Accuracy and limitations of published algorithms using the twelve-lead electrocardiogram to localize overt atrioventricular accessory pathways

Introduction: The purpose of this study was to evaluate the accuracy and li mitations of published algorithms using the 12-lead ECG to localize AV acce ssory pathways (APs), Methods and Results: The 11 relevant algorithms found in the literature (ME DLINE database and major scientific sessions) were tested on a series of 26 6 consecutive patients who successfully underwent radiofrequency catheter a blation of a single overt AV AP, The positive predictive values (PPV) of th e algorithms in applicable patients were significantly lower for algorithms with > 6 accessory location sites (40.6% +/- 10.9% vs 61.2% +/- 8.0%; P < 0.03) and show a tendency for algorithms not relying on delta wave polarity but on QRS polarity only (36.6% +/- 11.2% vs 52.3% +/- 13.1%; P = 0.09). T he PPV in applicable patients is related to the AP location (P < 0.001) and ranked from the highest to the lowest as follows: left lateral (mean PPV = 86.3%), posteroseptal (mean PPV = 65.2%), right anteroseptal (mean PPV = 4 5.2%), and right posterolateral (mean PPV = 23.3%). Conclusion: Our study suggests that the accuracy of algorithms relying on t he 12-lead ECG depends on AP locations as defined in the algorithms and on the number of AP sites, The accuracy tends to be lower when delta wave pola rity is not included in the algorithm's architecture. This should be consid ered then using these algorithms or when building new ones.