open access

Vol 20, No 5 (2013)
Review paper
Published online: 2013-09-24
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Congenital short QT syndrome: Landmarks of the newest arrhythmogenic cardiac channelopathy

Andrés Ricardo Pérez Riera, Adail Paixão-Almeida, Raimundo Barbosa-Barros, Frank G. Yanowitz, Adrian Baranchuk, Sergio Dubner, Antônio Carlos Palandri Chagas
DOI: 10.5603/CJ.a2013.0052
·
Cardiol J 2013;20(5):464-471.

open access

Vol 20, No 5 (2013)
Review articles
Published online: 2013-09-24

Abstract

Congenital or familial short QT syndrome is a genetically heterogeneous cardiac channelopathy without structural heart disease that has a dominant autosomal or sporadic pattern of transmission affecting the electric system of the heart. Patients present clinically with a spectrum of signs and symptoms including irregular palpitations due to episodes of paroxysmal atrialfibrillation, dizziness and fainting (syncope) and/or sudden cardiac death due to polymorphic ventricular tachycardia and ventricular fibrillation. Electrocardiographic (ECG) findings include extremely short QTc intervals (QTc interval ≤ 330 ms) not significantly modified with heart rate changes and T waves of great voltage witha narrow base. Electrophysiologic studies are characterized by significant shortening of atrial and ventricular refractory periods and arrhythmias induced by programmed stimulation. A few families have been identified with specific genotypes: 3 with mutations in potassium channels called SQT1 (Iks), SQT2 (Ikr) and SQT3 (Ik1). These 3 potassium channel variants are the “genetic mirror image” of long QT syndrome type 2, type 1 and Andersen-Tawil syndrome respectively because they exert opposite gain-of-function effects on the potassium channels in contrast to the loss-of-function of the potassium channels in the long QT syndromes. Three new variants with overlapping phenotypes affecting the slow inward calcium channels havealso been described. Finally, another variant with mixed phenotype affecting the sodium channel was reported. This review focuses the landmarks of this newest arrhythmogenic cardiac channelopathy on the main clinical, genetic, and proposed ECG mechanisms. In addition therapeutic options and the molecular autopsy of this fascinating primary electrical heart disease are discussed.

Abstract

Congenital or familial short QT syndrome is a genetically heterogeneous cardiac channelopathy without structural heart disease that has a dominant autosomal or sporadic pattern of transmission affecting the electric system of the heart. Patients present clinically with a spectrum of signs and symptoms including irregular palpitations due to episodes of paroxysmal atrialfibrillation, dizziness and fainting (syncope) and/or sudden cardiac death due to polymorphic ventricular tachycardia and ventricular fibrillation. Electrocardiographic (ECG) findings include extremely short QTc intervals (QTc interval ≤ 330 ms) not significantly modified with heart rate changes and T waves of great voltage witha narrow base. Electrophysiologic studies are characterized by significant shortening of atrial and ventricular refractory periods and arrhythmias induced by programmed stimulation. A few families have been identified with specific genotypes: 3 with mutations in potassium channels called SQT1 (Iks), SQT2 (Ikr) and SQT3 (Ik1). These 3 potassium channel variants are the “genetic mirror image” of long QT syndrome type 2, type 1 and Andersen-Tawil syndrome respectively because they exert opposite gain-of-function effects on the potassium channels in contrast to the loss-of-function of the potassium channels in the long QT syndromes. Three new variants with overlapping phenotypes affecting the slow inward calcium channels havealso been described. Finally, another variant with mixed phenotype affecting the sodium channel was reported. This review focuses the landmarks of this newest arrhythmogenic cardiac channelopathy on the main clinical, genetic, and proposed ECG mechanisms. In addition therapeutic options and the molecular autopsy of this fascinating primary electrical heart disease are discussed.

Get Citation

Keywords

congenital short QT syndrome, historical landmarks, channelopathies

About this article
Title

Congenital short QT syndrome: Landmarks of the newest arrhythmogenic cardiac channelopathy

Journal

Cardiology Journal

Issue

Vol 20, No 5 (2013)

Article type

Review paper

Pages

464-471

Published online

2013-09-24

DOI

10.5603/CJ.a2013.0052

Bibliographic record

Cardiol J 2013;20(5):464-471.

Keywords

congenital short QT syndrome
historical landmarks
channelopathies

Authors

Andrés Ricardo Pérez Riera
Adail Paixão-Almeida
Raimundo Barbosa-Barros
Frank G. Yanowitz
Adrian Baranchuk
Sergio Dubner
Antônio Carlos Palandri Chagas

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