Academic Spotlight: Jean Jacques Noubiap Nzeale, MD, PhD
The Bard of Atrial Fibrillation
“I love writing,” said Jean Jacques Noubiap Nzeale, MD, PhD, a postdoctoral scholar in the lab of cardiac electrophysiologist Gregory Marcus, MD, MAS, Endowed Professor of Atrial Fibrillation Research.
As a medical student in Cameroon, Dr. Noubiap Nzeale led his medical school journal. In his free time, he also wrote satirical short stories in French about culture, societal issues, and the difficulties that university students face. This passion for writing partly explains his incredible productivity. He has co-authored more than 340 peer-reviewed publications to date, and was ranked among the top 2 percent of most-cited global scientists in 2024. Many of his papers focus on cardiovascular risk factors in Africa and globally.
In recognition of his scholarship, Dr. Noubiap Nzeale has won numerous awards, including the Heart Rhythm Society Research Fellowship Scholarship, American Heart Association Award for Excellence in Research Addressing Cardiovascular Health Equity, Global Burden of Disease Emerging Researcher Award, World Heart Federation Emerging Leader Award, and the American Heart Association Early Career Investigator Award. He has also served as a member of the World Heart Federation Atrial Fibrillation Roadmap Update Expert Writing Group, World Stroke Organization-Lancet Neurology Commission Stroke Collaboration Group, and the Stroke Expert Collaboration Group.
His current work focuses on atrial fibrillation – the most common cardiac arrhythmia, or abnormal heart rhythm – and finding new ways to better identify and treat this condition.
An Epidemiological Transition
Dr. Noubiap Nzeale was born in Yaoundé, the capital of Cameroon, in central Africa. “When I was a kid, I was quite sick with malaria and some issues with my eyes, and I regularly visited the hospital,” he said. “I usually wasn’t sick enough to be admitted, but just being in contact with all the doctors made me want to be like them. The care was very good, and everyone was very nice.”
Dr. Noubiap Nzeale earned his Doctor of Medicine from the University of Yaoundé I, completing his thesis on the genetic causes of hearing loss. “Many people in Cameroon have hearing loss, but most of them don’t receive appropriate care,” he said. “At the time, there were no public schools for the deaf. I was interested because we didn’t know much about hearing loss, especially the genetic causes in our population.”
After graduating from medical school, he spent two years working in a semi-rural hospital in Cameroon. “There were many patients with infectious diseases like HIV, tuberculosis, hepatitis and malaria. For this reason, my first independent research projects were on infectious diseases, especially HIV and viral hepatitis B and C,” said Dr. Noubiap Nzeale. “But after those two years of being in charge of the internal medicine unit of my hospital, I realized that cardiovascular conditions such as hypertension, diabetes, dyslipidemia, obesity and stroke were quite prevalent, and that the affected patients had poor access to adequate care. This motivated me to shift my research from infectious diseases to cardiovascular risk factors and diseases.”
That shift in research focus also reflects an important phenomenon. “Currently, infectious diseases are the leading cause of death in Africa, but it’s projected that in the next two decades, noncommunicable diseases – especially cardiovascular diseases – will become the top killers in Africa,” said Dr. Noubiap Nzeale. “That’s what we call an ‘epidemiological transition.’ While it’s positive that we have been able to reduce morbidity and mortality from communicable diseases like malaria, tuberculosis, hepatitis and HIV, more people are living longer and have increased risk of developing chronic cardiovascular diseases that are more prevalent in older people. We also observe that cardiovascular diseases tend to occur at younger ages in our populations.”
Personal factors also shaped his decision: during his last years of training, two of his professors suffered from sudden cardiac death, and his father also died from cardiovascular disease. “Those losses were also very important motivators in working on cardiovascular diseases,” said Dr. Noubiap Nzeale.
Studying Cardiovascular Risk Factors in Africa
He then spent four years in Cape Town, South Africa, earning a Master of Medicine (MMed) from the University of Cape Town and completing a four-year fellowship training in internal medicine from the Colleges of Medicine of South Africa. During his clinical training he also conducted research focused on cardiovascular risk factors and diseases in Africa.
