The long QT syndromes: genetic basis and clinical implications
Chern-En Chiang, MD, PhD* and
Dan M. Roden, MD, FACC
* Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital and National Yang-Ming University School of Medicine, Taipei, Taiwan
Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Figure 1 Mutations causing the long QT syndrome in the sodium channel protein (SCN5A, top) and potassium channel protein complexes IKs, encoded by KvLQT1 and minK and IKr, encoded by HERG and MiRP1. The arrows show the locations of the pores through which sodium or potassium ions permeate. The unfilled symbols show the location of mutations reported in the autosomal dominant Romano-Ward form of the syndrome and the gray symbols are those associated with the autosomal recessive form (Jervell-Lange-Nielsen). Point mutations are shown by circles, insertion/deletion events or splice events that leave the open reading frame intact are shown by squares and truncations are shown by triangles (adapted from reference [44] with permission). HERG = human "ether-a-go-go" related gene; MiRP1 = minK related peptide 1; SCN5A = cardiac voltage-dependent sodium channel gene.
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Figure 2 Different patterns of ST-T wave complex in patients with long QT syndrome. Please see text for detail (adapted from reference [99] with permission).
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Figure 3 The short-long-short sequence before the onset of torsade de pointes in a patient with long QT syndrome.
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