The “hidden” concealed left-sided accessory pathway: An uncommon cause of SVT in young people
Publication Date
2018
Journal Title
Pacing Clin Electrophysiol
Abstract
© 2018 Wiley Periodicals, Inc. Background: Concealed left-sided accessory pathways (CLAP) are a cause of supraventricular tachycardia (SVT) in the young. Most are mapped with right ventricular (RV) apical/outflow pacing. Rarely, alternative means of mapping are required. We review our experience from three pediatric electrophysiology (EP) centers with a rare form of “hidden” CLAP. Methods: All patients “hidden” CLAP (defined as an accessory pathway [AP] for which RV pacing at cycle lengths [CL] stable for mapping did not demonstrate eccentric retrograde conduction) were included. Exclusion criteria: preexcitation. Demographic, procedural, and follow-up data were collected. Results: A total of 23 patients met the criteria (median age, 14.3 years [range 7–21], weight, 51 kg [31–99]). 21 (96%) had SVT and one AFIB (4%). APs were adenosine sensitive in 7/20 patients (35%) and VA conduction was decremental in six (26%). CLAP conduction was demonstrable with orthodromic reentrant tachycardia in all patients, with RV extrastimulus testing in seven (30%) and with rapid RV pacing (300) in three (13%). Left ventricular (LV) pacing demonstrated CLAP conduction in 17/17 (100%) patients in whom it was used. All 23 CLAPs were successfully ablated (100%) via transseptal approach with radiofrequency energy. Specific ablation techniques included: 16 (70%) during LV paced rhythm, four (17%) during orthodromic reciprocating tachycardia (ORT; 3/4 ventricular entrained), and three (13%) with brief rapid RV pacing. There were no complications. At 18 months (range 3–96), there was one recurrence (4%). Conclusions: Some CLAPs are only demonstrable with LV pacing, entrained ORT, or rapid RV pacing. LV pacing facilitated preferential AP conduction, allowing for mapping while maintaining stable hemodynamics.
Volume Number
41
Issue Number
4
Pages
368 - 371
Document Type
Article
Status
Faculty
Facility
School of Medicine
Primary Department
General Pediatrics
PMID
DOI
10.1111/pace.13279