St. John's Wort-Induced Supraventricular Tachycardia.

St. John's wort, a non-FDA-approved over-the-counter (OTC) herbal supplement with antidepressant activity known as Hypericum perforatum, has been found to induce supraventricular tachycardia (SVT) in the absence of any underlying structural cardiac abnormality or known medical history via currently unclear pathophysiology. In this case presentation, the authors present a case of a 33-year-old female who presented with recurrent episodes of palpitations one month after initiating St. John's wort for the treatment of depression, which ultimately resolved upon cessation of the herbal supplement. Therefore, the postulated insinuating event is suspected to be the ingestion of St. John's wort. This will be the first documented case of St. John's wort-induced SVT. This case study brings into question the safety of the use of this agent as an OTC supplement for the management of depression. Further investigation is required to aid in the knowledge and understanding of the causative mechanism and to identify those patients who are at potentially heightened risks of such manifestations.