A healthy 29-year-old man had been laboring all day in the summer sun. Hot and exhausted, he was desperate for a cold drink and stopped at a convenience store to purchase a frozen slushie.
He was grateful for the cool relief. Until the piercing headache struck. The brain freeze was painful but soon resolved, but it left in its wake an odd and disconcerting residue of irregularly irregular palpitations. When they did not readily resolve, he headed to the emergency department, where the monitor revealed paroxysmal atrial fibrillation. He was pharmacologically cardioverted and sent home with explicit instructions to avoid caffeine. (Am J Case Rep. 2016;17:23; https://bit.ly/37q73dQ.)
Wait, what?
Misleading Instructions
If you had been the treating physician, what arrhythmia advice would you have given this patient? In this case, the discharging physician didn't mention cold drinks. His focus was caffeine. The patient found that advice strange because his two-cup morning routine was unchanged and seemed unrelated. The slushie had provoked the brain freeze; why not also the concurrent AF? The doctor was steadfast, however. He had been taught about jittery caffeine heart, but had never heard of cold drink heart.
The patient disregarded the physician's advice, and continued his morning coffee but steered clear of any cold-drink triggers (noncompliance isn't always foolish). He went three years without any symptomatic AF until he returned to that same store for a Groundhog Day experience, which landed him back in the same ED. No doubts now. It wasn't the caffeine despite what two emergency physicians told him.
The Evidence
Blaming the double-shot latte and exonerating the slushie, as many of us would have done, is wrong on both counts. Little data support coffee as an AF trigger. A recent meta-analysis concluded that daily coffee does not cause AF, but is actually protective against it. (JACC Clin Electrophysiol. 2018;4[4]:425.) Use this when you need to defend your coffee addiction.
The highest-octane energy drinks may be more arrhythmogenic, but even here hard evidence is lacking. The team behind the European Cardiac Arrhythmia Society statement on cardiovascular events associated with energy drinks scoured the literature and could marshal only a few weak case reports. (J Interv Card Electrophysiol. 2019;56[1]:99.)
Patients recognize that ingesting cold drinks and food is a trigger for their paroxysmal AF. (Perm J. 2020;24[19]:238; https://bit.ly/3cVa5b4.) One large survey found that 13 percent of patients with paroxysmal AF reported that cold drink or food catapults them into AF. (Heart Rhythm. 2019;16[7]:996.) After this case report of cold-drink AF was published, we received emails from patients around the world. They were delighted to find out they were not alone. The validation was all the more critical because the cold-drink trigger had often been dismissed by their physicians.
When we say cold drink, we mean a nonalcoholic one. Not that an ice-cold IPA couldn't, by virtue of its temperature, trigger AF along with a sense of pleasant relaxation and COVID-19 escapism, but once large amounts of alcohol are involved, we move away from the more benign cold drink heart to the more nefarious holiday heart and its worrisome long-term implications. As we know, binge drinking alcohol, regardless of the temperature, is cardiotoxic. (Am Heart J. 1978;95[5]:555.) With repeat exposure, the arrhythmogenic mechanisms of alcohol multiply. Patients with frequent or persistent AF should be cautioned about the adverse cardiovascular effects of alcohol. (J Am Coll Cardiol. 2016;68[23]:2567; https://bit.ly/2AtZOFr.)
Take-Home Lessons
When patients present with paroxysmal AF, don't criticize their habitual caffeine intake or blame it as the cause. It probably isn't. Ask instead about two common and correctable ingestion triggers: alcohol bingeing and cold drinks and food. If a smoothie or frozen yogurt were the AF precipitant, you can inform your patients of their diagnosis (cold drink heart), its prevalence (about in one in 10 patients with paroxysmal AF), their home management (trigger avoidance) and why they should follow up with their primary care provider.
Because these patients are generally younger with structurally normal hearts (Int J Cardiol. 2015;201:415), most will have a low CHA2DS2-VASc score and won't need long-term thromboprophylaxis. With these informed discharge instructions, you will look smart and cool (we couldn't resist) and help your patients reduce AF recurrence and repeat ED visits.
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Dr. Vinsonis an emergency physician at Kaiser Permanente Sacramento Medical Center, a chair of the KP CREST (Clinical Research on Emergency Services and Treatment) Network, and an adjunct investigator at the Kaiser Permanente Division of Research (https://www.kpcrest.net/). Dr. Ballardis an emergency physician at San Rafael Kaiser, a past chair of the KP CREST Network, and the medical director for Marin County Emergency Medical Services. Read their past articles athttp://bit.ly/EMN-MedClear.
