CHICAGO – Consumption of an energy drink containing caffeine and taurine slightly, but significantly, altered left ventricular contractility in healthy volunteers, while consuming the same amount of caffeine alone did not lead to an alteration in contractility in a prospective study.
"A possible explanation for this finding could be the presence of taurine, which has been shown to increase the release of calcium in muscles," Dr. Jonas Dörner reported at the annual meeting of the Radiological Society of North America.
Courtesy of RSNA
To visualize cardiac magnetic resonance tagging, a cross-section of the heart in common imaging technique is seen on the left and tagged myocardium using CSPAMM is on the right.
Cardiac magnetic resonance imaging (MRI) was performed in 31 volunteers before and 1 hour after consuming an energy drink containing caffeine (32 mg/100 mL) and taurine (400 mg/100 mL). The average patient age was 27.7 years.
Postconsumption images revealed that mean peak strain increased 7% from baseline (–22.84 vs. –24.35; P < .0001) and peak systolic strain rate – a measure of deformation with respect to time– increased by 6% (–1.19 to –1.26; P = .0032), said Dr. Dörner, with the University of Bonn, Germany.
No significant changes were found in heart rate, systolic blood pressure, or left ventricular (LV) ejection fraction. LV end-diastolic volume and LV stroke volume increased significantly by 2% and 4%, respectively.
The same imaging protocol was repeated on a different day in 10 patients after consumption of caffeine only. No significant differences were seen in mean peak strain (–22.99 vs. –23.20) or mean peak systolic strain rate (–1.15 vs. –1.16) with caffeine alone, although diastolic blood pressure was significantly elevated and LV end-diastolic volume significantly decreased, Dr. Dörner said.
The current study took advantage of an MRI technique called complementary spatial modulation of magnetization (CSPAMM) for LV myocardial tagging. The technique is more exact than traditional ultrasound or speckle tracking and is able to measure very small differences in strain, he explained in an interview.
Dr. Jonas Dörner
Although the differences in strain in the study were "subtle," the findings need to be taken into perspective because younger patients often consume higher doses of caffeine and taurine via energy drinks. According to the Food and Drug Administration, caffeinated sodas cannot contain more than 71 mg of caffeine per 12 fluid ounces (approximately 20 mg/100 mL), but energy drinks often contain three times that amount, he noted.
More than 500 brands of energy drinks are available worldwide, and 30%-50% are consumed by children, teenagers, and young adults. A report by the European Food Safety Authority found no adverse effects for up to 1 g of taurine per kilogram of body weight per day.
Further studies are needed to evaluate the effect of long-term energy drink consumption and the effect of these drinks on patients with heart disease and in combination with alcohol, Dr. Dörner said.
Dr. Dörner reported having no financial disclosures; a coauthor reported consulting for Medtronic.