Author	Study type	Intervention	Primary endpoint	Results	Study conclusions
Priccila Zuchinali, et al. 2016	Systematic Review and Meta-Analysis	Caffeine administration	Impact of caffeine on VA	Risk of ventricular premature beats in humans within 24 hour of caffeine consumption: was 1.00 (95% CI 0.94 - 1.06; I(2) 13.5%, p = 0.32)	There is no significant relationship between caffeine consumption and VPB’s
Ramy Abdelfattah, et al. 2018	Meta-Analysis	Caffeine consumption (focused on coffee) 40 - 180 mg of caffeine and higher dosages (436 mg)	Caffeine consumption and risk of AF	No difference in AF rate in those who drank less than 2 cups of coffee compared to more than 2 cups 1.068 (0.937 - 1.216) Subjects who drank less coffee were at higher risk of AF Subjects who drank more than 436 mg of caffeine had a lower rate of AF	Caffeine consumption (coffee) does not increase the occurrence of AF. The risk of AF was reduced with caffeine consumption exceeding 436 mg/d.
Min Cheng, et al. 2014	Meta-Analysis	Habitual caffeine intake	Impact of habitual caffeine intake and AF	Caffeine consumption was weakly associated with reduced risk of AF (RR: 0.90, 95% CI: 0.81 - 1.01, p = 0.07). Low and high doses of caffeine were both associated with a decreased AF risk (RR: 0.89, 95% CI: 0.80 - 0.99, p = 0.032; RR: 0.84, 95% CI: 0.75 - 0.94, p = 0.002, respectively). The dose-response analysis revealed a 6% decrease in AF risk per 300 mg/d increase in habitual caffeine intake (RR: 0.94, 95% CI: 0.90 - 0.99).	The findings suggest caffeine consumption might reduce AF risk
Gregory M. Marcus, et al. 2023	Randomized Controlled Trial	Consumption of caffeinated coffee	Relationship between caffeine consumption and daily premature atrial contractions	Caffeinated coffee consumption did not significantly increase daily premature atrial contractions (PACs) compared to caffeine avoidance (rate ratio: 1.09; 95% CI: 0.98 to 1.20; p = 0.10). Caffeine was associated with a higher number of premature ventricular contractions (PVCs) (rate ratio: 1.51; 95% CI: 1.18 to 1.94)	Caffeine consumption did not result in more daily premature atrial contractions compared to avoidance of caffeine.
Daniel Caldeira, et al. 2013	Systematic Review and Meta-Analysis	Caffeine Consumption	Impact of caffeine consumption and risk of AF	Caffeine consumption was not associated with an increased risk of AF (OR 0.92, 95% CI 0.82 to 1.04, I(2) = 72%) High-quality studies showed a 13% reduced odds of AF with lower heterogeneity (OR 0.87; 95% CI 0.80 to 0.94; I(2) = 39%) Low-dose caffeine exposure had a protective effect (OR 0.85, 95% CI 0.78 to 0.92, I(2) = 0%)	Caffeine intake is not associated with increased risk of AF. Low caffeine consumption could have a protective effect.
Priccila Zuchinali, et al. 2016	Randomized Clinical Trial	Administration of high-dose caffeine to patients with HFrEF	Effect of high-dose (500 mg) caffeine on frequency of supraventricular and ventricular arrhythmias	500 mg caffeine administration to HFrEF patients did not lead to an increase in ventricular or supraventricular premature beats during continuous electrocardiographic monitoring or a symptom-limited exercise test. No differences were observed between caffeine and placebo groups for arrhythmia frequencies or exercise test-derived variables (p > 0.05)	Acute intake of high caffeine doses did not induce arrhythmias in patients with systolic heart failure and patients at high risks of ventricular arrhythmias.
Robert Lemery, et al. 2015	Randomized Controlled Trial	Administration of caffeine or placebo to patients with symptomatic supraventricular tachycardia who were undergoing an electrophysiologic study prior to catheter ablation.	To investigate the electrophysiological effects of caffeine on atrial and ventricular tissues	Caffeine caused significant increases in resting systolic and diastolic blood pressures compared to placebo. Resting HR remained similar between the groups. Caffeine didn’t affect atrial or ventricular refractory periods or AV node conduction. Nearly all patients developed SVT, with no significant difference in SVT inducibility or induced tachycardia cycle length between caffeine and placebo groups.	Caffeine intake had no significant effect or evidence on cardiac conduction and refractoriness. Caffeine did not have an effect on SVT induction or rapid rate of induced tachycardias.
David Lagier, et al. 2018	Randomized Controlled Trial	Administration of peri-operative oral caffeine (400 mg every 8 hours for 2 days) to patients undergoing heart valve surgery with cardiopulmonary bypass	The rate of AF during the postoperative hospital stay.	There was no significant difference in the incidence of AF during hospital stay between the caffeine group and the placebo group (33% vs. 29%, p = 0.67), as well as during the first 3 postoperative days (18% vs. 15%, p = 0.60). Adenosine plasma levels were associated with the primary outcome, but caffeine administration led to a higher incidence of postoperative nausea and vomiting (27% vs. 7%, p = 0.005).	Oral caffeine administration did not prevent postoperative AF after heart valve surgery with cardiopulmonary bypass, however it was associated with an increased rate of postoperative nausea and vomiting.
