Supraventricular Tachycardia (SVT) refers to a rapid heart rhythm originating in the upper chambers of the heart. While an SVT episode can be alarming due to its sudden onset and rapid heart rate, it is generally not considered life-threatening for most individuals. However, specific underlying conditions or severe symptoms can make it a more serious concern, prompting the need for medical evaluation.
Understanding SVT
During an episode of Supraventricular Tachycardia, the heart’s electrical signals misfire, causing the upper chambers (atria) to beat very quickly. This rapid electrical activity then travels to the lower chambers (ventricles), resulting in a sudden increase in heart rate, often ranging from 150 to 250 beats per minute. Individuals experiencing SVT commonly report a sensation of a racing or pounding heart, known as palpitations, or a fluttering sensation in the chest. These sensations can be quite intense and sudden. Other reported symptoms include lightheadedness, dizziness, shortness of breath, and anxiety. There are several types of SVT, each involving a different electrical pathway malfunction above the ventricles, though they all lead to a similar rapid heart rate.
Assessing the Threat: Is SVT Dangerous?
For most individuals, SVT episodes are more unsettling than dangerous, often resolving on their own or with simple measures while the heart’s pumping function remains stable. However, there are specific circumstances where SVT can become serious or pose a greater risk to health. SVT can be more concerning for individuals with pre-existing heart conditions, such as structural heart disease or heart failure, as the rapid heart rate can strain an already compromised heart, potentially worsening their condition. Prolonged episodes, lasting hours, or very frequent occurrences, even in otherwise healthy individuals, can also lead to complications. SVT accompanied by severe symptoms like chest pain, fainting (syncope), or significant difficulty breathing warrants immediate medical attention. Very young infants or elderly individuals with multiple health issues may also be more vulnerable to adverse effects from SVT, and while rare, sustained, untreated SVT can lead to heart muscle weakening over time or, in acute severe cases, a temporary drop in blood pressure causing fainting.
When to Seek Care
Seek medical attention for SVT symptoms if you experience a sudden onset of rapid heart rate, particularly if it feels new or unfamiliar. Immediate medical evaluation is necessary if SVT symptoms are accompanied by chest pain, severe dizziness, a feeling of lightheadedness that causes you to nearly faint, or significant difficulty breathing, as these can indicate a more serious underlying issue or complication.
If an SVT episode is prolonged and does not resolve with simple self-help techniques, such as bearing down (Valsalva maneuver) or splashing cold water on your face, medical intervention may be required. Individuals with a known underlying heart condition should always seek prompt medical advice if they experience an SVT episode. For severe symptoms, call emergency services immediately. Recurrent or concerning episodes, even if not severe, warrant a doctor’s consultation for diagnosis and guidance.
Diagnosis and Management of SVT
Diagnosing SVT begins with an electrocardiogram (ECG or EKG), which records the heart’s electrical activity and can capture an SVT episode if it is occurring during the test. For intermittent episodes, healthcare providers may use a Holter monitor, a portable device worn for 24 to 48 hours to continuously record heart rhythms. An event recorder, worn for weeks or months, allows patients to activate it when they feel symptoms, capturing the heart rhythm during an episode.
Acute management of an SVT episode involves vagal maneuvers, actions designed to stimulate the vagus nerve and slow the heart rate. In a hospital setting, intravenous medications like adenosine can be administered to quickly terminate an episode.
Long-term management strategies aim to prevent future episodes and may include lifestyle adjustments, such as avoiding common triggers like excessive caffeine, alcohol, or stress. Medications like beta-blockers or calcium channel blockers can be prescribed to help regulate heart rate and rhythm. For individuals with frequent or highly symptomatic SVT, a procedure called catheter ablation may be recommended, which targets and neutralizes small areas of heart tissue responsible for abnormal electrical signals, often providing a permanent cure.