Abstract 17905: Variations in the QRS Morphology of Ventricular Arrhythmias Arising Near the His Bundle Region of Tricuspid Annulus
Background: There are some variations in the ECG characteristics of the idiopathic ventricular arrhythmias arising near the His bundle region (VA-HB). The purpose of this study was to clarify the ECG variations of VA-HB.
Methods: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 17 patients with VA-HB. Activation mapping and pace mapping and/or RF ablation of VA-HB were performed in all cases using an electroanatomic mapping system. The VA-HB was defined as the ventricular arrhythmias of which origins were located near the His-bundle at least within 15mm of the largest His-bundle potential recording site.
Results: In all patients with VA-HB, the QRS complexes during the VA-HB exhibited left bundle branch block pattern and the precordial R-wave transition occurred beyond lead V1-V2. The duration of the QRS complex of the VA-HB was 148±18ms (range 124–192ms). The ECG characteristics of VA-HB were broadly divided into two types by the QRS polarity in lead III. Ten (83%) of 12 VA-HB with negative QRS polarity (qrS or QS pattern) in lead III showed also negative QRS polarity in lead III of the sinus beats. On the other hand, all of the remaining 5 VA-HB with positive QRS polarity in lead III showed positive QRS polarity in lead III of the sinus beats. The negative QRS polarity in lead III of the sinus beats predicted negative QRS polarity in lead III of the VA-HB with 83% sensitivity and 100% specificity. In 15(88%) of 17 VA-HB, an R or RR' pattern in lead I and aVL was recorded. Furthermore, R-wave amplitude in lead I and aVL of the VA-HB was taller than that of the sinus beats in 16 (94%) of 17 VA-HB. Lower R-wave amplitude in lead III than in lead II was recorded in all VA-HB. A QS pattern in lead V1 was recorded in 14 (82%). Successful RF catheter ablation was achieved near the His-bundle region of the tricuspid annulus in 13 (76%) of 17 patients. We had three unsuccessful cases and one untreated case for fear of creating complete atrioventricular block.
Conclusions: VA-HB has two types of ECG variations that are closely linked to the QRS polarity in lead III of the sinus beats. Knowledge of the unique QRS morphology allows us to identify the VA-HB precisely prior to RF catheter ablation.
- © 2010 by American Heart Association, Inc.