Heart Rhythm

Heart Rhythm: An Encyclopedic Reference in the Nutrition and Natural-Health Context

1. Definition and Overview

An arrhythmia is a problem with the heart's rhythm: it happens when electrical signals that tell the heart to beat do not work the way they should, causing the heart to beat too fast, too slow, or just irregularly. More precisely, arrhythmia is an abnormal rhythm of the heart; the only normal rhythm of the heart is normal sinus rhythm, in which an impulse is generated in the sinoatrial (SA) node, conducted through and slowed down in the atrioventricular (AV) node, and then conducted through the bundle of His, to the left and right bundle branches, and eventually into the Purkinje fibers. Any deviation from this conduction pathway results in arrhythmia.

The American Heart Association explains that arrhythmia refers to any problem in the rate and/or rhythm of a person's heartbeat, including such forms as atrial fibrillation, bradycardia, tachycardia, conduction disorders, rhythm disorders, ventricular fibrillation, and premature contractions. A fast heart rate in adults (more than 100 beats per minute) is called tachycardia; a slow heart rate (fewer than 60 beats per minute) is called bradycardia.

2. How It Presents: Signs and Symptoms

A person with an arrhythmia may feel as if the heart is racing, fluttering, pounding, skipping beats, or adding extra beats. When an arrhythmia is present, the heart may beat too quickly or too slowly, or there may be an irregular rhythm in which the heart feels as if it is "skipping a beat." Sometimes arrhythmias are silent, meaning they cause no obvious symptoms. A cardiac arrhythmia may not cause any symptoms at all; in rare cases, the first symptom may be a seizure or sudden cardiac death.

Some arrhythmias are so brief — such as a temporary pause or premature beat — that the overall heart rate or rhythm is not greatly affected. However, if arrhythmias last longer, they may make the heart rate too slow, too fast, or erratic, so the heart pumps less effectively. When the heart does not beat properly, it cannot pump blood effectively; when this happens, the lungs, brain, and all other organs cannot work properly and may shut down or be damaged.

3. Body Systems Involved

Heart rhythm is governed by the cardiac electrical conduction system, and disturbances in rhythm can affect multiple organ systems:

• Cardiac electrical system: The human heart normally maintains its own well-ordered intrinsic rhythm through the generation of stimuli by pacemaker tissue that results in a wave of depolarization spreading through specialized conducting tissue and then into and through the myocardium. The well-ordered propagation of electrical depolarizations through the heart causes coordinated contractions of the myocardium, resulting in the efficient pumping of blood. Abnormalities of excitable cardiac tissue can lead to abnormalities of heart rhythm called arrhythmias; all arrhythmias stem from one of two causes — abnormalities of impulse generation or abnormalities of impulse propagation.
• Autonomic nervous system: In a normally functioning heart, stimuli are generated under the influence of various physiological regulatory mechanisms to cause the heart to beat at a rate that maintains cardiac output at a level sufficient to meet the metabolic needs of the body.
• Electrolyte and mineral systems: Systemic factors that can cause or contribute to a rhythm disturbance include electrolyte abnormalities (particularly hypokalemia or hypomagnesemia), hypoxia, hormonal imbalances such as hypothyroidism and hyperthyroidism, and medications and toxins including alcohol and caffeine.
• Cardiovascular system at large: Issues with various parts of the heart or abnormal blood flow to the heart can affect the heart's normal rhythm. Having a normal heart rhythm matters because the heart supplies the whole body with nutrients and oxygen through the blood it pumps; having an abnormal rhythm may hinder this.

4. Major Types of Arrhythmia

Arrhythmias are commonly classified by site of origin and rate:

• Ventricular arrhythmias begin in the heart's ventricles or lower chambers.
• Bradyarrhythmias and junctional rhythms can happen because of issues in the heart's conduction system, like the sinoatrial (SA) node, atrioventricular (AV) node, or His-Purkinje network.
• Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the clinical setting, affecting approximately 34 million individuals worldwide; the disease is associated with significant burden of morbidity and mortality resulting from stroke, heart failure, and acute coronary syndrome.
• Fibrillation is a type of arrhythmia in which the heart quivers instead of beating normally; in atrial fibrillation, the atria quiver in an abnormal rhythm.
• Ventricular fibrillation can occur when tachyarrhythmias degrade into more serious forms in which electrical activity spreads through the myocardium in a disorganized fashion so that effective contraction does not occur; in this type, the heart pumps little or no blood to the body, and death can occur within minutes.

