Algorithms for locating accessory pathways: How far should we trust?

Algorithms for locating accessory pathways (APs) are widely used in planning catheter ablation for patients with ventricular preexcitation. These algorithms typically rely on characteristics of the delta wave and QRS complex to predict AP location. However, factors such as anatomical variations, age, the presence of multiple APs, and patient biotype can lead to inaccuracies. We present the case of a patient with ventricular preexcitation but no comorbidities, whose electrocardiogram (ECG) suggested an AP location entirely different from that predicted by standard algorithms. This discrepancy led to a change in the catheter ablation strategy, which was successfully performed via a retrograde aortic approach.