Paroxysmal Supraventricular Tachycardia (PSVT)

Paroxysmal Supraventricular Tachycardia (PSVT) is a condition that affects the heart's electrical system, causing episodes of very fast heartbeats that start and stop suddenly. These rapid heartbeats originate above the heart's ventricles, usually in the atria or the atrioventricular node. During an episode, the heart can beat much faster than normal, which may cause symptoms like palpitations, dizziness, or shortness of breath. The condition involves the cardiac conduction pathways and disrupts the normal rhythm of the heart. Although episodes can be brief, they can significantly impact a person's daily activities and overall heart function. Understanding this condition helps explain why the heart sometimes races unexpectedly.

Paroxysmal Supraventricular Tachycardia (PSVT) is defined as a sudden onset and termination of a narrow-complex tachycardia originating above the ventricles, typically involving reentrant circuits within or near the atrioventricular node. The core pathology involves abnormal electrical conduction pathways, such as an accessory pathway or dual AV nodal pathways, leading to rapid, repetitive activation of the atria and ventricles. The most common mechanism is AV nodal reentrant tachycardia (AVNRT), but other forms include AV reentrant tachycardia (AVRT) involving accessory pathways like the Kent bundle. PSVT is clinically significant because it causes symptomatic tachycardia with palpitations, lightheadedness, and sometimes syncope, and can lead to hemodynamic instability if sustained. It is important to distinguish PSVT from other supraventricular tachycardias and ventricular tachycardia due to differences in management and prognosis.