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Inferior lead discordance in ventricular arrhythmias: A specific marker for certain arrhythmia locations
Author(s) -
Enriquez Andres,
Pathak Rajeev K.,
Santangeli Pasquale,
Liang Jackson J.,
Al Rawahi Mohammed,
Hayashi Tatsuya,
Muser Daniele,
Frankel David S.,
Supple Gregory,
Schaller Robert,
Lin David,
Nazarian Saman,
Zado Erica,
Marchlinski Francis E.,
Garcia Fermin C.
Publication year - 2017
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.13287
Subject(s) - medicine , cardiology , ablation , qrs complex , ventricular tachycardia , catheter ablation , intracardiac injection , tachycardia , radiofrequency ablation , bigeminy
Background Most idiopathic ventricular arrhythmias (VAs) originate from the outflow tracts and are characterized by an inferior axis on the 12‐lead ECG. A group of patients will exhibit inferior lead discordance (ILD), demonstrating a positive QRS in lead II with negative QRS in III or the opposite finding. Methods and results We identified patients undergoing ablation of idiopathic premature ventricular contractions (PVCs) or ventricular tachycardia (VT) between 2013 and 2015. The site of earliest activation was determined using electroanatomic mapping and intracardiac echocardiography. Out of 281 patients, 25 (8.9%) exhibited ILD. In patients with positive/negative discordance (n = 18), the source was mapped to the parahisian region in 14 cases and to the right ventricular (RV) moderator band (MB) or papillary muscles (PMs) in 4, while all those with negative/positive discordance (n = 7) were mapped to the anterolateral PM (ALPM). In the group with positive/negative discordance, a later precordial transition (>V4), wider QRS duration, and the presence of notch in the inferior leads pointed toward a RV MB/PM origin. Complete PVC/VT suppression was achieved in 72%. In 2 patients with parahisian PVCs, ablation was not attempted due to risk of heart block. Conclusions The presence of ILD is associated with particular anatomical locations, namely, the parahisian region, RV MB/PM, and ALPM. The outcomes of ablation are more modest compared to other idiopathic VAs, reflecting the technical difficulties associated with these anatomical locations, such as the proximity to the conduction system in parahisian VAs or stability issues when ablating the PMs or MB.