To see all protocols that comply with the WHO Essential Medicine List 

Grade 1: average QTc 450 - 480 ms

Grade 2: average QTc 481 - 500 ms

Grade 3: Average QTc ≥ 501 ms; > 60 ms change from baseline

Grade 4: Torsade de pointes; polymorphic ventricular tachycardia; signs/symptoms of serious arrhythmia

Reference: Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0 Published: November 27, 2017