Hi there,
A detailed medical and psychiatric history is always needed for every case.Also is the detailed mental status examination of the case to come for a diagnosis and its management accordingly.
Next Steps
You have undergone some of the tests to rule out some of the symptoms which can be associated with the problems related to heart.
Health Tips
Do get the advice from the cardiologist again and start the treatment from a mental health professional if cardiac symptoms are excluded.
Be positive in your thoughts.
Take adequate sleep and balanced and healthy diet.