Can a potium level of 3.1 cause arrythmias and long QT interval?

I have had episodes of feeling lightheaded and some near fainting. Also diagnosed orthostatic hypertension, low potium, and low volume? My ECG showed repolorization disturbances, arrythymias, and a long QT interval. My dad and grandma both had similar problems and eventually started ping out and had to have pacemakers. Could mildly low potium cause all those problems or do I need to see a Cardiologist?