
A people with Atrial Fibrillation (AFib) are five times more likely to have a stroke. This is a big reason why knowing the signs of AFib is so important.
AFib is a heart problem that makes your heart beat irregularly and fast. It’s key to know the symptoms of AFib to get help quickly. So, what’s AFib like? It can feel different for everyone, but common signs are palpitations, shortness of breath, and feeling very tired.
Key Takeaways
- AFib significantly increases the risk of stroke.
- Common symptoms include palpitations and shortness of breath.
- Recognizing AFib signs is key for getting medical help fast.
- Understanding AFib helps people take care of their heart health.
- Checking for arrhythmia at home is a good way to start diagnosing.
Understanding Arrhythmia and Atrial Fibrillation

Atrial fibrillation (AFib) is a common serious heart rhythm problem. It affects the heart’s upper chambers, causing irregular beats. Knowing what arrhythmia is and how it affects the heart is key to understanding AFib.
What is an Arrhythmia?
An arrhythmia is when the heart beats irregularly, too fast, too slow, or in an odd rhythm. This happens when the heart’s electrical system gets disrupted. Arrhythmias can be mild or life-threatening, depending on their cause and how severe they are.
The heart’s electrical system is complex. It involves many pathways and nodes that control the heartbeat. When this system is disrupted, irregular heartbeats can occur. Knowing the cause of an arrhythmia is important for finding the right treatment.
What is Atrial Fibrillation (AFib)?
Atrial fibrillation is a specific arrhythmia with rapid and irregular heartbeats. It happens when the heart’s upper chambers (atria) beat chaotically and out of sync with the lower chambers (ventricles). This can cause symptoms like heart palpitations, shortness of breath, and fatigue.
AFib is serious because it raises the risk of stroke, heart failure, and other heart problems. Early detection and management of AFib are key to preventing these issues.
“Atrial fibrillation is a significant risk factor for stroke, and managing AFib is critical for reducing this risk.” – American Heart Association
How Common is AFib?
Atrial fibrillation is the most common sustained cardiac arrhythmia, affecting millions globally. It becomes more common with age, affecting about 1 in 10 people over 75. High blood pressure, heart disease, and obesity can increase the risk of AFib.
|
Age Group |
Prevalence of AFib |
|---|---|
|
65-69 years |
3.7% |
|
70-74 years |
5.1% |
|
75-79 years |
7.3% |
|
80-84 years |
10.4% |
|
85+ years |
13.7% |
Knowing the prevalence and risk factors of AFib helps individuals take steps to keep their heart healthy.
What Does AFib Feel Like? Common Sensations Explained

Atrial fibrillation, or AFib, can feel different for everyone. Yet, many people share common sensations. Knowing these can help spot AFib symptoms early.
AFib symptoms include palpitations, shortness of breath, and fatigue. Dizziness and feeling light-headed are also common. Spotting these signs is the first step to managing AFib.
Heart Palpitations and Racing Heart
Heart palpitations are a common AFib symptom. It feels like your heart is racing, pounding, or fluttering. This happens because AFib makes your heart beat irregularly and too fast.
This irregular heartbeat can make you feel anxious or uneasy. It’s a sign that something’s not right with your heart.
Chest Discomfort or Pain
Some people with AFib feel chest discomfort or pain. This can be a mild ache or a sharp, stabbing feeling. Chest pain in AFib is not always present but should be checked by a doctor.
It’s important to seek medical help if you have chest pain. This ensures you’re not dealing with a more serious condition.
Shortness of Breath
AFib can cause shortness of breath. This happens even when you’re resting or doing light activities. It’s because your heart isn’t pumping well, reducing oxygen to your body.
Fatigue and Weakness
Fatigue and weakness are common in AFib. The irregular heartbeat and poor heart pumping make you tired. Simple tasks can feel like a big challenge.
Knowing these common AFib sensations is key to early detection and management. If you notice any of these symptoms, see a doctor right away.
Signs and Symptoms of AFib You Shouldn’t Ignore
It’s important to know the signs and symptoms of AFib to get the right medical care. Atrial fibrillation shows up differently in everyone. Knowing how it can appear is key.
Obvious Symptoms vs. Silent AFib
Some people with AFib have clear symptoms, while others have silent AFib with no symptoms at all. Symptoms like heart palpitations, shortness of breath, and fatigue are common. Silent AFib is dangerous because it’s hard to find without a doctor’s check-up.
