heart and blood vessel disorders
Long QT Interval Syndromes
Symptoms of Long QT Interval Syndromes
The long QT interval syndromes do not cause symptoms unless torsades de pointes ventricular tachycardia occurs, which can cause palpitations (awareness of heart beats), light-headedness, or fainting. Torsades de pointes ventricular tachycardia may turn into ventricular fibrillation and cause cardiac arrest and sudden death. 