Adenosine for paroxysmal supraventricular tachycardia: dose ranging and comparison with verapamil. Assessment in placebo-controlled, multicenter trials. The Adenosine for PSVT Study Group. Adenosine: a clinical experience and comparison with verapamil for the termination of supraventricular tachycardias. Electrophysiological mechanisms and determinants of vagal maneuvers for termination of paroxysmal supraventricular tachycardia. Adenosine versus verapamil in the treatment of supraventricular tachycardia: a randomized double-crossover trial. Treatment of atrial fibrillation and paroxysmal supraventricular tachycardia with bidisomide. The Atrial Fibrillation Investigation with Bidisomide (AFIB) Investigators. A randomized, placebo-controlled trial of propafenone in the prophylaxis of paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation. UK Propafenone PSVT Study Group. Comparison of Treatment of Supraventricular Tachycardia by Valsalva Maneuver and Carotid Sinus Massage. Adenosine cardioprotection study in clinical setting of paroxysmal supraventricular tachycardia. Propafenone versus amiodarone in field treatment of primary atrial tachydysrhythmias.
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 The efficacy and side-effects of adenosine for treatment of supraventricular arrhythmias were compared to verapamil therapy in patients presenting to the emergency room . Clinical variables and the time interval from the initiation of treatment to the termination of the supraventricular tachycardia , as well as the time from the initial effective dose of medication to the termination of supraventricular tachycardia were compared for adenosine and verapamil . Adenosine was given to a total of 44 patients , 16 patients in the electrophysiology laboratory , and 28 patients in the emergency room for evaluation and termination of their tachycardia . In the electrophysiology laboratory , 7 patients had AV node reentry , 5 had Wolff-Parkinson-White syndrome , 2 of whom had atrial flutter and fibrillation but no bypass tract reentry , 1 had concealed bypass tract reentry , 1 had Lown-Ganong-Levine syndrome , 1 had intraatrial reentry , and 1 had an automatic atrial tachycardia . Twenty-five patients received  adenosine in the emergency room and 3 patients in the hospital for 31 episodes of supraventricular arrhythmias . In the emergency room , 11 patients had supraventricular tachycardia due to AV node reentry , 3 had Wolff-Parkinson-White syndrome , 6 had atrial flutter or intra-atrial re-entry , 2 had ventricular tachycardia , and 3 had sinus tachycardia . In the hospital , 2 patients had atrial flutter and one had sinus tachycardia . The group of 14 patients with supraventricular tachycardia due to Wolff-Parkinson-White syndrome or AV node reentry presenting in the emergency room were compared in a retrospective manner to the patients treated with st and ard verapamil therapy with respect to time from initiation of therapy to termination of supraventricular tachycardia and time from effective dose of medication to the termination of supraventricular tachycardia , as well as side-effects . There was no significant difference between the two groups with respect to clinical variables .  Adenosine converted 18 of 18 episodes of supraventricular tachycardia in 14 patients 24.6 + /- 9.6 seconds from the administration of the effective dose ( 0.104 + /- 0.024 mg/kg ) and a mean of 4.4 + /- 2.0 minutes from the initiation of therapy . Verapamil converted 29 of 32 episodes of supraventricular tachycardia in 20 patients , 10.9 + /- 7 minutes from the administration of the effective dose , and a mean of 16.8 + /- 20 minutes from the initiation of therapy using a mean of 8.4 + /- 3.4 mg of IV verapamil . ( ABSTRACT TRUNCATED AT 400 WORDS BACKGROUND The vagal maneuvers used for termination of paroxysmal supraventricular reentrant tachycardia ( PSVT ) appear to involve more complex mechanisms than we have known , and further study should be done to explore the possible mechanisms . METHODS AND RESULTS In this study , 133 patients with PSVT and 30 age- and sex-matched control subjects were included . We assessed the effects of different vagal maneuvers on termination of PSVT and compared baroreflex sensitivity and beta-adrenergic sensitivity between the patients with PSVT and control subjects . Out of 85 patients with atrioventricular reciprocating tachycardia ( AVRT ) , vagal maneuvers terminated in 45 ( 53 % ) . Of these , 28 ( 33 % ) terminated in the ante grade limb and 17 ( 20 % ) terminated in the retro grade limb . Out of 48 patients with atrioventricular nodal reentrant tachycardia ( AVNRT ) , vagal maneuvers terminated the tachycardia in the ante grade slow pathway ( 14 % ) or in the retro grade fast pathway ( 19 % ) . Baroreflex sensitivity was poorer but isoproterenol sensitivity test better in patients with AVNRT . Poorer ante grade atrioventricular node conduction properties and better vagal response determined successful ante grade termination of AVRT by vagal maneuvers . Poorer retro grade accessory pathway conduction property