Negative Concordance Pattern in Bipolar and Unipolar Recordings: An Additional Mapping Criterion to Localize the Site of Origin of Focal Ventricular Arrhythmias.

BACKGROUND: The relevance of the temporal relationship between unipolar (UEGM) and bipolar electrograms (BEGM) in determining the site of origin (SOO) of focal arrhythmias has been largely demonstrated. OBJECTIVE: We sought to demonstrate that also a negative concordance in the initial forces of these EGMs, is helpful in predicting the SOO of premature ventricular contractions (PVCs). METHODS: Mapping and radiofrequency (RF) ablation were performed in 41 patients with symptomatic PVCs in absence of structural heart disease. Simultaneous recordings of minimally filtered (0.5-500 Hz) UEGM and filtered BEGM (30-500 Hz) were analyzed at 247 mapping sites, where RF was attempted. EGMs of 63 mechanically-induced PVCs were separately analyzed as a validation group. All ablation sites had a QS pattern in the UEGM. Acute PVCs suppression was defined as complete disappearance of ventricular ectopic beats after a 60 sec pulse of RF. RESULTS: RF ablation obtained PVC suppression (RF+) in 33 sites (33/247, 13,3%). Negative concordance pattern (NCP) during the initial 20 ms of both UEGM and BEGM was observed in 31/33 (94%) RF+ sites compared to 10/214 RF- sites, p < 0,0001. The NCP criterion demonstrated to be an additional powerful predictor of acute RF success with sensitivity, specificity, positive and negative predictive values of 94%, 95%, 76%, 99% respectively. Similarly to RF+ sites, the NCP was observed in 60/63 sites (95,2%) in the mechanical PVCs group. CONCLUSIONS: A NCP in both UEGM and BEGM may be helpful as an additional criterion to localize the SOO of focal ventricular arrhythmias