Value of noncontact mapping for identifying left ventricular scar in an ovine model.

Background: We assessed the hypothesis that "virtual electrograms" from a noncontact mapping system (EnSite 3000) could be used to localize myocardial scar.

Methods And Results: Myocardial infarctions were induced in sheep by inflating an angioplasty balloon in the left anterior descending coronary artery for 3 hours. Scar mapping was performed on 8 sheep without inducible ventricular tachycardia by use of the noncontact mapping system and a 256-channel contact mapping system.

Noncontact mapping of the left ventricle: insights from validation with transmural contact mapping.

It is not clear whether the noncontact electrograms obtained using the EnSite system in the left ventricle resemble most closely endocardial, intramural, or epicardial contact electrograms or a summation of transmural electrograms. This study compared unipolar virtual electrograms from the EnSite system with unipolar contact electrograms from transmural plunge needle electrodes using a 256-channel mapping system. The study also evaluated the effects of differing activation sites (endocardial, intramural, or epicardial).