Symptomatic supraventricular tachycardia (SVT) is a common presentation in the Emergency Department which can be a lifethreatening condition and this requires immediate intervention. Stable SVTs are commonly treated with Adenosine but adenosine is more effective in AV nodedependant SVTs as it causes transient AV block [1] and causes normalization of the cardiac rhythm. American Heart Association AHA’s ACLS protocol recommends 6mg then 12mg (total 18mg) dose for SVTs [2]. However there is limited data as to how much maximum dose can be given for those SVTs that fail to terminate with standard dosing schedule [1]. This case report describes a 30 years old female with symptomatic SVT which failed to revert with normal dosing of adenosine neither with electrical cardioversion nor with multiple antiarrhythmic drugs but responded only to a much higher dose of adenosine.

Keywords: Supraventricular Tachycardia; AVRT (Atrioventricular ReEntry Tachycardia); AVNRT (Atrioventricular Reentrant Tachycardia); Adenosine; Cardioversion; ACLS (Advanced Cardiac Life Support); AV (Atrioventricular) Block; AHA (American Heart Association); ED (Emergency Department); Refractory; Ursodeoxycholic Acid; WPW Syndrome (Wolf Parkinson White).