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Direct comparison of adjacent endocardial and epicardial electrograms: implications for substrate mapping
Michifumi Tokuda1, Usha B Tedrow, Keiichi Inada
1Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
Journal of the American Heart Association
|October 12, 2013
Summary
Unipolar electrograms can indicate epicardial scar during endocardial mapping, but accuracy varies with cardiomyopathy type. Some patients may still have hidden arrhythmia substrates.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Epicardial scar detection using unipolar voltage maps is established.
- Limited data exists on optimal parameters for identifying remote scar.
- This study investigates endocardial electrogram characteristics near epicardial scar.
Purpose of the Study:
- To compare endocardial electrogram characteristics at sites adjacent to epicardial scar.
- To define optimal unipolar voltage parameters for predicting epicardial scar.
- To assess the accuracy of endocardial unipolar mapping in identifying epicardial scar in different cardiomyopathy types.
Main Methods:
- Analysis of endocardial and epicardial electroanatomical maps from 31 patients with scar-related ventricular tachycardia.
- Selection of 523 endocardial-epicardial point pairs based on predefined criteria.
- Multivariable analysis to identify predictors of epicardial scar and determine optimal unipolar voltage cutoffs.
Main Results:
- Endocardial sites adjacent to epicardial scar showed significantly lower unipolar voltage.
- Endocardial unipolar amplitude < 4.4 mV (RV) and < 5.1 mV (LV) were optimal predictors of epicardial scar.
- Good correlation between endocardial unipolar abnormality and epicardial scar was observed in 67% (LV) and 75% (RV) of maps, with poorer matches in nonischemic cardiomyopathy.
Conclusions:
- Unipolar electrograms can indicate overlying epicardial scar during endocardial mapping.
- Limitations in scar detection differ between nonischemic and ischemic cardiomyopathy.
- Epicardial arrhythmia substrate cannot be entirely excluded by unipolar endocardial mapping alone.
Keywords:
catheter ablationelectroanatomical mappingepicardialnonischemic heart diseaseventricular tachycardiaMore Related Videos
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