Differential effects of cardiac sodium channel mutations on initiation of ventricular arrhythmias in patients with Brugada syndrome.

Abstract

BACKGROUND:

Premature ventricular contractions (PVCs) do not occur frequently but can induce ventricular fibrillation (VF) in patients with Brugada syndrome. The effect of SCN5A mutation on the onset of ventricular arrhythmias is unknown.

OBJECTIVE:

The purpose of this study was to evaluate PVC morphology and onset of VF in patients with Brugada syndrome.

METHODS:

Morphology of PVCs was evaluated by 12-lead ECG in 32 patients with Brugada syndrome. Patients had spontaneous ventricular arrhythmia (n = 17) or sodium channel blocker-induced ventricular arrhythmia (n = 19). Patients were classified into two groups according to the existence of SCN5A mutation (22 mutation negative, 10 mutation positive).

RESULTS:

Patients without mutation often had PVCs of left bundle branch block (LBBB) morphology (82%), especially with inferior axis (77%). Patients with mutation had PVCs of both right bundle branch block (36%) and LBBB (64%) morphologies. Only two patients with mutation had PVCs of LBBB, inferior-axis morphology.

CONCLUSION:

Patients without SCN5A mutation often had PVCs of LBBB, inferior-axis morphology, suggesting a right ventricular outflow tract origin. Patients with SCN5A mutations had PVCs that originated from both the right and left ventricles.

• Authors: Hiroshi Morita, Satoshi Nagase, Daiji Miura, Aya Miura, Shigeki Hiramatsu, Takeshi Tada, Masato Murakami, Nobuhiro Nishii, Kazufumi Nakamura, Shiho T Morita, Takefumi Oka, Kengo F Kusano, Tohru Ohe
• Journal: Heart rhythm (Heart Rhythm) Vol. 6 Issue 4 Pg. 487-92 (Apr 2009) ISSN: 1556-3871 [Electronic] United States
• PMID: 19324308 (Publication Type: Journal Article)

Chemical References

• Muscle Proteins
• NAV1.5 Voltage-Gated Sodium Channel
• SCN5A protein, human
• Sodium Channels

Topics

• Brugada Syndrome (genetics, physiopathology)
• Electrocardiography
• Humans
• Male
• Middle Aged
• Muscle Proteins (genetics)
• Mutation
• NAV1.5 Voltage-Gated Sodium Channel
• Sodium Channels (genetics)
• Ventricular Fibrillation (genetics, physiopathology)
• Ventricular Premature Complexes (genetics, physiopathology)