Unipolar and bipolar electrogram characteristics predict exit block during pulmonary vein antral isolation.
BACKGROUND
The usefulness of unipolar electrograms (EGMs) has been reported in assessing lesion transmurality and conduction block along ablation lines. It is unknown whether unipolar and bipolar EGM characteristics predict exit block during pulmonary vein isolation (PVI) procedures.


RESULTS
Twenty patients (63 ± 7 years; 14 males [70%]) undergoing PVI with a circular mapping catheter (CMC) placed outside each PV ostium were retrospectively studied. After entrance block was achieved, pacing at each bipole around the CMC was performed to assess for absence of atrial capture (exit block). Bipolar EGMs recorded before pacing were examined for voltage, duration, fractionation, and monophasic morphology. Unipolar EGMs were examined for positive and negative amplitude, PQ segment elevation, fractionation, and monophasic morphology. The association of these parameters with atrial capture (absence of exit block) at each site was analyzed. After achievement of entrance block, only 23 of 64 PV antra (36%) exhibited exit block. Unipolar EGMs at sites with persistent capture were more likely to be fractionated and had larger negative deflections. Bipolar EGMs at sites with persistent capture showed higher amplitude, longer duration, were more likely to be fractionated, and were less likely to be monophasic. In a multivariate logistic regression model, bipolar and unipolar fractionation, bipolar duration, and lack of bipolar monophasic morphology were independently associated with persistent atrial capture.


CONCLUSIONS
Specific unipolar and bipolar EGM characteristics are associated with left atrium capture after PV antral isolation. These parameters might be useful in predicting the need for further ablation to achieve exit block.
UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Yoav
Y
Michowitz
Eric
E
Buch
Tara
T
Bourke
Roderick
R
Tung
Jason
J
Bradfield
Nilesh
N
Mathuria
Noel G
NG
Boyle
Kalyanam
K
Shivkumar
D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011667:Pulmonary Veins / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome