What advice would you give to a fairly healthy 32yo female patient who, despite reassurance from her doctor re: her health, has a heart attack phobia?

Anxiety and phobia: You are describing worried thinking (about heart attack) which causes anxiety (emotion) which can result in behavioral avoidance (phobia) of something (eg exercise). How you think leads to how you feel leads to behaviors. What leads to a heart attack is coronary artery disease, quite uncommon in a young person. Consult a cognitive-behavioral therapist about your worried thinking.

Risk factors: Discuss risk factors: high blood pressure family history diabetes high cholesterol, especially LDL > 100 smoking discuss with your doc and get an ultrasound of your heart - no big deal heart attacks usually need two risk factors at least probably everything will be normal - than take a break, go on vacation and sleep well.

Phobia: Talk to a counselor for supportive therapy to provide reassurance & explore fears.

See a therapist: If this is truly an irrational fear, then other explanations can be explored. Sometimes panic attacks can create a fear of heart attacks. Sometimes mitral valve prolapse can do the same. Is there a family history of heart disease that is scaring this person? Therapy can help her discover the origin of her fears.