Long QT Syndrome causing fainting

My 12 yr old son (140cm, 38kg) had a recent episode last month of sudden fainting, hit the back of his head on the concrete at high speed. Was unconscious for under a minute. Went to emergency via ambulance and his ECG showed QT prolonged 492ms. Question 1.Could the knock on his head of caused this ? (he did have a previous episode of unconsciousness but it was assumed that was caused by a exercise ball knocking him out) He has since had two more ECGs done at different locations, results 456ms, 416ms. but report says normal...is it? Subsequently I had a ECG and it showed 452. Question 2.. Is this considered prolonged? the report says normal but my GP and so do I after researching on the internet, that it is indeed prolonged. I am 46yo female 140cm in stature, 40kgs. Question 3. what is considered normal range for people of our size and stature age....! Question 4 what further tests would you recommend? thank you

Much more likely: an arrhythmia caused the fall. If a diagnosis of Long QT Syndrome is confirmed, it can be complicated by conditiosns called torsade, ventricular tachycardia or even 'sudden cardiac death'. All of these could reduce the bloodflow to your son's brain dramatically, thus cause fainting or worse - hence a fall!

At this point a diagnosis of Long QTc (QT intervals, corrected for heart rate (QTc) that are longer than 440 mseconds) has not been confirmed. I suggest a consultation with a pediatric cardiologist as the next step. Whether small size plays a role I can't tell. Long QT Syndrome can run in the family, so it may be important to find out whether this is the case.

Hope this helps,

Dr T



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