Applied Research Of Doppler Tissue Imaging Technique In Evaluating Accessory Pathways In Wolff-Parkinson-White Syndrome

Objective To evaluate the accuracy, practical value and methods of Doppler tissue imaging(DTI) in localizing the ventricular emergence site of accessory atrioventricular pathways. Methods Forty patients with WPW syndrome were examined by DTI before intracardiac electrophysiologic studies(EP) and radiofrequency catheter ablation(RFCA). The preexcitation zone was determined as a zone of maximum acceleration with "DTI acceleration mode" at the tune of the delta wave or before the onset of the QRS complex. At the same time, the contraction velocity was measured from subendocardium of corresponding myocardial segment by "pulsed wave Doppler imaging". Results Assuming the results of EP and RFCA as a gold standard, the correct localization by DTI was 80% but was only 47.5% and 52.5% by eletrocardiographic algorithms(P<0.05). The bypass tract myocardial contraction velocity was much higher than that of control group(P<0.05). After effective ablation, the abnormalities corresponding to the electrophysiologic delta wave disappeared in 30 of 32 cases, and the myocardial contraction velocity in all patients was lower than that of pre-operation(P<0.05). Conclusions Maybe, DTI is a high efficiency, intuitional, handy, safe and reproducible non-invasive investigation, which has an important value to define bypass of WPW syndrome and to increase successful rate and security of interventional procedures. It's necessaryto study this technique ulteriorly.