What is the purpose of having t.waves, q.t. intervals, long q.t syndrome studies with stress & ekg tests for? what are they and what reason/diagnosis?

Arrythmia: The different waves on the ekg represent the electrical impulses reaching different parts of the heart as it beats. Long qt syndrome is a condition where the electrical signals take longer than normal to pass through the heart. It may be caused by medication or may be congenital. Long qt may progress to life-threatening arrhythmias, so it is important to be monitored by your doctor frequently.

See below: T-waves and qt intervals are among the measurements performed on ECG tracings that provide a window into the health of the muscle and the electrical system of the heart. Long qt is a potentially severe abnormality in the way the heart's electrical system resets itself after a heart beat. Some cardiac and electrical abnormalities can be unmasked at faster heart rates and thefore the stress test.