measured from the beginning of the QRS complex to the end of the T wave.
MEASURES: time taken for ventricular depolarization and repolarization.
PROLONGED QTI = may cause monomorphic ventricular tachycardia, polymorphic ventricular tachycardia (torsades de pointes) and sudden cardiac death.
Normal QTIs are based on HEART RATE:
- slower HR = longer QTI
- faster HR = shorter normal QTI