If you mean as a possible side effect from taking an antidepressant, if that is happening, then you need to contact your doctor right away. Even, if necessary call 911 or go to the emergency room of your hospital. No one here can judge the seriousness of what you are describing.
If not, I know Health Central has a site devoted to the heart which you can find here.
Important:
We hope you find this general health information helpful. Please note however, that this Q&A is meant to support not replace the professional medical advice you receive from your doctor. No information in the Answers above is intended to diagnose or treat any condition. The views expressed in the Answers above belong to the individuals who posted them and do not necessarily reflect the views of Remedy Health Media. Remedy Health Media does not review or edit content posted by our community members, but reserves the right to remove any material it deems inappropriate.