PSVT vs SVT: Key Differences
PSVT (Paroxysmal Supraventricular Tachycardia) is a specific clinical subset of SVT (Supraventricular Tachycardia), not a different entity—PSVT refers to SVTs that start and stop abruptly, while SVT is the broader umbrella term encompassing all tachycardias originating from or above the His bundle. 1
Understanding the Terminology
SVT is the umbrella term that describes any tachycardia (heart rate >100 bpm at rest) where the mechanism involves tissue from the His bundle or above 1. This broad category includes:
- Inappropriate sinus tachycardia
- Atrial tachycardia (focal and multifocal)
- Atrial flutter
- Junctional tachycardia
- AVNRT (atrioventricular nodal reentrant tachycardia)
- AVRT (atrioventricular reentrant tachycardia via accessory pathways)
Importantly, SVT does not include atrial fibrillation, despite AF technically being supraventricular in origin 1.
What Makes PSVT Different
PSVT represents a clinical syndrome characterized by three defining features 1:
- Regular and rapid tachycardia (typically 150-250 bpm)
- Abrupt onset (sudden start)
- Abrupt termination (sudden stop)
These characteristics are most commonly seen in:
- AVNRT (most common cause)
- AVRT (second most common)
- Atrial tachycardia (less frequently)
Clinical Distinction
The key difference is temporal pattern and presentation:
PSVT patients experience discrete episodes with sudden palpitations that start and stop abruptly 2, 3. They can often pinpoint the exact moment symptoms began and ended.
Other SVTs (like inappropriate sinus tachycardia, multifocal atrial tachycardia, or persistent atrial flutter) may have gradual onset, persistent patterns, or irregular rhythms that don't fit the paroxysmal pattern 1.
Epidemiology Clarification
The incidence of PSVT specifically is approximately 36 per 100,000 persons per year, with about 89,000 new cases annually in the US 1. Women have twice the risk of men, and individuals >65 years have >5 times the risk of younger persons 1, 4.
Why This Distinction Matters Clinically
The paroxysmal nature of PSVT makes it amenable to specific acute interventions that terminate reentrant circuits:
- Vagal maneuvers are effective because they interrupt the reentrant circuit 3
- Adenosine works specifically by blocking AV nodal conduction, breaking the circuit (91% effective) 3
- Catheter ablation has exceptionally high success rates (94.3-98.5%) for PSVT because the reentrant circuits can be mapped and eliminated 3
In contrast, other SVTs like inappropriate sinus tachycardia or multifocal atrial tachycardia don't respond to these interventions because they don't involve reentrant mechanisms 1.
Common Pitfall to Avoid
Don't use "SVT" and "PSVT" interchangeably in documentation or communication. When you say "PSVT," you're specifically indicating a reentrant mechanism with abrupt onset/termination, which has different management implications than saying "SVT," which could include any supraventricular rhythm disturbance. This distinction affects treatment decisions, particularly regarding the appropriateness of catheter ablation as first-line therapy 3.