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Changes in ventriculoatrial intervals with bundle branch block aberration during reciprocating tachycardia in
Insights
Changes in ventriculoatrial (VA) intervals during bundle branch block (BBB) effectively localize accessory atrioventricular pathways. This method aids in differentiating septal from free wall pathways, guiding surgical intervention for tachycardia.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Accessory atrioventricular pathways can cause reciprocating tachycardia.
- Localization of these pathways is crucial for effective treatment.
- Ventriculoatrial (VA) interval changes during bundle branch block (BBB) have been used for pathway localization.
Purpose of the Study:
- To evaluate the utility of VA interval changes during BBB for localizing accessory atrioventricular pathways.
- To differentiate between septal and free wall accessory pathways based on VA interval response to BBB.
Main Methods:
- Analysis of VA intervals in 93 patients with single accessory atrioventricular pathways during induced bundle branch block (BBB).
- Correlation of VA interval changes with pathway location confirmed during surgical interruption.
- Differentiation of pathway locations based on the magnitude and pattern of VA interval changes with right bundle branch block (RBBB) and left bundle branch block (LBBB).
Main Results:
- Patients with free wall pathways showed significant VA min interval increase (61 +/- 19 msec) with ipsilateral BBB, but no change with contralateral BBB.
- Septal pathways exhibited smaller VA min interval changes (<= 25 msec) with either RBBB or LBBB.
- Anteroseptal pathways prolonged VA min with RBBB (16 +/- 9 msec), while posteroseptal pathways prolonged VA min with LBBB (13 +/- 8 msec).
Conclusions:
- Observed changes in VA min intervals during BBB are a reliable indicator of accessory pathway location.
- This electrophysiological method can guide the selection of surgical therapy for accessory pathway-mediated tachycardia.
Abstract:
During reciprocating tachycardia in patients with accessory atrioventricular pathways, the observation of changes in ventriculoatrial (VA) intervals with bundle branch block (BBB) aberration has been used to localize the site of the pathway and prove the participation of the pathway in the tachycardia. In this report we present the changes observed during BBB in 93 patients with single atrioventricular pathways in whom the site of their pathways was subsequently proved at the time of their surgical interruption. In patients with left or right free wall pathways, the minimum VA interval (VA min) increased by 61 +/- 19 msec with ipsilateral BBB, whereas no change occurred with contralateral BBB. The smallest increase in the VA interval was 35 msec. In 14 patients, shortening of the AH intervals resulted in changes in overall cycle length that were less than 35 msec. Patients with septal pathways all had changes in VA min of 25 msec or less with either right or left bundle branch block (RBBB or LBBB), which suggests that a clear differentiation between septal and free wall pathways can be made on the basis of changes in VA min. In patients with anteroseptal pathways, VA min intervals frequently prolonged with RBBB (16 +/- 9 msec) but not with LBBB. In patients with posteroseptal pathways, VA min frequently prolonged with LBBB (13 +/- 8 msec) but not with RBBB. Therefore, the observed changes in VA min with BBB may serve as an important indicator of the site of an accessory pathway and may provide guidance in the choice of surgical therapy.