TY - JOUR
T1 - Characterization of trans-septal activation during septal pacing criteria for identification of intramural ventricular tachycardia substrate in nonischemic cardiomyopathy
AU - Betensky, Brian P.
AU - Kapa, Suraj
AU - Desjardins, Benoit
AU - Garcia, Fermin C.
AU - Callans, David J.
AU - Dixit, Sanjay
AU - Frankel, David S.
AU - Hutchinson, Mathew D.
AU - Supple, Gregory E.
AU - Zado, Erica S.
AU - Marchlinski, Francis E.
PY - 2013/12
Y1 - 2013/12
N2 - Background-Identification of intramural basal-septal ventricular tachycardia (VT) substrate is challenging in nonischemic cardiomyopathy. We sought to (1) characterize normal/abnormal trans-septal right ventricular (RV) to left ventricular activation; (2) assess the effect of opposite RV pacing on left ventricular septal bipolar electrograms (EGMs); and (3) establish criteria for the identification of intramural septal VT substrate. Methods and Results-Endocardial activation mapping and local EGM assessment of the left interventricular septum was performed during RV basal septal pacing in 40 patients undergoing VT ablation with no evidence of septal scar (group 1, n=14) and with septal scar (group 2, n=26) defined by low septal unipolar voltage (<8.3 mV) and delayed enhancement on cardiac MRI with/without abnormal bipolar voltage (<1.5 mV) in sinus rhythm. Left ventricular trans-septal activation time was prolonged in Group 2 compared with Group 1 (55.3±33.0 versus 25.7±8.8 ms; P=0.003). In 6 group 2 patients, left ventricular septal breakthrough was displaced to the scar border. During RV pacing, group 2 had fractionated (8.8%), late (2.8%), and split (5.7%) EGMs not seen in group 1. Trans-septal activation >40 ms (sensitivity 60%, specificity 100%; P<0.001) and EGM duration >95 ms during pacing (sensitivity 22%, specificity 91%; P<0.001) identified septal scar (13/26 pts). Conclusions-In patients with nonischemic cardiomyopathy, VT and septal scar, delayed transmural conduction time (>40 ms) and fractionated, late, split, and wide (>95 ms) bipolar EGMs during RV basal pacing identify intramural VT substrate. In select cases, the basal septum appears compartmentalized as the stimulated wavefront is rerouted to the scar border.
AB - Background-Identification of intramural basal-septal ventricular tachycardia (VT) substrate is challenging in nonischemic cardiomyopathy. We sought to (1) characterize normal/abnormal trans-septal right ventricular (RV) to left ventricular activation; (2) assess the effect of opposite RV pacing on left ventricular septal bipolar electrograms (EGMs); and (3) establish criteria for the identification of intramural septal VT substrate. Methods and Results-Endocardial activation mapping and local EGM assessment of the left interventricular septum was performed during RV basal septal pacing in 40 patients undergoing VT ablation with no evidence of septal scar (group 1, n=14) and with septal scar (group 2, n=26) defined by low septal unipolar voltage (<8.3 mV) and delayed enhancement on cardiac MRI with/without abnormal bipolar voltage (<1.5 mV) in sinus rhythm. Left ventricular trans-septal activation time was prolonged in Group 2 compared with Group 1 (55.3±33.0 versus 25.7±8.8 ms; P=0.003). In 6 group 2 patients, left ventricular septal breakthrough was displaced to the scar border. During RV pacing, group 2 had fractionated (8.8%), late (2.8%), and split (5.7%) EGMs not seen in group 1. Trans-septal activation >40 ms (sensitivity 60%, specificity 100%; P<0.001) and EGM duration >95 ms during pacing (sensitivity 22%, specificity 91%; P<0.001) identified septal scar (13/26 pts). Conclusions-In patients with nonischemic cardiomyopathy, VT and septal scar, delayed transmural conduction time (>40 ms) and fractionated, late, split, and wide (>95 ms) bipolar EGMs during RV basal pacing identify intramural VT substrate. In select cases, the basal septum appears compartmentalized as the stimulated wavefront is rerouted to the scar border.
KW - Mapping
KW - Tachycardia
KW - Ventricular
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UR - http://www.scopus.com/inward/citedby.url?scp=84892179111&partnerID=8YFLogxK
U2 - 10.1161/CIRCEP.113.000682
DO - 10.1161/CIRCEP.113.000682
M3 - Article
AN - SCOPUS:84892179111
SN - 1941-3149
VL - 6
SP - 1123
EP - 1130
JO - Circulation: Arrhythmia and Electrophysiology
JF - Circulation: Arrhythmia and Electrophysiology
IS - 6
ER -