Supraventricular tachycardia

Supraventricular tachycardia (SVT) represents a group of arrhythmias, or irregular heart rhythms, characterized by a heart rate exceeding the typical range and originating from cardiac tissue above the level of the ventricles. This means the abnormal rhythm arises either from the atria or the atrioventricular (AV) node.

Etiology and Pathophysiology

SVT typically results from faulty electrical activity in the heart. While several factors may contribute to its development, SVT commonly stems from a reentrant pathway, where the electrical impulses circularly move through the heart's conduction system, or an ectopic pacemaker, where a site other than the sinus node initiates the electrical signal.

Clinical Presentation

Symptoms of SVT can vary, ranging from almost unnoticed to debilitating. Common symptoms include palpitations, shortness of breath, chest discomfort, and light-headedness. In extreme cases, it can lead to unconsciousness or cardiac arrest, though this is rare.

Diagnosis

The primary tool for diagnosing SVT is an electrocardiogram (ECG), which records the electrical activity of the heart. In SVT, the ECG typically shows a rapid heart rate and narrow QRS complexes, but aberrant conduction or preexcitation may sometimes be present. Additional diagnostic tools can include Holter monitoring, exercise stress testing, and electrophysiological study.

Treatment and Management

The management of SVT aims at controlling the heart rate, preventing recurrences, and managing potential complications. Initial treatment options can include vagal maneuvers or medications that slow the heart rate such as beta-blockers or calcium channel blockers. In cases where these approaches are ineffective or if the patient has recurrent episodes, catheter ablation may be considered. This procedure targets and destroys the abnormal electrical pathways causing SVT.

See Also

• Arrhythmia
• Electrocardiogram
• Atrioventricular node
• Atria

References

Supraventricular tachycardia Resources
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