Energy drinks and life-threatening heart rhythm problems: the mounting evidence

When a 17 year-old girl, with a potentially life-threatening heart disorder, recently presented to me with an abnormally fast and irregular heart rhythm, I wondered how the natural history of her disease could so abruptly lead to a potentially fatal electrical rhythm disturbance. Until I questioned her more about the moments leading to the rhythm problem. Uncharacteristically, she had consumed a significant volume of a popular energy drink. Within an hour, she was in hospital receiving electrical shocks to her heart to bring her heart back into a normal rhythm. A mere co-incidence, or did consuming an “energy drink” trigger her potentially fatal heart rhythm?

Energy drink consumption has grown exponentially over the last 5-10 years.  Energy drink sales are increasing at double the rate of total carbonated beverage sales [1]. Energy drinks are primarily targeted at the vulnerable youth and young adult market with aggressive advertising and marketing, and the potential medical complications of ingesting such drinks are becoming more and more apparent, both to cardiologists, as well as other health specialists.

So what is in energy drinks which could potentially trigger cardiac events? Energy drinks typically comprise of high levels of caffeine, guarana, taurine and sugar with various other amino acids often also included. The combined levels of caffeine in these energy drinks are much higher than a standard cup of coffee [2,3]. Adverse events and complications from energy drinks largely arise from their caffeine content. Furthermore, energy drinks are targeted to be drunk fast, and more recently, have ben condensed to smaller volumes, so called “energy shots”, freely available in petrol stations and other convenience stores.

So what are the medical effects of energy drinks? Based on currently available peer-reviewed scientific literature, there are many effects. From a cardiac perspective, there are three main effects, i.e. an increase in heart rate, an increase in blood pressure, and evidence of increasing blood viscosity that can lead to clots forming in the heart and beyond. Most recently, 3 independent cases have been described in the medical literature where consumption of energy drinks led to catastrophic consequences, including cardiac rhythm disturbances and cardiac arrest. [4-6]. In addition, many other non-cardiac effects of energy drinks have been reported, including anxiety, insomnia, vomiting, nervousness and irritability. As well as this, many young adults combine high-energy drinks with alcohol or physical activity, which can further exacerbate the potential risks of the active ingredients.

These three recent cases further highlight the potential detrimental cardiac effects of energy drink consumption, particularly in those who may be predisposed to arrhythmias due to an underlying genetic heart disease. Given the potential catastrophic consequences of energy drink consumption amongst susceptible young individuals, greater community education and awareness needs to be promoted. This may include somewhat more drastic measures, including more graphic and clear warnings on energy drink cans to warn people of the potential dangers, much like the highly successful packaging of cigarette cartons which include images of the consequences of smoking such as cancer. Another key initiative may be to restrict the sales of energy drinks to children and adolescents, often the target of current energy drink advertising and under significant peer influence. The collective goal of such measures is to prevent the incidence of potentially life-threatening cardiac rhythm problems, particularly in the young, by raising awareness in the community of the potential detrimental effects of energy drinks.


[1] AC Nielsen. Nielsen Convenience Report, 2010.

[2] Gunja N, Brown JA. Energy Drinks: health risks and toxicity. Med J Aust 2012; 196: 46-9.

[3] Higgins JP, Tuttle TD, Higgins CL. Energy Beverages: Content and Safety. Mayo Clin Proc. 2010; 85: 1033-41.

[4] Dufendach KA, Hornder JM, Bryan BC, Ackerman MJ. Congenital type I long QT syndrome unmasked by a highly caffeinated energy drink.  Heart Rhythm. 2012; 9: 285-8.

[5] Rottlaender D, Motloch LJ, Reda S, Larbig R, Hoppe UC. Cardiac arrest due to long QT syndrome associated with excessive consumption of energy drinks. Int J Cardiol 2011; Nov 4 [Epub].

[6] Rutledge M, Witthed A, Khouzam RN. It took a Redbull to unmask Brugada syndrome. Int J Cardiol 2012; Mar 31 [Epub].

[7] Gray B, Das J, Semsarian C. Consumption of energy drinks: a new provocation test for primary arrhythmogenic diseases. Int J Cardiol 2012; June 15 [Epub]


Whole genomes and personalised medicine: where are we heading?

Last week I gave a number of invited lectures in Queensland and Tasmania about genetic heart diseases, sudden death in the young, and the key role of genetic testing in diagnosis and targeting disease prevention. In one of the lectures, I was asked to give a specific prediction related to my lecture topic. Considering my thoughts about human disease, the role of genetics, and the prolific advances in genetic technologies, my specific prediction was as follows:

“By 2016, 50% of the adult population in developed countries will have their own entire genome completely sequenced”.

