Introduction

Supraventricular tachycardia (SVT) is the most common cardiac cause of sustained palpitations. It affects 2 in 1000 adults and is a frequent cause of referral to cardiology services, both as an outpatient and acutely during an attack.1 Since 1992, clinical guidelines have favoured adenosine2 as a first-line treatment of SVT in the acute setting instead of voltage-dependent calcium channel antagonists (CCA; verapamil or diltiazem). However, adenosine is associated with frequent and unpleasant adverse effects including anxiety, confusion and even a sensation of impending death. These effects, though transient, can be highly distressing; it is not uncommon to encounter patients who are reluctant to receive adenosine due to such effects. Furthermore, adenosine is considerably more expensive than CCA, which has implications for many healthcare providers worldwide. Therefore, despite the effectiveness of adenosine, its primacy in the management of SVT in the UK should not prevent examination of alternative treatments, and several trials have compared the performance of adenosine against CCA.

We therefore performed a Cochrane systematic review update3 to incorporate new trials performed since a previous review in 2006.4 The review compared the effects of adenosine versus CCAs in terminating SVT (table 1).