MON-483 Supraventricular Tachycardia Requiring Cardioversion Following Adrenocorticotropic Hormone Stimulation Test

Abstract Disclosure: R. Hassan: None. D. Skiada: None. Adrenocorticotropic Hormone (ACTH) stimulation tests are commonly used to diagnose adrenal insufficiency. While generally safe, rare cardiovascular complications can occur. A 74-year-old female with a past medical history of autism (minimally verbal at baseline), chronic kidney disease (CKD), hypertension and hyperlipidemia presented to the emergency room with reduced oral intake and lethargy. She was found unresponsive and the time of her last being well was unknown. On examination, the patient was nearly unresponsive and hypotensive. Initial laboratory results revealed severe hyponatremia (sodium 114 mEq/L) and hyperkalemia (potassium 5.9 mEq/L) with acute kidney injury (AKI) superimposed on CKD. Work-up in the Emergency Department ruled out the possibility of a stroke. She was admitted to the Intensive Care Unit for management of symptomatic hyponatremia, mild hyperkalemia and AKI. Given her presentation, the possibility of adrenal insufficiency was raised. A random cortisol level was 11.9 mcg/dL, and thus an ACTH stimulation test was pursued. 30 minutes after administration of cosyntropin (0.25 mg Intravenously), the patient developed significant tachycardia with heart rate up to 220 beats/minute. An electrocardiogram was consistent with Supraventricular Tachycardia (SVT). This was refractory to carotid massage, repeated doses of adenosine, and eventually required electrical cardioversion. A dose of 200 joules (J) synchronized cardioversion was administered without success, however the patient responded to a second attempt and converted to sinus rhythm. The patient's hospital course was otherwise unremarkable and her condition improved. Her ACTH stimulation test was negative, with cortisol level after 1 hour of cosyntropin administration being 20.1 mcg/dL. This case illustrates a rare but serious complication of cosyntropin administration during an ACTH stimulation test. The United States Federal Food and Drug Administration (FDA) package insert for cosyntropin lists a number of possible complications including bradycardia and tachycardia. However, SVT is not listed and the incidence of those complications is not defined. To our knowledge, this represents the first report of refractory SVT as a complication of cosyntropin administration. It is unclear if cosyntropin adverse cardiovascular effects are directly related to the medication - as shown in some animal models - or the resulting downstream cortisol increase. This case serves as a reminder for clinicians to be prepared for potential cardiovascular complications during ACTH stimulation tests, particularly in elderly patients with multiple comorbidities. It also highlights the need for readily available resuscitation equipment and expertise in advanced cardiac life support in settings where such tests are performed. Presentation: Monday, July 14, 2025