A new study published on June 5th in Heart Rhythm, the official journal of the Heart Rhythm Society, the Cardiac Electrophysiology Society and the Pediatric and Congenital Electrophysiology Society, examined the potential dangers of energy drink consumption for patients with genetic heart diseases.

The study, conducted at the Mayo Clinic in the United States, examined a group of 144 survivors of sudden cardiac arrest, of which seven patients (5%) had consumed one or more energy drinks shortly before the cardiac event.

Although the study did not prove direct causality, caution is recommended, and doctors advise that patients consume energy drinks in moderation.

"The energy drink market in the United States has steadily grown in recent years, raising concerns about the potential combined effects of caffeine and unregulated additional ingredients in these drinks", said Dr. Michael J. Ackerman, the study's lead researcher, a genetic cardiologist at Mayo Clinic and director of the Genomic Lab, in a statement.

Energy drinks are not regulated by the U.S. Food and Drug Administration (FDA), so researching their effects on these patients is of major importance, he stated. Energy drinks contain caffeine ranging from 80 mg to 300 mg per serving, compared to 100 mg in a regular cup of coffee.

However, most of these energy drinks also contain other stimulant ingredients besides caffeine, which are not regulated by the FDA, such as taurine and guarana.

It has been hypothesized that these highly stimulating ingredients alter heart rhythm, blood pressure, heart contractility and cardiac repolarization in a potentially proarrhythmic manner.

"Establishing a probable cause of an arrhythmia includes investigating potential exposure to toxins or drugs", said Dr. Ehud Chorin from Tel Aviv Sourasky Medical Center and Tel Aviv University Medical School, in an editorial accompanying the study.

An increasing number of substances in the standard diet have been found to have unwanted cardiac effects, leading to the consideration of a new subcategory in a patient's clinical history intake: arrhythmogenic foods. Energy drinks fall into this category.

The findings reported in this study should be viewed in the context of the large body of evidence suggesting the arrhythmogenic effects of certain foods, especially when consumed in large quantities or high concentrations by high-risk patients, the authors say.

In addition to examining the consumption of energy drinks among the cohort of sudden cardiac arrest survivors, researchers closely analyzed the type of cardiac event and the conditions surrounding the event, such as physical exercise and other known stress factors associated with cardiac arrhythmias linked to genetic heart diseases.

"We would be remiss if we didn't sound the alarm"

"While there appeared to be a temporal relationship between energy drink consumption and the sudden cardiac arrest event of the seven patients, a multitude of potential 'agitators' could have also contributed to an arrhythmia associated with genetic heart diseases, such as sleep deprivation, dehydration, extreme dieting or fasting, concurrent use of QT-prolonging medications or the postpartum period. Thus, the unusual consumption of energy drinks most likely combined with other variables to create a 'perfect storm' of risk factors leading to sudden cardiac arrest in these patients", explained Dr. Ackerman.

"Critics might say these findings are merely coincidental associations. We, as the Mayo Clinic group, are fully aware that there is no clear and definitive evidence that energy drinks indeed cause life-threatening arrhythmias and that more data is needed, but we would be remiss if we didn't sound the alarm. At some point, clinical experience, a solid understanding of pathophysiology and common sense should come together and speak out", said Dr. Peter J. Schwartz from the Italian Auxological Institute, Center for Cardiac Arrhythmias of Genetic Origin and Cardiovascular Genetics Laboratory in Milan, in a second editorial accompanying the study.

Although the risk is relatively low, and the absolute risk of sudden death after consuming an energy drink is even lower, patients with a known genetic heart disease that predisposes them to sudden death should weigh the risks and benefits of consuming such drinks, the authors concluded.