5. Contributing and Associated Factors

5.1 Structural and Genetic Factors

Any heart disease, including congenital abnormalities of structure such as accessory atrioventricular connections, or function such as hereditary ion channelopathies, can disturb rhythm. Most arrhythmias happen because of an issue with the heart's arteries, valves, or muscles.

5.2 Metabolic and Hormonal Factors

Systemic factors that can cause or contribute to a rhythm disturbance include electrolyte abnormalities (particularly hypokalemia or hypomagnesemia), hypoxia, and hormonal imbalances such as hypothyroidism and hyperthyroidism. Inherited conditions like long QT syndrome, as well as fever, infection, dehydration, stress, inflammation, and lack of sleep, can also cause or contribute to arrhythmias.

5.3 Obesity, Hypertension, and Diabetes

Atrial fibrillation is the most common sustained cardiac arrhythmia associated with a two-fold increase in mortality caused by a higher risk of stroke and heart failure; it is present in approximately 2% of the general population. Obesity, hypertension, diabetes mellitus, obstructive sleep apnea, and alcohol consumption all increase the risk of AF. Each unit of increase in BMI increases the risk of AF by 3%, and intensive weight loss is associated with reduced AF recurrence. Hypertension increases the risk of AF by 50% in men and by 40% in women, and explains approximately 20% of new AF cases.

A study by Pathak and colleagues revealed that weight loss of 10% or more in patients suffering from AF resulted in a sixfold greater probability of arrhythmia-free survival compared to patients who lost less than 10% of their body weight in the same period; the study also associated sustained weight loss with significant maintenance of sinus rhythm.

5.4 Alcohol

Alcohol may contribute as a trigger of AF, and long-term regular consumption promotes progressive atrial remodeling. Acute alcohol consumption, as a trigger, may act on the electrophysiological milieu for AF through cellular and autonomic effects such as shortening atrial and pulmonary vein action potential, shortening atrial effective refractory period, and slowing atrial conduction.

In the I-STOP-AFib randomized clinical trial of 466 patients, acute exposure to alcohol increased AF risk (OR = 2.15; 95% CI: 1.17–3.61), with no evidence that other exposures including caffeine triggered AF. In another study of 100 subjects, 56 of whom had at least one episode of AF, within 4 hours of consuming one drink the risk of AF was doubled (OR = 2.02; 95% CI: 1.38–3.17), with a greater than 3-fold higher odds with at least two drinks (OR = 3.58; 95% CI: 1.63–7.89).

5.5 Obstructive Sleep Apnea

Patients with obstructive sleep apnea are at four times higher risk of developing AF than subjects without sleep apnea. Sleep disorders not only elevate the risk of developing AF but also impair the effectiveness of antiarrhythmic therapies.

5.6 Smoking and Other Lifestyle Factors

Smoking — both active and passive — increases the risk of AF, with traditional cigarettes and non-combustible tobacco products contributing to its pathogenesis. Lifestyle factors play a critical role in the development and management of AF; key factors include physical activity, smoking, sleep disorders like obstructive sleep apnea, air pollution, and diet.

5.7 Inflammation

A nutritious diet supports cardiovascular health by helping to manage risk factors such as hypertension, obesity, and high cholesterol, which are risk factors for AF. Chronic inflammation is a strong risk indicator of AF; a diet rich in anti-inflammatory foods can be beneficial.

6. Nutrients, Minerals, and Natural Ingredients Studied in Relation to Heart Rhythm

6.1 Magnesium

Mechanisms and background: Magnesium may influence the incidence of cardiac arrhythmias by: (1) a direct effect; (2) an effect on potassium metabolism; (3) an effect as a calcium blocking agent. In the event of magnesium deficiency, the cell cannot attract potassium against the transmembrane concentration gradient, because magnesium deficiency interferes with the function of membrane ATPase — thus impairing the pumping of sodium out of the cell and potassium into the cell. The interference from magnesium deficiency on the equilibrium of potassium between intra- and extracellular spaces may result in changes in resting membrane potential, changes in potassium conductance across the cell membrane, as well as disturbances in the repolarization phase.

Scientific evidence: There are conflicting data regarding the impact of serum potassium and magnesium levels on susceptibility to ventricular premature complexes (VPCs) in the clinical setting. The Framingham Offspring Study examined the associations of serum potassium and magnesium levels with the prevalence of complex or frequent VPCs in 3,327 eligible subjects (mean age 44 years) free of clinically apparent heart disease; complex or frequent VPCs were present in 183 subjects (5.5%). Lower potassium (p = 0.002) and lower magnesium (p = 0.010) levels were associated with higher prevalence rates of arrhythmia; in logistic regression analyses, potassium (p = 0.0021) and magnesium (p = 0.0311) levels were inversely associated with the occurrence of complex or frequent VPCs after adjustment for multiple confounders. A 1 standard deviation decrement in potassium (0.48 mEq/liter) or magnesium (0.16 mEq/liter) level was associated with a 27% (95% CI 6%–51%) and a 20% (95% CI 3%–41%) greater odds of complex or frequent VPCs, respectively.

Two randomized, double-blind, placebo-controlled trials showed that both intravenous and oral administration of magnesium chloride results in a significant reduction in the frequency and complexity of ventricular arrhythmias in patients with congestive heart failure; magnesium administration was well tolerated and serious adverse effects were rare. Recent publications have documented that perioperative use of magnesium can reduce the incidence of arrhythmic events on both the atrial and ventricular level; oral magnesium has been used for many years in patients with symptomatic extrasystoles. The main indications for intravenous application of magnesium are torsade de pointes tachycardias, digitalis toxicity-induced tachyarrhythmias, and multifocal atrial tachycardias.

Evidence strength: Moderate. Associations are consistent in observational data; small clinical trials support efficacy in specific populations (congestive heart failure, perioperative care). Larger, well-designed RCTs are still needed.

6.2 Potassium

Scientific evidence: Cardiac arrhythmia is often present in patients with acute coronary syndrome (ACS) and may be due to electrolyte imbalance. Hypokalemia was observed in 34% of patients in one study and was significantly associated with the occurrence of life-threatening ventricular arrhythmias (26% of patients with potassium level <4 mmol/l vs. 11.9% of patients with normokalemia, p<0.001); however, no relationship was found between potassium level and supraventricular arrhythmias or in-hospital mortality in that cohort.

Low plasma potassium and magnesium concentrations have been advanced as risk factors for ventricular fibrillation (VF); for potassium, this assertion is based almost exclusively on retrospective data, while for magnesium the evidence shows an association with ventricular arrhythmias but not a direct association with VF. Combined K+ and Mg2+ deficiency, which frequently occur together, can lead to abnormal ionic transfer of Na+, K+, and Ca2+ with development of automaticity, triggered impulses, and reentrant tachycardia.

Evidence strength: Moderate for the association between hypokalemia and ventricular arrhythmia risk; prospective RCT evidence for oral potassium supplementation in arrhythmia reduction specifically remains limited.

6.3 Omega-3 Fatty Acids (EPA and DHA)

Scientific evidence — complex and nuanced: Some, but not all, large-scale randomized controlled trials (RCTs) investigating the effects of marine omega-3 fatty acid supplementation on cardiovascular outcomes have reported increased risks of atrial fibrillation; the potential reasons for disparate findings may be dose-related.

Meta-analyses of 8 RCTs and 17 prospective cohort studies comprising 83,112 and 54,799 individuals, respectively, investigated the link between omega-3 intake and incident AF. The RCTs reported that treatment with DHA and/or EPA was associated with a 24% increased relative risk of AF (absolute risk 4.0% vs. 3.3%; relative risk 1.24, 95% CI 1.11–1.38, p = 0.0002). This association was dose-dependent: DHA + EPA doses of approximately 1,000 mg/day increased AF risk approximately 12%, whereas 1,800–4,000 mg/day increased AF risk by approximately 50%.

In contrast, consumption of marine sources of omega-3 such as fish and seafood has been consistently associated with lower risks for developing AF in observational data. The overall evidence base for omega-3 and AF is hypothesis-generating; heterogeneity in study design and duration, doses used, and study populations makes it difficult to draw firm conclusions, and causality cannot be established.

Evidence strength: Mixed. Supplemental omega-3 (especially at higher doses) is consistently associated with increased AF risk in RCT meta-analyses, while dietary fish intake shows a neutral to protective association. The mechanistic divergence between supplement and food sources remains under investigation.

6.4 Vitamin D

Scientific evidence: Observational studies consistently associate low 25(OH)D concentrations with increased risk of hypertension, atherosclerosis, myocardial infarction, heart failure, arrhythmias, stroke, and cardiovascular mortality. Mechanistic investigations have revealed that vitamin D modulates cardiomyocyte calcium handling, endothelial function, vascular smooth muscle proliferation, inflammation, oxidative stress, and the renin–angiotensin–aldosterone system activity, establishing biologically plausible links to cardiovascular outcomes.

Despite these associations, large randomized trials of vitamin D supplementation have failed to demonstrate reductions in major cardiovascular events, likely due to heterogeneity in baseline status, dosing regimens, intervention timing, genetic variability, and underlying comorbidities. Vitamin D may function more effectively as a biomarker of cardiovascular risk rather than a universal therapeutic agent, with deficiency reflecting systemic vulnerability rather than acting as a dominant causal factor.

In clinical trial studies, the incidence of cardiovascular diseases among the vitamin D-consuming group was not significantly different from that in the placebo group (RR: 0.99, 95% CI: 0.95–1.03; P = 0.77); CVD mortality was also not significantly different between the two groups (RR: 0.97, 95% CI: 0.90–1.05; P = 0.72).

Evidence strength: Weak for supplementation reducing arrhythmia; observational associations are consistent, but RCT results do not support a therapeutic role for vitamin D supplementation specifically in arrhythmia prevention.

6.5 Coenzyme Q10 (CoQ10 / Ubiquinone)

Background: CoQ10, also known as ubiquinone, was first discovered by Frederick Crane and colleagues in 1957. It is a lipid-soluble molecule synthesized endogenously in the human body and available from dietary sources such as meat, fish, and vegetables. Primarily located in the inner mitochondrial membrane, CoQ10 participates in the electron transport chain and plays a crucial role in ATP production, thereby supporting cellular energy metabolism.

Mitochondrial dysfunction is increasingly recognized as a pivotal factor in the pathogenesis of various cardiovascular diseases, including heart failure and ischemic heart disease. As an essential component of the mitochondrial electron transport chain, CoQ10 has garnered attention for its potential cardioprotective effects.

Evidence strength: Preliminary for arrhythmia specifically. CoQ10 has established evidence for broader cardiovascular metrics (heart failure outcomes, blood pressure), but targeted RCT evidence for anti-arrhythmic effects in humans remains sparse.

7. Herbs and Plant-Derived Compounds

7.1 Hawthorn (Crataegus spp.)

Traditional use: Hawthorn (Crataegus oxyacantha), also known as haw, maybush, or whitehorn, is part of a genus of spiny shrubs and trees native to temperate regions in the Northern Hemisphere in Europe, Asia, and North America, belonging to the Rosaceae family. Hawthorn has been used in folk medicine for the treatment of diarrhea, gallbladder disease, insomnia, and as an antispasmodic agent. In Chinese medicine, hawthorn was also used for a variety of conditions including digestive problems, hyperlipidemia, poor circulation, and dyspnea. The use of extracts from the hawthorn plant as cardiovascular agents dates back to the 1st century.

Scientific evidence: Evidence is accumulating from various in vivo and in vitro studies that hawthorn extracts exert a wide range of cardiovascular pharmacological properties, including antioxidant activity, positive inotropic effect, anti-inflammatory effect, anticardiac remodeling effect, antiplatelet aggregation effect, vasodilating effect, endothelial protective effect, protective effect against ischemia/reperfusion injury, antiarrhythmic effect, lipid-lowering effect, and decrease of arterial blood pressure. Reviews of placebo-controlled trials have reported both subjective and objective improvement in patients with mild forms of heart failure (NYHA I–III), hypertension, and hyperlipidemia.

Wild hawthorn species are widespread in the temperate climate of the Northern Hemisphere, including Europe and Asia. Over 300 chemical compounds have been detected in Crataegus, especially C. monogyna, including flavonoids, procyanidins, organic acids, and many other biologically active substances.

Evidence strength: The antiarrhythmic effects of hawthorn have been demonstrated primarily in in vitro and animal studies. Clinical trial evidence is largely indirect, focusing on heart failure and hypertension rather than on arrhythmia endpoints specifically. The European Commission E has approved hawthorn leaf and flower preparations for declining cardiac function; further controlled trials are needed for arrhythmia-specific claims.

7.2 Berberine

Traditional use: Berberine is widely used in traditional Chinese medicine as an antimicrobial in the treatment of dysentery and infectious diarrhea. Berberine (BBR) is an extract of the traditional Chinese medicine Huanglian, which is widely used in the treatment of heart disease, especially in the treatment of arrhythmias; it can be used to treat different types of arrhythmias through multiple channels and multiple targets.

