This kind of behavior can happen sometimes related to stressful or traumatic events. I would still suggest that you discuss with you doctor about an MRI/ CT scan
of the brain. Sometimes a massive heart attack
may cause some minor damage to the brain and it may present with subtle symptoms of abnormal behavior.
Stick with her and help her out. If the MRI/CT are normal you can have her consult a good psychiatrist
or a clinical psychologist
who would help her deal with the problem,
Hope this was helpful
Dr. Om Lakhani