What do you think? Well here is my simple thinking behind this prediction, with two main points.

The first point is the increasing availability and decreasing cost of whole genome sequencing. When the first whole genome (i.e. sequencing all ~23,000 genes that we each have) was sequenced and completed in 2000, the cost for this one whole genome was $US3 billion! As one can see from the graph attached (adapted from The Economist), later in 2012, the cost of sequencing a whole genome (red line) will be under $US1000. As a result, the genome is now within reach of many in our populations, both in terms of cost and availability. This is dramatically reflected in the exponential increase in the number of people who are already having their genomes sequenced! The black line in the graph shows the dramatic increase in the number of genomes sequenced over recent years (note the log scale of the y-axis!).

The second point is the potential value of knowing your whole genome. The genetic information for an individual person is mind blowing. Broadly speaking, there are two types of relevant genetic information involving DNA variations (changes in our genetic sequences). The first group of genetic variations may directly cause disease, such as we see in cardiomyopathies, long QT syndrome, cystic fibrosis, multiple sclerosis, and various genetic syndromes. The second group of genetic variations may not directly cause disease, but are associated with risk of disease, such as the risk of developing diabetes, cancer, or Alzheimer’s disease, as well as predicting how people will respond to different drug therapies (so called “pharmacogenomics”).

Collectively, understanding our genetic risks provides an important platform for early diagnosis, initiation of pre-clinical treatment and monitoring strategies, and in some cases, provision of early opportunities for prevention therapies. As a clinician, the greatest promise of whole genome information is to optimise care of patients, and to reduce the risks of developing disease and its related complications.  The understanding that each person in the world is genetically unique provides the basis for individualised care, or personalised medicine, whereby each person may be treated slightly different depending on their genetic make-up. The benefit of such strategies holds great promise.

Of course, there are many issues that arise in the setting of whole genome sequencing that must be considered, debated, and discussed. While we can sequence every gene in our bodies, medical research is nowhere near understanding what each gene in the body does, and how changes in the sequence of the specific genes lead to disease. There are also many ethical, moral and legal issues that need to be worked through as we learn more about whole genome sequencing. Do we really want to know what diseases we will get in 5, 10 or 20 years? Will our life insurance companies want to know our genetic risks? What are the implications for genetic screening at birth, or prenatally, or even pre-implantation? The number of questions posed is substantial. However the reality is, whole genome sequencing is now more readily available, the cost is now affordable, and there are already clear trends that people around the world want to have the testing performed.

The next few years will be a fascinating and exciting journey. Whether its 50% or 5% of the population by 2016, and irrespective of the potential issues, whole genome sequencing for humans is here. It represents the most exciting phase in human genetics that we will see in our lifetimes. The potential impact of genetic knowledge on how we can identify disease risk is the most exciting aspect, as it will then provide opportunities for early diagnosis, treatment, and prevention, and facilitate our ultimate goal to prevent disease and improve human health.

Prof Chris

Preventing heart disease amongst children in rural Cambodia

Chris with the local Cambodian children

In October last year, I took part in a research project like no other. We spent a week in rural Cambodia evaluating Cambodian children aged 5-15 years for evidence of rheumatic heart disease. The initiative, supported by The University of Sydney, saw a team of researchers from around the world, including locals from Cambodia, visit the small village of Sophi, approximately 2.5 hrs drive west of Siem Reap on the Thai border. For me, it was a total eye-opener in every way!

At the age of 45 years, I had never stayed in a place with such poverty. No electricity, no clean water, the lowest of living standards. Yet, meeting the children and families was amazing. The smiles were heart warming. The love and appreciation they showed us was infinite. We clinically evaluated and performed heart checks on a total of 500 Cambodian children in just over 4 days. We set up our “medical centre” at the local school. The project was named “500 Hearts” (

What were we looking for? We wanted to determine how frequently children get rheumatic heart disease (RHD), a totally preventable disease if treated and prevented with antibiotics. While rare in affluent countries, RHD is a major public health problem in the developing world in populations living in poverty with low socioeconomic status and limited access to adequate healthcare. Current estimates suggest 15.6 million people worldwide have RHD with 282,000 newly diagnosed cases and 233,000 deaths each year.  RHD causes damage to the structures of the heart including the valves. Our former prime minister, Mr Kevin Rudd, has required heart valve surgery because of RHD as a child. Importantly, early case identification of RHD in children is critical to reduce the risk of advanced valvular disease by implementing effective programmes of prevention and control.

