New findings published in JAMA Internal Medicine counter the counsel heath care providers commonly give patients with chronic HF to reduce their caffeine intake because of risk for ventricular arrhythmias.
“We found no association between caffeine ingestion and arrhythmic episodes,” Luis E. Rohde, MD, ScD, of the Medical School of the Federal University of Rio Grande do Sul, Porto Alegre, Brazil, told Cardiology Today. “In fact, our results challenge the perception that patients with CVD, and at risk for arrhythmias, should avoid or limit caffeine intake.”
The results come from a double blind, randomized trial of 51 patients (74% men; mean age, 60 years) conducted by Rohde, with Priccila Zuchinali, ScD, and colleagues at a HF and cardiac transplant clinic affiliated with their institution.
“Caffeine-rich beverages have been implicated as a common cause of several cardiac-related symptoms such as palpitations, tachycardia or irregular heartbeats,” Rohde said.
An “intuitive assumption” propels clinicians to recommend that patients with any CVD reduce or avoid caffeine consumption, he added.
Risk not shown
“There were no contemporary data regarding the risk for cardiac arrhythmias in patients with CVD, demonstrating that it is safe to drink caffeine-rich beverages,” Rohde said.
The researchers enrolled patients with chronic HF and moderate-to-severe systolic dysfunction (left ventricular ejection fraction < 45%; mean, 29%) who were categorized as NYHA Class I to III. Of those, 31 patients (61%) had an implantable cardioverter defibrillator.
Patients received caffeine (100 mg) or lactose capsules, in addition to 100 mL decaffeinated coffee at 1-hour intervals over 5 hours (500 mg) or placebo over the same time. The researchers performed a treadmill stress test 1 hour after ingestion. Following a 1-week washout, the same protocol was repeated. The patients then underwent a 1-week crossover washout.
The researchers primarily sought ventricular and supraventricular premature beats through continuous ECG monitoring during each phase. They also looked at non-sustained ventricular and supraventricular tachycardia, appropriateness of ICD therapy and functional capacity.
ECG tracings showed no significant between-group differences in number of ventricular beats (185 with caffeine vs. 239 with placebo, P = .47) or supraventricular beats (6 vs. 6, respectively; P = .44); the same was true for couplets, bigeminal cycles and non-sustained tachycardia.
Further, caffeine did not appear to influence ventricular or supraventricular premature beats during exercise, nor did it effect duration, peak oxygen consumption or heart rate.
No increases were observed in ventricular premature beats in patients with higher vs. lower levels of plasma caffeine concentration or in the placebo group.
“Our results indicate the short-term use of caffeine in these patients was not pro-arrhythmic,” Rohde told Cardiology Today. “Our data provide reassurance that most patients with CVD might drink moderate doses of caffeine-rich beverages with no major risks.”
With approximately half of the patients already habitual coffee drinkers, the researchers note the effect of acute caffeine on arrhythmic events could be dampened and acknowledge they are unable to ensure that caffeine intake over the long term or at high doses would be without pro-arrhythmic effects.
“Prospective studies that evaluate long-term use of caffeine in patients with heart problems might confirm that this is safe for everyday drinkers,” Rohde said.
Modest consumption safe
In a related commentary, Jacob P. Kelly, MD and Christopher B. Granger, MD, both from Duke University, call the findings on modest caffeine consumption in patients with HF reassuring but underscore unanswered questions.
“The longer-term safety of moderate- and high-dose consumption of caffeine, including in popular energy drinks and in patients at high risk for arrhythmias, remains unknown,” they wrote. “For the time being, it seems reasonable to reassure our patients that modest caffeine consumption appears to be safe, including for most patients with HF.” – by Allegra Tiver
For more information:
Luis E. Rohde, MD, ScD, can be reached at Serviço de Cardiologia, Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, Room 2061, Porto Alegre, RS, Brasil 90035-003; email: email@example.com.
Disclosure: The study was supported by a research grant from the National Council for Scientific and Technological Development. The researchers, Granger and Kelly report no relevant financial disclosures.