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Synonyms: autosomal-dominant long QT syndrome, long QT syndrome type 1, LQTS1, RWS, Romano-Ward long QT syndrome, Ward-Romano syndrome
Romano-Ward syndrome is an inherited heart disorder characterised by prolongation of the QT interval, often in association with episodes of ventricular tachyarrhythmia, torsades de pointes, syncope and sudden death.
KCNQ1 (formerly called KVLQT1) is a voltage-gated potassium-channel gene responsible for the long QT 1 subtype of long QT syndromes. In general, heterozygous mutations in KCNQ1 cause Romano-Ward syndrome (LQT1 only), while homozygous mutations cause Jervell and Lange-Nielsen syndrome (LQT1 and deafness).
Attacks of ventricular tachyarrhythmia are usually associated with sympathetic stimulation such as exercise, stress or emotion, dependent on genotype.
- The disorder may be sporadic or transmitted as an autosomal-dominant trait.
- Six different genes have so far been identified as being involved in the development of congenital long QT syndromes and heterozygote mutations in KCNQ1 (a potassium-channel gene) are thought to be responsible for Romano-Ward syndrome.
- The severity ranges from those with no apparent symptoms to others who develop tachyarrhythmias resulting in episodes of syncope, cardiac arrest and, potentially, sudden death.
- Between such episodes, sinus bradycardia is often seen.
- There may be a family history of recurrent syncope or sudden death.
Other causes of prolongation of the QT interval:
- Congenital: Jervell and Lange-Nielsen syndrome, which is associated with deaf mutism and transmitted as autosomal recessive.
- Electrolyte disturbances: hypokalaemia, hypocalcaemia, hypomagnesaemia.
- The diagnosis should be considered in all patients who present with syncope.
- An ECG with calculation of the QT interval should be performed on all patients with a suggestive history.
- All other family members must be fully assessed.
- Drug treatment:
- If drug treatment is unsuccessful then selective high left stellate ganglionectomy has been shown to be effective.
- Permanent pacing in combination with betablockers may also be effective in reducing symptoms.
- For high-risk patients, an implantable cardioverter defibrillator (ICD) reduces mortality.
- Defibrillator implantation is often a first-line therapy if there has been a cardiac arrest.
The prognosis of untreated congenital long QT syndrome is poor, with a high incidence of sudden death in childhood.
Further reading and references
Watanabe A, Nakamura K, Morita H, et al; Long QT syndrome. Nippon Rinsho. 2005 Jul63(7):1171-7.
Herbert E, Trusz-Gluza M, Moric E, et al; KCNQ1 gene mutations and the respective genotype-phenotype correlations in the long QT syndrome. Med Sci Monit. 2002 Oct8(10):RA240-8.
Haack B, Kupka S, Ebauer M, et al; Analysis of candidate genes for genotypic diagnosis in the long QT syndrome. J Appl Genet. 200445(3):375-81.
Sovari AA et al; Long QT Syndrome, Medscape, Jun 2012
Moss AJ, McDonald J; Unilateral cervicothoracic sympathetic ganglionectomy for the treatment of long QT interval syndrome. N Engl J Med. 1971 Oct 14285(16):903-4.
Chiang CE; Congenital and acquired long QT syndrome. Current concepts and management. Cardiol Rev. 2004 Jul-Aug12(4):222-34.