https://onlinelibrary.wiley.com/doi/10.1111/joim.13757


ECG abnormalities were present in 40% of hypokalemic patients and included t-wave flattening/inversion, ST-segment depression, QTc prolongation, longer QRS duration, and high heart rate. 

 after adjustment for potential confounders, only heart rate >100 beats per minute and not the ECG abnormalities was associated with those adverse outcomes, and this association was noted only when potassium levels were <3.0 mmol/L.

hypokalemia is not good and certainly not hypokalemia < 3.0 but its not the proarrhythmic effects of hypokalemia that is bad it is the acute illness it is the under lying reason the patient has a potassium of less than 3.