title: Cardiac rhythm disturbances in patients with left atrial isomerism.
abstract: This long-term study sought to determine the clinical implication of defective sinus node and AV conduction tissue in patients with left atrial isomerism (LAI). From 1984 to 1998, a total of 22 patients were identified as LAI. Patient age at the last follow-up ranged from 2 to 276 months (90+/-70 months). Associated cardiac anomalies were interruption of the inferior vena cava (n = 18, 82%), common atrium (n = 9, 41%), AV canal (n = 14, 64%), double-outlet right ventricle (n = 8, 36%), and pulmonary stenosis (n = 15, 68%). Palliative interventions were performed in 16 patients (Fontan-type operation in 4 patients, shunt followed by Fontan-type operation in 2, repair of septal defect in 4, and extracardiac intervention in 6). During the follow-up, over half of the patients (n = 14, 64%) developed bradyarrhythmia (onset age: from 1 to 264 months; median 78 months): junctional rhythm (n = 11), sinus bradycardia (n = 8) (5 patients also had junctional rhythm), and AV block (n = 2, both also had junctional rhythm). The probability free from bradyarrhythmia was 80% and 46% at the age of 2 and 6 years, respectively. None of the bradyarrhythmias were directly related to open-heart surgery. Besides, junctional ectopic tachycardia occurred after Fontan-type operation in three of six patients. In two patients, a Mahaim-like pathway was identified during the electrophysiological study. The patients with LAI had a high probability of developing bradyarrhythmias due to abnormal sinus node function. Varied AV conduction abnormalities may include compromised AV conduction, junctional ectopic tachycardia after Fontan-type operation, and an association of Mahaim-like pathway.
authors.affiliation: Department of Pediatrics, National Taiwan University, Taipei. mhwu@ha.mc.ntu.edu.tw
authors.forename: M H
authors.initials: MH
authors.lastname: Wu
authors.forename: J K
authors.initials: JK
authors.lastname: Wang
authors.forename: J L
authors.initials: JL
authors.lastname: Lin
authors.forename: L P
authors.initials: LP
authors.lastname: Lai
authors.forename: H C
authors.initials: HC
authors.lastname: Lue
authors.forename: F J
authors.initials: FJ
authors.lastname: Hsieh
mesh_terms: D000293:Adolescent; D000328:Adult; D001919:Bradycardia / Q000209:etiology*; D002304:Cardiac Pacing, Artificial; D002648:Child; D002675:Child, Preschool; D015716:Electrocardiography, Ambulatory; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects; D006325:Heart Atria / Q000002:abnormalities*; D006330:Heart Defects, Congenital / Q000150:complications / Q000601:surgery; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D012849:Sinoatrial Node / Q000002:abnormalities* / Q000503:physiopathology; D013613:Tachycardia, Ectopic Junctional / Q000209:etiology*