Well it is likely that your body has made some recovery from your regime changes to lifestyle and I congratulate you on this. Good diet, low stress and relaxation has been shown to improve arterial function. Cutting right down on cigarettes will make a huge difference because Oxygen levels in your blood will be higher. As for a prolapse improving, I'm not really sure. It probably depends on the initial cause. Why dont you ask your GP to request an echocardiogram to see?
Strangely enough I have just been looking into MVP and it seems that many people are, and have been, misdiagnosed with this problem. Investigations are being run and new protocols are being put into place. So, to see if you was misdiagnosed, I would request a new echocardiogram. Again, well done on the changes.