Where does paroxysmal ventricular tachycardia (PVT or v-tach) originate?

Where does paroxysmal ventricular tachycardia (PVT or v-tach) originate?

• A. An irritable atrial automaticity focus
• B. An ectopic ventricular focus
• C. An irritable ventricular automaticity focus
• D. A conduction pathway within the AV node

Answer: (C)

Paroxysmal ventricular tachycardia (PVT or v-tach) originates from an irritable ventricular automaticity focus. This means that the abnormal electrical activity responsible for v-tach emerges from a specific area in the ventricles that exhibits increased automaticity, which is the focus's ability to initiate impulses independent of the normal cardiac conduction system.

This focus becomes hyperexcitable and can generate rapid electrical impulses, leading to a sustained, rapid heart rate characteristic of v-tach. This automaticity is distinct from the typical control by the sinoatrial node, where more regulated rhythm originates. Understanding this origin helps in diagnosing and managing v-tach effectively, as treatment may focus on addressing the irritable focus directly.

Other potential areas implicated in arrhythmias, such as the atria or conduction pathways within the AV node, do not specifically account for the mechanisms driving paroxysmal ventricular tachycardia. These areas are involved in different types of arrhythmias that would not lead to the same ventricular-based tachycardia seen in PVT.