Understanding Atrial Fibrillation and What Happens During an Attack
Atrial fibrillation, commonly called AFib, is a heart rhythm condition where the upper chambers of the heart beat irregularly and often too fast. Instead of contracting in a steady, coordinated way, the atria quiver or fibrillate. This irregular rhythm can cause blood to pool in the heart chambers, which increases the risk of blood clots. According to the American Heart Association, approximately 2.7 to 6.1 million people in the United States have AFib, making it one of the most common heart arrhythmias.
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During an AFib attack, you may experience a sudden onset of symptoms that can last from a few minutes to several hours, or even longer. The heart may beat very rapidly—sometimes 100 to 200 beats per minute or more—compared to the normal resting rate of 60 to 100 beats per minute. This rapid, irregular beating happens because the electrical signals in your heart are misfiring, causing the atria to beat out of sync with the lower chambers, called the ventricles.
The physical sensation of an AFib attack varies from person to person. Some people describe it as a fluttering feeling in the chest, like a bird trapped in the ribcage. Others feel a pounding or racing heartbeat that is noticeable and sometimes frightening. The irregular rhythm means that blood is not being pumped as efficiently as it should be, which can trigger symptoms throughout your body. Understanding what is happening during an attack—that your heart is beating irregularly but that many attacks resolve on their own—can help reduce anxiety, which itself can worsen symptoms.
Research shows that AFib attacks can be triggered by various factors, including physical exertion, emotional stress, caffeine consumption, alcohol use, sleep deprivation, infections, thyroid problems, and underlying heart disease. Some people have paroxysmal AFib, meaning the attacks come and go unpredictably. Others develop persistent AFib, where the irregular rhythm continues until treated. Knowing your personal triggers is valuable information that can help you manage future episodes.
Practical Takeaway: Keep a simple log of when AFib attacks occur, what you were doing beforehand, and how long the attack lasted. This information helps you identify your personal triggers and provides valuable details for your healthcare provider.
Recognizing the Symptoms of an AFib Attack
AFib symptoms can range from barely noticeable to severe and alarming. The most common symptom is palpitations—the awareness that your heart is beating, often described as a racing, pounding, or fluttering sensation in the chest. Some people feel this in their neck or throat as well. The sensation may be constant or may come and go in waves. Palpitations can be mild enough that you might ignore them, or severe enough to interrupt your daily activities and cause significant worry.
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Beyond palpitations, many people experience shortness of breath during an AFib attack. This happens because the irregular heartbeat reduces how effectively blood is pumped throughout your body, including to your lungs. You might notice you cannot take a deep breath, or that normal activities like climbing stairs suddenly leave you breathless. Some people describe a sensation of suffocation or panic accompanying the breathlessness, which can create a cycle of anxiety that makes symptoms feel worse.
Dizziness and lightheadedness are also common during AFib attacks. Because the heart is not pumping blood as efficiently, less oxygen reaches the brain. This can cause a sensation of spinning, feeling faint, or a sense of disconnection from your surroundings. Some people experience chest discomfort, though it is typically not the sharp, crushing pain associated with a heart attack, but rather a vague pressure or tightness.
Fatigue is another symptom many people report during and after an AFib attack. The poor pumping efficiency of an irregular heartbeat means your body is working harder to circulate blood and oxygen, which is exhausting. You might feel weak or drained, sometimes for hours after the attack ends. Some people also experience anxiety or a sense of impending doom, partly because the physical sensations are alarming and partly because of the body's natural stress response to an irregular heartbeat.
It is important to note that some people have AFib with few or no symptoms at all. This is sometimes called silent AFib. A person might feel completely normal while in AFib, only to discover they are in the rhythm when they go to the doctor for an unrelated reason. This is why regular checkups and knowing your risk factors matter.
Practical Takeaway: Write down the specific symptoms you experience during an attack and in what order they appear. This helps you recognize when an attack is starting so you can respond appropriately and informs conversations with your healthcare provider about your condition.
Immediate Actions to Take When an AFib Attack Begins
When you feel an AFib attack starting, the first priority is to stay calm, even though that is easier said than done. Anxiety and panic can increase your heart rate further and make symptoms worse. Take slow, deep breaths—breathe in through your nose for a count of four, hold for four counts, and exhale through your mouth for four counts. This breathing technique activates your parasympathetic nervous system, which naturally slows your heart rate. Repeat this pattern for several minutes. Many people find that this calming technique alone can reduce the severity of an attack or sometimes even stop it.
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Next, stop whatever activity you are doing and sit or lie down in a comfortable position. If you are standing, sitting down prevents you from falling if dizziness worsens. If you are lying down, elevate your head with pillows so you are not completely flat—this position can sometimes help with breathing. Rest is important because physical exertion during an AFib attack puts additional strain on your heart. Give your body time to settle.
Some people find that a technique called the Valsalva maneuver may help restore normal rhythm. This involves bearing down as if you are straining during a bowel movement, or coughing forcefully. This maneuver stimulates the vagus nerve, which can sometimes interrupt the electrical signals causing AFib. However, this does not work for everyone, and you should discuss whether this technique is appropriate for you with your doctor before trying it during an attack.
If you have been prescribed medication to take during an AFib attack, take it as directed. Some people are given medications specifically for acute AFib episodes. Take the medication with water and remain seated or lying down. If your doctor has not prescribed specific medications for attacks, do not take any medication without checking first.
Avoid stimulating your heart further during an attack. This means avoiding caffeine, even though you might be tempted to drink a sugary beverage for comfort. Put your phone down, turn off the television or music, and minimize visual stimulation. A quiet, calm environment helps your nervous system settle down. If someone is with you, ask them to stay nearby but to remain calm themselves, since your body can pick up on others' anxiety.
Time how long the attack lasts. Most AFib attacks last from a few minutes to a few hours. Many attacks resolve on their own without any intervention. However, if your attack lasts longer than a few hours, if you experience chest pain or severe shortness of breath, or if you feel like you might pass out, seek emergency medical attention by calling 911 or going to an emergency room.
Practical Takeaway: Create a simple action card to keep in your wallet or phone with your personalized steps: your breathing technique, your doctor's contact information, medications you should take (if any), and the warning signs that mean you need emergency care.
Managing Symptoms During an AFib Episode
Once you have taken initial steps and are in a calm, rested position, focus on managing the specific symptoms you are experiencing. For palpitations, continued slow breathing and relaxation are your best tools. Some people find it helpful to place one hand on their chest and one on their belly, focusing on feeling their breath move rather than thinking about their heartbeat. This redirects your attention away from the uncomfortable sensation. Avoid checking your pulse repeatedly, as this focuses attention on the symptom and can increase anxiety.
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If you experience shortness of breath, sitting upright or in a semi-reclined position helps your lungs expand more easily. Open windows if possible to ensure adequate air circulation. Practice the slow breathing technique again—sometimes people with AFib hold their breath without realizing it, which worsens the feeling of breathlessness. Slow, measured breathing,