Key differences between obvious symptoms and silent AFib:
- Obvious symptoms are noticeable and can be distressing.
- Silent AFib lacks noticeable symptoms, making it harder to diagnose without medical screening.
Duration and Frequency of Symptoms
The time and how often AFib symptoms show up can differ a lot. Some people have symptoms all the time, while others have them in episodes. Knowing your symptom pattern helps manage AFib better.
Tracking symptom duration and frequency:
|
Symptom Pattern |
Description |
|---|---|
|
Persistent |
Symptoms are continuous and ongoing. |
|
Paroxysmal |
Symptoms occur in episodes that start and stop suddenly. |
Symptom Severity Scale
A symptom severity scale helps understand and talk about AFib symptoms. It shows how symptoms affect daily life.
Symptom Severity Scale:
|
Severity Level |
Description |
|---|---|
|
Mild |
Symptoms are noticeable but do not interfere with daily activities. |
|
Moderate |
Symptoms cause some discomfort and may interfere with daily activities. |
|
Severe |
Symptoms are significantly distressing and substantially interfere with daily activities. |
AFib Heart Rate: What’s Normal and What’s Not
Atrial fibrillation (AFib) can change heart rate a lot. It’s key to know what’s normal and what’s not. AFib makes the heart beat irregularly and fast, causing symptoms and problems. Knowing how AFib affects heart rate helps manage and treat it better.
What is a Normal Heart Rate for Someone with AFib?
A normal heart rate is 60 to 100 beats per minute. But for those with AFib, it’s often irregular and fast. A normal heart rate for AFib patients is usually under 100 beats per minute at rest.
It’s important for AFib patients to talk to their doctor. They need to find a heart rate range that’s safe and right for them.
Rapid vs. Controlled AFib
AFib can be different for everyone. Some people have a fast heart rate, over 100 beats per minute. Others have a controlled AFib, where the heart rate is kept normal with treatment.
Rapid AFib can cause symptoms like palpitations and shortness of breath. Controlled AFib tries to reduce these symptoms and improve life quality.
Heart Rate Variability in AFib
Heart rate variability (HRV) is the change in time between heartbeats. It shows how well the heart adapts to stress. In AFib, HRV is usually lower because of the irregular rhythm.
Watching HRV can help understand heart function and health. It guides treatment and lifestyle changes.
Differentiating AFib from Anxiety Symptoms
It’s important to know the difference between AFib and anxiety symptoms. Many people have symptoms that could be from either. So, it’s key to tell them apart.
Similar Physical Sensations
AFib and anxiety can both cause heart palpitations, shortness of breath, and feeling uneasy. A fast or irregular heartbeat can be from AFib or anxiety. It’s vital to watch these symptoms closely to figure out why they happen.
Key Differences to Watch For
Even though symptoms can be similar, there are important differences. AFib often has more serious and lasting heart rhythm problems. Anxiety symptoms can change based on the situation.
Keeping a symptom journal helps track when symptoms happen and what might cause them. This gives doctors useful information.
When Anxiety Triggers AFib
Anxiety and AFib have a complex relationship. Anxiety can make AFib worse or start it. Stress and anxiety can mess with heart rate and make AFib symptoms worse. Managing anxiety is key to controlling AFib.
Knowing the difference between AFib and anxiety symptoms helps people deal with their health better. They can work with doctors to find the best way to manage their condition.
Risk Factors for Developing Atrial Fibrillation
Knowing the risk factors is key to managing and preventing atrial fibrillation. Atrial fibrillation (AFib) is a complex condition. It is influenced by age, medical history, and lifestyle choices. Understanding these factors can help individuals take proactive steps towards maintaining heart health.
Age and Gender Considerations
Age is a significant risk factor for AFib. The risk of developing AFib increases with age, after 65. Men are generally at a higher risk than women, though women’s risk increases after menopause. We must consider these demographic factors when assessing overall risk.
Medical Conditions That Increase Risk
Certain medical conditions can significantly increase the risk of developing AFib. These include:
- Hypertension (high blood pressure)
- Heart valve diseases
- Heart failure
- Diabetes
- Obesity
- Sleep apnea
Individuals with these conditions should be vigilant about monitoring their heart health. They should discuss their risk factors with their healthcare provider.
