Novel surface ECG criteria for differentiation between left- and right-sided manifest inferoseptal accessory pathways

Differentiation between left- and right-sided inferoseptal accessory pathways by existing ECG algorithms is unsatisfactory. We reviewed the 12-lead ECGs of 113 consecutive patients undergoing successful ablation of a single manifest inferoseptal pathway (40% at the mitral, 60% at the tricuspid annulus). For prediction of a right-sided location, the most useful criteria were a) a negative QRS polarity in all three inferior leads and in V1 (positive predictive value (PPV) 0.90, negative predictive value (NPV) 0.51) and b) a negative QRS polarity in >= 2 inferior leads and in V1 (PPV 0.80, NPV 0.56). A positive QRS polarity in >= 1 inferior lead predicted a left- sided location (PPV 0.54, NPV 0.80). A new algorithm had an accuracy of 76%. (C) 2008 Elsevier Ireland Ltd. All rights reserved.