Focal Atrial Tachycardia in the Right Atrium in a Postsurgical Patient: Rare but Possible
This is a 43-year-old male patient who, at the age of 15, underwent surgery for tetralogy of Fallot and tricuspid valvuloplasty for associated Ebstein disease. Ten years later, he began complaining of palpitations, which became more frequently recurrent and drug refractory, so that in 1999 he underwent an electrophysiology procedure in our institution. At the time of our initial observations, a description of the surgical intervention was unavailable. However, clinical atrial tachycardia at a cycle length of 440 ms was reproducibly inducible and it was diagnosed as an intraatrial macroreentrant tachycardia, with the critical isthmus of slow conduction located between the coronary sinus os and the inferior vena cava. Limited radiofrequency energy delivery in that region suppressed the tachycardia. No other tachycardia was inducible thereafter. Of interest, conventional mapping during sinus rhythm showed two vertical lines of double potentials along the septum and the anterolateral right atrium, likely related to surgical incisions/sutures. Moreover, during programmed atrial stimulation, conduction delay over the anterolateral right atrial wall, where a 20-pole catheter had been placed, was observed. In this area, preserved voltage amplitude was present at that time. The patient remained asymptomatic until February 2004, when recurrence of the palpitations was documented at electrocardiogram as the arrhythmia shown in Fig. 1. Since the QRS complex was superimposible with the one recorded on sinus rhythm, the supraventricular origin of the arrhythmia was clear; however, the wide QRS complex due to right bundle branch block did not allow analysis of P wave morphology. Adenosine injection reproducibly terminated the tachycardia, so that the surface electrocardiogram did not facilitate determination of its origin.
KeywordsSinus Rhythm Sinus Node Atrial Tachycardia Right Bundle Branch Block Electroanatomic Mapping
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