Ischemic ventricular tachycardia from below the posteromedial papillary muscle, a particular entity: Substrate characterization and challenges for catheter ablation

Andres Enriquez, David Briceno, Carlos Tapias, Yasuhiro Shirai, Daniele Muser, Jackson Liang, Tatsuya Hayashi, Pasquale Santangeli, David S. Frankel, Gregory E. Supple, Robert D. Schaller, Jeffrey Arkles, Diego Rodriguez, David J. Callans, Francis E. Marchlinski, Luis Saenz, Fermin C. Garcia

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Background: In patients with ischemic ventricular tachycardia (VT), substrate may be “protected” by the posteromedial papillary muscle (PMPM), explaining failure of endocardial-only ablation. Objective: We sought to characterize the arrhythmogenic substrate and ablation approach in patients with ischemic VT mapped to the inferior left ventricle in which endocardial ablation failed because of inaccessible substrate underlying the PMPM. Methods: We included 10 patients with recurrent ischemic VT, evidence of inferior scar, and failed endocardial ablation. In all patients, epicardial mapping was performed via a percutaneous (n = 9) or surgical (n = 1) approach, and VT elimination was achieved by ablation opposite to the PMPM. Clinical characteristics, electrocardiographic characteristics, and procedural data were analyzed. Results: In all patients, intracardiac echocardiography showed hyperechoic scar below the PMPM, and 5 exhibited a pattern characterized by subendocardial basal scar that became intramural and epicardial at distal segments. In 4 patients, VT remained inducible despite endocardial scar isolation, manifested by the absence of electrograms, dissociated potentials, and/or exit block. Eleven inducible VTs were mapped to the epicardium underlying the PMPM: 8 had a right bundle branch block configuration with variable transition, while 3 exhibited left bundle branch block with negative concordance. An inferior QS pattern was present in 10 of 11 VTs. Noninducibility was achieved in 8 patients, and 7 patients remained arrhythmia-free after a mean follow-up of 27 ± 23 months. Conclusion: In patients with inferior ischemic scar, VT may arise from the area underneath the PMPM, limiting endocardial ablation. Intracardiac echocardiography accurately defines the substrate distribution, and an epicardial approach may eliminate VT. A pattern of “basal-endocardial/apical-epicardial” ischemic involvement is described.

Original languageEnglish (US)
Pages (from-to)1174-1181
Number of pages8
JournalHeart Rhythm
Volume16
Issue number8
DOIs
StatePublished - Aug 2019

Keywords

  • Catheter ablation
  • Ischemic cardiomyopathy
  • Papillary muscle
  • Substrate
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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