Long QT syndrome is transmitted as an autosomal recessive condition when associated with deafness or as an autosomal dominant condition without this association. The syndrome may be marked by sudden loss of consciousness due to tachyarrhythmia and possibly death due to torsade de pointe. The QT measurement should be corrected by dividing its value by the RR2 interval to obtain the QTc. The longer the QTc, the greater the risk of an acute event. The QT may be influenced by medication so that moderately prolonged QT intervals may become symptomatic in some circumstances.
Note: An ME who is unsure if the QTc is prolonged should send the ECG to a cardiologist for interpretation, as prescribed in the GD ‘Examination Procedures.
If a prolonged QTc is confirmed or if the ME is still uncertain about the tracing characteristics, the ME may seek a further ECG review by CAA prior to deciding whether to proceed via the section 27B(1) pathway. Alternatively the ME may consider outright to assess the application under section 27(B2).
The ME should also consider any medication used by the applicant, capable of affecting the QT and QTc duration.