Intra-atrial re-entrant tachycardia in patients with congenital heart disease: factors associated with disease severity.

Aim: Intra-atrial re-entrant tachycardia (IART) is a common complication in patients with congenital heart disease (CHD) and is related to increased morbidity and mortality. Few reports have been published about factors associated to IART severity. The aim of this study is to analyse factors associated to severe clinical presentation of IART. Methods and Results: Observational study of all consecutive CHD patients who underwent a first IART ablation from January 2009 to December 2015 (94 patients, 39.4% female, and age: 36.55 ± 14.9 years). Severe clinical presentation was defined as heart failure, syncope, shock, electromechanical dissociation (EMD), or aborted sudden death. The majority of patients had moderately or highly complex cardiac defect (90.4%). Types of IART included cavotricuspid isthmus(CTI) dependent in 51% (48), non-CTI-related in 22.3% (20), and both types in 27.7% (26). In 38 patients (40.4%), a severe event occurred and in 16 (17%), the symptoms included shock, syncope, sudden death, or EMD. In 21 (22.3%), severe symptoms were the first manifestation of IART. In multivariate analysis, transposition of the great arteries (TGA) with right systemic ventricle (OR 5.32, 95% C.I. 1.6-7.02, P = 0.0005) and severe dilation of the venous atrium (VsA) (OR 4.17; 95% CI 1.4-8.12, P = 0.0009) were factors independently associated with severity. Conclusion: In our series of 94 CHD patients with a high proportion of moderately to highly complex cardiac defects, severe consequences of IART were frequent. Transposition of the great arteries with systemic right ventricle and severe dilation of VsA were independently associated to severity. Early invasive procedures should be considered for these high-risk patients.