Atrial Endocardial Unipolar Voltage Mapping for Detection of Viable Intramural Myocardium: A Proof-of-Concept Study

Hagai Yavin, Arwa Younis, Israel Zilberman, Alison Krywanczyk, Zachary P. Bubar, Koji Higuchi, Michael Barkagan, Elad Anter*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background: Endocardial bipolar voltage amplitude is largely derived from endocardial and subendocardial wall layers. This may result in situations of low bipolar voltage amplitude despite the presence of mid-myocardial including epicardial (ie, intramural-epicardial) viable myocardium. This study examined the utility of endocardial unipolar voltage mapping for detection of viable intramural-epicardial atrial myocardium. Methods: In 15 swine, an atrial intercaval ablation line with an intentional gap was created. Animals survived for 6 to 8 weeks before electroanatomical mapping followed by sacrifice. Gaps were determined by the presence of electrical conduction and classified based on the histopathologiclly layer(s) of viable myocardium into the following: (1) transmural, (2) endocardial, and (3) intramural-epicardial. Voltage data from healthy, scar, and gap points were exported into excel. The sensitivity and specificity of bipolar and unipolar voltage amplitude to detect intramural-epicardial gaps were compared using receiver operating characteristic analysis. Results: In 9 of 15 (60%) swine, a focal ablation gap was detected in the intercaval line, while in the remainder 6 of 15 (40%), the line was complete without gaps. Gaps were classified into transmural (n=3), endocardial (n=3), or intramural-epicardial (n=3). Intramural-epicardial gaps were characterized by very low bipolar voltage amplitude that was similar to areas with transmural scar (P=0.91). In comparison, unipolar voltage amplitude in intramural-epicardial gaps was significantly higher compared to transmural scar (P<0.001). Unipolar voltage amplitude had higher sensitivity (93% versus 14%, respectively) and similar specificity (95% versus 98%, respectively) to bipolar voltage for detection of intramural-epicardial gaps. Conclusions: Atrial unipolar voltage mapping may be a useful technique for identifying viable intramural-epicardial myocardium in patients with endocardial scar.

Original languageEnglish
Pages (from-to)E011321
JournalCirculation: Arrhythmia and Electrophysiology
Issue number1
StatePublished - 1 Jan 2023
Externally publishedYes


  • arrhythmias
  • cardiomyopathy
  • catheter
  • endocardium
  • myocardium


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