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]


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

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!