ECG and EKG are the same thing. Some nations seem to think cardio is spelt Kardio :) With regards to the ischemia question you ask, nobody can answer it, not even the best cardiologist in the world. You could literally go on as you are for years if you make lifestyle changes, or you could go on for months before it gets worse. If you don't smoke, cut out as much sugar from your diet as possible and avoid as much emotional stress as possible, then you may well find that you improve slightly and that you may not require intervention for years.
You pose a difficult question without knowing all the details of your history, your physical examination and all the test results. It seems that the first and most important thing is get your blood pressure under control. You need to see a cardiologist especially if you are having chest discomfort or pain.