What’s the Difference between SVT and AFib?
Because your heartbeat is a complicated event, composed of many different elements, heart arrhythmias can come in many different forms. It’s important to distinguish between these different forms because the potential medical complications and necessary treatments for each one can be very different.
Two common arrhythmias that can sometimes be confused are supraventricular tachycardia (SVT) and atrial fibrillation (AFib). Although these arrhythmias can feel similar and can even look similar on an electrocardiogram (EKG), they are very different and mean different things for your heart health.
SVT and AFib Are Different Arrhythmias
First, it’s important to understand that SVT and AFib are different arrhythmias.
In SVT, the heart begins beating very rapidly, typically 150 to 220 beats per minute, but rates of 300 beats per minute have been recorded. This can come and go quickly, but you may go through episodes of SVT that last for minutes or days. SVT is caused by out of sync signals from the heart’s electrical regulating nodes.
In AFib, your heart’s four chambers aren’t beating together. Typically, the atria (upper chambers of the heart) are beating out of sync with the lower chambers of the heart (the ventricles). As the heart is struggling with this irregular rhythm, it can beat very fast. Some people experience episodes of AFib that come and go, but other people may experience constant irregular heartbeats.
Risk factors are also different in these conditions, especially age. AFib typically affects older people, most often 65 and up, while SVT commonly occurs at any age. Even children can have it.
Do SVT and AFib Feel Different?
As different as SVT and AFib are, you would expect that they would feel very different. The truth is that sometimes they do, and sometimes they don’t.
There are several reasons for this. First, it’s that these conditions aren’t uniform. Some people have textbook SVT or AFib, while other people experience a variation that might feel more similar to the other.
Second, our bodies aren’t as good at sensing and communicating what’s happening inside as on the skin. For example, if you get a cut on your hand, you’re probably going to feel it as pain in your hand. But pain originating in the heart can be felt in chest or in the stomach, back, neck, jaw, or arms. Irregular heartbeats aren’t usually felt in other places, but they don’t always feel like what they are.
Finally, you probably don’t have such detailed knowledge of how your normal heartbeat functions that you can tell exactly what is different, especially given the vagaries of heart sensations.
How SVT and AFib Can Feel
With both SVT and AFib, you can feel that your heartbeat is racing. In both conditions you might also experience:
- Heart palpitations
- Shortness of breath
- Fatigue
- Dizziness or lightheadedness
- Anxiety
- Chest pain
- Pounding feeling in the neck
You might also get alerts about an irregular heartbeat if you have a wearable device.
SVT and AFib Have Different Complications
SVT and AFib are both serious conditions that require appropriate treatment and management. However, the conditions have different complications when not properly managed or treated.
SVT can weaken the heart and potentially lead to other heart conditions. Sometimes, SVT can cause your heart to stop, called sudden cardiac arrest. Other times, SVT can lead to heart failure.
AFib can cause blood to pool in the heart because it is not being efficiently pumped out. This pooled blood can clot, and when it does get pumped out, the blood clots can go to different parts of the body, including the brain or the blood vessels supplying the heart. The clots then block the blood vessels, leading to a stroke or heart attack.
SVT and AFib Require Different Treatments
SVT and AFib are treated and/or managed in different ways. Often, SVT and AFib can be cured.
Treating and Curing SVT
Sometimes you can slow your heartbeat with vagal maneuvers if you have SVT—but not always. Vagal maneuvers are designed to trigger your vagus nerve’s ability to influence your heart’s pace. These can be a great first-line treatment for SVT, but they’re not recommended until you’ve talked to a doctor about your condition first.
If vagal maneuvers aren’t working well, medications can also help control SVT until you can get a curative treatment.
SVT can be cured with cardiac ablation. In this procedure, a cardiologist, typically specializing in cardiac electrophysiology, will remove the parts of the heart that are giving off the signals that trigger SVT. This treatment is highly effective treatment, with a success rate of 95% or higher, according to some studies.
Managing and Curing AFib
Medications can be used to manage AFib. These may include beta blockers, calcium channel blockers, blood thinners, and, sometimes, anti-arrhythmics.
Cardiac ablation has been proven to be an effective treatment for AFib, but success rates are lower than for SVT.
How to Get an Accurate Diagnosis
Getting an accurate diagnosis of your arrhythmia is critical to getting proper treatment for your condition.
The first step to diagnose your arrhythmia is typically EKG. However, for arrhythmias that aren’t constant, EKG might not detect them. Other tests might be helpful, including:
- Stress test: A stress test can be used to see how your heart performs in situations of high demand, which can help a cardiologist understand your condition.
- Holter monitor: A less-detailed version of the EKG that you wear
- Loop recorder: An implantable device set up to monitor your heart over a long period of time.
- Echocardiogram: This test gives a cardiologist an image of your heart so that they can determine whether areas of the heart are experiencing overdevelopment, atrophy, or injury.
