Adenosine for Supraventricular Tachycardia

Initial Management Approach

• The American College of Cardiology, American Heart Association, and Heart Rhythm Society recommend attempting vagal maneuvers before any medication, with a Class I recommendation 1, 2, 3
• Vagal maneuvers should be performed with the patient supine, using techniques such as the Valsalva maneuver or carotid massage, with a success rate of approximately 27.7% when switching between techniques 4

Adenosine Administration

• The American College of Cardiology recommends adenosine as the first-line injectable medication for treating supraventricular tachycardia, with a Class I recommendation, and a success rate of 69-95% for terminating AVNRT and AVRT 1, 4
• Adenosine should be administered as a rapid bolus of 6 mg IV push, followed by a 20 mL saline flush, via a large proximal vein 5

Alternative Injectable Options

• The American College of Cardiology recommends IV calcium channel blockers, such as diltiazem or verapamil, as a second-line agent for hemodynamically stable patients, with a Class IIa recommendation, and conversion rates of 64-98% 1, 2, 3
• IV beta blockers are a reasonable alternative for hemodynamically stable SVT, with a Class IIa recommendation, and an excellent safety profile but less effective than calcium channel blockers 1, 2, 3

Critical Safety Considerations

• A defibrillator must be immediately available when administering adenosine, especially if Wolff-Parkinson-White syndrome is possible, and continuous ECG monitoring should be performed during administration 5
• The initial dose of adenosine should be reduced to 3 mg for patients taking dipyridamole or carbamazepine, transplanted hearts, or central venous access 5

Special Populations

• Adenosine is safe and effective during pregnancy, according to the American College of Cardiology 5

Diagnostic Considerations

• If wide-complex tachycardia is present, it should be assumed to be ventricular tachycardia unless proven otherwise, and adenosine can be used diagnostically for stable wide-complex tachycardia, with a Class IIb recommendation 7