What is supraventricular tachycardia? What causes it? How is it diagnosed and treated? Get the answers to these questions and more in this comprehensive guide.

What is Supraventricular Tachycardia?

Supraventricular tachycardia (SVT) is a type of abnormally fast heart rhythm that originates in the upper chambers of the heart, known as the atria. This condition is also referred to as paroxysmal supraventricular tachycardia, as the fast heart rhythms can start and stop abruptly, occurring with intervals of normal heart rhythm.

Normally, a special group of cells in the sinoatrial (SA) node initiates the electrical signal that triggers the heartbeat. In an adult, the sinus node sends out a regular electrical pulse 60 to 100 times per minute at rest. This signal then travels down the heart’s conducting system to the ventricles, the two lower chambers of the heart. However, in SVT, the abnormal rhythm starts in the upper heart chambers, causing the heart to suddenly beat much faster than normal.

Causes of Supraventricular Tachycardia

Supraventricular tachycardia occurs when the electrical system that controls the heart’s rhythm is not functioning properly. This can cause the heart to suddenly beat much faster, often at a rate above 100 beats per minute. The fast heart rate can then slow down abruptly.

Some common triggers for SVT episodes include:

• Tiredness
• Caffeine intake
• Alcohol consumption
• Certain medications or drugs

However, in many cases, there is no obvious trigger for the onset of an SVT episode.

Symptoms of Supraventricular Tachycardia

The primary symptom of supraventricular tachycardia is a sudden, rapid heartbeat. This can last for a few minutes, but in some cases, it may continue for several hours. People with SVT may also experience:

• Chest pain
• Weakness, breathlessness, or lightheadedness
• Fatigue
• Nausea or vomiting

It’s important to note that some individuals with SVT may not experience any additional symptoms other than the rapid heartbeat.

Diagnosing Supraventricular Tachycardia

If you experience recurring episodes of a fast heartbeat, it’s important to consult a healthcare professional. They may perform tests, such as an electrocardiogram (ECG), to determine the cause of your symptoms and diagnose supraventricular tachycardia.

An ECG is a non-invasive test that measures the electrical activity of your heart, which can help identify any abnormalities in your heart’s rhythm.

Treating Supraventricular Tachycardia

The treatment for supraventricular tachycardia depends on the severity and frequency of your symptoms. In some cases, if the episodes are brief and not bothersome, no treatment may be necessary. However, if you experience longer or more frequent episodes, you may require medical intervention, which may include:

• Medications to control the episodes of SVT, such as tablets or intravenous drugs
• Cardioversion, a procedure that uses a small electric shock to the heart to help it return to a normal rhythm
• Catheter ablation, a treatment where thin tubes are inserted into your heart through a vein or artery to correct the electrical system problem, which can permanently cure the condition in most patients

When to Seek Immediate Medical Attention

If you have been diagnosed with supraventricular tachycardia and your episode has lasted longer than 30 minutes, or if you experience sudden shortness of breath along with chest pain, you should call 999 or go to the nearest emergency department immediately. These symptoms require prompt medical treatment.

Managing Supraventricular Tachycardia

If your episodes of SVT are relatively short and do not significantly impact your daily life, you may not require immediate treatment. However, there are some lifestyle changes you can make to help reduce the frequency of your episodes, such as:

• Cutting down on caffeine and alcohol consumption
• Quitting or cutting back on smoking
• Ensuring you get enough rest

Your healthcare provider may also be able to recommend some simple techniques to help stop episodes when they occur.