Epicardial mapping in patients with "nodoventricular" accessory pathways

Area of Science:

• Electrophysiology
• Cardiology
• Cardiac Surgery

Background:

• Some patients exhibit electrophysiologic features suggestive of nodoventricular fibers.
• These patients may have right parietal atrioventricular (AV) accessory pathways with decremental conduction properties.
• Intraoperative findings have correlated these features with specific pathway locations.

Purpose of the Study:

• To review the experience with patients who had electrophysiologic features consistent with a nodoventricular pathway.
• To correlate electrophysiologic findings with intraoperative demonstrations of accessory pathways.
• To investigate the characteristics and surgical outcomes of these pathways.

Main Methods:

• Retrospective review of 11 patients undergoing operative correction for suspected nodoventricular pathways.
• Electrophysiologic studies including atrial pacing and extrastimulus testing.
• Intraoperative mapping to identify accessory pathway location and ventricular insertion site.

Main Results:

• All patients demonstrated maximal preexcitation with left bundle branch block morphology and progressive AH/AV interval prolongation during testing.
• Atrioventricular reentrant tachycardia was initiated in 10 patients, and AV node reentrant tachycardia in 1 patient.
• Intraoperative mapping confirmed right parietal accessory pathways in all patients, with ventricular insertion into the right bundle branch system in 7 and the AV groove in 4.

Conclusions:

• Electrophysiologic features suggestive of nodoventricular pathways are associated with right parietal AV accessory pathways.
• These pathways exhibit decremental conduction properties and can sustain reentrant tachycardias.
• Intraoperative mapping is crucial for identifying the precise location and insertion of these accessory pathways.