“There was a significant research gap, and we were among the first to comprehensively summarize the epidemiology of cardiovascular risk factors and diseases in African populations,” said Dr. Noubiap Nzeale. His research efforts in the field have resulted in numerous publications in top-tier journals such as The Lancet Public Health, The Lancet Global Health, The Lancet Child & Adolescent Health, and Neurology. In an analysis of fifty years of cardiovascular research in Africa from 1971 to 2021, Dr. Noubiap Nzeale showed that despite recent progress, the cardiovascular research productivity in Africa remains low and out of proportion to the increasing burden of cardiovascular diseases on the continent. These findings highlight an urgent need to build capacity, fund and expand collaborative research networks in Africa.
Dr. Noubiap Nzeale and his colleagues studied cardiovascular risk factors and diseases in the general population in Africa, but also in special populations, including people with HIV. “As their life expectancy increases and they are living longer, their burden of cardiovascular disease also increases,” said Dr. Noubiap Nzeale. “Another population we studied was pregnant women with hypertensive disorders, who are increased risk of major maternal and fetal complications, as well as long-term cardiovascular diseases.”
Yet another subgroup he and his colleagues studied was children and adolescents with cardiometabolic disease. “In Africa, the rate of obesity is increasing fast, because of societal and cultural transitions that cause people to be more sedentary and eat less healthy foods,” said Dr. Noubiap Nzeale. “In the past, people were more active doing farmwork and similar occupational activities, and walking from one place to another, but now they have cars and take taxis even for short distances.” Dr. Noubiap Nzeale’s research has shown a high prevalence of elevated blood pressure among children and adolescents in Africa, with overweight and obesity being important drivers. He has also provided global, regional and country estimates of metabolic syndrome burden in children and adolescents. “Multisectoral interventions are needed to address this increasing burden of cardiometabolic disease in children and adolescents, including policy changes and community-level interventions to promote healthy lifestyles,” he said.
Dr. Noubiap Nzeale and his collaborators have studied other cardiovascular disease risk factors that may be more prevalent in Africa compared to other parts of the world, such as indoor air pollution resulting from using wood stoves to cook. Another major health problem is rheumatic heart disease. This is the most commonly acquired heart disease in people under age 25, and can occur when a streptococcal infection, also known as strep throat, is not treated promptly with antibiotics. In some patients, the body’s immune response can cause rheumatic fever, which may inflame and scar the heart valves and eventually cause rheumatic heart disease. “Rheumatic heart disease is an important cause of heart failure in Africa, so prevention and screening are important for our populations,” he said. Dr Noubiap’s research in African populations has also covered other important conditions, including infective endocarditis, venous thromboembolism, pericardial diseases, sickle cell disease, heart failure, and the impact of diabetes on tuberculosis, among others.
Focusing on Atrial Fibrillation
After completing his studies in Cape Town, Dr. Noubiap Nzeale earned his PhD in medicine from The University of Adelaide in Australia. “I decided to focus mostly on atrial fibrillation, which is highly prevalent and one of the most important causes of stroke,” he said. “The incidence of stroke has significantly increased in Africa, especially among people at younger ages. In both Africa and globally, atrial fibrillation is associated with one-third of ischemic strokes, and those strokes are more severe than strokes from other causes.”
Atrial fibrillation causes the heart to quiver rather than to squeeze efficiently, which increases risk of blood pooling in the heart and forming clots. These clots may travel to the brain and cause ischemic stroke.
The University of Adelaide is one of the world’s premier centers of atrial fibrillation research. Dr. Noubiap Nzeale’s dissertation focused on the screening, risk stratification and management of atrial fibrillation. It was a tour de force, resulting in 15 publications and garnering a 2023 University Doctoral Research Medal, awarded to the highest quality PhD dissertations across all disciplines at the university.
Among other topics, he found that reduced breathing function was associated with increased risk of atrial fibrillation; the importance of implantable cardiac monitors and other rhythm-monitoring strategies to detect atrial fibrillation following stroke; an assessment of various factors traditionally used to risk-stratify patients with atrial fibrillation; the possible usefulness of incorporating various biomarkers and forms of cardiac imaging in these calculations; and the increased risk of acute coronary syndromes and acute pulmonary embolism associated with atrial fibrillation.
