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Facilitatory and inhibitory effects of SCN5A mutations on atrial fibrillation in Brugada syndrome.
- Source :
-
Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology [Europace] 2011 Jul; Vol. 13 (7), pp. 968-75. Date of Electronic Publication: 2011 Jan 26. - Publication Year :
- 2011
-
Abstract
- Aims: Brugada syndrome (BrS) is associated with increased risk for atrial fibrillation (AFib). However, the role of SCN5A mutations in the occurrence of AFib remains unclear. Cardiac sodium current reduction caused by SCN5A mutations may facilitate AFib by slowing intra-atrial conduction and inducing structural changes, but also prevent it by suppressing atrial ectopic activity. Here, we examined the relation between SCN5A mutations, atrial conduction velocity, atrial structural changes, and atrial ectopic activity in BrS.<br />Methods and Results: Data from 214 BrS patients [78 with an SCN5A mutation (patients with an SCN5A mutation, BrSSCN5A+) and 136 without an SCN5A mutation (patients without an SCN5A mutation, BrSSCN5A-)] were collected. Intra-atrial conduction velocity was assessed by measuring P-wave durations at baseline and during sodium channel provocation testing. Atrial structural changes were assessed by measuring atrial dimensions using cardiac magnetic resonance imaging. Atrial ectopic activity was assessed by determining the incidence of atrial ectopic beats using 24 h Holter recordings. Clinical characteristics (including AFib occurrence) did not differ between BrSSCN5A+ and BrSSCN5A-. Baseline P-wave durations were longer in BrSSCN5A+ than in BrSSCN5A-, but lengthened markedly in BrSSCN5A- during provocation testing. Atrial dimensions did not differ. Atrial ectopic beats occurred more often in BrSSCN5A-, and the proportion of patients experiencing one or more atrial ectopic beats was larger in BrSSCN5A- than in BrSSCN5A+.<br />Conclusion: In BrS, the presence of an SCN5A mutation is associated with intra-atrial conduction slowing and suppressed atrial ectopic activity. Intra-atrial conduction slowing may provide a plausible substrate for AFib maintenance, while reduced atrial ectopic activity may constitute inhibition of the trigger for AFib initiation.
- Subjects :
- Adult
Atrial Fibrillation physiopathology
Brugada Syndrome physiopathology
Case-Control Studies
Electrocardiography
Electrocardiography, Ambulatory
Female
Heart Atria pathology
Heart Atria physiopathology
Heart Conduction System physiopathology
Humans
Magnetic Resonance Imaging
Male
Middle Aged
NAV1.5 Voltage-Gated Sodium Channel
Retrospective Studies
Risk Factors
Atrial Fibrillation epidemiology
Brugada Syndrome complications
Brugada Syndrome genetics
Mutation genetics
Sodium Channels genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1532-2092
- Volume :
- 13
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
- Publication Type :
- Academic Journal
- Accession number :
- 21273195
- Full Text :
- https://doi.org/10.1093/europace/eur011