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Three Part Question

[In an asthmatic patient with a SVT] is [treatment with adenosine] associated with [an increased risk of bronchospasm]?

Clinical Scenario

A 32 year-old woman with asthma presents to the Emergency Department with a 20-minute history of palpitations. On examination she is cardiovascularly stable, there is no bronchospasm and the ECG shows a supraventricular tachycardia (SVT) that fails to respond to vagal manoeuvres. You would like to use IV adenosine but you are aware that asthma is a contraindication treatment. You wonder what evidence there is that IV adenosine will cause bronchospasm.

Search Strategy

Medline 1966-09/00 using the OVID interface.
([exp tachycardia OR exp tachycardia, supraventricular OR narrow complex tachycardia.mp OR exp arrythmia OR exp tachycardia OR dysrhythmia.mp] AND [exp asthma OR asthma.mp OR exp respiratory sounds OR wheezing.mp OR exp bronchial spasm OR bronchospasm.mp] AND (exp adenosine OR adenosine.mp OR adenosine.ae.ct]) LIMIT to human and english.

Search Outcome

16 papers were found of which 14 were irrelevant or of insufficient quality for inclusion. The remaining 2 papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Larsson K and Sollevi A, 1988, Sweden	7 well subjects with a previous diagnosis of asthma Increasing doses of adenosine vs placebo	Crossover placebo trial	HR	No significant difference	Children only Retrospective chart review
			BP	No significant difference
			Pulmonary function	No significant difference
Losek JD et al, 1999, USA	82 patients aged 18 yrs or less who received IV adenosine in the ED for the treatment of SVT 13 had documented evidence of asthma	Survey	Successful cardioversion	72% cardioversion success rate	Dose of adenosine very different to that used clinically Subjects well, and in normal sinus rhythm
			Adverse effects	22 adverse patient events, no bronchospasm but 2 complaints of "dyspnoea" in non-asthmatic patients

Comment(s)

There is very little evidence recording the effect of IV adenosine on asthmatic airways. Many studies have documented that inhaled adenosine is a potent bronchoconstrictor in asthmatic but not normal patients. In the literature there are 4 case reports of patients with asthma or COAD developing bronchospasm following treatment with IV adenosine. This level of evidence has many limitations. Similarly there are many studies looking at the efficacy of adenosine that report no "significant side effects" some specifically mention no patients reported bronchospasm.

Clinical Bottom Line

At worst adenosine is only relatively contraindicated in the treatment of asthmatic patients with supraventricular tachycardia.

References

1. Larsson K, Sollevi A. Influence of Infused Adenosine on Bronchial Tone and Bronchial Reactivity in Asthma. Chest 1988;93(2):280–84.
2. Losek JD, Endom E, Dietrich A, et al. Adenosine and Pediatric Supraventricular tachycardia in the Emergency Department: Multicenter Study and Review. Ann Emerg Med 1999;33(2):185–91.