How is the diagnosis?
The diagnosis is usually made after a heart attack with fainting, possibly after successful resuscitation after cardiac arrest. In some cases, diagnosed after the sudden death of a family member, and where the assessment of other family members revealed the condition in some patients diagnosed after an ECG taken to at random have demonstrated QT prolongation.
At the physical examination of the patient is the doctor who usually completely normal conditions the ECG with measurement of the QT interval that provides the diagnosis. Diagnosis should be made to the heart specialist. Usually there will also be conducted an ultrasound examination of the heart, echocardiography, to rule out other diseases and to look for any underlying heart disease. However, for the vast majority of the echocardiography show normal conditions.
It is defined 10 different types of LQTS based on the genetic defects underlying. It is now offered in Norway about genetic testing with proven LQTS. The outcome of the genetic test cannot affect the choice of treatment, and counseling in relation to family members.