We were able to provide stocks of antibiotics to the local hospital so that children with early rheumatic changes could be treated. We helped educate the community, including local medical students and doctors. It’s a small step, but the journey has only just begun. We are now planning our next visit in October this year! We will visit a different village in Cambodia, closer to Siem Reap. We hope to be able to identify more children at risk of developing heart problems and initiating early prevention therapy, such that they don’t develop heart disease. Like the previous visit, there will also be “extra bits”… providing the locals with over 200kg worth of clothes, toys, dental hygiene kits, books, colouring pencils, soccer balls and many other fun stuff!

I must confess that in all the research I have conducted to date, our initiative amongst the children and families in rural Cambodia has touched my heart more than any other. Perhaps it’s the smile of the Cambodian children, or maybe the eyes of appreciation and hope amongst their parents. Maybe it’s the awesome team I was a part of, with professors, medical students, nurses, archeologists, and many locals all working together with a common goal to serve a community. Whatever it is, I have developed a real passion for this important initiative to help prevent heart disease in the children of Cambodia.

Prof Chris

More info and photos at

A year of sadness for Norway continues: the tragic sudden death of a world champion swimmer

Within the space of 6 weeks, a third elite athlete has had a cardiac arrest. Bolten footballer Fabrice Muamba survived a cardiac arrest during an FA cup match, while Livorno midfielder Permario Morisini died during an Italian second division match. From elite footballers, today we heard the tragic news of , a world champion swimmer who was one of Norway’s top medal hopes for the London Olympics, who died from cardiac arrest after collapsing in his bathroom during a training camp in Flagstaff, Arizona. He was 26. At this time, the cause of death remains unclear and results of the post-mortem are pending.

As I wrote in my recent blog, a very likely cause of Alexander’s death is an underlying genetic heart disorder, such as a hypertrophic cardiomyopathy or a primary arrhythmogenic disorder. The death again highlights the unpredictable nature of genetic heart diseases. People with these diseases can reach the highest levels of sporting excellence, in this instance, at the Olympic level, yet on a particular day, at a particular time, cardiac arrest occurs and death strikes. On this occasion, the death occurred not during sporting activity, but essentially during very light effort having a shower. Sudden death in the young can occur during exercise, but we have also seen in our clinics that many young deaths occur with minimal exercise or at rest. In some young people, death occurs during sleep. The reasons why sudden cardiac death in the young can occur at any time remain unclear.

After the tragic terrorist attack in Norway on July 22, 2011 that killed 69 innocent civilians, Alexander Dale Oen gave a grieving and hurting nation great hope and a reason to smile with his outstanding efforts in the swimming pool. He was marked as a possible gold medallist in the London Olympics. As with all sudden cardiac deaths in the young, Alexander Dale Oen’s death is a terrible tragedy. We await news of the cause of his death. Norway, and indeed the world, mourns.



Why would a busy professor be part of a flashmob?

Yesterday, I did something I’ve never done before! After three dance and choreography classes over 3 weeks, I was part of an awesome flashmob in the middle of the Sydney, at Pitt Street Mall! With some Gaga, shuffling, and Bollywood, the flashmob was very well received by the massive crowd which poured out of Myer, Zara, and other stores! The flashmob was professionally filmed, so stay tuned for the YouTube clip!! So why would a 45yo busy professor and cardiologist, with not the greatest dancing talents, participate in a flashmob?

Well it was all for raising community awareness of heart disease in children and young adults, highlighting the importance of providing supportive care as young people come to terms with a life-long diagnosis of a congenital or genetic heart disease. Specifically, the flashmob highlighted a relatively new organisation, Hearts4Heart, whose focus is to support young people with heart disease (

As a cardiologist who focuses on heart disease in the young, it’s important to realise that heart disease in a 16yo is very different to heart disease in a 60yo! The diagnosis of a congenital or genetic heart disease in a young person implies many things. The diagnosis is usually life-long, and so the young person is labelled as a heart disease patient for many decades ahead. Treatment is often life-long, and may include daily medications and open-heart surgery. In many childhood heart diseases, young patients are also advised to avoid competitive sports as this can itself be a trigger for cardiac complications. As many of these diseases are genetic, there are also implications for these young patients as they grow older and consider starting a family. There is usually a 50% chance of the offspring of a genetic heart disease patient having the same disease. All of these factors contribute to significant psychological and social consequences as the lives of these young people with heart disease take shape.

It is therefore essential that in addition to the sorts of things I do every day in terms of diagnosis and treatment of heart disease in the young, appropriate support for these young people and their families exists. Education, psychological and social support are essential factors in the life-long management of these young patients. The newly formed Hearts4Heart is one organisation that is specifically focusing on helping these young patients and their families. While I am always reluctant to add to my busy professional and family life, I was delighted to accept an invitation to be a director on the Hearts4Heart Board, with the ultimate goal to help children, teenagers and young adults with heart disease.

