What is Atrial Fibrillation and How Does it Increase Stroke Risk?

Atrial fibrillation (AF) is a common condition I often encounter in my clinical practice and affects millions worldwide. Surprisingly, many patients may not show symptoms, and your healthcare provider may incidentally make the diagnosis during a routine pulse check, electrocardiogram (ECG), or heart monitor assessment. Let’s have a look at this arrhythmia in some detail.


When you palpate the pulse in someone with AF, you’ll notice that it’s “irregularly irregular,” reflecting the unpredictable timing of the heartbeats caused by the irregular electrical activity within the heart.


What is Atrial Fibrillation?

Atrial fibrillation (AF) is a heart condition characterized by irregular and often rapid heartbeats. In contrast to the normal sinus rhythm, where the heart’s electrical signals follow a coordinated pattern, AF involves erratic electrical impulses that originate from various areas around the atria, the heart’s upper chambers. These disorganized signals can disrupt the heart’s natural rhythm and coordination, leading to an irregular heartbeat. When you palpate the pulse in someone with AF, you’ll notice that it’s “irregularly irregular,” reflecting the unpredictable timing of the heartbeats caused by the irregular electrical activity within the atria.


In atrial fibrillation, rather than electrical stimuli coming only from the sinus node (I like to call this the power station of our heart), activity arises from areas around the heart’s top two chambers, the right and left atria. From there, multiple signals travel down to the ventricles to make the heart beat irregularly and often fast.



Symptoms of AF can vary widely, ranging from mild to more pronounced. Some individuals might not experience noticeable symptoms, while others may have a heightened awareness of their irregular heartbeat. Common symptoms include:

  • Palpitations: Sensation of rapid, fluttering, or irregular heartbeats.
  • Fatigue: Unexplained tiredness or lack of energy.
  • Dizziness or lightheadedness.
  • Shortness of breath, especially during physical activity or exertion.
  • Chest discomfort or pain.
  • Fainting or near-fainting spells (syncope).

It’s important to note that symptoms can be intermittent and occasionally challenging to detect. If you suspect you might be experiencing symptoms of AF, seeking medical evaluation is crucial for accurate diagnosis and appropriate management.


Causes of Atrial Fibrillation

AF can arise from a diverse array of factors, including:

  • Age: Advanced age is a common risk factor, with AF becoming more prevalent as people age.
  • Genetics: Family history can play a role, as individuals with a family history of AF may be at a higher risk.
  • High Blood Pressure: Hypertension can strain the heart and increase the likelihood of irregular heart rhythms.
  • Certain Medical Conditions: Underlying heart conditions, such as coronary artery disease, heart valve disorders, congenital heart issues, and heart failure, can contribute to AF.
  • Lifestyle Factors: Choices such as smoking, excessive alcohol consumption, and the use of recreational drugs can trigger or exacerbate AF.
  • Obstructive Sleep Apnea: This condition, characterized by interrupted breathing during sleep, can strain the heart and lead to AF.
  • Following heart surgery: Stress due to heart surgery can sometimes trigger AF.
  • Other Chronic Conditions: Chronic lung diseases, thyroid disorders, and diabetes can also increase the risk of AF.

Recognizing this intricate interplay of factors is essential in understanding the origins of AF and devising appropriate strategies for its management.


Stroke Risk and Atrial Fibrillation

Many patients who lack apparent AF symptoms are often taken aback by the realization that they are at a notable risk of experiencing a stroke. Let’s delve deeper into this association to gain a better understanding.

Individuals with AF are at a higher risk of stroke than those without the condition. This elevated risk stems from AF’s propensity to encourage the development of blood clots within the heart. These clots can then travel to the brain, potentially causing a stroke. The irregular contraction of the heart chambers and the enlargement of the atria contribute to this phenomenon. Specifically, clots might conceal themselves in a section known as the left atrial appendage. From here, a clot can dislodge and embark on a journey to the brain, posing a stroke risk.

Reducing this risk involves effectively managing underlying medical conditions like high blood pressure, diabetes, obstructive sleep apnea, and maintaining a health-conscious lifestyle. Particularly crucial is reducing alcohol consumption, as there is a clear association here.

Thankfully, effective interventions are available to minimize the stroke risk in individuals with AF, and one such strategy is anticoagulation therapy. However, it’s essential to acknowledge that each AF patient’s situation is unique, necessitating a personalized approach to decisions about anticoagulation. To aid clinicians in making these decisions, the CHA2DS2-VASc score is a valuable tool, offering guidance tailored to individual circumstances.

The elevated risk of stroke stems from AF’s propensity to encourage the development of blood clots within the heart. These clots can then travel to the brain, potentially causing a stroke. The irregular contraction of the heart chambers and the enlargement of the atria contribute to this phenomenon. In particular, clots might conceal themselves in a section known as the left atrial appendage. From here, a clot can dislodge and embark on a journey to the brain, posing a stroke risk.


