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Molecular and genetic basis of sudden cardiac death
Alfred L. George Jr.
Alfred L. George Jr.
Published January 2, 2013
Citation Information: J Clin Invest. 2013;123(1):75-83. https://doi.org/10.1172/JCI62928.
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Review Series

Molecular and genetic basis of sudden cardiac death

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Abstract

The abrupt cessation of effective cardiac function due to an aberrant heart rhythm can cause sudden and unexpected death at any age, a syndrome called sudden cardiac death (SCD). Annually, more than 300,000 cases of SCD occur in the United States alone, making this a major public health concern. Our current understanding of the mechanisms responsible for SCD has emerged from decades of basic science investigation into the normal electrophysiology of the heart, the molecular physiology of cardiac ion channels, fundamental cellular and tissue events associated with cardiac arrhythmias, and the molecular genetics of monogenic disorders of heart rhythm. This knowledge has helped shape the current diagnosis and treatment of inherited arrhythmia susceptibility syndromes associated with SCD and has provided a pathophysiological framework for understanding more complex conditions predisposing to this tragic event. This Review presents an overview of the molecular basis of SCD, with a focus on monogenic arrhythmia syndromes.

Authors

Alfred L. George Jr.

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Figure 2

Afterdepolarizations and ventricular arrhythmias.

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Afterdepolarizations and ventricular arrhythmias.
EADs and DADs occur du...
EADs and DADs occur due to dysregulation of depolarizing ionic currents. (A) EAD illustrated in the context of prolonged action potential duration. EADs typically result from increased activation of voltage-gated (L-type) Ca2+ channels or persistent activation of voltage-gated Na+ channels. (B) ECG from a typical polymorphic VT (also known as torsades de pointes), which is associated with EADs. (C) Illustration of a DAD arising after completion of action potential repolarization. DADs are commonly due to spontaneous intracellular Ca2+ release and efflux of Ca2+ through the electrogenic NCX (stoichiometry 3Na+:1Ca2+), which generates a a transient INa. (D) ECG of VF, which is associated with DADs.

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