Medical Bulletin 07/ June/ 2024

A new study, published in Heart Rhythm by Elsevier, examined the potential dangers of consuming energy drinks for patients with genetic heart diseases.

Energy drinks contain caffeine ranging from 80 mg to 300 mg per serving, compared with 100 mg in an 8-ounce cup of brewed coffee. However, most of these energy drinks contain other stimulating ingredients in addition to caffeine that are unregulated by the FDA, such as taurine and guarana. It has been postulated that the highly stimulating and unregulated ingredients alter heart rate, blood pressure, cardiac contractility, and cardiac repolarization in a potentially pro-arrhythmic manner.

In the study, a cohort of 144 sudden cardiac arrest survivors was examined, of which seven patients (5%) had consumed one or more energy drinks in close proximity to their cardiac event. In addition to examining the consumption of energy drinks among the cohort of sudden cardiac arrest survivors, the researchers also looked closely at the type of cardiac event as well as the conditions surrounding the event, such as exercise and other stressors known to be associated with genetic heart disease-associated cardiac arrhythmias.

The results showed that among 144 sudden cardiac arrest survivors, 7 experienced an unexplained sudden cardiac arrest associated temporally with energy drink consumption. Three patients (43%) consumed energy drinks regularly. Six patients (86%) required a rescue shock, and 1 (14%) was resuscitated manually.

While the study did not prove direct causation, caution is advised, and doctors recommend that patients consume energy drinks in moderation.

"While there seemed to be a temporal relationship between energy drink consumption and the seven patients' sudden cardiac arrest event, a myriad of potential 'agitators' that could have also contributed to a genetic heart disease-associated arrhythmia occurred, like sleep deprivation, dehydration, dieting or extreme fasting, or the postpartum period. Although the relative risk is small and the absolute risk of sudden death after consuming an energy drink is even smaller, patients with a known sudden death predisposing genetic heart disease should weigh the risks and benefits of consuming such drinks in the balance,” said Michael J. Ackerman, lead investigator of the study.

Reference: Katherine A. Martinez, Sahej Bains, Raquel Neves, John R. Giudicessi, J. Martijn Bos, Michael J. Ackerman; Sudden cardiac arrest occurring in temporal proximity to consumption of energy drinks; Published: June 05, 2024; DOI: https://doi.org/10.1016/j.hrthm.2024.02.018

A new study to be presented at the SLEEP 2024 annual meeting found that circadian misalignment, which is highly prevalent in adolescents, is linked with carbohydrate consumption and sedentary behaviour in teens.

According to the American Academy of Sleep Medicine, sleep is essential to health, and healthy sleep requires adequate duration, good quality, appropriate timing and regularity, and the absence of sleep disturbances or disorders. A delayed sleep schedule, characterized by sleep timing that is later than conventional or socially acceptable timing, is more common among adolescents and young adults.

A late sleeping schedule is also closely linked to increased carbohydrate consumption. Going to bed late decreases overall activity levels, leading to more sedentary behaviour. This reduction in physical activity can influence dietary habits, causing individuals to consume quick energy sources, such as carbohydrates, to compensate for the lack of movement and energy expenditure.

“Delaying sleep schedules is normal during puberty and adolescence; however, some adolescents delay their sleep schedule to an extent that they become misaligned with the day-night cycle, their social schedules, and responsibilities,” said principal investigator Julio Fernandez-Mendoz.

The study involved 377 adolescents who had a minimum of three nights of at-home actigraphy and one night of in-lab polysomnography. These tests helped calculate their sleep midpoint and sleep regularity. Physical activity was also measured and carbohydrate intake was assessed using a survey.

Results showed that a later sleep schedule was significantly associated with greater intake of carbohydrates, and this relationship was partially explained by irregular sleep timing. A later sleep schedule was associated with greater sedentary behaviour, even after adjusting for variables such as demographics, sleep disorders, and insufficient sleep.

“Proper circadian alignment is necessary for the health of adolescents. Circadian misalignment of the sleep-wake cycle, and its associated variability in sleep duration, should be an integral part of interventions targeting poor dietary choices and sedentarism in youth,” said Fernandez.

Reference: Pura Ballester-Navarro, Natasha Morales-Ghinaglia, Susan Calhoun, Jason Liao, Alexandros Vgontzas, Duanping Liao, Edward Bixler, Julio Fernandez-Mendoza, 0165 Association of Circadian Misalignment with Diet and Physical Activity in Adolescents, Sleep, Volume 47, Issue Supplement_1, May 2024, Page A71, https://doi.org/10.1093/sleep/zsae067.0165

Two new studies to be presented at the SLEEP 2024 annual meeting showed that narcolepsy is an independent risk factor for cardiovascular disease and adverse cardiac events.

According to the American Academy of Sleep Medicine, narcolepsy is a central disorder of hypersomnolence primarily characterized by repeated daily episodes of an irrepressible need to sleep or lapses into drowsiness or sleep. In some cases, sleepiness manifests as sudden, irresistible sleep “attacks” that may occur in unusual situations such as eating or walking. People who have narcolepsy also may experience episodes of cataplexy, which involve the sudden loss of muscle tone with retained consciousness, along with hallucinations or sleep paralysis during the transition from wake to sleep.

The cohort studies used the 2005-2021 Commercial and Medicare Supplemental databases to identify people with a first diagnosis of narcolepsy and a comparison cohort of people without narcolepsy. Both study samples comprised 34,562 people with narcolepsy and 1,00,405 matched controls. The researchers controlled for the use of stimulants, oxybates, and other wake-promoting agents because these medications are commonly used to treat excessive daytime sleepiness associated with narcolepsy.

Results showed that people who have narcolepsy, compared with those without narcolepsy, had a 77% increased risk of any cardiovascular disease and an 82% increased risk of major adverse cardiovascular events.

Their risk of stroke was two times higher, and they also had a 64% increased risk of heart failure or myocardial infarction, and a 58% increased risk of atrial fibrillation.

In another analysis of the same study population that controlled for the use of stimulants, oxybates, and wake-promoting agents at baseline, as well as time-varying stimulant use, people who have narcolepsy had an 89% higher risk of cardiovascular disease and a 95% higher risk of major adverse cardiac events.

“Our investigation revealed a significant finding: the connection between narcolepsy and cardiovascular disease persisted even after accounting for stimulant use. This suggests a direct correlation between cardiovascular disease and narcolepsy. Understanding the positive relationship between narcolepsy and cardiovascular disease independent of stimulants is meaningful for health care providers, especially when determining treatment options for patients,” said lead author Munaza Riaz.

Reference: Christopher Kaufmann, Munaza Riaz, Haesuk Park, Wei-Hsuan Lo-Ciganic, Debbie Wilson, Atul Malhotra, Emerson Wickwire, R Bhattacharjee, 0857 Evidence for an Independent Association of Cardiovascular Disease in Patients with Narcolepsy, Sleep, Volume 47, Issue Supplement_1, May 2024, Page A368, https://doi.org/10.1093/sleep/zsae067.0857