Are there certain sports which are pre-disposed to long QT?

There is certainly a connection between certain sport deaths and long QT syndrome. The most common sporting discipline that is associated with sudden death  in long QT syndrome is swimming. The thought process is that the dive into the water at the beginning of a swimming contest incites an adrenergic surge – that is a rapid rise in adrenalin levels – probably because the face and the body hits cold water suddenly. This surge in adrenalin causes the heart to go into an abnormal rhythm – so most deaths in long QT syndrome appear to occur in swimmers.
Unfortunately, many people don’t recognise that this death may be due to an abnormal cardiac problem and these deaths are falsely attributed to drowning. There are many situations where there is an excellent swimmer who went out to swim in a lake and drowned suddenly and people feel that they may have run into trouble or it’s an unusual cause of death, unusual drowning. But such drowning should be investigated and family members of such individuals must be screened for long QT syndrome. It’s usually the females that die during swimming more so than males.