Romano-Ward Syndrome

Synonyms: Autosomal Dominant Long QT Syndrome, Long QT Syndrome Type 1, LQTS1, RWS , Romano-Ward Long QT Syndrome, Ward-Romano Syndrome

• An inherited heart disorder characterised by prolongation of the Q-T interval, often in association with episodes of ventricular tachyarrhythmia, torsade de pointes, syncope and sudden death.¹
• KCNQ1 (formerly called KVLQT1) is a voltage-gated potassium channel gene responsible for the Long QT 1 sub-type 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).²
• 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 syndromes³ and heterozygote mutations in KCNQ1 (a potassium channel gene) are thought to be responsible for Romano-Ward syndrome.²

• 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.
• Acquired:
  • Electrolyte disturbances: hypokalaemia, hypocalcaemia, hypomagnesaemia
  • Hypothermia
  • Drugs:
    • Antiarrhythmic drugs: amiodarone, procainamide, sotalol, quinidine, disopyramide
    • Tricyclic antidepressants
    • Non-sedative antihistamines: terfenadine, astemizole
    • Antibiotic (erythromycin), and antimalarial (halofantrine)

• 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:⁴
  • Beta-blockers are the drugs of choice.
  • Beta-blockers are effective in preventing cardiac events in approximately 70% of patients.
  • Propranolol and nadolol are the beta-blockers most frequently used, but atenolol and metoprolol are also used.
• If drug treatment is unsuccessful then selective high left stellate ganglionectomy has been shown to be effective.⁵
• Permanent pacing in combination with beta-blockers may also be effective in reducing symptoms.
• For high-risk patients, an implantable cardioverter-defibrillator (ICD) reduces mortality.⁶
• 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.