title: Overdrive atrial stimulation during transesophageal electrophysiological study: usefulness of post-pacing VA interval analysis in differentiating supraventricular tachycardias with 1:1 atrio-ventricular relationship.
abstract: We evaluated the feasibility and usefulness of overdrive atrial pacing to identify the relationship between atrial and ventricular activation in supraventricular tachycardias with a stable 1:1 atrio-ventricular (AV) conduction ratio during a transesophageal electrophysiological investigation. Overdrive atrial stimulation was performed in 42 consecutive patients (11 males and 31 females; mean age 49 +/- 17 years) during AV junctional reentrant tachycardia, orthodromic AV reentrant tachycardia and ectopic atrial tachycardia (22, 13 and seven subjects, respectively). Trains of 12 stimuli at a constant rate were introduced starting at a cycle length 10 ms shorter than the tachycardia cycle length; stimulation was repeated with a 10-ms decrement in pacing cycle length at each step until tachycardia terminated and/or second-degree AV block occurred. The difference between the VA interval duration at baseline and in the first post-pacing tachycardia beat was measured at each step and provided identification of the AV relationship. At least one post-pacing VA interval was evaluable in 90% of the cases and measured 2 +/- 4 and 1 +/- 3 ms in AV junctional and AV reentrant tachycardia groups, respectively, and 83 +/- 42 ms in the ectopic atrial tachycardia group (P < 0.0000001 ectopic atrial tachycardia group vs. others). When three or more post-pacing VA intervals were obtained during the same tachycardia, a curve was constructed by plotting their values against the corresponding pacing cycle lengths. A curve could be constructed in 36% of the cases and was flat in all patients with AV junctional and AV reentry, while it was completely irregular in the ectopic atrial tachycardia group (P < 0.003). The analysis of post-pacing VA interval behaviour in response to overdrive atrial stimulation provides a rapid and reliable differentiation between supraventricular tachycardias with 1:1 AV conduction ratio during a transesophageal electrophysiological study.
authors.affiliation: Division of Cardiology, Oncology Institute, Bari, Italy. mtritto@cnn.it
authors.forename: M
authors.initials: M
authors.lastname: Tritto
authors.forename: C D
authors.initials: CD
authors.lastname: Dicandia
authors.forename: P
authors.initials: P
authors.lastname: Calabrese
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004947:Esophagus; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000503:physiopathology; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis / Q000503:physiopathology; D013617:Tachycardia, Supraventricular / Q000145:classification* / Q000503:physiopathology*