Understanding Afib: The Most Common Heart Rhythm Disorder

Atrial fibrillation, commonly called Afib, is the most common heart rhythm disorder. In Afib, the heart’s upper chambers (the atria) beat irregularly and often too quickly, which causes them to lose coordination with the lower chambers (the ventricles). This disrupts normal blood flow through the heart and increases the risk of stroke and heart failure. As the global population ages, Afib is becoming more common, making it an increasingly important public health concern.

This overview of Afib and its many aspects is largely based on the most recent clinical guidelines for Afib management published by the European Society of Cardiology (2024) and by the American Heart Association/American College of Cardiology  (2023).

While both provide valuable guidance:

• The 2024 European guidelines emphasize a more holistic and patient-centered approach, including lifestyle changes and the management of other health conditions alongside Afib. 

• The 2023 US guidelines focus more on established diagnostic assessments and standard treatment strategies in a structured, task-oriented framework.

Both guidelines are valuable resources for anyone who wants a deeper understanding of Afib and how it can be managed.

Quick facts:

• The incidence and prevalence of atrial fibrillation are rising globally.

• In 2016, the Global Burden of Disease project estimated that about 46.3 million people worldwide had Afib.

• Afib is associated with a five-fold increase in risk of stroke.

How Afib develops 

Afib is a rapid, irregular heart rhythm that starts in the atria, the heart’s upper chambers. Unlike a normal heartbeat, which follows smooth and coordinated electrical signals initiated by the sinoatrial node (the heart’s natural pacemaker), Afib develops when these electrical signals are generated or conducted in a disorganized way.

This disruption is often linked to structural changes in the atrial tissue and altered connections between heart cells, which interfere with the normal flow of electrical impulses.

Afib can start with abnormal electrical impulses, called ectopic beats, that often originate in the pulmonary veins of the left atrium. In addition, changes in the atrial tissue itself can create a vulnerable “substrate” that disrupts how electrical signals travel through the heart.

While a few isolated ectopic beats may cause short episodes of irregular heart rhythm, sustained Afib usually requires a larger or more irregular substrate that allows these abnormal signals to keep circulating within the atria.

What makes Afib more likely?

In Afib, the heart’s electrical system in the upper chambers (atria) changes in ways that make irregular rhythms more likely. Problems with how calcium and tiny “electrical gates” (ion-channels) in heart cells work can shorten the time the heart needs to recover between beats, making it easier for chaotic signals to start.

Changes in the “connection points” between heart cells slow down and break up the electrical signals as they travel. These changes can be influenced by things like genetics, inflammation, getting older, and health issues such as sleep apnea, together making Afib more likely to stick around.

As we age or develop health problems, such as hypertension, obesity and diabetes, the atria can become less efficient and may suffer small amounts of damage, called atrial cardiomyopathy. Atrial damage may include fibrosis (build-up of scar tissue), fat deposits, and inflammation. This affects how the heart’s electrical signals are made and passed along.

Changes in how heart cells handle calcium and how they connect to each other can make signals travel more slowly or break apart. This creates the perfect conditions for the heart’s rhythm to become irregular, which can lead to Afib. Conditions causing increased atrial pressure or volume, such as heart valve disease, can worsen remodeling and Afib risk.

Inflammation in the body, long-term stress on the heart (oxidative stress), and certain hormone systems (such as the renin–angiotensin–aldosterone system, which helps regulate blood pressure) can gradually change the structure and function of the heart’s upper chambers. Over time, these changes make it easier for Afib to start and continue. Keeping blood pressure, weight, and blood sugar under control can help reduce this strain on the heart and lower the risk.

The autonomic nervous system influences both the initiation and maintenance of Afib. Sympathetic and parasympathetic nervous system activity can trigger Afib by influencing how the heart’s electrical system behaves. The sympathetic system, which drives your “fight-or-flight” response, increases heart rate and excitability, while the parasympathetic system, which regulates your “rest-and-digest” functions, slows heart rate and shortens recovery time between beats. Both affect ion channel function and the refractory period, creating conditions that can promote Afib. Afib itself can disrupt autonomic regulation, creating a feedback loop that sustains the arrhythmia.

