Assessment of accessory atrioventricular pathways by Doppler myocardial imaging.

Purpose: The use of electrophysiologic studies (EPS) for the localization of accessory atrioventricular connections in Wolff-Parkinson-White syndrome (WPW) requires accurate evaluation of the site of bypass tract insertion. Doppler myocardial imaging (DMI) is a new ultrasound technique that allows the detection of abnormal and early regional myocardial depolarization. The purpose of this study was to identify an abnormal pathway site in WPW patients.

Methods: Twenty-one patients with ventricular preexcitation were studied by DMI. Two-dimensional color DMI, velocity maps, acceleration maps, and pulsed-wave applications were used. A subsequent diagnostic EPS was performed. The results of EPS were taken as the gold standard diagnostic procedure. Radiofrequency catheter ablation therapy was then performed on all patients.

Results: The anomalous pathway was detected by DMI in 16 (76%) of 21 patients (9 [90%] of 10 with left pathways and 7 [64%] of 11 with right pathways), with respect to results of the EPS. Pathway detection was better with pulsed-wave DMI (76%) with its higher temporal resolution as compared with M-mode velocity map (57%) and acceleration map (47%). In most of the patients with successful radiofrequency ablation, an immediate resolution of the abnormal ventricular depolarization occurred and was detectable by DMI.

Conclusions: Our findings demonstrate the feasibility of DMI to assess the early ventricular contraction associated with atrioventricular accessory pathways. Therefore, DMI appears to be a clinically useful adjunct to noninvasive evaluation of abnormal myocardial depolarization in WPW and to evaluate the results after radiofrequency ablation, even though its accuracy is considerably better for left-sided accessory pathways than for right-sided ones.