From the Guidelines
Adenosine is indicated for the acute treatment of patients with orthodromic AVRT, as it is effective for conversion of orthodromic AVRT in 90% to 95% of patients, with minor and brief side effects occurring in approximately 30% of patients 1. The typical dosing regimen for adenosine in this context begins with 6 mg given as a rapid IV bolus, followed by a saline flush. If the first dose is ineffective, a 12 mg dose can be administered, with a possible third dose of 12 mg if needed. Some key points to consider when using adenosine for tachycardia include:
- It works by temporarily blocking AV nodal conduction, interrupting the reentry circuit responsible for the tachycardia 1.
- Patients should be warned about transient side effects including flushing, chest pain, dyspnea, and a sense of impending doom, which typically resolve within seconds.
- Adenosine should be used with caution in patients with asthma or COPD due to potential bronchospasm, and is contraindicated in those with second or third-degree heart block or sick sinus syndrome without a pacemaker 1.
- It's also useful diagnostically to unmask atrial flutter or atrial fibrillation when the ventricular response makes the underlying rhythm difficult to identify. In the context of real-life clinical medicine, it's essential to prioritize the use of adenosine for patients with orthodromic AVRT, given its high efficacy and relatively low risk of side effects, as supported by the most recent and highest quality study available 1.
From the Research
Indication for Adenosine in Tachycardia
The indication for adenosine in tachycardia is primarily for the treatment of supraventricular tachycardia (SVT) 2, 3, 4, 5.
- Adenosine is effective in converting SVT to a normal sinus rhythm, particularly in cases where vagal maneuvers fail 2, 3, 4, 5.
- It is commonly used as a first-line therapy for SVT, with calcium channel blockers and beta blockers considered as alternative or additional treatments 2, 3, 4, 5.
- Adenosine is particularly useful for terminating atrioventricular node-dependent SVTs, as it causes a transient heart block 6.
Specific Uses of Adenosine
- Adenosine can be used to treat various types of SVT, including atrioventricular nodal re-entrant tachycardia, atrioventricular re-entrant tachycardia, and atrial tachycardia 4, 5.
- In cases where standard doses of adenosine are ineffective, higher doses may be considered, as demonstrated in a case report where a patient received 24 mg and 36 mg of adenosine to successfully convert SVT to a normal sinus rhythm 6.
Considerations for Adenosine Use
- Adenosine has a significant side-effect profile, including minor adverse events such as nausea, chest tightness, shortness of breath, and headache, which occur more frequently than with calcium channel blockers 2.
- Patients should be fully informed of the risks and benefits of adenosine treatment prior to administration 2.
- Collaboration with a cardiac electrophysiology expert may be necessary when initial management tactics are not successful 6.