternative of transhepatic or transbaffle ablations exposes the patients to procedure durations of up to
10 hours, with frequently more than 40‒60 minutes of fluoroscopy. Using magnetic navigation, our average procedure time is now below the four-hour time-mark, with rarely more than two minutes of radiation. As these patients have been exposed to multiple procedures since early childhood, the reduction of radiation exposure is really important, besides the quite obvious benefit of successful ablation.
You have trained a good number of physicians in magnetic navigation catheter ablation; what are the biggest challenges you have seen physicians encounter using this technology?
The biggest hurdle in my observation is that colleagues try to translate the motion that they would do with a manual catheter one-to-one to the magnetic system. However, the approach to stability and accessibility is a completely different one. Close observation of the beat-to-beat changes of the local signal is key for a successful lesion deployment.
Realising the lower contact force of the system, one needs to carefully increase the radiofrequency energy settings to allow a transmural lesion formation. Secondly, the uneasiness of being away from the patient and sitting in the control room is initially a really unpleasant experience that challenged me as well very much. One has the feeling of losing control about the instant feedback the patient gives (even non-verbally) during the procedure. I had to hold on to the table edge, in the beginning, to allow my hands to hold something during remote ablation. The task of holding our catheters absolutely still during radiofrequency energy delivery makes you somewhat helpless if there is nothing to hold on to in the control room.
What are your current areas of research?
Since my appointment at the Royal Brompton Hospital, I have tried to find solutions for patients with congenital heart disease and have successfully applied remote magnetic navigation to this patient cohort. Regular atrial or ventricular tachycardia is nowadays a manageable task in the vast majority of patients, however, AF plays an ever-growing role in these relatively young patients; hence, I am now trying to find a reproducible ablation strategy for patients with mostly massively dilated atria. So I am returning to my academic roots in AF ablation at last. Equally, I have been very interested in 3D image integration for complex arrhythmia management and have started to integrate 3D functional images from nuclear medicine into my ablation procedures. These functional images can not only depict the information scar in 3D but also offer unprecedented information about the sympathetic innervation of the myocardium. This information is absolutely unique and we have applied this to both AF and ventricular tachycardia ablation. I also continue to strive to use as little as possible achievable radiation exposure in my manual ablation cases. My goal is to perform the entire procedure without any radiation at all—a goal that is in close sight but at present, my record is 33 seconds for an AF ablation with the double transseptal puncture.
What do you consider could be the next breakthrough technology in cardiac rhythm management?
Multisite leadless pacing.
If you had not been a medical doctor, what would you have been?
Some kind of computer scientist or engineer possibly. I simply love to develop new things and come up with better solutions for everyday problems. At home, I am responsible for repairing all the electric equipment and I am very proud to follow in the footsteps of my father who taught me from early on how to fix broken things.
Outside of medicine, what other hobbies or interests do you have?
Unfortunately, my professional career takes a considerably large toll and a number of my hobbies have come second or even last. I am trying to stick to my love of running and try to exercise regularly. Whenever the opportunity arises, I try to attend classical concerts at various venues in London. During the summertime, the Proms at the Royal Albert Hall are a great opportunity to see and hear world-class performers within walking distance from Imperial College and the Brompton Hospital. I have also learned to love the English summer operas in the countryside and regularly attend the performances at Glyndebourne and Garsington.
Fact file
Current appointments
2007– Lead electrophysiology research/consultant cardiologist, Royal Brompton and Harefield Hospital, London, UK
2011– Associate lead for Cardiac Imaging in the Biomedical Research Unit of the Royal Brompton Hospital
2011– Honorary consultant cardiologist at the Liverpool Heart and Chest Hospital, Liverpool, UK
Education and qualifications
1990–1997 Medical Studies, University Ulm, Germany
1996– Internship (Medicine), Tufts Medical Schools, New England Medical Center, Boston, USA
1996–1997 Internship (General Surgery), Department of Surgery, Kantonsspital Glarus, Switzerland
2003– Board-certified internal medicine specialist
2004– Board-certified cardiologist
Professional memberships
2008– Fellow of the European Society of Cardiology (ESC)
2008– Member of the Executive Board of the Arrhythmia Alliance UK
2008– Steering committee for Electrophysiology International Community
2015– Member of the European Heart Rhythm Association (EHRA) ‘Women in EP’ committee
2015– Heart Rhythm Society programme committee
2016– Member of the EHRA educational committee
Editorial board memberships
2005– Europace
2005– Journal of Interventional Cardiovascular Electrophysiology
2013– Wissenschaftliches Kommittee der Zeitschrift “Herzschrittmacher + Elektrophysiologie”
2013– Associate Editor of Heart
2014– Circulation Arrhythmia and Electrophysiology
