Story by: David Steen Martin; Reviewed by Hassan Khan, M.D., Ph.D. on December 28, 2023
Heart palpitation, or a rapid heartbeat, can bring on dizziness and even fainting and can be a symptom of a potentially serious heart condition.
When the fast heart rate begins in the upper heart chambers, it is called supraventricular tachycardia (soop-rah-ven-TRICK’-yoo-lar TAK-ih-KAR-dee-ah), also known as SVT. When it starts in the lower chambers, it’s called ventricular tachycardia or VT.
When the heart is beating too fast, it doesn’t have a chance to fill up with blood between beats. As a result, the heart has a hard time pumping enough blood. The reduced blood flow sends less oxygen out to the body, causing lightheadedness or dizziness, chest pain, weakness or fatigue, and shortness of breath.
“Though the symptoms are similar, the outlook is very different for patients with supraventricular tachycardia and those with ventricular tachycardia,” said Hassan Khan, M.D., Ph.D., an electrophysiologist with the Norton Heart & Vascular Institute Heart Rhythm Center. “SVT is usually not serious. VT, on the other hand, can lead to sudden cardiac death and needs to be monitored closely.”
A rapid heartbeat or pounding heart also can be a sign of a panic attack, which should not be taken lightly and warrants medical attention.
A normal resting heart rate is 60 to 100 beats a minute. With SVT and VT, the heart will beat much faster, often in the range of 170 or more beats per minute. SVT, VT and bradycardia (a slow heartbeat) are forms of cardiac arrhythmia or irregular heartbeat. Atrial fibrillation, another heart rhythm disorder, is a form of supraventricular arrhythmia.
Premature beats, or ectopic beats, may feel like your heart skipped a beat. These typically are not a serious medical condition.
Treatment options for arrhythmias depend on your symptoms and the cause of your heart condition. Options include: lifestyle modification, medications and cardiac ablation to interrupt the errant electrical signals causing the irregular heartbeat or a surgically implanted cardioverter defibrillator to reset your heart if you develop a dangerous ventricular arrhythmia episode.
SVT is rare, with 2 in 1000 people estimated to be affected. In a normal heart rhythm, electrical signals follow a specific pathway through the heart, regulating the heart rate and rhythm. However in SVT, abnormal pathways or circuits can form, causing the heart to beat faster than normal.
SVT can affect children or adults, but many people have their first symptoms between the ages of 25 and 40. SVT can be initiated by stress, drinking large amounts of caffeine or alcohol, certain medications, and hormonal imbalances, such as hyperthyroid disorder. In some cases, the cause is not known.
With SVT, the rapid heart rate can occur daily or only once a year. It can be sporadic. SVT typically lasts for a couple of minutes but can last for several hours.
Symptoms of SVT may be difficult to see in infants and very young children. In addition to a rapid pulse, signs of SVT in infants and very young children include sweating, poor feeding and pale skin.
SVT is usually not serious, but it may require treatment. In rare cases, it can cause you to lose consciousness or go into cardiac arrest.
If you have a medical emergency, call 911.
If you have heart palpitations and dizziness, talk to your primary care provider.
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VT can occur in an otherwise healthy heart but is usually more common in abnormal heart muscle tissue, which can be result of other cardiovascular issues. These include coronary artery disease, an enlarged heart or abnormal heart valves.
If you’ve had a heart attack or heart surgery, that can contribute to VT. If you’re older or have a family history of cardiac arrhythmia or sudden death you’re also more likely to develop VT.
VT begins in the heart’s lower two chambers, called ventricles. It can be caused in two ways. VT can happen when an abnormal heart circuit within the ventricular muscle becomes triggered, or it can occur when an abnormal ventricular muscle self-activates.
VT is defined as three or more beats in a row at a rate of more than 100 beats per minute. VT that lasts for only a few seconds may not need to be treated. VT that lasts more than a few seconds at a time can become life-threatening.
VT in a structurally normal heart is not serious if the fast heartbeat stops on its own.
Call your health care provider if you experience an abnormal heart rhythm or very fast heartbeat for the first time.
With VT, you should call 911 if you feel lightheaded, have chest pain or experience a sustained rapid heartbeat that lasts 30 seconds or more.
With SVT, you should call 911 if you have an episode of SVT that lasts for more than a few minutes or if you also have chest pain, have trouble breathing or are feeling very faint.
If you think your infant or child has SVT, ask your child’s pediatrician about an SVT screening.
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