Afib has a heritable component. Both common and rare genetic variants affecting heart structure, ion channels and electrical function contribute to Afib, especially in younger individuals.

Why Afib persists 

Once Afib manifests, changes in the atria can allow it to continue – even without a clear trigger. Research using detailed electrical mapping in patients with Afib has identified two key mechanisms that help sustain the arrhythmia:

1. Fragmented electrical signals
In damaged atrial tissue, electrical signals often encounter areas where conduction is temporarily blocked or uneven. This causes the electrical waves to break apart into smaller, fragmented waves that move chaotically through the atria. These wandering wavelets constantly shift their location and direction, fueling the irregular heart rhythm seen in Afib.

2. Disrupted signal layers
Beyond surface conduction issues, new electrical waves sometimes suddenly appear on the outer surface of the atria, called the epicardium. These epicardial breakthroughs indicate that the electrical activity in the outer and inner layers of the atrial wall is not synchronized, or that signals travel through complex three-dimensional pathways within the thickened atrial tissue. 

These processes vary between individuals, depending on risk factors such as genetics or underlying diseases like heart failure. This is why Afib looks different for everyone.

Afib symptoms

Afib presents with a wide range of symptoms that go beyond the classic feeling of a racing heart. While nearly 90% of people with Afib experience symptoms, some episodes can go unnoticed. The presence or absence of symptoms doesn’t predict the risk of stroke or death, but it plays a major role in how patients feel day-to-day. In fact, non-specific symptoms like fatigue are more common than heart-related ones like palpitations. Women with Afib tend to report more symptoms and a greater impact on their quality of life. Afib is also linked to higher rates of anxiety and depression, particularly in women. 

Common Afib-related symptoms include 

• Fatigue or low energy

• Shortness of breath (especially during exertion)

• Palpitations (irregular or rapid heartbeat)

• Light-headedness or dizziness

• Chest discomfort or pain

• Reduced exercise capacity

• Anxiety or a sense of unease

• Sleep disturbances
  
  

These symptoms may vary over time and can sometimes be caused by other coexisting health conditions rather than Afib itself.

Living with Afib symptoms can be unpredictable, exhausting and frustrating. But the good news? You can take control. By logging and tracking your symptoms, you can monitor how Afib affects your quality of life and uncover patterns that help you manage it better.

Types of Afib

Afib is not a one-size-fits-all condition and its diagnosis can be tricky due to its progressive evolution. Below is an outline of the ESC 2024 clinical guidelines for diagnosing Afib stage. Afib progression can be split into four different stages: 

Afib that has not been identified previously, regardless of symptoms, temporal pattern, or duration.

Afib that ends spontaneously within 7 days or with the help of an intervention. Most self-terminating episodes last less than 48 hours.

Afib episodes that do not end on their own. Many clinical studies use 7 days as the cut-off to define persistent Afib. Long-standing persistent Afib is defined as continuous Afib lasting at least 12 months, where rhythm control is still a possible treatment option, which distinguishes it from permanent Afib.

Afib where no further attempts to restore sinus rhythm are planned, following a shared decision between patient and physician.

Common risk factors

What puts you at risk for developing Afib? In the CHARGE-AF model, several clinical and demographic characteristics were found to significantly influence the five-year risk of developing Afib. 

Age, race, body size, blood pressure, smoking status, diabetes, and a history of myocardial infarction all contributed to elevated Afib risk. Notably, age and white race were among the strongest predictors, while higher diastolic blood pressure was associated with a reduced risk.

Key risk factors include: 

• Age: Every additional 5 years increases Afib risk by 66%.

• Race: People of European descent are 59% more likely to develop Afib than non-white individuals.

• Height: Every 10 cm (about 4 inches) of added height increases risk by 28%.

• Weight: Every 15 kg (about 33 pounds) increases risk by 12%.

• Systolic blood pressure: Every 20 mm Hg increase raises risk by 22%.

• Diastolic blood pressure: Every 10 mm Hg increase actually reduces risk by 10%.

• Smoking: Current smokers are 42% more likely to develop Afib than former or never smokers.

• Diabetes: People with diabetes are more likely to develop Afib 

• Heart attack history: Those with a previous myocardial infarction are 64% more likely to develop Afib.