In fact, we frequently have patients attending the Emergency Department in the early hours of a weekend having had solid drinking sessions who feel average and are in fast atrial fibrillation.


The CHA2DS2-VASc score

The CHA2DS2-VASc score is a valuable risk assessment tool, aiding in predicting stroke risk in individuals with AF. It considers several clinical factors, including age, sex, history of heart failure, hypertension, diabetes, prior stroke or transient ischemic attack (TIA), and vascular disease. This comprehensive evaluation assigns points for each factor, where a higher score signifies an elevated stroke risk with AF.

Ranging from 0 to 9, the CHA2DS2-VASc score provides a clear gradient of risk, with higher scores correlating to an increased likelihood of stroke. Patients with a score of 0 are typically categorized as low-risk and may not necessitate anticoagulation therapy. Those with a score of 1 fall into the moderate-risk category and might benefit from anticoagulation, factoring in other considerations like bleeding risk. Individuals with a score of 2 or more are deemed high-risk and are recommended for anticoagulation.

In conjunction with lifestyle modifications, medications play a pivotal role in reducing stroke risk among individuals with AF. Anticoagulants play a preventive role by inhibiting the formation of blood clots, while antiarrhythmic drugs contribute to controlling heart rate. Engaging in an open discussion with your doctor is essential to determine the optimal treatment plan tailored to your needs and circumstances.


The CHA2DS2-VASc score provides a systematic way to assess stroke risk in AF patients, assigning points based on these factors and helping guide decisions about anticoagulation therapy.

The factors considered as part of the CHA2DS2-VASc score: 

  • Congestive heart failure or left ventricular dysfunction (1 point)
  • Hypertension (1 point)
  • Age 75 years or older (2 points)
  • Diabetes mellitus (1 point)
  • Stroke, transient ischemic attack (TIA), or thromboembolism history (2 points)
  • Vascular disease (prior myocardial infarction, peripheral artery disease, or aortic plaque) (1 point)
  • Age 65 to 74 years (1 point)
  • Sex category (female gender) (1 point)


CHA2DS2-VASc Score Stroke Risk Category Anticoagulation Recommendation
0 Low-risk May not require anticoagulation therapy
1 Moderate-risk Consider anticoagulation, based on bleeding risk
2 or more High-risk Recommended for anticoagulation


What is the risk of stroke with atrial fibrillation?

The CHA2DS2-VASc Score has been validated across 90 490 patients throughout follow-up, and, as expected, the higher the score and risk factors someone has together with atrial fibrillation, the higher the risk of stroke or thromboembolism.


CHA₂DS₂-VASc Score

Risk of ischemic stroke

Risk of stroke/TIA/systemic embolism

































Reducing Stroke Risk with AF: Warfarin & DOACs

If your doctor has determined your risk of developing a clot and subsequent stroke, they will recommend a medicine to prevent clot formation. Traditionally, warfarin has been employed for this purpose due to its ability to inhibit vitamin K-dependent clotting factors. However, warfarin comes with complexities that demand close monitoring of the International Normalized Ratio (INR), interactions with specific medications, and dietary restrictions to maintain its effectiveness.

What is Atrial Fibrillation and How Does it Increase Stroke Risk? Heart Matters

In my practice, I tend to transition patients over to Direct Oral Anticoagulants (DOACs) if they are on warfarin or use this class of medicine upfront if initiating anticoagulant therapy for those at risk with AF. Their advantages over warfarin include a more predictable dosing regimen and reduced interactions with food and other drugs.

Direct Oral Anticoagulants (DOACs) are a modern and practical approach to reducing stroke risk in patients with atrial fibrillation. These medications, also known as novel oral anticoagulants (NOACs), have simplified the landscape of anticoagulation therapy. Notable DOACs currently in clinical use include:

  1. Dabigatran etexilate (Pradaxa)
  2. Rivaroxaban (Xarelto)
  3. Apixaban (Eliquis)
  4. Edoxaban (Savaysa, Lixiana)

Unlike traditional warfarin, DOACs selectively target specific clotting factors, offering more predictable dosing regimens and fewer interactions with other medications and food. Their convenience and efficacy have made them a valuable alternative for patients seeking optimal stroke prevention while minimizing the complexities associated with traditional anticoagulation therapy.

It’s essential to recognize that deciding to switch therapies is always a collaborative effort between patients and their healthcare teams, ensuring a well-informed and tailored approach to stroke prevention in AF patients.


In summary, AF is a common heart rhythm disorder marked by rapid, irregular heartbeat. Symptoms like palpitations, dizziness, or breathlessness may occur, often unnoticed. Irregular electrical signals in the heart’s upper chambers cause AF. It heightens the risk of heart-clot formation, leading to strokes, underscoring stroke prevention’s vital role. Healthcare providers assess risks using tools like the CHA2DS2-VASc score. Direct Oral Anticoagulants (DOACs) emerge as a revolutionary solution, targeting clotting factors for streamlined stroke prevention, excelling over warfarin. Collaboration between patients and healthcare teams remains paramount for tailored strategies in AF management, addressing symptoms, and mitigating stroke risk.


