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Dual-loop circuits in postoperative atrial macro re-entrant tachycardias
  1. Jens Seiler,
  2. Dorothy K Schmid,
  3. Thiemo A Irtel,
  4. Hildegard Tanner,
  5. Martin Rotter,
  6. Nicola Schwick,
  7. Etienne Delacrétaz
  1. Swiss Cardiovascular Center Bern, University Hospital, Bern, Switzerland
  1. Correspondence to:
    Professor E Delacrétaz
    Swiss Cardiovascular Center Bern, University Hospital, CH-3010 Bern, Switzerland; etienne.delacretaz{at}insel.ch

Abstract

Background: Patients may develop dual-loop re-entrant atrial arrhythmias late after open-heart surgery, and mapping and catheter ablation remain challenging despite computer-assisted mapping techniques.

Objectives: The purpose of the study was to demonstrate the prevalence and characteristics of dual-loop re-entrant arrhythmias, and to define the optimal mapping and ablation strategy.

Methods: 40 consecutive patients (mean (SD) age 52 (12) years) with intra-atrial re-entrant tachycardia (IART) after open-heart surgery (with an incision of the right atrial free wall) were studied. Dual-loop IART was defined as the presence of two simultaneous atrial circuits. After an abrupt tachycardia change during radiofrequency ablation, electrical disconnection of the targeted re-entry isthmus from the remaining circuit was demonstrated by entrainment mapping. Furthermore, the second circuit loop was localised using electroanatomical mapping and/or entrainment mapping.

Results: Dual-loop IART was demonstrated in eight (20%, 5 patients with congenital heart disease, 3 with acquired heart disease) patients. Dual-loop IART included an isthmus-dependant atrial flutter combined with a re-entry related to the atriotomy scar. The diagnosis of dual-loop IART required the comparison of entrainment mapping before and after tachycardia modification. Overall, 35 patients had successful radiofrequency ablation (88%). Success rates were lower in patients with dual-loop IART than in patients without dual-loop IART. Ablation failures in three patients with dual-loop IART were related to the inability to properly transect the second tachycardia isthmus in the right atrial free wall.

Conclusions: Dual-loop IART is relatively common after heart surgery involving a right atriotomy. Abrupt tachycardia change and specific entrainment mapping manoeuvres demonstrate these circuits. Electroanatomical mapping appears to be important to assist catheter ablation of periatriotomy circuits.

  • CTI, cavo-tricuspid isthmus
  • IART, intra-atrial re-entrant tachycardia
  • IAT, incisional atrial tachycardia
  • IDAF, isthmus-dependent atrial flutter
  • PPI, post-pacing interval

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Footnotes

  • Published Online First 15 September 2006

  • Funding: ED is supported by a grant from the Swiss National Research Foundation (632-066101).

  • Competing interests: None.

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