but better vagal response determined successful retro grade termination of AVRT . Better sympathetic and vagal response associated with poorer retro grade atrioventricular node conduction determined retro grade termination of AVNRT by the Valsalva maneuver . CONCLUSIONS Both the vagal response and conduction properties of the reentrant circuit determine the tachycardia termination by vagal maneuvers . Improved underst and ing of the interaction of autonomic and electrophysiological mechanisms in maintaining or terminating PSVT may provide important insight into the pathophysiology of these two tachycardias The safety and efficacy of verapamil and adenosine in the acute termination of supraventricular tachycardia were compared in a r and omized double-crossover trial . Of 32 eligible patients with either spontaneous or induced narrow complex tachycardia , seven ( 22 % ) patients experienced conversion to sinus rhythm with carotid sinus massage . The other 25 patients were r and omly assigned to receive either adenosine ( n = 14 ) or verapamil ( n = 11 ) . Relative drug efficacies were 100 % for adenosine versus 73 % for verapamil , p = NS . Adenosine given at less than or equal to 120 micrograms/kg caused conversion in 12 ( 86 % ) of 14 patients . The other two patients required 20 mg adenosine for conversion . After conversion the systolic blood pressure increased significantly in the adenosine group but not in the verapamil group . Reinitiation of tachycardia occurred in two ( 14 % ) of 14 patients r and omized to the adenosine group . Serious adverse hemodynamic effects were observed in one ( 9 % ) of 11 patients r and omized to verapamil . The incidence of conversion arrhythmias was similar in both treatment groups ( adenosine 57 % , verapamil 50 % , p = NS ) BACKGROUND Atrial fibrillation and paroxysmal supraventricular tachycardia are common disorders of the heart rhythm for which antiarrhythmic drug therapy is commonly prescribed . The Atrial Fibrillation Investigation with Bidisomide ( AFIB ) study was a r and omized , placebo-controlled clinical trial design ed to accomplish three goals in a single protocol : ( 1 ) to determine the efficacy of the antiarrhythmic drug bidisomide in the treatment of these two arrhythmias ; ( 2 ) to establish the appropriate dose range for bidisomide ; and ( 3 ) to detect an adverse mortality effect of bidisomide if one were present in patients with atrial fibrillation . METHODS AND RESULTS In this clinical trial , 1227 patients with atrial fibrillation and 187 with paroxysmal supraventricular tachycardia were r and omly assigned to bidisomide ( 200 , 400 , or 600 mg BID ) or placebo ; patient groups with each arrhythmia were analyzed separately . Symptomatic recurrences of atrial fibrillation and paroxysmal supraventricular tachycardia were documented with the use of transtelephonic ECG monitoring . The time to the first symptomatic arrhythmia recurrence was measured in each patient and compared among treatment groups . Among the atrial fibrillation patients , there was no significant difference in the time to first symptomatic recurrence between the placebo group and any of the three bidisomide treatment groups ; the hazard ratios ( placebo : treatment ) were 1.19 , 1.03 , and 1.14 for bidisomide 200 , 400 , and 600 mg BID , respectively . Among paroxysmal supraventricular tachycardia patients , there was a similar lack of a significant treatment effect ; the hazard ratios were 1.30 , 1.93 , and 1.59 for bidisomide 200 , 400 , and 600 mg BID , respectively . In the primary safety analysis of mortality , 3 of 493 patients taking placebo  died , compared with 9 of 488 patients taking one of the two higher doses of bidisomide ( P>.10 ) . CONCLUSIONS Bidisomide in the doses tested did not have a clinical ly important antiarrhythmic effect . The AFIB study provided a novel clinical trial design to test antiarrhythmic drugs for both safety and efficacy BACKGROUND Few antiarrhythmic agents have been shown in r and omized controlled trials to be effective and well tolerated in the prophylaxis of paroxysmal supraventricular tachycardia or paroxysmal atrial fibrillation .  Propafenone , a class IC anti-arrhythmic agent with weak beta-adrenoceptor antagonist properties , has shown promise in preliminary clinical studies . METHODS AND RESULTS A double-blind , placebo-controlled trial of the efficacy and tolerability of propafenone was undertaken in 100 patients with paroxysmal supraventricular tachycardia ( [ PSVT ] n = 52 ) or atrial fibrillation/flutter ( [ PAF ] n = 48 ) who had recorded two or more symptomatic arrhythmia recurrences by transtelephonic ECG monitoring during a 3-month drug-free observation period . Patients were r and omized into two consecutive crossover periods of propafenone ( 300 mg BID ) versus placebo followed by 300 mg TID propafenone versus placebo . Analysis was based on the time to treatment failure , defined as the interval from treatment onset to the occurrence of either ECG-documented arrhythmia or an intolerable adverse event . With a proportional-hazards model , we