Be prepared for her to evolve into a new, healthier person, someone who is more focused on her own health and well-being. Her former lifestyle may have contributed to her heart disease, so she will need to change what she eats and how much she exercises. She may also, gradually and over time, become introspective and sort through her life's priorities. Her spirituality may deepen as her need for emotional and psychological healing emerges. She is on a very personal journey to re-shape her life and take better care of herself. While some of these changes may be subtle and mysterious to you, she will need your support and encouragement. All change is intimidating but if you can walk this path with her, you will both arrive at a more meaningful and healthy life.
Try to keep lines of communication open or confide your feelings to her or a close friend, as she may be pre-occupied with her own feelings and recovery. You do not need to "walk on eggshells" around her, but understand that you both have suffered a very real crisis and both will need time to recover. If handled well, this time can lead to a deeper and richer relationship, as well as a renewed appreciation for the fragility of life.