Lifestyle Factors That Contribute to AFib
Lifestyle choices also play a role in the risk of developing AFib. Factors such as smoking, excessive alcohol consumption, and lack of physical activity can contribute to AFib. Maintaining a healthy lifestyle, including a balanced diet and regular exercise, can help mitigate some of these risks.
People with AFib are five times more likely to have a stroke than the general population. This statistic highlights the importance of understanding and managing AFib risk factors.
|
Risk Factor Category |
Specific Factors |
|---|---|
|
Age and Gender |
Age over 65, Male gender |
|
Medical Conditions |
Hypertension, Heart valve diseases, Heart failure, Diabetes, Obesity, Sleep apnea |
|
Lifestyle Factors |
Smoking, Excessive alcohol consumption, Lack of physical activity |
By understanding and addressing these risk factors, individuals can reduce their likelihood of developing AFib and its associated complications.
Home Methods for Checking Your Heart Rhythm
You can help keep your heart healthy by checking it at home. Checking your pulse can help find and treat AFib. This could stop many of the 80,000 AFib-related strokes each year. There are many ways to do this, from simple manual checks to using advanced technology.
Manual Pulse Check Technique
One easy way to check your heart rhythm at home is by manually checking your pulse. Find your pulse on your wrist or neck. Place your fingers on the pulse point and count the beats for 15 seconds. Then, multiply that number by four to find your heart rate per minute.
It’s important to sit calmly and avoid hard activity before checking your pulse. This helps get an accurate reading.
A normal heart rate is between 60 to 100 beats per minute. If your heart rate is too high or too low, or if it’s not steady, see your doctor.
Smartphone Apps for Heart Rhythm Monitoring
There are many smartphone apps to monitor your heart rhythm. These apps can spot irregular heartbeats, including AFib. Some can even make an ECG tracing. Look for apps that are FDA-cleared and have good reviews.
Some apps use the phone’s camera to find pulse problems. Others connect to external ECG monitors. While these apps are helpful, don’t rely on them alone for a medical diagnosis.
Consumer Heart Rate Monitors
Heart rate monitors used during exercise can also find irregular heartbeats. Some devices can alert you to an irregular heartbeat, telling you to see a doctor.
When picking a heart rate monitor, choose ones that are clinically tested for accuracy. Look for devices with extra features like ECG monitoring or alerts for irregular rhythms.
May not be as accurate as medical-grade devices
|
Method |
Advantages |
Limitations |
|---|---|---|
|
Manual Pulse Check |
Simple, cost-effective, no equipment needed |
May not detect all irregularities, requires manual counting |
|
Smartphone Apps |
Convenient, can detect AFib, some offer ECG tracing |
Accuracy varies, not all apps are FDA-cleared |
|
Consumer Heart Rate Monitors |
Can detect irregular heartbeats, useful during exercise |
Wearable Technology for AFib Detection
Wearable technology has changed how we find and manage Atrial Fibrillation (AFib). These devices let us monitor our hearts all the time. They catch AFib episodes and give important data to both patients and doctors.
Smartwatches with ECG Capability
Smartwatches with ECG are now common for checking heart rhythms. They can record a single-lead electrocardiogram. This lets users spot irregular heartbeats that might mean AFib. Key features to look for include:
- ECG recording capability
- Notification for irregular heart rhythms
- Data storage for tracking over time
Dedicated Heart Monitoring Devices
Dedicated heart monitoring devices are made just for finding and watching heart arrhythmias, like AFib. They are usually more precise than smartwatches. They give more detailed info about heart rhythm.
Accuracy and Limitations of Wearable Devices
Wearable devices are great for finding AFib, but we must know their limits. Factors affecting accuracy include:
- Device quality and technology
- User compliance with wearing and charging the device
- Presence of other heart conditions
As wearable tech gets better, we’ll see better AFib detection and care. New monitoring tech and wearables could change how we find and treat heart and circulatory diseases in the future.
Home ECG Monitors: Options and Effectiveness
Portable ECG devices have changed how we monitor our heart health at home. These devices record the heart’s electrical activity. They give us insights into heart rhythm and function.
Single-Lead vs. Multi-Lead ECG Devices
Home ECG monitors are mainly single-lead or multi-lead. Single-lead devices record from one angle. Multi-lead devices give a more detailed view by recording from several angles.
