In the pooled analysis there was no significant difference in reversion rate or relapse rate between the two drugs .
Adenosine and verapamil are both effective treatments for supraventricular tachycardia in the majority of patients .
BACKGROUND Patients with paroxysmal supraventricular tachycardia frequently present to the Emergency Department .
Where vagal manoeuvres fail , the two most commonly used drugs are adenosine and calcium channel antagonists .
Both are known to be effective but both have a significant side-effect profile .
OBJECTIVES To examine the relative effects of adenosine and calcium channel antagonists and , if possible , to determine which is most appropriate for the management of supraventricular tachycardia .
Adenosine for paroxysmal supraventricular tachycardia: dose ranging and comparison with verapamil. Assessment in placebo-controlled, multicenter trials. The Adenosine for PSVT Study Group.
OBJECTIVE To assess the safety and efficacy of intravenous adenosine in terminating acute episodes of paroxysmal supraventricular tachycardia .  DESIGN Two prospect i ve , double-blind , r and omized , placebo-controlled trials to evaluate dose response in patients receiving adenosine  and to compare the effects of adenosine with those of verapamil . PATIENTS A total of 359 patients with a tachycardia electrocardiographically consistent with paroxysmal supraventricular tachycardia were entered into the two protocol s. Patients subsequently found to have arrhythmias other than paroxysmal supraventricular tachycardia were excluded from the efficacy analysis . INTERVENTIONS The first protocol compared sequential intravenous bolus doses of 3 , 6 , 9 , and 12 mg of adenosine to equal volumes of saline . In the second protocol , patients received either 6 mg and , if necessary , 12 mg of adenosine or 5 mg and , if necessary , 7.5 mg of verapamil . MEASUREMENTS AND MAIN RESULTS When data are expressed in terms of cumulative response in eligible patients , intravenous adenosine terminated acute episodes of paroxysmal supraventricular tachycardia in 35.2 % , 62.3 % , 80.2 % , and 91.4 % of patients who received maximum doses of 3 , 6 , 9 , and 12 mg , respectively , in a four-dose sequence , whereas 8.9 % , 10.7 % , 14.3 % , and 16.1 % of patients responded to four sequential placebo doses ( P less than 0.0001 ) . In the second trial , cumulative response rates after 6 mg followed , if necessary , by 12 mg of adenosine were 57.4 % and 93.4 % , and after 5 mg followed , if necessary , by 7.5 mg of verapamil were 81.3 % and 91.4 % . The average time after injection to termination of tachycardia by adenosine was 30 seconds . Adenosine caused adverse effects in 36 % of patients , but they lasted less than 1 minute and were usually mild . CONCLUSIONS Adenosine in grade d doses up to 12 mg rapidly and effectively terminates acute episodes of paroxysmal supraventricular tachycardia in which the atrioventricular node is an integral part of the re-entrant circuit . The overall efficacy of adenosine is similar to that of verapamil , but its onset of action is more rapid . Adverse reactions to adenosine are common but are minor and brief
In the pooled analysis there was no significant difference in reversion rate or relapse rate between the two drugs .
Adenosine and verapamil are both effective treatments for supraventricular tachycardia in the majority of patients .
BACKGROUND Patients with paroxysmal supraventricular tachycardia frequently present to the Emergency Department .
Where vagal manoeuvres fail , the two most commonly used drugs are adenosine and calcium channel antagonists .
Both are known to be effective but both have a significant side-effect profile .
OBJECTIVES To examine the relative effects of adenosine and calcium channel antagonists and , if possible , to determine which is most appropriate for the management of supraventricular tachycardia .