Electrocardiographic and Electrophysiologic Characteristics of Idiopathic Ventricular Arrhythmias Originating From the Basal Inferoseptal Left Ventricle

Jackson J. Liang, Yasuhiro Shirai, David F. Briceño, Daniele Muser, Andres Enriquez, Aung Lin, Matthew C. Hyman, Ramanan Kumareswaran, Jeffrey S. Arkles, Pasquale Santangeli, Robert D. Schaller, Gregory E. Supple, David S. Frankel, R. Deo, Andrew E. Epstein, Fermin C. Garcia, Michael P. Riley, S. Nazarian, D. Lin, David J. CallansFrancis E. Marchlinski, Sanjay Dixit

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Objectives: This study sought to characterize ventricular arrhythmia (VA) ablated from the basal inferoseptal left ventricular endocardium (BIS-LVe) and identify electrocardiographic characteristics to differentiate from inferobasal crux (IBC) VA. Background: The inferior basal septum is an uncommon source of idiopathic VAs, which can arise from its endocardial or epicardial (crux) aspect. Because the latter are often targeted from the coronary venous system or epicardium, distinguishing between the 2 is important for successful ablation. Methods: Consecutive patients undergoing ablation of idiopathic VA from the BIS-LVe or IBC from 2009 to 2018 were identified and clinical characteristics and electrocardiographs of VA were compared. Results: Of 931 patients undergoing idiopathic VA ablation, Virginia was eliminated from the BIS-LVe in 19 patients (2%) (17 male, age 63.7 ± 9.2 years, LV ejection fraction: 45.0 ± 9.3%). QRS complexes typically manifested right bundle branch block morphology with “reverse V2 pattern break” and left superior axis (more negative in lead III than II). VA elimination was achieved after median of 2 lesions (interquartile range [IQR]: 1–6; range 1 to 20) (radiofrequency ablation time: 123 s [IQR: 75–311]). Compared with 7 patients with IBC VA (3 male, age 51.9 ± 20.1 years, LV ejection fraction: 51.4 ± 17.7%), BIS-LVe VA less frequently had initial negative forces (QS pattern) in leads II, III, and/or aVF (p < 0.001), R-S ratio <1 in lead V1 (p = 0.005), and notching in lead II (p = 0.006) were narrower (QRS duration: 178.2 ± 22.4 vs. 221.1 ± 41.9 ms; p = 0.04) and more frequently had maximum deflection index of <0.55 (p < 0.001). Conclusions: The BIS-LVe region is an uncommon source of idiopathic VA. Distinguishing these from IBC VA is important for procedural planning and ablation success.

Original languageEnglish (US)
Pages (from-to)833-842
Number of pages10
JournalJACC: Clinical Electrophysiology
Issue number7
StatePublished - Jul 2019
Externally publishedYes


  • catheter ablation
  • epicardial
  • left ventricular ostium
  • premature ventricular complexes
  • ventricular arrhythmia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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