Magnesium Sulfate as a Rescue Therapy for Refractory Unstable Supraventricular Tachycardia in the Emergency Department: A Case Report

Refractory unstable supraventricular tachycardia (SVT) that is unresponsive to both chemical cardioversion and electrical cardioversion is a rare phenomenon that may lead to significant morbidity and mortality. For this subcategory of patients, there are no clear recommendations in the current American Heart Association (AHA)/American College of Cardiology (ACC)/European Society of Cardiology (ESC) guidelines for their management. A 59-year-old male sought care in the emergency department due to chest pain, palpitation, shortness of breath, and pre-syncope. On evaluation, the patient had an unstable SVT as evidenced by acute heart failure on examination and an electrocardiogram demonstrating SVT. The SVT was unresponsive to both chemical (adenosine and amiodarone) and synchronized electrical cardioversion. With no other chemical cardioversion options and no clear recommended management guidelines, the patient was successfully converted with the use of 2 g intravenous magnesium sulfate. This case highlights the importance of considering unconventional therapy, such as magnesium sulphate, as a rescue agent in cases where the standard recommendations are ineffective, unavailable, or contraindicated.