If you have dilated cardiomyopathy caused by prolonged arrhythmia, would it go away when treated properly? Or is damaged- damaged and won't go away?
Yes. frequent cardiac irregularity such as ventricular premature beats including those considered benign like outflow track PVCs can cause a cardiomyopathy which can be reversible by catheter ablation. This is a possibility when an underlying structural heart disease is ruled out. A cardiologist can help sort this out.
See a cardiologist. Arrhythmia is a symptom of cardiomyopathy, not the cause. The course is highly variable, i.e. different in almost every patient. Presumably you are under the care of a cardiologist, right? If so, ask him or her and follow the advice you get. If not, see a cardiologist ASAP and take it from there. Good luck!