SVT (Supraventricular Tachycardia): Symptoms, Causes, Treatment

What are the symptoms of SVT?

Supraventricular tachycardia (SVT) is a type of rapid heart rate that originates above the ventricles. Symptoms of SVT can vary but commonly include:

• Palpitations: A rapid or irregular heartbeat that may feel like a fluttering or pounding in the chest.
• Dizziness or Lightheadedness: Feeling faint or dizzy, which can result from the heart beating too quickly and not pumping blood efficiently.
• Shortness of Breath: Difficulty breathing or feeling winded, often due to the heart’s reduced ability to pump blood effectively.
• Chest Pain or Discomfort: A sensation of pain or pressure in the chest, which may be caused by the heart working harder than normal.
• Fatigue: A general feeling of tiredness or weakness, which can result from the heart’s inefficiency in supplying adequate blood and oxygen.
• Sweating: Excessive sweating, often associated with the body’s stress response to the rapid heartbeat.
• Fainting: In severe cases, SVT can lead to syncope or fainting due to a drop in blood pressure and reduced blood flow to the brain.

The symptoms of SVT can sometimes be mistaken for other conditions, and episodes can vary in frequency and duration. If SVT symptoms are experienced, especially if they are sudden or severe, it is important to seek medical evaluation for accurate diagnosis and appropriate management.

What are the causes of SVT?

Supraventricular tachycardia (SVT) can be caused by various factors, often involving abnormal electrical pathways or triggers in the heart. Common causes and triggers include:

• Reentry Circuits: SVT often results from reentry circuits, where electrical signals continuously loop within the heart’s electrical pathways. These circuits can occur in conditions like atrioventricular nodal reentrant tachycardia (AVRT) or atrioventricular reentrant tachycardia (AVRT) involving accessory pathways.
• Accessory Pathways: Some individuals have extra electrical pathways in the heart, such as in Wolff-Parkinson-White (WPW) syndrome, which can lead to SVT.
• Atrial Fibrillation or Flutter: Abnormal electrical activity in the atria can lead to episodes of SVT. Conditions like atrial fibrillation or atrial flutter can sometimes present as SVT.
• Heart Disease: Structural heart conditions, such as congenital heart defects or heart disease, can create conditions that facilitate SVT.
• Electrolyte Imbalances: Imbalances in electrolytes like potassium or sodium can disrupt normal electrical signaling in the heart, potentially triggering SVT.
• Stress and Stimulants: Emotional stress, caffeine, alcohol, and certain medications or recreational drugs can provoke SVT episodes.
• Hyperthyroidism: Overactive thyroid (hyperthyroidism) can increase the risk of SVT due to its effect on heart rate and rhythm.
• Infections or Fever: Illnesses that cause fever or systemic infections can sometimes trigger SVT, particularly in individuals with predisposing conditions.
• Increased Sympathetic Activity: Situations that increase sympathetic nervous system activity, such as exercise or anxiety, can trigger SVT in some people.

Identifying and addressing the underlying cause or trigger is essential for effective management and treatment of SVT.

What is the treatment for SVT?

Treatment for supraventricular tachycardia (SVT) focuses on managing symptoms, controlling episodes, and addressing the underlying causes. The approach depends on the frequency and severity of episodes, as well as the overall health of the patient. Common treatment options include:

• Vagal Maneuvers: These are techniques used to stimulate the vagus nerve, which can help slow the heart rate and potentially terminate an SVT episode. Common maneuvers include holding one’s breath, coughing, or performing a Valsalva maneuver (forcefully exhaling with a closed mouth and nose).
• Medications: Various medications can be used to manage SVT, including:
• Adenosine: Administered intravenously in an emergency setting to rapidly restore normal heart rhythm.
• Beta-Blockers: Such as metoprolol or atenolol, to reduce heart rate and prevent SVT episodes.
• Calcium Channel Blockers: Such as diltiazem or verapamil, to help control the heart rate.
• Antiarrhythmic Drugs: Medications like flecainide or propafenone can be used to prevent SVT episodes.
• Electrical Cardioversion: In cases of persistent or severe SVT, a controlled electrical shock may be delivered to the heart to restore a normal rhythm. This procedure is typically performed in a hospital setting.
• Catheter Ablation: A procedure where a catheter is inserted into the heart to destroy or isolate the abnormal electrical pathways causing SVT. This can provide long-term relief or potentially cure SVT in many cases.
• Lifestyle Modifications: Identifying and avoiding triggers, such as excessive caffeine, alcohol, or stress, can help reduce the frequency of SVT episodes.
• Management of Underlying Conditions: Treating any underlying conditions, such as hyperthyroidism or heart disease, can help manage or reduce SVT episodes.
• Regular Monitoring and Follow-Up: Ongoing follow-up with a healthcare provider to monitor the effectiveness of treatment, adjust medications, and manage any potential side effects is important.

Treatment plans are individualized based on the patient’s specific situation, including the type of SVT, the frequency of episodes, and the presence of any underlying health conditions.