An Accurate Stepwise Electrocardiographic Algorithm for localization of Accessory Pathways in Patients With Wolff-Parkinson-White Syndrome from a Comprehensive Analysis of Delta Waves and R/S Ratio During Sinus Rhythm

A long slanted transseptal accessory pathway

“…The possibility of the existence of atrioventricular accessory pathways was first raised by Kent et al in 1913. In this case, one of the challenges that may be encountered during accessory pathway ablation was shown in the baseline ECG presenting the R/S > 1 in V2 and negative delta at leads III and V1, which suggested the location of an accessory pathway at the right posterior septum under the algorithm documented by Chiang et al 7 However, the earliest atrial activation was located at the left posterior portion during tachycardia. This discrepancy of antegrade and retrograde accessory pathways included double accessory pathways and slanted accessory pathway.…”

Choice of Management in a Rare Case of Symptomatic Wolff-Parkinson-White (WPW) Syndrome Type B

“…This finding has been reinforced with evidence from various sources such as when Durrer and Roos were the very first ones to locate a right free wall AP via intraoperative mapping and cooling [7]. Since the advent of radiofrequency ablation as a suitable method to successfully treat this condition, algorithms have been developed to accurately predict APs in ECGs for multiple reasons; to reduce morbidity, shorten procedure time, selection of the ablator with appropriate curves and to minimize mechanical trauma [8] [9]. One of the first known attempts was in an article written in 1987 by Milsten and Sharma et al published an algorithm by attempting to identify four APs in 141 patients, namely right free wall, anteroseptal, posteroseptal and left free wall using the morphology of delta wave [8].…”

“…They then went on to develop a relatively simple 4-step process that required examining 4 leads: V1, V2, Lead III and aVF. They discovered that their algorithm was able to predict the location of APs with an overall accuracy of 93% when they used the algorithm to predict their remaining 187 patients as compared to 86%, 85% and 85% respectively [9]. In 2014, a paper by Taguchi and Yoshida et al recognized that using the delta wave morphology analysis method can often be difficult with many limitations such as the need for maximal pre-excitation.…”

A Novel Technique for Zero-Fluoroscopy Catheter Ablation Used to Manage Wolff–Parkinson–White Syndrome With a Left-Sided Accessory Pathway

“…The 12-lead electrocardiogram (ECG) showed preexcitation with an R/S ratio of 1 or more in lead V 2 and a positive delta wave in lead III, suggesting a left lateral/left anterolateral accessory pathway [2] (Fig. 1a).…”