title: The presence of extensive atrial scars hinders the differential diagnosis of focal or macroreentrant atrial tachycardias in patients with complex congenital heart disease.
abstract: OBJECTIVE
  Atrial tachycardias (ATs) frequently develop in patients with congenital heart defects (CHDs). This study aimed to evaluate the effects of extensive atrial scar formation on the total atrial activation time (TAAT) and its relation to the tachycardia cycle length (CL) to classify AT.
  
  
  RESULTS
  Seventy-one patients were included and divided into two groups: patients without CHD (Group I, 35 patients) and with CHD (Group II, 36 patients). All patients underwent CARTO electroanatomical activation mapping. Two subgroups were created: centrifugal (CAT) or macroreentrant AT (MRAT). Total atrial activation time, CL, and mean bipolar signal amplitude (BiSA) were analysed. In Group I, 18 patients (51.4%) had CAT and 17 (48.6%) MRAT. The mean BiSA for Group I was 1.30 ± 0.32 mV. Total atrial activation time/CL ratios were different between CAT and MRAT (28.4 ± 16.9 vs. 66.6 ± 14.3%, P < 0.001). In Group II, 18 patients (50%) had CAT and 18 patients (50%) MRAT. The mean BiSA was 0.94 ± 0.50 mV and was not different for CAT and MRAT subgroups (1.04 ± 0.64 vs. 0.85 ± 0.29, P = 0.243). Total atrial activation time/CL ratios were comparable between CAT and MRAT patients (69.0 ± 40.4 vs. 83.6 ± 8.3%, P = 0.243). A significant lower BiSA was found for CAT with TAAT/CL ratios above 40% (0.62 ± 0.11 vs. 1.90 ± 0.18 mV, P < 0.001). A strong negative correlation was identified between the BiSA and the TAAT/CL ratio in patients with CAT in Group II (-0.742; P < 0.001).
  
  
  CONCLUSIONS
  Low mean BiSA values in CHD patients are associated with altered impulse propagation, making TAAT- and CL-based diagnostic tools inaccurate. Further diagnostic tests are needed to determine the correct mechanism of ATs.
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Ferdi
authors.initials: F
authors.lastname: Akca
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Tamas
authors.initials: T
authors.lastname: Bauernfeind
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Natasja M S
authors.initials: NM
authors.lastname: De Groot
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Tchavdar
authors.initials: T
authors.lastname: Shalganov
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Bruno
authors.initials: B
authors.lastname: Schwagten
authors.affiliation: Clinical Electrophysiology, Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands t.szilitorok@erasmusmc.nl.
authors.forename: Tamas
authors.initials: T
authors.lastname: Szili-Torok
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis*; D000328:Adult; D018780:Body Surface Potential Mapping / Q000379:methods*; D002921:Cicatrix / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006325:Heart Atria; D006330:Heart Defects, Congenital / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000150:complications / Q000175:diagnosis*; D013612:Tachycardia, Ectopic Atrial / Q000150:complications / Q000175:diagnosis*
keywords: Atrial tachycardia; Catheter ablation; Congenital heart defect