A fast heartbeat can be frightening, especially when it begins suddenly and seems to have no clear cause. One condition that can cause sudden episodes of a very rapid heartbeat is supraventricular tachycardia. It is a type of abnormal heart rhythm, also called an arrhythmia, that begins in the upper areas of the heart rather than the lower chambers.
During an episode, the heart can beat much faster than normal. A resting adult heart commonly beats between about 60 and 100 times per minute, while an episode may cause the heart rate to rise to around 150 to 220 beats per minute. Episodes can begin and end suddenly and may last for a few minutes or longer. Mayo Clinic
Although a rapid heartbeat can feel alarming, many cases are manageable and are not life-threatening. However, repeated episodes or symptoms such as chest pain, fainting, severe dizziness, or difficulty breathing should always be taken seriously.
What Is SVT?
SVT is an abnormal heart rhythm caused by changes in the electrical signals that control the heartbeat. The heart normally uses a carefully organized electrical system to maintain a steady rhythm. An electrical signal begins in the sinus node, travels through the upper chambers, and then passes through the atrioventricular node before reaching the lower chambers.
In SVT, an electrical signal can follow an abnormal pathway or create a rapid electrical circuit. This causes the heart to beat much faster than usual. Because the heart is beating so quickly, it may have less time to fill with blood between beats. This can contribute to symptoms such as dizziness, weakness, or shortness of breath. Mayo Clinic
There are several types of SVT. The three commonly discussed forms include atrioventricular nodal reentrant tachycardia, atrioventricular reciprocating tachycardia, and atrial tachycardia. The exact type depends on where the abnormal electrical activity begins and how it travels through the heart.
Common Symptoms
Symptoms can vary from person to person. Some people experience obvious episodes, while others may have mild symptoms or no noticeable symptoms at all.
Common signs include:
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A sudden racing or pounding heartbeat
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A fluttering feeling in the chest
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A rapid pulse
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A feeling of pressure or discomfort in the chest
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Dizziness or lightheadedness
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Shortness of breath
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Weakness or unusual tiredness
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Sweating
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Feeling close to fainting
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Fainting in some cases
One important feature is that an episode can start suddenly and may also stop suddenly. Some people describe the sensation as though a switch has been turned on and off. The length of an episode can differ considerably, ranging from a short period to several hours or, in some cases, longer. Mayo Clinic
Children and infants may show different signs. A young child may have difficulty feeding, sweating, unusual tiredness, or a noticeably fast heartbeat. Parents or caregivers should seek medical advice when these symptoms occur.
What Causes It?
The main cause is abnormal electrical signaling within the heart. In many people, there is an electrical pathway or circuit that allows signals to travel in a way that produces a very rapid rhythm.
SVT can occur in people who otherwise have healthy hearts. It can also be associated with certain heart conditions, previous heart surgery, congenital heart problems, thyroid disease, or other medical conditions. Some medicines and substances may also contribute to episodes. Mayo Clinic
Certain factors may trigger an episode in people who are already prone to the condition. These can include emotional stress, excessive caffeine, alcohol, smoking or nicotine, stimulant drugs, and some medications. Lack of sleep and physical strain may also make symptoms more noticeable for some people.
However, a trigger is not always present. An episode may happen while a person is resting, working, exercising, or sleeping.
Who Is More Likely to Experience It?
SVT can affect people of different ages, including children and adults. Some forms are particularly common in younger people, while other forms may become more likely when an individual has an underlying heart condition.
Women can have a higher likelihood of experiencing certain forms of paroxysmal SVT. Pregnancy can also influence heart rhythm because of changes in blood volume, hormones, and the cardiovascular system. professional.heart.org
Having a family history of abnormal heart rhythms may also increase risk. Other possible risk factors include heart disease, congenital heart defects, thyroid disorders, diabetes, lung conditions, and sleep apnea. Still, having a risk factor does not mean that a person will definitely develop the condition.
How Is It Diagnosed?
A healthcare professional usually begins by asking about symptoms, medical history, medications, lifestyle habits, and family history. The doctor may also check the pulse and blood pressure and listen to the heart.
An electrocardiogram, commonly called an ECG or EKG, is one of the most important tests. It records the heart’s electrical activity and can sometimes identify the specific rhythm causing symptoms.