Remo H M Furtado et al. 2021	Meta-Analysis	Administration of Caffeine in two Spanish Cohorts Participants classified into 3 groups based on caffeine (coffee) consumption (Less than or equal to 3 cups per month, 1 to 7 cups per week and more than 1 cup per day)	To investigate the association between caffeine consumption (coffee) and the risk of developing AF.	1 - 7 cups of coffee per week was linked to reduced risk of AF (HR = 0.53, 95% CI 0.36 - 0.79), higher consumption of caffeine (more than 1 cup of coffee per day) did not show significant association (HR = 0.79, 95% CI 0.49 - 1.28). Both cohorts depicted an inverse relationship between moderate coffee intake and reduced risk of AF (HR = 0.60, 95% CI 0.44 - 0.82).	Moderate caffeine consumption (1 - 7 cup of coffee per week) was associated with a reduced risk of AF in both cohorts.
Gregory M Marcus et al. 2022	Randomized Controlled Trial	Participants were given instructions to consume or avoid self-selected triggers in randomized 1 week blocks for 6 weeks	Self selected triggers. AFEQT score at 10 weeks. AFEQT score is used to assess the impact of AF on the quality of life of individuals facing AF.	446 total participants. Self-selected triggers encompassed caffeine (n = 53), alcohol (n = 43), reduced sleep (n = 31), exercise (n = 30), lying on left side (n = 17), dehydration (n = 10), large meals (n = 7), cold food or drink (n = 5), specific diets (n = 6), and other personalized triggers (n = 4). AFEQT scores demonstrated no notable difference, during the subsequent 4-week post-intervention phase. A notable decrease in daily AF episodes emerged following trigger testing, in contrast to controls (adjusted relative risk, 0.60; 95% CI, 0.43 - 0.83; p < 0.001). A meta-analysis of individualized trials showed solely alcohol exposure correlated with significantly escalated AF event risks.	Testing of AF triggers did not affect AFEQT but was associated with a lower rate of AF. Exposure to alcohol only increased AF risk, exposure to caffeine did not increase AF risk.
Belinda Gray et al. 2019	Randomized Controlled Trial	Caffeinated energy drink consumption in patients with LQTS aged 16 - 50.	To determine whether caffeine consumption (energy drinks) in patients with LQTS would result in an increase in QTc by more than 20 milliseconds. Change in blood pressure was also assessed.	24 LQTS patients (mean age 29 ± 9 years, 54% female, 33% probands) consumed ED and acted as their own controls with a one-week washout. Primary outcome: No significant QTc change with ED compared to control (12 ± 28 ms vs. 16 ± 27 ms, p = 0.71). Systolic and diastolic blood pressure increased significantly with ED (7 ± 16 mmHg vs. 1 ± 16 mmHg, p = 0.046 and 8 ± 10 mmHg vs. 2 ± 9 mmHg, p = 0.01), correlated with serum caffeine (14.6 ± 11.3 vs. 0.5 ± 0.1 μmol/L, p < 0.001) and serum taurine (737 ± 199 vs. −59 ± 22 μmol/L, p < 0.001). Three patients experienced dangerous QTc prolongation (≥50 ms) after energy drink consumption.	Caffeinated ED’s causie an increase in blood pressure. Dangerous QTc prolongation was observed in some LQTS patients therefore young patients with LQTS are recommended to consume ED with caution.
Guido Mandilaras et al. 2022	Randomized Controlled Trial	Administration of ED and placebo to healthy children and adolescents.	To investigate the acute cardiovascular effects of ED in healthy children and adolescents.	ED consumption by healthy children and adolescents resulted in a significant increase in SVES compared to the placebo. No dangerous arrhythmias were observed, ED consumption lowered mean heart rate but did not affect QTc intervals.	ED consumption was associated with an increased number of SVES in healthy children and adolescents. Significant decrease in HR was observed which was possibly caused by rise in systolic and diastolic blood pressure. No significant QTc changes were seen after ED consumption and were similar to placebo. Minors with heart rhythm conditions may develop malignant arrhythmias after ED consumption.
Isabel Lasheras et al. 2021	Systematic review	Acute consumption of ED.	To investigate the effects of acute ED consumption on HR and ECG parameters.	After evaluating 43 clinical studies, ED consumption led to a rise in resting HR in 71.1% of studies (pooled p < 0.001, significant in 38%), exercise-related HR elevation in 55.5%, and post-exercise HR elevation in 71.4% (pooled p-value < 0.001). Evidence on PR interval was contradictory, while corrected QTc increased compared to baseline in all but one study, surpassing the pathological limit in two instances. T wave changes were noted in two studies, with one reporting a 5:1 ratio of ectopic beats	Acute consumption of ED can change ECG in certain risk populations, at risk underaged individuals should consume with caution.