title: [Unidirectional block and longitudinal dissociation in an accessory pathway induced by radiofrequency].
abstract: This report describes an unusual arrhythmia due to partial damage of an accessory pathway by radiofrequency energy delivered during a catheter ablation procedure. The following phenomena were observed after the first radiofrequency current application: a) manifest anterograde conduction over the Kent bundle was abolished, so that preexcitation disappeared; b) concealed anterograde conduction over the accessory pathway was interrupted, resulting in initiation of orthodromic re-entrant tachycardia by any sinus impulse; c) retrograde conduction through the accessory pathway was impaired, but still present, and a pattern of longitudinal dissociation manifested; this was suggested by alternation of the R-P intervals, that during orthodromic tachycardia were alternatively long and short. Following a second radiofrequency application, the R-P interval during orthodromic tachycardia became markedly prolonged (0.36 sec), to the extent that the pattern mimicked a form of atrial or sinus tachycardia. Retrograde accessory pathway conduction was totally interrupted following a third radiofrequency energy application.
authors.affiliation: Istituto Pluridisciplinare di Clinica Medica, Università di Messina.
authors.forename: G
authors.initials: G
authors.lastname: Oreto
authors.forename: F
authors.initials: F
authors.lastname: Gaita
authors.forename: F
authors.initials: F
authors.lastname: Luzza
mesh_terms: D000328:Adult; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D006327:Heart Block / Q000209:etiology* / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology / Q000528:radiation effects; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D011226:Pre-Excitation Syndromes / Q000503:physiopathology; D011846:Radio Waves; D013610:Tachycardia / Q000503:physiopathology; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology
vernacular_title: Blocco unidirezionale e dissociazione longitudinale in una via accessoria indotti dalla radiofrequenza.