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Typical AVNRT--an update on mechanisms and therapy.
Kevin F Kwaku1, Mark E Josephson
1Harvard-Thorndike Electrophysiology Institute and Arrhythmia Service, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Cardiac Electrophysiology Review
|November 20, 2002
Summary
Typical atrioventricular reentrant tachycardia (AVNRT) is a common arrhythmia. Catheter ablation targeting the slow pathway in the Triangle of Koch offers a safe and effective definitive treatment for most patients.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Science
Background:
- Typical atrioventricular reentrant tachycardia (AVNRT) is the most prevalent paroxysmal supraventricular tachycardia in adults, causing significant morbidity.
- The underlying dual pathway physiology is likely due to anisotropic tissue properties within the triangle of Koch, not distinct anatomical tracts.
- Debate exists on whether atrial participation is essential for the reentrant circuit.
Purpose of the Study:
- To review evidence supporting functional anisotropic reentry within subatrial tissues as the primary mechanism for typical AVNRT.
- To emphasize the efficacy and safety of catheter ablation as the primary therapeutic strategy.
Main Methods:
- Review of current evidence regarding the electrophysiological mechanisms of typical AVNRT.
- Analysis of outcomes from catheter-based radiofrequency ablation series targeting the posterior Triangle of Koch.
Main Results:
- Current evidence favors functional anisotropic reentry in subatrial tissues as the mechanism for typical AVNRT.
- Catheter ablation at the posterior Triangle of Koch (slow pathway region) is a highly effective and safe treatment.
- Anterior or left-sided approaches for ablation are rarely necessary.
Conclusions:
- Functional anisotropic reentry is the favored mechanism for typical AVNRT.
- Radiofrequency ablation targeting the slow pathway is the definitive therapy of choice for most patients with typical AVNRT.
- This catheter-based approach demonstrates excellent safety and efficacy.