Hello, I'm a young man in general good health. However, lately, during exercise like biking or jogging, I've felt as if I'm about to pass out, only I never do. I read about Long QT Syndrome, or Sudden Death Syndrome, and learned that a symptom might be feeling faint after exercise. Now, I know I've had through out my life several ECGs, does that mean that if I had Long QT Syndrom I would know it by now? Is an ECG all it takes? Thanks in advance.