title: A low amplitude His-bundle potential predicts failure of the right-sided approach for atrioventricular junction ablation.
abstract: In 30 patients with drug refractory atrial fibrillation-flutter who underwent radiofrequency (RF) ablation of the atrioventricular (AV) junction, 23 were successfully ablated using the conventional right-sided approach (group A). Seven patients required a left-sided approach (group B) after multiple applications from the conventional right-sided approach failed to produce complete AV block. The amplitude of the His-bundle potential recorded at the ablation site differed significantly between the 2 groups (0.23+/-0.11 mV in group A vs 0.12+/-0.04 mV in group B; p<0.005). Also, the amplitude of the His-bundle potential recorded in the standard position across the tricuspid annulus differed significantly between the 2 groups (0.27+/-0.35 mV in group A vs 0.11+/-0.44 mV in group B; p<0.007). There was no significant difference in the amplitude of the ventricular potential between the 2 groups. The probability of successful ablation of the AV junction with a conventional right-sided approach was 6 out of 12 patients (50%) if the His amplitude was <0.12mV, and 17 out of 18 patients (94%) if the His amplitude was >0.12mV (p<0.005). Patients in group B had a mean of 20.5+/-13.0 failed right-sided RF applications (5-33 applications), but required a mean of only 2 subsequent RF applications for success on the left side (1-6 applications). The His-amplitude recorded from the left side using the same catheter was significantly greater than that on the corresponding right-side (0.22+/-0.09 mV on the left side vs 0.12+/-0.04 mV on the right side: p<0.05). Total mean fluoroscopic time was 62+/-12min for group B and 20+/-13min for group A patients. In patients that underwent RF ablation of the AV junction, a maximum His amplitude <0.12 mV predicted a success rate of approximately 50% in the present study. An early switch to a left-sided approach may avoid multiple RF applications and prolonged fluoroscopic time in patients with a low amplitude His-bundle potential.
authors.affiliation: Division of Cardiology, The Hospital of the Good Samaritan, Los Angeles, CA, USA.
authors.forename: H
authors.initials: H
authors.lastname: Abe
authors.forename: A K
authors.initials: AK
authors.lastname: Bhandari
authors.forename: R
authors.initials: R
authors.lastname: Lerman
authors.forename: N
authors.initials: N
authors.lastname: Isber
authors.forename: E
authors.initials: E
authors.lastname: Abdullah
authors.forename: B
authors.initials: B
authors.lastname: Firth
authors.forename: D S
authors.initials: DS
authors.lastname: Cannom
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis