Reliability of retrograde atrial activation patterns during ventricular pacing for localizing accessory pathways

Area of Science:

• Electrophysiology
• Cardiology
• Medical Devices

Background:

• Accessory pathways are a common cause of supraventricular tachycardia.
• Definitive localization typically relies on atrial activation during tachycardia, which isn't always feasible.
• Alternative methods are needed for patients where tachycardia induction is difficult or dangerous.

Purpose of the Study:

• To evaluate the accuracy of ventricular pacing for localizing accessory pathway sites.
• To compare retrograde atrial activation patterns during ventricular pacing with those during supraventricular tachycardia.
• To establish a reliable method for accessory pathway identification when tachycardia is not inducible.

Main Methods:

• Assessed retrograde atrial activation during orthodromic supraventricular tachycardia and ventricular pacing in 41 patients.
• Measured the difference in conduction time (delta A-SVT and delta A-VP) to account for normal atrioventricular conduction.
• Correlated atrial activation times from ventricular pacing with characteristic intervals for known accessory pathway locations.

Main Results:

• Characteristic delta A-SVT intervals were identified for specific accessory pathway locations.
• Ventricular pacing accurately predicted accessory pathway sites when delta A-VP intervals matched delta A-SVT.
• A high correlation (r=0.91) was found between delta A-SVT and maximal delta A-VP intervals.
• 98% of accessory pathway sites (40/41) were correctly identified using ventricular pacing.

Conclusions:

• Ventricular pacing is a reliable method for accessory pathway localization.
• This technique provides an accurate alternative when supraventricular tachycardia induction is not possible.
• Accurate localization of accessory pathways can be achieved through analysis of retrograde atrial activation during ventricular pacing.