His thesis also analyzed sex differences in the management of and outcomes of atrial fibrillation. “While women represent a great proportion of people with atrial fibrillation, unfortunately they are not well represented in randomized controlled trials to develop treatments, and tend to have lower access to important treatments like catheter ablation,” said Dr Noubiap. He also provided important information on sex differences in outcomes of intensive risk factors modification, an important pillar of atrial fibrillation management.
Identifying Ways to Prevent Atrial Fibrillation
After completing his PhD in 2023, Dr. Noubiap Nzeale moved to the U.S. to begin a postdoctoral research fellowship at UCSF in the lab of cardiac electrophysiologist Gregory Marcus, MD, MAS, Endowed Professor of Atrial Fibrillation Research and associate chief of cardiology for research at UCSF Health. Dr. Marcus is an expert in the cardiovascular effects of lifestyle factors such as alcohol and caffeine. “I’m interested in preventive cardiology, and discovering how we can prevent the occurrence of atrial fibrillation rather than just giving medications or doing catheter ablations to treat it,” said Dr. Noubiap Nzeale.
His first project used statewide databases from California to estimate the prevalence of atrial fibrillation in the U.S. “Previous studies were two decades old, and made projections about what the current prevalence would be now,” said Dr. Noubiap Nzeale. “We estimated that there are at least 10.5 million adults with atrial fibrillation in the U.S., which is almost three times the previous projections of about 3 million adults. That means that about 4.5 percent of the adult population is affected. Given the devastating complications of atrial fibrillation and its associated health care costs, this calls for more efficient prevention and treatment strategies.”
He and his colleagues also studied trends in the incidence of major complications of atrial fibrillation over time. They found that the incidence of ischemic stroke, hemorrhagic stroke, and mortality in patients with atrial fibrillation have significantly decreased in the recent years, indicating improved care. “However, the reduction was significantly lower in Black and Hispanic populations, suggesting that more efforts are needed to enhance quality of care and promote health equity in these communities,” said Dr. Noubiap Nzeale.
He is also interested in the relation between lifestyle factors and risk of cardiac arrhythmias. For example, he and Dr. Marcus analyzed the California’s Department of Health Care Access and Information database, studying the number of emergency department visits and hospital admissions on or around April 20 over a 15-year period. April 20, also known as “420,” is a day when cannabis consumption is widely celebrated, especially around 4:20 p.m. They found that this date was associated with an increase in the number of health care encounters with a diagnosis of atrial fibrillation or cannabis-related disorders, suggesting that cannabis consumption may trigger acute atrial fibrillation episodes detectable at the population level.
Similarly, Dr. Noubiap Nzeale and his collaborators found that use of cocaine and methamphetamine is associated with an increase in the incidence of ventricular arrhythmias, cardiac arrest and death. “Avoiding these illicit stimulant drugs would likely help reducing the burden of ventricular arrhythmias,” he said.
One of his current projects is the Disrupted Sleep and Concurrent Ectopy or Atrial Fibrillation (DISCRETE AF) randomized trial. “Some studies have suggested that poor sleep might be a trigger for atrial fibrillation, but that has not been demonstrated in strong studies,” said Dr. Noubiap Nzeale. Previous research has relied on subjective self-reports of sleep quality. By contrast, DISCRETE AF will be the first randomized case-crossover assessment to reveal immediate relationships between sleep disruption and more frequent, clinically relevant common cardiac arrhythmias, including atrial fibrillation episodes.
“Compelling evidence of the direct impact of sleep disruption on discrete atrial fibrillation episodes would be directly and immediately relevant to clinical care of our patients,” said Dr. Noubiap Nzeale. “In fact, identifying near-term triggers of atrial fibrillation is a high priority for these patients and may effectively determine lifestyle modifications that can meaningfully affect the risk of an arrhythmia occurrence.”
One cause of poor sleep can be obstructive sleep apnea. It occurs when the throat muscles overly relax and the soft palate and back of the tongue block the airway. The brain senses the resulting loss of oxygen and briefly wakes the person so they reopen their airway, a process that repeats throughout the night and interrupts deep, restful sleep.
