Enlargement of the heart as the sole cause of death is impossible. Heart enlarges in the after prolonged stress to uncontrolled hypertension, compromised valves, inflammation, and long term or chronic ischemia(ineffective blood supply at the coronary vessels). When a certain heart enlarges, no drug can ever reduced back its size to its original. The only thing we doctors can do is to prevent its further enlargement by treating the actual cause of enlargement and treating its complication. Anyway, as I told you, it won t be a sole cause of death of person. Therefore, you can have a huge heart and still can survive.