Key differences between single-lead and multi-lead ECG devices:
|
Feature |
Single-Lead ECG |
Multi-Lead ECG |
|---|---|---|
|
Number of Leads |
1 |
3 or 12 |
|
Complexity of Use |
Simple, user-friendly |
More complex, may require professional guidance |
|
Information Provided |
Limited, basic heart rhythm information |
Detailed, complete heart activity data |
How to Use Home ECG Devices Correctly
To get accurate readings, follow the manufacturer’s instructions. This means placing electrodes on your chest or fingers and staying calm during the recording.
Here are some tips for using home ECG devices:
- Make sure your skin is clean and dry before applying electrodes.
- Follow the device’s instructions for where to place the electrodes.
- Stay calm and relaxed while recording.
- Record at the same time every day for consistent results.
Interpreting Home ECG Results
Understanding ECG results takes some knowledge. A normal tracing shows a steady pattern. Irregularities might mean arrhythmias or heart problems.
When looking at your ECG results, check for:
- How regular the heartbeat is
- If there are P waves before each QRS complex
- If the PR interval is consistent
If you’re not sure about your results or see any odd patterns, talk to your doctor.
Keeping a Symptom Journal: What to Track
For those with AFib, a symptom journal can be a big help. It lets you track your symptoms, find patterns, and spot triggers. This way, you can better manage your condition.
Important Symptoms to Document
It’s key to write down all symptoms related to AFib. These include:
- Heart palpitations or irregular heartbeats
- Chest discomfort or pain
- Shortness of breath
- Fatigue and weakness
- Dizziness or lightheadedness
Accurate documentation helps you and your doctor understand your AFib better.
Tracking Triggers and Patterns
It’s also good to track what might cause your symptoms. This includes:
- Activities or events that precede AFib episodes
- Dietary factors that may influence symptoms
- Stress levels and emotional states
- Sleep patterns and quality
Knowing these can help you make changes to lessen your AFib episodes.
Digital vs. Paper Tracking Methods
You can choose between digital or paper symptom journals. Digital tracking is easy with reminders and data analysis. It also lets you share your data with doctors. Paper-based tracking is more hands-on and doesn’t need tech.
Whether to use digital or paper depends on what you prefer. Some people like both for different needs.
Understanding Different Types of Arrhythmias at Home
Arrhythmias come in many forms, each needing its own care plan. Atrial fibrillation (AFib) is common, but there are others too. Knowing about these types is key to managing them at home.
How AFib Differs from Other Arrhythmias
AFib makes your heart beat irregularly and fast. It starts in the atria, unlike some other arrhythmias. This makes managing and treating it different.
Other arrhythmias like atrial flutter, supraventricular tachycardia (SVT), and ventricular tachycardia have their own traits. For example, atrial flutter has a more regular rhythm than AFib.
Premature Beats vs. Sustained Arrhythmias
Premature beats, or ectopic beats, are early heart signals. They can feel like skipped beats or palpitations. While occasional ones are fine, too many might mean a problem.
Sustained arrhythmias last longer, like AFib. Knowing if your arrhythmia is ongoing or not helps decide how to treat it.
Recognizing Potentially Dangerous Rhythms
Some arrhythmias are serious and need quick medical help. Ventricular fibrillation is one, as it can cause cardiac arrest.
Signs of danger include severe chest pain, shortness of breath, dizziness, or fainting. If you see these, get help right away.
|
Arrhythmia Type |
Characteristics |
Potential Risks |
|---|---|---|
|
Atrial Fibrillation (AFib) |
Irregular, often rapid heart rhythm originating in the atria |
Stroke, heart failure |
|
Atrial Flutter |
Regular atrial rhythm, often with a characteristic “sawtooth” pattern on ECG |
Similar to AFib, with risk of stroke and heart failure |
|
Ventricular Tachycardia |
Rapid heart rhythm originating in the ventricles |
Can degenerate into ventricular fibrillation, leading to cardiac arrest |
Knowing about arrhythmia types helps manage them at home. Working with your doctor is also vital for a good care plan.
When to Seek Emergency Medical Attention
Getting emergency medical help on time is key for AFib patients. Some symptoms can wait, but others need quick action. Knowing the difference helps manage the condition better.
