Atrial Tachycardia in End-stage Atrial Disease: Ablate or Isolate?

DOI: 10.19102/icrm.2011.020504

ADOLFO FONTENLA, MD, MARíA LÓPEZ-GIL, MD, PhD FERNANDO ARRIBAS, MD, PhD

Hospital 12 de Octubre, Cardiac Electrophysiology Unit, Cardiology Department, Madrid, Spain

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KEYWORDS. catheter ablation, atypical flutter, arrhythmia isolation, atrial tachycardia, pulmonary hypertension.

The authors report no conflicts of interest for the published content.
Manuscript received March 24, 2011, final version accepted April 8, 2011.

Address correspondence to: Adolfo Fontenla, C/Vallehermoso, 40. 28015. Madrid, Spain, E-mail: drfontenla@gmail.com

Isolation of the source of a tachycardia from the rest of the myocardium is an accepted endpoint in some ablation procedures such as atrial fibrillation ablation.¹ An unusual case of curative myocardial isolation in a patient during atypical atrial flutter ablation is presented.

A 72-year-old woman with pulmonary hypertension secondary to scleroderma and haemodynamically poorly tolerated atrial tachycardia was referred for ablation. A previous echocardiogram showed severe dilatation of the right chambers. Atrial activation was registered using two multipolar catheters placed around the tricuspid annulus DUO (Livewire (TM) Duo-Decapolar Steerable Catheter, St. Jude Medical, St. Paul, MN) and into the coronary sinus ORB (Orbiter 24-Pole Woven Diagnostic Catheter, Bard Electrophysiology, Lowell, MA) (Figure 1a,b). A voltage map of the right atrium was obtained by an electroanatomical mapping system and showed large areas of scar (Figure 1c). Suring entrainment mapping, the post pacing interval – tachycardia cycle length was short (<20 ms) at two anatomically separated points (lateral wall and roof of the right atrium) suggesting a macro-re-entrant circuit anchored at the anterior wall of the right atrium (RA). Radiofrequency applications at high lateral RA resulted in interruption of the tachycardia, but it was easily inducible. Reinduction after few additional lesions at the roof, where complex electrograms and short post-pacing intervals were also registered (ablation catheter position in Figure 1a), resulted in isolation of the tachycardia from the rest of the RA, which remained in sinus rhythm and controlled cardiac rhythm (Figure 1d). Tachycardia was then interrupted by overdriving the isolated portion (violet area in the voltage map) without capture of the rest of the atrium, which remained disconnected, demonstrating bidirectional block (Figure 1e). There were no recurrences of tachycardia during 1 year of follow up.

Disconnecting the area of the atrium that includes the tachycardia circuit instead a classical ablation of a critical isthmus may be an acceptable endpoint during ablation of atypical atrial flutter. This result is more feasible in patients with advanced atrial disease, where scar zones and low conduction make it possible to isolate part of the myocardium by delivering a relatively low amount of radiofrequency energy.² Isolation of the circuit was an accidental but effective endpoint in this patient.

References

1. Natale A, Raviele A, Arentz T, et al. Venice chart international consensus document on atrial fibrillation ablation. J Cardiovasc Electrophysiol 2007; 18:560–580. [CrossRef] [PubMed]
2. Nakagawa H, Shah N, Matsudaira K, et al. Characterization of reentrant circuit in macroreentrant right atrial tachycardia after surgical repair of congenital heart disease. isolated channels between scars allow “focal” ablation. Circulation 2001; 103:699–709. [CrossRef] [PubMed]