Clinical features | Medibuddy
13th March 2024

Clinical features

Congenital LQTS can be split syndromes based on the phenotype:

Inheritance and genetics Phenotype
Romano-Ward syndrome Autosomal dominant

Any genetic mutation causing LQTS

Pure cardiac phenotype – prolonged QT and cardiac events

Not associated with deafness

Jervell and Lange-Nielsen syndrome Autosomal recessive

KCNQ1

Severe LQTS and sensorineural deafness

Cardiac events in infancy

Andersen-Tawil syndrome Autosomal dominant Periodic paralysis

Ventricular tachyarrhythmias

Typically, LQTS presents by the time someone is 30 years old. Presentation may be with syncope or syncope followed by seizures. Symptoms, including chest pain, breathlessness or palpitations, will usually precede syncopal episodes. There may be distinct triggers (see above), such as swimming or being startled. Sudden cardiac arrest is an uncommon but possible presentation of LQTS. All of these cardiac events are the result of arrhythmias caused by a prolonged QT interval.

Some people with congenital LQTS are asymptomatic and remain so throughout their lives. Diagnosis may occur through screening of an affected family member.

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