Warning Signs That Require Immediate Care
Certain symptoms mean you need to see a doctor right away. These include:
- Severe chest pain or pressure
- Shortness of breath or trouble breathing
- Dizziness or fainting
- Rapid or irregular heartbeat
- Confusion or trouble speaking
If you or someone with you has these symptoms, call emergency services or get to a hospital fast.
Symptoms That Can Wait for a Regular Appointment
Some AFib symptoms are scary, but others can wait for a doctor’s visit. These might be mild palpitations, tiredness, or slight breathing trouble that doesn’t get worse. But, always talk to your doctor about these symptoms to figure out what to do next.
What to Tell Emergency Responders
When you call for emergency help, giving the right info is important. It helps responders and doctors act fast and right. Be ready to:
- Tell them about your symptoms and when they started
- Share the medicines you’re taking now
- Give your medical history, including heart problems
- Talk about what makes your AFib episodes happen
Being ready and informed means you get the care you need when you need it.
Discussing Your Home Monitoring with Healthcare Providers
Talking to your healthcare team about your home monitoring is key to managing AFib. Knowing your condition well helps you share your experiences. This lets your healthcare providers make better decisions for your care.
Preparing for Your Appointment
Before your appointment, organize your home monitoring data. This includes:
- Compiling your symptom journal entries
- Gathering data from your home ECG monitor or other devices
- Noting any changes in your symptoms or medication
Tip: Make a summary sheet with important info. This can help your healthcare provider understand your AFib better.
Sharing Your Symptom Journal Effectively
Your symptom journal is very helpful for your healthcare provider. When sharing it, focus on:
- Highlighting patterns or triggers you’ve identified
- Noting the severity and duration of your symptoms
- Correlating your symptoms with any lifestyle changes or medication adjustments
Example: “I’ve noticed that my AFib episodes tend to occur more frequently after consuming caffeine. I’ve tried to reduce my intake, and it seems to help.”
Questions to Ask Your Doctor
Coming prepared with questions is important. Some key questions to ask include:
- What do my home monitoring results indicate about my AFib management?
- Are there any adjustments needed in my treatment plan?
- How can I improve my home monitoring technique?
By working with your healthcare provider and sharing your data, you can improve your AFib management. Remember, your healthcare provider is there to help. Don’t be afraid to ask questions or clarify any concerns.
Lifestyle Modifications to Manage AFib at Home
Making lifestyle changes is key to controlling AFib symptoms and improving heart health. By changing our daily habits, we can manage our condition better.
Dietary Considerations for AFib Patients
Eating a balanced diet is vital for managing AFib. Eat more fruits, vegetables, and whole grains to keep your heart healthy. Try to eat less saturated fats, sodium, and sugar. Drink plenty of water to stay hydrated.
“A healthy diet is not just about avoiding certain foods, but also about incorporating nutrient-rich foods that support heart health,” says a leading cardiologist. Foods rich in omega-3 fatty acids, like salmon and walnuts, are very beneficial.
- Reduce caffeine and alcohol intake, as they can trigger AFib episodes.
- Limit consumption of processed and high-sodium foods.
- Increase intake of potassium-rich foods like bananas and avocados.
Exercise Recommendations and Limitations
Regular physical activity is vital for heart health. But, people with AFib should talk to their doctor before starting any new exercise. Moderate-intensity exercises like brisk walking, cycling, or swimming are recommended.
Avoid overexertion and listen to your body. If you feel dizzy or short of breath, stop and rest. Yoga and stretching exercises can also help improve flexibility and reduce stress.
- Start with low-intensity exercises and gradually increase intensity.
- Avoid extreme temperatures during exercise.
- Stay hydrated before, during, and after exercise.
Stress Management Techniques
Stress can make AFib symptoms worse, so managing stress is key. Techniques like meditation, deep breathing exercises, and progressive muscle relaxation can help reduce stress.
“Stress management is not a one-size-fits-all approach. It’s about finding what works best for you and incorporating it into your daily routine,” advises a stress management expert.
Doing hobbies, spending time with loved ones, and getting enough sleep are also important for managing stress and overall well-being.
The Psychological Impact of Living with AFib
Living with Atrial Fibrillation (AFib) is tough, both physically and mentally. It can really affect your mental health and how you feel overall.
