High-dose adenosine for treatment of refractory paroxysmal supraventricular tachycardia.

Paroxysmal supraventricular tachycardia (PSVT) is one of the more common arrhythmias requiring treatment in the emergency department. Intravenous adenosine is recommended as the initial medication of choice for treatment of PSVT, given in escalating doses up to a maximum of 12 mg. With a serum half-life of less than 10 s, adenosine must be given rapidly to allow for adequate time for it to reach the heart via venous return. In over 10% of adult patients, PSVT will not be terminated with maximum doses of adenosine. We report a case of a patient requiring a higher-than recommended dose of adenosine for termination of PSVT. The patient had a history of pulmonary hypertension with resultant right heart failure at the time of presentation. We believe the higher dose of adenosine was necessary in this patient because of the impaired venous return to her right heart. This case indicates that patients with impaired venous return to the right heart may require higher-than-recommended doses of adenosine for effective termination of PSVT.