Understanding Paroxysmal Supraventricular Tachycardia (PSVT)

Paroxysmal Supraventricular Tachycardia (PSVT) refers to sudden episodes of rapid heartbeats originating from above the ventricles (in the atria or AV node). Identifying the most common cause is crucial for diagnosis and treatment.

Most Common PSVT Mechanism

Among the different types of PSVT, re-entry circuits involving the atrioventricular (AV) node are the most frequent. Specifically, AV Nodal Reentry Tachycardia (ANVRT) accounts for the majority of PSVT cases.

Types of Supraventricular Tachycardia

Several mechanisms can cause PSVT. The common types include:

• AV Nodal Reentry Tachycardia (ANVRT): This involves a re-entry circuit within or immediately adjacent to the AV node. It is the predominant cause of PSVT, often seen in younger individuals without structural heart disease.
• Atrial Tachycardia: Originates from an ectopic focus within the atria.
• Reentry involving Accessory Pathways: Such as those seen in Wolff-Parkinson-White (WPW) syndrome, where an extra electrical connection between the atria and ventricles facilitates re-entry. While common, ANVRT occurs more frequently.
• Junctional Ectopic Tachycardia (JET): Less common, often associated with specific conditions like congenital heart disease or post-cardiac surgery.
• Accelerated Junctional Rhythm: This is a regular rhythm originating from the junction, typically slower than a true tachycardia and not usually classified under the typical PSVT mechanisms.

Based on prevalence studies and clinical observations, AV Nodal Reentry Tachycardia (ANVRT) is recognized as the most common mechanism underlying Paroxysmal Supraventricular Tachycardia.