The upper chamber (atrium) increases in size abnormally from obesity and/or high blood pressure. Treatment for the conditions named would/could return size to normal and that would be medication that would widen the vessels to reduce the heart's workload.
Usually it is the mitral valve that is between upper left chamber (atrium) and the lower chamber (ventricle). It usually isn't a problem unless the leakage is calculated to be moderate to severe. At that degree of leakage there would be shortness of breath, chest pain, fatigue, etc. Often the leakage is not serious and no treatment is necessary. Any treatment would involve operational intervention.
High blood pressure is almost always successfully treated. Hope this helps, and if you have any followup questions you are welcome to respond. Thanks for sharing and take care.