Scientific evidence: Berberine has positive inotropic, negative chronotropic, antiarrhythmic, and vasodilator properties. Both berberine and its derivatives have antiarrhythmic activity. Some cardiovascular effects of berberine and its derivatives are attributed to the blockade of K+ channels (delayed rectifier and K(ATP)) and stimulation of Na+–Ca(2+) exchanger. Berberine has been shown to prolong the duration of ventricular action potential.

It has been shown that berberine can prevent the occurrence of atrial fibrillation by prolonging the action potential and effective refractory period of atrial myocytes; it can also target different types of K+ channels to achieve class III antiarrhythmic effects.

Although berberine's cardioprotective properties have shown satisfactory effects on cardiac arrhythmia, it causes prolonged QT interval, bradycardia, hypotension, and cardiotoxicity as possible adverse effects; more clinical studies are needed to obtain more reliable results.

Evidence strength: Preliminary to moderate. Preclinical and limited clinical studies are encouraging, but the potential for QT prolongation and cardiotoxicity requires careful consideration. Large, well-designed human trials are lacking.

7.3 Resveratrol

Traditional use: Resveratrol is a stilbenoid polyphenol found in grapes, red wine, and certain berries. It does not have a classical traditional medicine monograph in the same sense as herbs such as hawthorn, but grape-derived preparations have longstanding use in European and Asian traditions for cardiovascular support.

Scientific evidence: Resveratrol was identified in a comprehensive systematic review as one of the most studied phytochemicals for antiarrhythmic effects, found to have multiple mechanisms of antiarrhythmic action. Resveratrol has been classified as exhibiting class III antiarrhythmic activity through modulation of K+ channels as well as class IV activity through Ca2+ channel inhibition, with inhibitory effects on Nav channels also reported. Studies have shown that these phytochemicals, including resveratrol, can modulate K+ channel currents and affect action potential duration, thereby protecting the heart against ischemia-reperfusion-induced arrhythmias.

Evidence strength: Predominantly preclinical (animal and in vitro). Human trial evidence on resveratrol specifically for arrhythmia prevention or treatment is very limited.

7.4 Curcumin

Traditional use: Curcumin is the principal bioactive polyphenol from turmeric (Curcuma longa), used for millennia in Ayurvedic and Traditional Chinese medicine for a range of inflammatory and systemic conditions.

Scientific evidence: In the same systematic review of antiarrhythmic phytochemicals, curcumin was identified as one of the most studied phytochemicals with multiple mechanisms of antiarrhythmic action. Curcumin has been classified as having class I, III, and IV antiarrhythmic activities — modulating Na+ channels, K+ channel currents, and Ca2+ channels, and protecting the heart against ischemia-reperfusion-induced arrhythmias.

In a systematic review and meta-analysis including 24 animal studies (503 animals) and four human studies (435 patients), the meta-analysis of animal studies demonstrated that compared with the control group, curcumin significantly reduced myocardial infarction size (p < 0.00001) and improved cardiac function indexes; in terms of clinical studies, curcumin reduced the incidence of cardiac dysfunction and myocardial infarction in hospital, which might be related to its anti-inflammatory and anti-oxidative properties.

Evidence strength: Predominantly preclinical for arrhythmia outcomes specifically. Human trials show cardioprotective signals in the context of myocardial ischemia-reperfusion, but arrhythmia as a primary endpoint has not been evaluated in adequately powered RCTs.

7.5 Overview of the Phytochemical Landscape

A systematic review searched PubMed, Embase, and the Cochrane Library from inception to June 2021 to find plant extracts, phytochemicals, and multi-component herbal preparations with antiarrhythmic activities; from 7,337 identified results, 57 original studies consisting of 49 preclinical and eight clinical studies were finally included. Three plant extracts, eight multi-component herbal preparations, and 26 phytochemicals were found to have antiarrhythmic effects mostly mediated by affecting K+ channels, followed by modulating Ca2+ channels, upstream target pathways, Nav channels, gap junction channels, and autonomic receptors; the most investigated medicinal plants were Rhodiola crenulata and Vitis vinifera; resveratrol, oxymatrine, and curcumin were the most studied phytochemicals with multiple mechanisms of antiarrhythmic action. The most prevalent limitation of the studies was their unqualified methodology; future well-designed experimental and clinical studies are necessary to provide more reliable evidence.