While risk factors increase the risk of developing Afib, what actually triggers Afib for individuals can change from person to person. To find out more about what can trigger an Afib episode, you can read about commonly reported triggers here. 

Treatment at a glance

Afib treatment focuses on three main goals:

• Rate & rhythm control
• Stroke prevention
• Personalized care

Rhythm control is achieved through antiarrhythmic medications, cardioversion (electrical or pharmacological), and catheter ablation, tailored to individual patient risk and disease stage.

Stroke prevention with anticoagulation with direct oral anticoagulants (DOACs) is preferred over warfarin to reduce stroke, mortality, and bleeding risks.

Risk assessment is also very important in order to evaluate what kind of treatment is needed. Stroke risk scores like CHA₂DS₂-VA guide anticoagulation decisions, with treatment recommended for higher-risk patients.

Treatment should not follow the ‘one size fits all’ approach. Treatment should instead be tailored to each person’s individual needs. 

You can find a more in-depth breakdown of treatment recommendations in the European and American guidelines.

Self-management: what you can do

Risk factors for Afib are made up of unmodifiable risk factors such as age and race but also modifiable risk factors such as physical inactivity, weight and alcohol consumption. Managing these modifiable risk factors through lifestyle changes can be a powerful tool in potentially reducing your risk of Afib. The American Heart Association recommends focusing on the following lifestyle changes: 

Weight management

Obesity is one of the strongest lifestyle-related drivers of Afib. Excess weight causes changes to the structure and function of the atria, increasing the likelihood of rhythm disturbances.

• A target of at least 10 percent weight loss has been shown to significantly reduce Afib symptoms, recurrence, and progression.

• Weight loss also improves outcomes after catheter ablation procedures and is associated with better maintenance of normal heart rhythm.

Structured programs that include dietary counseling, exercise, and regular monitoring are more effective than self-directed attempts at weight loss so it is important to consult with your medical professional when making major lifestyle changes.

Physical activity

Regular exercise improves heart health and reduces Afib burden. 

• Moderate to vigorous aerobic activity for a total of 210 minutes per week is recommended.

• Exercise can reduce Afib episodes and improve functional capacity, particularly in individuals with paroxysmal Afib.

• High-volume endurance training (more than three hours per day) has been associated with increased Afib risk in some studies, particularly in men, suggesting that moderation is key.

Those with existing Afib should tailor exercise intensity based on other health conditions and consult with healthcare providers to ensure appropriate heart rate control during activity.

Alcohol consumption

Alcohol affects the heart’s electrical system and increases Afib risk in a dose-dependent manner. Binge drinking, in particular, is a well-established trigger. Reducing alcohol intake can lower Afib recurrence and prevent progression from intermittent to persistent Afib. Randomized trials show that even reducing intake to fewer than three drinks per week can significantly decrease Afib burden.

Smoking cessation

Cigarette smoking is independently associated with a higher risk of developing Afib and worse cardiovascular outcomes in those already diagnosed. Smoking cessation reduces the risk of stroke, heart failure, hospitalization, and death among individuals with Afib.

Diet 

There is growing interest in the role of diet in Afib prevention, although clear recommendations are still evolving. Heart-healthy diets, such as the Mediterranean or DASH diets, are associated with better cardiovascular outcomes and may help reduce Afib risk. Low-carbohydrate diets have been associated with an increased risk of developing Afib , regardless of the source of fat or protein used as a substitute.

Dietary approaches should focus on whole foods, reduction of processed items, and balanced macronutrient intake, rather than reliance on supplements or restrictive patterns. Read more about diet and Afib here.

How MyAfib can help

Afib doesn’t look the same for everyone – and your experience matters. 

MyAfib is designed to help you track your experiences and turn them into insights. By logging symptoms, daily habits, triggers and treatments, you and your healthcare team can spot patterns and understand what may trigger your Afib.

With these insights, you can make more informed decisions about lifestyle changes and treatments. MyAfib takes complex heart information and turns it into simple, actionable guidance, helping you take control of your heart health.

As the global burden of Afib rises, empowering people with the tools to manage their own condition becomes not only a personal priority but a public health necessity. Better insights lead to better conversations, better decisions – and ultimately, better care for everyone.