Dear Doctors: I am 66 years old and an avid cyclist. Last winter, after we went for a long ride, I suddenly felt lightheaded and then fainted. My doctor ordered a series of heart scans that found slight mitral valve prolapse. What is that? Should I be worried?
Dear Reader: Mitral valve prolapse is a condition that interferes with the one-way flow of blood through two of the four chambers of the hea…