Nassir Marrouche


Nassir Marrouche is a prominent electrophysiologist, executive director of the Comprehensive Arrhythmia Research and Management (CARMA) Centre at the University of Utah in Salt Lake City, USA, and director of the Western Atrial Fibrillation Symposium (23–24 February 2018, Park City, USA). In this interview, he discusses the importance of an integrated approach to understanding atrial fibrillation (AF), personalised medicine and the groundbreaking results of the CASTLE-AF trial.

When did you first decide on a career in medicine?

I was 11 years old. My grandmother said I should become a doctor, so I knew she was right. When you want to be a doctor from that age you plan for it—knowing you have to go to school and prepare for it every single day to eventually graduate into the field. So in every class I took, I was motivated by my dream to become a doctor. At this point, I cannot imagine being anything else.

Why did you choose to specialise in arrhythmias?

I did my PhD work at the University of Heidelberg on cellular cardiology and electrophysiology, and there were a lot of unknowns back then. I loved the ion channels, all the changes and action potentials that define the propagation of the aorta, and how vulnerable they are. Particularly in cardiac electrophysiology, there were a lot of unanswered questions, and I just got hooked because it was so fascinating. I knew then that it was an area of medicine that could grow to become very important, and I love tackling challenges and solving puzzles.

Have you had mentors to guide you during your career?

I had a lot of mentors; in Germany, I had Johannes Brachmann (Hospital Klinikum Coburg, Coburg, Germany), in Seattle I had Gust Bardy (University of Washington, Seattle, USA), in San Francisco, there was Melvin Scheinman and Michael Lesh (University of San Francisco, San Francisco, USA), and at the Cleveland Clinic I had an entire leadership team to learn from. Everybody was a mentor at that clinic. All these people had a role in shaping my life, pushing me in the right direction because they were all so driven and constantly striving to find the next big thing.

What do you consider the most important development in the field during your career?

There have been two major breakthroughs. Number one is the birth of the AF ablation procedure, which happened early in the beginning of my career, and I was lucky to be there for that. AF ablation was not only an issue of treatment, but it also gave us access to the heart and helped us to better understand atrial fibrillation pathologically, and we are still learning from that. Before, our understanding of AF was limited to viewing it from outside, so with the ablation procedure, we suddenly had that access to view the inter-cardiac behaviour of this disease.

The second important development in AF is the improved understanding of structural changes in the atrium. Within the last 10 years, we have been able to image that structure and track it, and that is just as important or maybe more important than the AF itself. It is something that is becoming very important for understanding, monitoring and treating AF.

What important new research have you seen come out in the past year?

The fact that we have found atrial fibrosis and atrial myopathy as independent risk factors for major cardiovascular events, strokes, mortality and hospitalisation. That is a big deal in terms of the work of the last 10 years to define the myopathy as a major risk factor for strokes and AF, and it is the first major step to precision medicine and personalised treatment in my opinion.

What are your current areas of research?

Precision AF medicine and everything belonging to it.

Atrial fibrosis or myopathy, the foundation of AF has been a major focus in our research, from basic science to clinical studies.

We are also developing novel magnetic resonance imaging (MRI) compatible ablation modalities, and working on tissue direct visualisation to better improve and personalise ablation outcomes.

Finally, mobile health technology has been a major part of our work at CARMA for the last nine years. We are trying to understand how to implant novel sensor technologies, biometric and electrocardiogram (ECG) devices into managing AF to help further personalise treatments.

What led you to create the CARMA centre at the University of Utah?

I realised that the physician is involved in only 10% of AF treatment. This is true for many diseases and particularly in cardiology, where the physician is involved in a small part of the treatment—sometimes less than 10%. The rest of the work is done by engineers, basic scientists, outcome researchers, software engineers, physician assistants, medical students and so on.

I came to the University of Utah with the purpose of building the CARMA centre and bring all these subspecialties together to sit at the same table and tackle one issue, whether it is AF, ventricular arrhythmia, or something else. We knew that the physician alone is not enough and we needed all these people who are equally hungry for research and elevation in their field. So we created the CARMA centre as a place to work together and optimise the collaboration of different types of expertise.

In 2017, you presented results from the CASTLEAF study, showing that catheter ablation procedures lower mortality in AF patients with heart failure. How do you think this research will affect clinical decisions on AF ablation?

There are many studies showing that AF ablation improves outcomes, including ejection fraction, quality of life and AF recurrence, with subanalyses showing improved mortality as well. However, there had never been a single study conducted, finished and published to show that ablation in patients with AF can save lives and reduce hospitalisations. In that way, CASTLE-AF was a game-changer. Before CASTLE-AF, we had been ablating in hundreds of thousands of people with the endpoint of improving symptoms. Now we have to consider the fact that we can improve mortality and hospitalisation of patients, as well as the quality of life. I think it will affect the way clinical decisions are made, and ablations have now become a widely accepted first-line treatment. At the same time, advances have been made in medical treatments for AF with novel oral anticoagulants (NOACs) and other interventions like left atrial appendage closure, which is important because not all patients can or should undergo ablation procedure. The closure device is an interesting new concept and there is no doubt that NOACs provide major developments in AF management. These treatments do not compete but rather complement each other, providing solutions for different types of patients in different stages of AF.

What is your most memorable patient case?

I have done more than three thousand ablations, and all of them are memorable—I remember every patient, but the most positive cases stand out as well. It is incredible to be able to help someone, having seen the issues that some people have before treatment and see their improvement afterwards. One patient was a passionate scuba diver. He was finally able to go diving again after his ablation and he sent me a photo he captured with an underwater camera from the bottom of the ocean. Another patient was able to pursue her dream of climbing Kilimanjaro post-treatment and wrote “CARMA” on the side of the mountain.

How do you like to spend your time outside of work?

I like to spend time with my wife and five-year-old daughter— that is the most important thing for me in my free time. Hobbies and interests come and go, but I like to hike and I play golf as often as I can find the time for it. I like to watch football (soccer) whenever the Champions League is on (go Bayern München!). In med school, I loved to dance, because of the freedom of movement that comes with it, and now my daughter dances too. We love to dance together


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