Managing Fear and Anxiety
Fear and anxiety are big issues for people with AFib. The unpredictable nature of episodes can be very distressing. Here are some ways to handle these feelings:
- Education: Learning about AFib and how to manage it can help reduce fear.
- Relaxation Techniques: Deep breathing, meditation, and yoga can help lower anxiety.
- Support Groups: Joining groups with others who have AFib can offer emotional support and advice.
Building Confidence in Self-Monitoring
Self-monitoring is key in managing AFib. By checking your heart rhythm and keeping a symptom journal, you can better understand your condition. This helps you make informed decisions about your care.
|
Self-Monitoring Activity |
Benefits |
|---|---|
|
Regular Heart Rhythm Checks |
Early detection of AFib episodes, better understanding of triggers |
|
Symptom Journaling |
Identifying patterns, tracking symptom severity |
Support Resources for AFib Patients
Having the right support can greatly help in managing AFib. These include:
- Healthcare Providers: Regular check-ups and consultations offer reassurance and guidance.
- Online Communities: Forums and social media groups connect you with others who get what you’re going through.
- Educational Materials: Books, websites, and pamphlets provide valuable info on managing AFib.
By using these resources and strategies, people with AFib can manage the mental impact of their condition. This improves their overall quality of life.
Conclusion: Empowering Yourself Through Home Monitoring
Understanding Atrial Fibrillation (AFib) and managing it actively can lead to a healthier life. Home monitoring is key in managing AFib. It lets people track their heart rhythm and spot issues early.
We’ve looked at different ways to monitor at home, like manual pulse checks, smartphone apps, and wearable tech. These tools give valuable insights into heart health. They help people make better care choices.
Empowering yourself through home monitoring is more than just tech. It’s about a full approach to managing AFib. By monitoring at home, making lifestyle changes, and working with healthcare, people can manage their condition well. This improves their quality of life.
As medical technology advances, home monitoring’s role in AFib management will grow. Taking charge of heart health can lower the risk of complications. This leads to a more fulfilling life.
FAQ
What does AFib feel like?
AFib can feel like your heart is quivering or fluttering. You might also feel irregular or rapid heartbeats. Other symptoms include shortness of breath and feeling tired.
How can I check for arrhythmia at home?
To check for arrhythmia at home, you can use a manual pulse check. You can also use smartphone apps, heart rate monitors, or wearable devices with ECG.
What is a normal heart rate for someone with AFib?
A normal heart rate for someone with AFib is usually between 60-100 beats per minute. But, it can be higher when you’re in AFib.
Can anxiety trigger AFib?
Yes, anxiety can trigger AFib in some people. Stress and anxiety can cause irregular heartbeats and make AFib symptoms worse.
How often should I monitor my heart rhythm at home?
How often you should monitor your heart rhythm at home depends on your condition and your doctor’s advice. It’s often done daily or weekly.
What are the risk factors for developing atrial fibrillation?
Risk factors for atrial fibrillation include age and gender. Medical conditions like high blood pressure and heart disease are also risks. Lifestyle factors like drinking too much alcohol and smoking can increase your risk too.
Can I use a smartwatch to detect AFib?
Yes, some smartwatches can detect AFib with ECG capability. But, it’s important to know their accuracy and talk to your doctor about it.
How do I interpret home ECG results?
To understand home ECG results, you need to know how the device works. Then, talk to your doctor about any irregularities or abnormalities found.
What lifestyle modifications can help manage AFib at home?
To manage AFib at home, try making dietary changes and exercising regularly. Also, manage stress and avoid triggers that make symptoms worse.
When should I seek emergency medical attention for AFib?
Seek emergency medical attention for AFib if you have severe symptoms like chest pain, shortness of breath, or dizziness. Or if you’re worried about your condition.
How can I manage fear and anxiety related to AFib?
To manage fear and anxiety related to AFib, build confidence in monitoring yourself. Seek support from doctors and support groups. Also, practice stress management techniques.
What are the signs and symptoms of AFib that I shouldn’t ignore?
Don’t ignore signs and symptoms of AFib like heart palpitations, chest discomfort, shortness of breath, fatigue, and irregular or rapid heartbeats. These are serious symptoms.
References
Centers for Disease Control and Prevention. Evidence-Based Medical Insight. Retrieved from https://www.cdc.gov/heart-disease/about/atrial-fibrillation.html