So why was I happy to be part of a flashmob? Well, first, I thought the idea of a flashmob to raise awareness of young people with heart disease via Hearts4Heart showed great creativity, something that is lacking in many other organisations. But mainly… I love watching artistic expression in all forms, I love being part of a passionate, dedicated, and creative team, I’ve always admired Bollywood dance, and above all, I would do most things which will ultimately improve how we care for our young patients and families with heart disease!


Sudden cardiac death in athletes: the paradox

This morning, I woke to hear of yet another tragic death of a high level, elite athlete. Piermario Morosini, a 25 year old Italian football player, died during a game. An apparently well, healthy and fit young man, who represented Italy as an under-21 year old, is now dead. Why?

At this point the cause of Morosini’s death has not been revealed, but statistically, the most likely cause is an underlying genetic heart disease. These diseases are caused by a fault (DNA mutation) in one of the 23,000 genes we are born with, which can then lead to a variety of heart diseases that can affect the structure, function, and electrical rhythm of the heart. The most common cause of sudden death is hypertrophic cardiomyopathy (HCM), which affects up to 1 in 500 people. Tragically, these genetic heart diseases are often silent. The individuals have no symptoms. And even more sadly, sudden death can be the first presenting symptom in up to 50% of young people who die suddenly.

So how can a person who carries a gene fault which can lead to these heart diseases, get to such an elite level of sports before any symptoms arise? This is the paradox, i.e. athletes who represent the peak of physical and sporting excellence, can also be carrying genetic faults that for no apparent reason suddenly cause a fatal rhythm disturbance leading to cardiac arrest and sudden death. Some are very lucky and survive, such as Bolton player Fabrice Muamba, who collapsed a few weeks ago during an FA Cup quarter final, required 17 defibrillator shocks, and miraculously survived. However, the vast majority, like Morosini, are unable to be resuscitated. Some have argued that diseases such as HCM, a disease which results in the thickening of the heart muscle, may initially give athletes a “super heart” leading to sporting excellence, but ultimately can trigger arrhythmias leading to sudden death. Others have postulated that high-level exercise may remodel the heart that can lead to rhythm problems. The paradox however remains. Elite sports people can achieve the highest levels of sporting excellence, yet be at risk of sudden cardiac death.

So how can we prevent sudden cardiac death, particularly in the young, in our community? In my opinion, sudden cardiac death in the young is a complex problem and so the solution must address the problem from a number of perspectives. These include a number of practical approaches:

  1. Raising community awareness that young people can develop life threatening heart diseases, which can lead to sudden death.
  2.  In families where there is a history of young sudden death, or heart disease at a young age, clinical screening of all relatives should be undertaken.
  3. If young people have symptoms such as blackouts (syncope), fast heart rhythms, and exercise-related symptoms, they should have a medical review.
  4. Greater use of public access defibrillators, which have been shown to improve the chances of survival from a cardiac arrest in the community, e.g. in airports, train stations, sporting clubs, major sporting venues.
  5. Population-based screening: this remains a much-debated issue. For example, in Italy, a national ECG screening program exists for all high school students. Most countries do not have such national programs but have screening programs within particular sports programs, sporting clubs, and sports institutes. The debate hinges around many factors including the low incidence of these genetic heart diseases, the high rate of “false positives” on ECG changes which may preclude some kids unnecessarily from sports, the cost-effectiveness of finding rare diseases, and whether you can actually diagnose some of the diseases. For example, the diagnosis of hypertrophic cardiomyopathy, the most common cause of sudden death in the young, including athletes, is made on echocardiography (ultrasound) and not an ECG.

The key point is that if we can identify those young people at risk of developing sudden death, we can initiate prevention strategies today to stop sudden death, such as lifestyle modifications, medical therapies such as beta-blockers, and implantable cardioverter-defibrillator (ICD) therapy. Targeted research focused on the problem of sudden death in the young, including genetic, clinical, public health, and health economic aspects, will be critical as we aim to prevent all sudden cardiac deaths amongst the young in our community.


Improving heart health

I am a cardiologist and researcher passionate about improving heart health in our community. My particular area of interest is in patients and families with genetic heart diseases, such as cardiomyopathies and electrical rhythm disorders, including sudden death. As a result, many of my patients are young – children, teenagers and young adults. My ultimate goal is to prevent and ultimately cure these diseases, through collaborative research efforts around the world. This is my first blog post! Hope to be able to share my thoughts (all views are my own) on various issues related to genetic heart diseases, from diagnosis and treatment, to prevention and cure – both in Australia and globally. Chris