A cardiologist will help you get the right tests to diagnose your condition.
South Denver Cardiology Can Help
South Denver Cardiology is home to an advanced, dedicated Arrhythmia Clinic, staffed by doctors and nurses offering a comprehensive and multidisciplinary approach to managing arrhythmias. Our goal is to match each patient with the proper treatment that will help them meet their heart health and lifestyle goals.
Sometimes, managing your arrhythmia focuses on lifestyle changes and managing adjacent conditions like diabetes and high blood pressure. Other times, medication makes the most sense for you. But when your arrhythmia requires advanced procedures, our specialists can offer leading-edge treatments comparable to any clinic in the country.
To learn how South Denver Cardiology can help treat your arrhythmia, please contact us today.
Frequently Asked Questions: SVT vs. AFib
What is the difference between SVT and AFib?
Supraventricular tachycardia (SVT) and atrial fibrillation (AFib) are two distinct heart arrhythmias. In SVT, out-of-sync signals from the heart’s electrical regulating nodes cause the heart to beat very rapidly, usually 150 to 220 beats per minute. In AFib, the heart’s upper chambers (atria) beat out of sync with the lower chambers (ventricles), producing an irregular and often fast rhythm.
How fast does the heart beat during SVT?
During an SVT episode, the heart typically beats 150 to 220 beats per minute, and rates as high as 300 beats per minute have been recorded. SVT episodes can start and stop suddenly, lasting anywhere from a few minutes to several days.
Who is most likely to get SVT or AFib?
AFib most often affects older adults, especially people age 65 and older. SVT, by contrast, can occur at any age, including in children. Age is one of the clearest differences in risk between the two arrhythmias.
Do SVT and AFib feel different?
SVT and AFib sometimes feel different and sometimes feel nearly identical. Both conditions vary from person to person, the body is not good at precisely sensing what is happening inside the heart, and most people don’t know their normal heartbeat well enough to identify exactly what has changed. For these reasons, symptoms alone cannot reliably tell the two apart.
What are the symptoms of SVT and AFib?
Both SVT and AFib can cause a racing heartbeat, heart palpitations, shortness of breath, fatigue, dizziness or lightheadedness, anxiety, chest pain, and a pounding feeling in the neck. People who use a wearable device may also receive alerts about an irregular heartbeat.
Can SVT and AFib look the same on an EKG?
Yes. Although SVT and AFib are different arrhythmias, they can sometimes look similar on an electrocardiogram (EKG). Because an EKG may also miss arrhythmias that come and go, a cardiologist may recommend additional testing to confirm the diagnosis.
What are the complications of untreated SVT?
Untreated SVT can weaken the heart and may lead to other heart conditions, including heart failure. In some cases, SVT can cause sudden cardiac arrest, in which the heart stops beating.
Why does AFib increase the risk of stroke?
AFib increases stroke risk because the irregular rhythm prevents the heart from pumping blood out efficiently, allowing blood to pool and form clots. When these clots are pumped out of the heart, they can travel to the brain and cause a stroke, or block blood vessels supplying the heart and cause a heart attack.
How is SVT treated?
SVT treatment may include vagal maneuvers, which use the vagus nerve to slow the heart, and medications to control episodes. Vagal maneuvers should only be tried after discussing your condition with a doctor. SVT can often be cured with cardiac ablation, a procedure with a success rate of 95% or higher in some studies.
What is cardiac ablation?
Cardiac ablation is a procedure, typically performed by a cardiologist specializing in cardiac electrophysiology, that targets the specific areas of heart tissue producing abnormal electrical signals. It can cure SVT in most cases and is also an effective treatment for AFib, though success rates for AFib are lower than for SVT.
How is AFib treated?
AFib is commonly managed with medications such as beta blockers, calcium channel blockers, blood thinners, and sometimes anti-arrhythmic drugs. Cardiac ablation is a proven, effective treatment option for AFib, although it is less successful for AFib than for SVT.
Can SVT and AFib be cured?
Both SVT and AFib can often be cured, most commonly through cardiac ablation. SVT ablation has particularly high success rates, reaching 95% or higher in some studies, while AFib ablation is effective but less consistently curative.
How are SVT and AFib diagnosed?
An electrocardiogram (EKG) is usually the first test used to diagnose an arrhythmia. Because SVT and AFib can come and go, a cardiologist may also use a stress test, a wearable Holter monitor, an implantable loop recorder for long-term monitoring, or an echocardiogram to image the heart’s structure.
Why is an accurate diagnosis of SVT or AFib important?
An accurate diagnosis matters because SVT and AFib carry different complications and require different treatments. AFib, for example, often calls for blood thinners to reduce stroke risk, while SVT may respond to vagal maneuvers or be cured with ablation. South Denver Cardiology’s Arrhythmia Clinic offers comprehensive testing and treatment to match each patient with the right care.
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