The challenge is that episodes may stop before the patient reaches a medical facility. In such cases, longer-term heart monitoring can be useful. A Holter monitor can record heart activity during normal daily activities, while an event monitor may be used for a longer period when episodes occur less frequently. Mayo Clinic
Additional tests may include blood tests, an echocardiogram, an exercise stress test, or an electrophysiology study. These tests can help doctors identify possible causes and understand how electrical signals are moving through the heart.
Treatment Options
Treatment depends on how often episodes occur, how severe the symptoms are, the person’s overall health, and the specific type of rhythm problem.
Some people do not need regular treatment if their episodes are brief, infrequent, and not causing significant problems. Others may need medication or a procedure to prevent repeated episodes. Mayo Clinic
During some episodes, healthcare professionals may recommend vagal maneuvers. These are specific actions designed to influence the vagus nerve and slow the heart rate. Examples can include certain controlled breathing or bearing-down techniques. These methods should be performed only as instructed by a healthcare professional.
Medication may be prescribed when episodes happen frequently or cause troublesome symptoms. Depending on the situation, medicines may help slow the heart rate or prevent abnormal rhythms.
For people who continue to have significant episodes, catheter ablation may be an option. During this procedure, a specialist guides thin catheters into the heart and identifies the area responsible for the abnormal electrical signal. Heat or cold energy can then be used to create a small area of scar tissue that prevents the faulty signal from continuing. Mayo Clinic
In urgent situations, cardioversion may be used to restore a normal heart rhythm, particularly when symptoms are severe or other methods have not worked.
Lifestyle and Prevention
Lifestyle changes cannot always prevent SVT, but they may help reduce triggers and support overall heart health.
People who experience episodes may benefit from identifying personal triggers. Keeping a simple record of when symptoms occur can be useful. The record can include the time of the episode, how long it lasted, what the person was doing, food or drinks consumed beforehand, sleep patterns, stress levels, and any medicines taken.
Limiting excessive caffeine and alcohol may help some people. Avoiding smoking and nicotine is also important for cardiovascular health. Regular physical activity, adequate sleep, a balanced diet, and stress management can support general heart health.
People should not stop prescribed medicines or begin new supplements without discussing them with a healthcare professional. Some over-the-counter medicines, particularly certain cold and stimulant products, may affect heart rate.
When Should You Seek Emergency Help?
A fast heartbeat should not automatically be assumed to be harmless. Emergency medical attention is important when a rapid heartbeat is accompanied by chest pain, severe shortness of breath, fainting, significant dizziness, severe weakness, or other concerning symptoms.
It is also important to seek medical advice if a very fast heartbeat occurs for the first time, keeps returning, or lasts longer than expected. A healthcare professional can determine whether the rhythm is SVT or another type of heart problem. Mayo Clinic
People with known heart disease may require particular attention because a rapid rhythm can have greater consequences when the heart is already affected by another condition.
Living With SVT
For many people, SVT can be managed successfully. Understanding personal symptoms that someone must stop normal activities. The appropriate level of exercise and activity depends on the person’s health and the advice of their healthcare professional. Some people may need treatment before returning to certain and triggers can make episodes less frightening and help patients communicate more effectively with their healthcare team.
A diagnosis does not necessarily mean that someone must stop normal activities. The appropriate level of exercise and activity depends on the person’s health and the advice of their healthcare professional. Some people may need treatment before returning to certain activities, while others can continue their usual routines.
It can also be helpful to learn what symptoms require immediate medical attention and what steps a doctor has recommended if an episode occurs.
Conclusion
SVT is a common type of rapid heart rhythm that begins above the heart’s lower chambers. It can cause a sudden racing heartbeat, dizziness, weakness, shortness of breath, chest discomfort, and other symptoms. Episodes may occur in otherwise healthy people, although certain medical conditions and triggers can increase the risk.
Diagnosis usually involves an ECG or another form of heart monitoring, while treatment depends on the frequency and severity of episodes. Options can include observation, lifestyle changes, medication, vagal maneuvers, cardioversion, and catheter ablation. Mayo Clinic
The most important step is not to ignore unexplained episodes of rapid heartbeat. Proper medical evaluation can identify the cause, rule out more serious problems, and help determine the safest approach to treatment. With appropriate care, many people with SVT are able to manage their condition and maintain a normal, active life. See more