Key result
Brugada syndrome patients with SCN5A mutations had significantly larger right and left ventricular volumes and lower left ventricular ejection fractions compared to patients without SCN5A mutations.
Why the study?
Does the presence of SCN5A mutations affect cardiac dimensions and contractility in patients with Brugada syndrome?
Cross-Sectional (n=156)
Observers blinded to clinical history and genetic screening results
No
Does the presence of SCN5A mutations affect cardiac dimensions and contractility in patients with Brugada syndrome?
Absolute Event Rate: 42.8% vs 38.2%
p-value: p=0.015
SCN5A mutations in Brugada syndrome are associated with structural cardiac changes, including biventricular dilatation and reduced left ventricular ejection fraction, suggesting the Nav1.5 channel plays a role in cardiac structural integrity.
Should not yet change Brugada management; leaves open SCN5A's role in ventricular remodeling.
BACKGROUND: The cardiac sodium channel (Na(v)1.5) controls cardiac excitability. Accordingly, SCN5A mutations that result in loss-of-function of Na(v)1.5 are associated with various inherited arrhythmia syndromes that revolve around reduced cardiac excitability, most notably Brugada syndrome (BrS). Experimental studies have indicated that Na(v)1.5 interacts with the cytoskeleton and may also be involved in maintaining structural integrity of the heart. We aimed to determine whether clinical evidence may be obtained that Na(v)1.5 is involved in maintaining cardiac structural integrity. METHODS: Using cardiac magnetic resonance (CMR) imaging, we compared right ventricular (RV) and left ventricular (LV) dimensions and ejection fractions between 40 BrS patients with SCN5A mutations (SCN5a-mut-positive) and 98 BrS patients without SCN5A mutations (SCN5a-mut-negative). We also studied 18 age/sex-matched healthy volunteers. RESULTS: SCN5a-mut-positive patients had significantly larger end-diastolic and end-systolic RV and LV volumes, and lower LV ejection fractions, than SCN5a-mut-negative patients or volunteers. CONCLUSIONS: Loss-of-function SCN5A mutations are associated with dilatation and impairment in contractile function of both ventricles that can be detected by CMR analysis.
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Hoorn et al. (2012) conducted a cross-sectional in Brugada Syndrome (n=156). SCN5A mutations vs. Brugada syndrome patients without SCN5A mutations was evaluated on Right ventricular end-systolic volume corrected for body surface area (RVESV/BSA) in ml/m2 (p=0.015). Brugada syndrome patients with SCN5A mutations had significantly larger right and left ventricular volumes and lower left ventricular ejection fractions compared to patients without SCN5A mutations.
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