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other anti-anginals

When first-line therapies for angina, such as beta blockers, calcium channel blockers, and nitrates, prove inadequate or are not well-tolerated, second-line therapies may be considered.
Perhexiline is a unique medication that enhances the heart's ability to utilize fatty acids for energy, reducing its reliance on oxygen and lowering oxygen demand. This action helps improve blood flow and alleviates chest pain in some patients with refractory angina.
Nicorandil is another second-line option with a dual mechanism of action. It opens potassium channels in smooth muscle cells, causing vasodilation and enhancing coronary blood flow. Additionally, nicorandil also stimulates nitric oxide release, further dilating blood vessels and reducing heart workload.
Trimetazidine is an anti-ischemic agent that improves cardiac efficiency by enhancing glucose metabolism and shifting the heart's energy production to a more oxygen-efficient process. As second-line therapies, these medications offer alternative approaches for managing angina in individuals who do not respond adequately to first-line treatments or those experiencing side effects from other medications.

lipid lowering therapies

Lipid-lowering therapies play a critical role in managing coronary artery disease (CAD), a condition characterized by the narrowing of blood vessels that supply the heart. Among the most commonly discussed and debated classes of medications are statins, which effectively reduce cholesterol levels and are widely prescribed to lower the risk of cardiovascular events. Alongside statins, other medications like ezetimibe, fibrates, and niacin are also utilized to target specific aspects of lipid metabolism, such as cholesterol absorption, triglyceride levels, and raising high-density lipoprotein (HDL) cholesterol. Additionally, the introduction of medications that inhibit PCSK9, an enzyme involved in cholesterol metabolism, has provided a promising new approach to further lower LDL cholesterol levels. These PCSK9 inhibitors, such as Repatha (evolocumab), have shown significant efficacy in reducing LDL cholesterol levels in patients with CAD, especially for those who may not respond well to traditional therapies.


Nitrates are widely used to treat angina and provide quick relief for chest pain. Commonly available in the form of sublingual sprays or tablets, patches, and long-acting tablets, nitrates work by dilating blood vessels, allowing for increased blood flow and reduced resistance. This dilation eases the heart's workload, leading to a decreased demand for oxygen and prompt alleviation of angina symptoms. Sublingual nitrates act rapidly and are often used to provide immediate relief during angina attacks, while patches and long-acting tablets are employed for preventive purposes. However, nitrates may cause side effects such as headaches, dizziness, and flushing, which usually subside over time.

calcium channel blockers

Calcium channel blockers, including amlodipine, felodipine, cardizem (diltiazem), and verapamil, are commonly prescribed for the treatment of angina. These medications work by inhibiting the influx of calcium into the muscle cells of the heart and blood vessels, leading to their relaxation. As a result, blood vessels widen, promoting improved blood flow and reduced blood pressure. In the context of angina, this relaxation decreases the heart's workload, lowering the demand for oxygen and alleviating chest pain. Calcium channel blockers offer a valuable treatment option for individuals with angina, but it is essential to be aware of potential side effects, which may include headaches, dizziness, flushing, and ankle swelling.

Beta blockers

Beta blockers, such as metoprolol, propranolol, atenolol, carvedilol, and bisoprolol, play a crucial role in treating angina. By blocking certain receptors in the heart, they effectively reduce heart rate and the force of contraction, thereby easing the heart's workload. This mechanism of action leads to a decreased demand for oxygen, making beta blockers highly effective in relieving chest pain associated with angina. As with any medication, it's important to consider potential side effects, including tiredness, worsened asthma, erectile dysfunction in some males, and more vivid dreams during sleep. Consult your healthcare provider to determine the suitability of beta blockers for managing your angina and overall heart health.

Anti-platelet Medications

Anti-platelet medications play a crucial role in preventing blood clot formation, reducing the risk of serious cardiovascular events such as heart attacks and strokes. Among the widely used anti-platelet drugs are aspirin, clopidogrel, and ticagrelor.

Aspirin: This well-known medication inhibits platelet activation, making it less likely for platelets to stick together and form clots. Aspirin is commonly used for primary and secondary prevention of heart attacks and strokes.

Clopidogrel: As a potent anti-platelet agent, clopidogrel works by blocking specific receptors on platelets, preventing them from aggregating. It is often prescribed to patients with acute coronary syndrome, those undergoing stent procedures, and for some cases of peripheral arterial disease.

Ticagrelor: Ticagrelor is another effective anti-platelet drug that works by inhibiting platelet activation. It is used in acute coronary syndrome, often given alongside aspirin to reduce the risk of heart-related events.