Is consuming a lot of alcohol at once, getting "drunk" occasionally bad for the heart valves, I had mitral valve repair heart surgery.?

Somewhat. It may not be too bad for the valves but it it certainly very bad for the heart muscle (myocardium) when you do acute excessive ingestion of alcohol. Long term it may develop "alcoholic cardiomyopathy" Also, if you are on blood thinners (warfarin) it will throw all values off. You know the effects of alcohol on the liver. You already had a close encounter with you own mortality: Why risk it?