determined the relative risk ( 95 % confidence interval ) of treatment failure after the achievement of steady-state drug levels for placebo compared with propafenone 300 mg BID to be 6.8 ( 2.2 to 21.2 , P < .001 , n = 45 ) for PSVT and 6.0 ( 1.8 to 20.0 , P = .004 , n = 30 ) for PAF . Due to a greater incidence of adverse events on high-dose propafenone , the relative risks of receiving placebo rather than propafenone 300 TID were only 2.2 ( 0.9 to 5.3 , P = .1 , n = 34 ) for PSVT and 1.9 ( 0.7 to 4.7 , P = .2 , n = 25 ) for PAF . However , if adverse events were excluded in the high-dose comparison , relative risks for arrhythmia recurrence were 15.0 ( 2.0 to 113 , P = .009 ) for PSVT and incalculable ( no preferences for placebo , P = .0002 ) for PAF . One episode of wide-complex tachycardia was documented during propafenone therapy . CONCLUSIONS Propafenone is of value in the prophylaxis of both PSVT and PAF . A dose of 300 mg BID is effective and well tolerated . A larger dose of 300 mg TID causes more adverse effects but may be more effective in those who can tolerate it STUDY OBJECTIVE To compare the efficacy of the Valsalva maneuver with that of carotid sinus massage ( CSM ) in terminating paroxysmal supraventricular tachycardia ( SVT ) in the ED . METHODS This prospect i ve , r and omized case study was performed in the ED of a tertiary care institution . Patients were at least 10 years of age with regular narrow complex tachycardia and had an ECG diagnosis of SVT . Patients with regular narrow complex tachycardia were r and omly assigned to undergo either the Valsalva maneuver or CSM . If the tachycardia was not terminated by the method chosen by r and omization , then the alternative method of vagal maneuver was used . If the tachycardia was not converted by both methods of vagal stimulation , patients would undergo either synchronized electrical cardioversion or a pharmacologic method of conversion at the discretion of the treating physician , depending on the patient 's hemodynamic status . RESULTS One hundred forty-eight instances of SVT were studied . Sixty-two patients underwent Valsalva maneuver first with conversion in 12 ( success rate of 19.4 % ) . Eighty-six underwent CSM first with conversion in 9 ( success rate 10.5 % ) . Carotid sinus massage was used in the 50 cases of SVT in which conversion was not achieved with the Valsalva maneuver . Conversion occurred in 7 cases ( success rate 14.0 % ) . For the 77 cases of SVT in which initial CSM did not achieve conversion , conversion occurred in 13 with the Valsalva maneuver ( success rate 16.9 % ) . The Valsalva maneuver and CSM achieved conversion in a total of 41 instances of SVT ( success rate 27.7 % ) . CONCLUSION Vagal maneuvers are efficacious in terminating about one quarter of spontaneous SVT cases . There is no detectable difference in efficacy between the Valsalva maneuver and CSM . [ Lim SH , Anantharaman V , Teo WS , Goh PP , Tan ATH : Comparison of treatment of supraventricular tachycardia by Valsalva maneuver and carotid sinus massage . Ann Emerg Med January 1998;31:30 - 35 . ] PSVT attack of > 20min and frequency > 160 is well-recognized model of myocardial dysfunction . We measured 6-keto-PGF1alpha and TXB(2 ) before and after adenosine administration to assess its cardioprotective potential . A total of 64 patients were r and omly assigned as having acute episode of PSVT to adenosine or verapamil group . A bolus of 6 mg of adenosine up to the maximum dose of 12 or 5 mg of verapamil up to the maximum dose of 10 mg were given , until the sinus rhythm was restored . The levels of PGI(2 ) , TXA(2 ) and TAS were measured in three different time intervals . In adenosine group all parameters were normalized after 20min of conversion to sinus rhythm . The ratio of PGI(2)/TXA(2 ) increased after 5min of conversion to SR ( P<0.01 ) . Also , the ratio of TXA(2)/TAS was decreased for ADO ( P<0.01 ) . This is the first study to demonstrate that adenosine exerts cardioprotective effect Thirty-nine patients with paroxysmal atrial fibrillation or supraventricular tachycardia r and omly received amiodarone or propafenone intravenously at home . Fifteen patients received amiodarone and 24 received propafenone ; 87.5 % of the patients who received propafenone and 40 % of the patients who received amiodarone were converted at home to sinus rhythm ( P less than .005 ) . The median time of conversion was 10 minutes ( range 5 to 35 ) for propafenone and 60 minutes ( range 20 to 130 ) for amiodarone ( P less than 0.005 ) . When either drug failed to terminate atrial tachydysrhythmias at home , the same drug always restored sinus rhythm with subsequent oral treatment during hospitalization . No major side effects were observed after the infusion of either drug . The incidence of minor side effects was not significantly different between the two drugs . Both the drugs are efficacious and safe in the acute management of primary supraventricular tachydysrhythmias .  Propafenone showed a greater rapidity of action
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 .