SVT & WPW

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About SVT & WPW

Supraventricular tachycardia (SVT) encompasses rapid heart rhythms originating above the ventricles, while Wolff-Parkinson-White (WPW) syndrome involves an accessory electrical pathway that can predispose patients to specific types of SVT. WPW creates a substrate for reentrant tachyarrhythmias and carries risk for sudden cardiac death if atrial fibrillation occurs with rapid ventricular response.

Pathophysiology

SVT typically results from reentrant circuits involving the AV node, atrial tissue, or accessory pathways, leading to heart rates of 150-250 bpm. WPW syndrome features an accessory pathway (Bundle of Kent) that bypasses normal AV node conduction delay, creating a delta wave on ECG and enabling bidirectional conduction that facilitates atrioventricular reentrant tachycardia (AVRT).

Clinical Reasoning

Patients with SVT present with palpitations, chest discomfort, dyspnea, and potential hemodynamic instability requiring immediate rhythm assessment and vagal maneuvers or adenosine for termination. WPW patients require careful evaluation as certain antiarrhythmic drugs like digoxin or calcium channel blockers can paradoxically worsen ventricular response during atrial fibrillation by blocking the AV node while leaving the accessory pathway uninhibited.

References

  1. Supraventricular Tachycardia - StatPearls. StatPearls / NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK441972/
  2. Wolff-Parkinson-White Syndrome - StatPearls. StatPearls / NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK554437/
  3. 2015 ACC/AHA/HRS Guideline for SVT. Circulation. https://doi.org/10.1161/CIR.0000000000000311

Related Topics

Atrial FibrillationReasonDxACLS RhythmsEKG Interpretation