الفهرس 
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Abstract
Introduction
Wolf Parkinson White (WPW) syndrome is a form of ventricular pre-excitation where part of the ventricular myocardium is depolarized early by one or more AP. Preprocedural localization of the site of AP helps in the success and provides for better planning and decreases the exposure to ionizing radiation.
Several algorithms have been published that helps to identify the site of AP using 12 lead surface electrocardiogram (ECG). Most of these algorithms are based on the analysis of delta wave morphology(5,6,7,8). However accurate determination of delta wave is morphology is occasionally difficult. Other algorithms based on the QRS polarity have been reported (9-14), but there accuracy is still limited.
Aim of work
Studying new criteria for prediction of the site of AP from surface ECG during maximal preexcitation.
Patients and methods
Our study was a prospective observational study. It included 73 patients referred for radiofrequency catheter ablation of a manifest AP.
Each patient had a baseline ECG obtained 24 hours before the ablation procedure. AP localization using Arruda’s algorithm was done.
Maximal preexcitation was obtained during EP study by decremental atrial pacing during determinantion of the AP AERP, or by preexcited atrial fibrillation.
ECG during maximal preexcitation was used to predicted the site of the AP using both, Arruda’s algorithm and Pambrun’s algorithm.
Both Arruda’s algorithm (using baseline ECG and maximally preexcited ECG) was compared to Pamburn’s algorithm.
Results
73 patients with WPW syndrome were enrolled in the study.26 patients (35.5%) were females and 47 patients (64.5%) were males with mean age was 32.8 ±11.9 years. Arruda’s algorithm using baseline ECG accurately detected 46 patients, with 77.5% accuracy, 63% sensitivity, 92% specificity, 47% positive predictive value and 94% negative predictive value.Arruda’s algorithm using maximally preexcited ECG detected 56 patients with 85.5% accuracy, 77% sensitivity, 94% specificity,55% positive predictive value and 96% negative predictive value. Pamburn’s algorithm detected 52 patients with 84% Accuracy, 72% sensitivity, 96% Specificity, 69% positive predictive value and 95.5% negative predictive value.
Conclusions
The accuracy of the algorithms used for prediction of the site of APs depends on the degree of preexcitation, increased preexcitation increases the accuracy of AP localization, Maximal preexcitation provides for the best localization of the site of AP.
Arruda’s algorithm using maximally preexcited ECG and depending on delta wave polarity provided better detection of the site of AP than Pamburn’s algorithm (depending on QRS polarity) especially for Posteroseptal APs. Both algorithms provided more accurate detection compared to Arruda’s algorithm using baseline ECG.
Pamburns algorithm is more sensitive than Arruda’s in predicting right free wall APs.
Posteroseptal or inferior paraseptal APs, which represent the second most common atrioventricular (AV) connection site after left free wall APs, often pose a diagnostic challenge. This reflects the complex anatomy at the crux of the four cardiac chambers, where a small area may encompass APs that may be approached from the right or left endocardium, or require an ablation performed epicardially inside the coronary sinus (CS).