A sad thing for sure..........RIP Gaines An enlarged heart can be a congenital condition from birth. However since the heart is a muscle it can remodel based on the demands on it. Resistance/strength training will thicken the walls of the heart to enlarge it.......while running/areobic exercise increases the volumn of the chamber of the heart and can enlarge it that way. Now a person over 6' 2" is considered within the top 25% in height amoung humans.......one negative of being tall is the potential for enlargement of the heart since tall people have larger hearts to begin with..........add exercise and the risk factor goes up. Even so......its rare to have a ventrical chamber issue (lower two chambers) that can lead to a fatal arrythmia....however some enlargements such as with the atrial chambers (upper two chambers) can lead to non life threatening arrythymias like atrial fib.......a condition found in some older athletes especially tall ones like ex NBA players.......Larry Bird has this condition for instance....So does Mario Lemuex Enlargement remodeling can also come from a history of high blood pressure and/or drugs (precription and/or recreational).........in those situations the heart enlargement is often not reversable and must be treated appropriately.........The same with one from birth. But the good news for an anthlete is if the enlarged heart is a result from exercise is a reversable condition......rest for a month or two will allow the heart to atrophy back to its normal size....... The reason an enlarged heart causes issues is that the whole surface of the inner heart wall lining is like an electrical switch board..........and an ever increasing surface allows for more rough electric patterns or storms that can interfer with the hearts normal beating. Also, inflammation of that lining can cause the same issues. America is very negligant in testing the heart of athletes........ In Italy they lead the world in regards to circulatory testing for their athletes........In Italy every person who participates in sports is given an echocardiogram to check 3 dimensionally for any structural heart defects......they do this annually from the age of 14 on up. In this country we hardly ever check until it is too late.. It needs to change as we lose too many young people without the proper testing.......and I hope this helps in some understanding of the subject.