Piratebike,
Your second comment sounds to me as if what you really need is to talk to a cardiologist who can answer they questions you posed there. A second opinion is something you should actively seek. Not all doctors are open to your fears, some are just doing a job to treat your heart, staying unengaged to the your emotional/psychological needs. While a cardiologist can't be expected to also be a therapist, she/he should be able to explain your condition to you to clarify your thoughts so that you can seek help to give you strength to make changes. And while exercise can be positive in many post-attack cases, you should undertake an exercise regimen only under explicit instructions.

If your heart problems were not caused by unfavorable lifestyle but rather from a structural defect, a doctor can determine and clarify this. If you need to change your diet and lose weight, make a plan to do it. If you need help to realize your plan, seek that help here and with a good therapist. Many people have overcome poor lifestyle choices by taking control of the choices they make - but this must be done under the care of competent specialists.

If you and a physician arrive at a solution which includes antidepressants, be aware than most prescribing doctors are unwilling to EVER take you off (they don't want to be liable to lawsuits if a patient has an adverse outcome after stopping a drug), and many don't even know how to determine whether your prescribed medication is the right one. Some docs simply try increasing doses. I am not saying that you should stay away from antidepressants - they can be lifesavers. IMHO, if taking this type of drug, one would be best advised to also partake talk therapy from a cognitive therapist. This type of therapy allows one to challenge thought patterns so that the patient can determine which negative or depressive thoughts are objectively false. If one simply believes every thought without critical questioning, depressive spirals can deepen rather than abate.

Please let us know how you make out! And good luck!