One newer treatment is called upper airway stimulation, in which an ear, nose and throat surgeon implants a device that stimulates the hypoglossal nerve. This reduces blockage of the airway and helps maintain unobstructed oxygen flow to the lungs, which also supports better sleep. This device can be turned on before bedtime.
The DISCRETE AF trial will enroll volunteers who have received this device and are willing to wear a cardiac monitor for two weeks. For 14 nights, they will be randomized to either have their device turned on or off. The cardiac monitor will continuously measure the number of “extra” heartbeats originating in the upper chambers of the heart (also called premature atrial contractions) or lower chambers of the heart (known as premature ventricular contractions), as well as atrial fibrillation episodes.
“Sleep quality will be assessed,” said Dr. Noubiap Nzeale. “We will see whether participants have more arrhythmias during or after a night of disrupted sleep when their device is turned off, compared with a night with the device turned on. In this way, each patient serves as their own control. We will determine whether poor sleep leads to more cardiac arrhythmias.”
Always Seeking to Improve
Dr. Noubiap Nzeale appreciates the opportunity to work in Dr. Marcus’s lab. “Dr. Marcus is an amazing scientist,” said Dr. Noubiap Nzeale. “He cares a lot about details, and always makes sure that you challenge yourself, find solutions to those challenges, and expand your boundaries. If an experiment doesn’t work as expected or the method used for analysis was not as good as possible, he teaches his mentees how to find solutions and think how to make it work. I am a perfectionist, so I always want to find the ideal solution, the gold standard. But if we can’t do that, what other methods could help us understand this phenomenon? We can acknowledge that it's not perfect, but we can still make important discoveries.”
“Dr. Noubiap Nzeale is undaunted when confronting even the largest and most complex datasets, and does an outstanding job applying sophisticated statistical analyses to yield highly impactful results,” said Dr. Marcus. “He is an incredible machine of productivity, cranking out one original scientific contribution after the next at an especially impressive pace.”
To fuel that prolific output, Dr. Noubiap Nzeale reads voraciously. “I read a lot of other authors and ensure that I’m up-to-date,” he said. “I subscribe to most of the top journals in my field and at least read the abstracts to make sure I know what other people are doing. That gives me new ideas. When the paper is really interesting, I read the entire article. That’s how I learn and improve.”
He also spends considerable time as a journal reviewer. Dr. Noubiap Nzeale currently serves as a senior scientific editor for the Pan African Medical Journal, allowing him the opportunity to improve the quality of research in Africa, and as a member of the editorial board of the Journal of the American College of Cardiology, where he is frequently asked to share his opinion on papers focused on global health and global cardiology. “I learn a lot from assessing, commenting on and criticizing papers,” he said. “Articulating what I think about a paper is very important in terms of critical thinking.”
In all his endeavors, Dr. Noubiap Nzeale challenges himself to keep growing. “I always ask myself, ‘Can I do something better than what I’ve just done?’” he said. “I always try to add something new, whether it’s a new type of analysis or a new study design. I also try to be as focused as possible – to have a clear objective and stick to it. The other thing I’ve realized is that working in teams is really effective. People have different skills: some are very good statisticians, others are very good at planning the research or writing papers. Working together, you achieve more and also learn from the skills of others. I’m passionate about collaboration, especially with younger colleagues.”
Outside of research and medicine, Dr. Noubiap Nzeale enjoys reading novels, listening to music, and lake fishing, a pastime that reminds him of his childhood and also helps him cultivate patience.
After he completes his postdoctoral fellowship, Dr. Noubiap Nzeale plans to finish his clinical training in cardiology and continue his research on cardiac arrhythmias, especially atrial fibrillation. He hopes to pursue a career in academic cardiology, combining both research and clinical practice.
His ultimate goal is to improve health disparities. “There has been a lot of progress in medicine, but it needs to benefit all people, not just a few,” said Dr. Noubiap Nzeale. “The endpoint is ensuring that we have health equity – that’s really my dream.”
Editor’s note: Dr. Noubiap Nzeale generally goes by Dr. Noubiap.
- Elizabeth Chur