Recognizing when to seek medical assistance for atrial fibrillation (AFib), a common heart rhythm condition, is crucial for ensuring timely and effective care.

Atrial fibrillation (AFib) is a condition where your heart’s rhythm becomes irregular. Often, your heart beats too fast in AFib, but it’s also possible for the heart rate to be normal or even slow and still have AFib.

AFib can increase your risk of stroke and other cardiovascular complications, which is why it’s important to recognize the condition and seek treatment if necessary.

Bottom line

If you have AFib, ideally, your resting heart rate should be between 60–100 beats per minute.

If it becomes faster or slower than that for longer than a few minutes, you should try to seek medical attention.

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In AFib, a dangerous heart rate depends on several factors, including your overall health, any underlying medical conditions, your age, and whether you’re experiencing symptoms.

In general, a heart rate that’s excessively fast (referred to as rapid ventricular response [RVR]) in the context of AFib can be concerning and may lead to hemodynamic instability.

Hemodynamic instability means that your heart is beating so rapidly that it affects your blood flow and overall cardiovascular function, potentially causing symptoms such as shortness of breath, chest pain, dizziness, and even fainting.

Dangerous heart rates

Medical guidelines provide varying heart rate thresholds that might be considered dangerous or indicative of potential instability.

  • The Advanced Cardiovascular Life Support guidelines suggest considering medical intervention for heart rates more than 150 beats per minute, as this threshold is often associated with potential instability.
  • The Acute Cardiac Care Association of the European Society of Cardiology and the European Heart Rhythm Association position statements recommend considering medical evaluation for heart rates exceeding 120 beats per minute, as they believe even lower heart rates could potentially lead to instability.

On the other hand, a dangerously low heart rate in AFib, referred to as “bradycardia,” can occur when the heart beats too slowly, usually below 60 beats per minute.

Both extremely high and low heart rates in AFib can lead to symptoms, discomfort, and potentially serious complications, emphasizing the importance of medical attention and management.

Learn how to lower your heart rate with vagal maneuvers here.

Resting heart rates exceeding 100–120 beats per minute are often considered concerning and may warrant medical attention, especially if symptoms are present.

But the heart rate at which you should go to the hospital depends on several factors, including your overall health, any existing medical conditions, and whether you’re experiencing symptoms related to the rapid heart rate.

As mentioned earlier, different medical recommendations offer varying heart rate thresholds at which medical evaluation should be considered due to potential hemodynamic instability. These thresholds are often around 120–150 beats per minute, depending on the recommendations.

It’s important to note that symptoms are a critical factor. If you’re experiencing any of the following symptoms along with your rapid heart rate, it’s advisable to seek medical attention:

A normal resting heart rate typically falls between 60–100 beats per minute.

The heart rate at which a person with AFib is considered safe can differ based on whether they’re resting, engaging in physical activity, or experiencing symptoms such as shortness of breath, dizziness, or fatigue.

In general, if you have AFib and are experiencing a consistently high resting heart rate, a healthcare professional can work with you to determine a target heart rate that balances symptom relief with safety.

One study looked at how heart rate affected the outcomes of a large group of people who already had AFib at the beginning of the study. They followed these individuals for about 3.9 years to see if their initial heart rate was related to any negative health events that occurred during that time.

After analyzing data from 1,679 people with AFib, it was found that heart rate wasn’t significantly associated with heart failure hospitalization, stroke or systemic embolism, or death, suggesting that strict heart rate control might not be necessary for stable outpatients with AFib.

This can be reassuring for both people with AFib and healthcare professionals, as it implies that focusing solely on aggressively controlling heart rate might not be required to prevent these reactions in individuals with stable AFib.

AFib is characterized by irregular and often rapid heartbeats originating in the atria (upper chambers of your heart).

A heart rate that’s excessively fast and irregular (RVR) in AFib can be dangerous, potentially leading to hemodynamic instability and symptoms such as chest pain, shortness of breath, and fainting.

Guidelines and recommendations vary, but heart rates exceeding 120–150 beats per minute are generally considered concerning and might necessitate medical evaluation, especially if symptoms are present.