[Induction of a double nodal pathway in dogs by transcatheter ablation with high frequency currents].
A dog weighing 15 kg and anesthetized with intravenous sodium thiopental was subjected to transcatheter ablation of the AV junction with high-frequency currents, in order to induce a partial alteration in AV conduction (first degree AV block). Two conventional bipolar electrode-catheters were introduced through the right femoral vein and used one for atrial pacing and the other for His bundle recording and current delivering. The catheter used for ablation was situated in the AV junction where the distal monopolar recording of the His bundle electrogram showed an A/V ratio close to one in the presence of His bundle deflection. Three discharges were delivered under continuous electrocardiographic monitoring. The output power used was 15 watts and current application time was up to five seconds after attaining complete AV block; 1:1 AV conduction was quickly restored on concluding discharge. After the second discharge, a discontinuous nodal function curve of the dual AV nodal pathway type was obtained (absent in control and after first discharge studies). Following the third discharge the conduction through the slow pathway was abolished. The study was repeated after four weeks, an a dual AV nodal pathway type curve similar to that found during the acute phase was obtained. The histologic findings showed a collagen scar partially replacing nodal tissue and creating a partial septation of the AV node. To conclude: The structural alterations of the AV node may induce a dual AV nodal pathway response.
J
J
Sanchis
F J
FJ
Chorro
V
V
López Merino
R
R
García Civera
A
A
Camañas
D000818:Animals; D001283:Atrioventricular Node / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery; D004285:Dogs; D004562:Electrocardiography; D004564:Electrocoagulation; D006329:Heart Conduction System / Q000502:physiology*
Inducción de una doble vía nodal en el perro por ablación transcatéter con corrientes de alta frecuencia.