8. Dietary Patterns and Lifestyle Factors

8.1 The Mediterranean Diet

There is a growing body of evidence supporting the role of diet in the treatment of cardiovascular disease and its complications; one of the most recommended is the Mediterranean diet, known for its emphasis on fruits, vegetables, whole grains, and healthy fats like olive oil.

One case-control study (AFHRI) showed that adherence to the Mediterranean diet, and especially the intake of plant-based foods such as nuts, vegetables, and fruits, as well as preference for white meat over red meat, was less frequently reported by AF patients; larger clinical studies are required to confirm the extent to which high-quality dietary patterns such as the Mediterranean diet are able to influence the onset of AF.

Adopting heart-healthy dietary patterns such as the Mediterranean diet and DASH diet is considered particularly beneficial for AF management in current reviews.

8.2 Plant-Based Dietary Approaches

The research on dietary patterns and their relation to AF risk has been gaining significant momentum; a key example is the study by Pathak and colleagues showing that weight loss of 10% or more in patients with AF resulted in a sixfold greater probability of arrhythmia-free survival. Nutritional approaches, including plant-based diets, are considered of paramount importance in addressing underlying predisposing conditions.

Diet modification is the foundation of cardiovascular disease prevention; a nutritious diet supports cardiovascular health by helping to manage risk factors such as hypertension, obesity, and high cholesterol. Chronic inflammation is a strong risk indicator of AF, and a diet rich in anti-inflammatory foods can be beneficial; a heart-healthy diet low in sodium and high in potassium can also contribute to blood pressure management.

8.3 Coffee and Caffeine

While alcohol and tobacco are linked to AF, there is only a weak association between caffeine intake and developing the disease; the data do not implicate caffeine as a significant risk factor, and prospective studies on the role of caffeine are lacking. Coffee has also been linked to decreased inflammation because it contains high levels of antioxidants such as cafestol, polyphenols, trigonelline, chlorogenic acid, and quinine; moderate coffee consumption, through these mechanisms, has been linked to a decreased incidence and risk of developing AF.

8.4 Dietary Fiber and Whole Foods

Lifestyle factors, in particular dietary intake, have been recognized as important, modifiable risk factors for cardiovascular disease; studies have shown that dietary components such as alcohol, caffeine, fiber, and fish-derived long-chain polyunsaturated fatty acids (PUFAs) influence cardiovascular morbidity and mortality.

8.5 Sodium and Potassium Balance

A heart-healthy diet low in sodium and high in potassium is associated with contributions to blood pressure management, which is itself a key risk factor for arrhythmia. The role of dietary potassium in maintaining cardiac electrophysiology is reinforced by its well-established connection to ventricular arrhythmia risk described in the electrolyte literature above.

8.6 Physical Activity

Engaging in regular physical activity has been shown to reduce the incidence of AF and limit related complications. However, extreme endurance exercise appears to increase the risk of developing AF by approximately 5-fold, suggesting that moderation of exercise type and intensity is relevant.

8.7 Sleep

Studies show that sleep apnea in those with AF ranges from 21% to 87%; people with sleep-disordered breathing have a 2-fold increased AF risk. Sleep apnea treatment may decrease AF burden and lead to better AF outcomes; those with severe sleep-disordered breathing appear less likely to respond to antiarrhythmic medications.

8.8 Nutritional Factors in Long QT Syndrome

Long QT syndrome (LQTS) is an umbrella term for a group of genetic cardiac channelopathies characterized by prolonged ventricular repolarization and increased risk of life-threatening arrhythmias. Although beta-blockers and lifestyle modifications remain central to management, specific dietary components may influence repolarization and arrhythmic risk, particularly in genetically predisposed individuals. A 2025 review summarized mechanistic and clinical evidence on the electrophysiological effects of selected nutrients, food constituents, and supplements — including grapefruit juice, licorice, over-the-counter products, and energy drinks — and their gene–nutrient interactions and impact on ion channel function, drug metabolism, and electrolyte balance.

References

• Cleveland Clinic: Arrhythmia — Types, Symptoms & Treatment
• MedlinePlus Medical Encyclopedia: Arrhythmias
• American Heart Association: What Is an Arrhythmia?
• StatPearls (NCBI Bookshelf): Arrhythmias
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• PMC: Effect of Crataegus Usage in Cardiovascular Disease Prevention: An Evidence-Based Approach
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• PMC: Vitamin D in Cardiovascular Medicine: From Molecular Mechanisms to Clinical Translation
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