title: Spatial resolution of epicardial pace mapping using body surface potentials.
abstract: Body surface potential maps (BSPMs) recorded during pace mapping provide an important non-invasive means for identifying local cardiac events; recent clinical studies demonstrated that endocardial pacing sites can be resolved within less than 10 mm. We sought to determine whether similar spatial resolution could be achieved during epicardial pacing. Four patients who were undergoing either heart valve replacement (one), aortocoronary bypass graft (one), or both (two) were studied. In each patient, a pair of epicardial electrodes was placed intraoperatively at the middle aspect of the right ventricular free wall. The distance between the neighbouring electrodes was 10 mm. Five days after the surgery, ECGs were acquired from 35 leads during pacing from each epicardial electrode. We determined the distributions of QRS integrals (the net area under the ECG signal) and compared integrals corresponding to pacing from each of the adjacent electrodes using statistical indices. Student's t-test was applied to these indices and in all the patients revealed that differences in distributions of QRS integral maps were statistically significant (p < 0.01). Results of our study indicate that the non-invasive acquisition of body surface ECGs could resolve epicardial breakthrough sites within 10 mm, which may be useful in facilitating therapeutic ablations in patients with ventricular tachycardias.
authors.affiliation: Department of Cardiovascular Surgery, Medical Center Ljubljana, Zaloška 7,1000 Ljubljana, Slovenia, Slovenia.
authors.forename: Silvia
authors.initials: S
authors.lastname: Samarin
authors.affiliation: Institute of Mathematics, Physics and Mechanics, Jadranska 19,1000 Ljubljana, Slovenia, Slovenia.
authors.forename: Rok
authors.initials: R
authors.lastname: Hren
authors.affiliation: Jožef Stefan Institute, Jamova 39,1000 Ljubljana, Slovenia, Slovenia.
authors.forename: Roman
authors.initials: R
authors.lastname: Trobec
authors.affiliation: Jožef Stefan Institute, Jamova 39,1000 Ljubljana, Slovenia, Slovenia.
authors.forename: Viktor
authors.initials: V
authors.lastname: Avbelj
authors.affiliation: Department of Cardiovascular Surgery, Medical Center Ljubljana, Zaloška 7,1000 Ljubljana, Slovenia, Slovenia.
authors.forename: Borut
authors.initials: B
authors.lastname: Geršak
keywords: Key words body surface potentials; electrocardiography; epicardium; pace mapping; spatial resolution