Adenosine: a clinical experience and comparison with verapamil for the termination of supraventricular tachycardias. Adenosine for paroxysmal supraventricular tachycardia: dose ranging and comparison with verapamil. Assessment in placebo-controlled, multicenter trials. The Adenosine for PSVT Study Group. Adenosine versus verapamil in the treatment of supraventricular tachycardia: a randomized double-crossover trial. Adenosine cardioprotection study in clinical setting of paroxysmal supraventricular tachycardia. Comparison of Treatment of Supraventricular Tachycardia by Valsalva Maneuver and Carotid Sinus Massage. Intravenous administration of diltiazem in the treatment of supraventricular tachyarrhythmias. Acute conversion of paroxysmal supraventricular tachycardia with intravenous diltiazem. IV Diltiazem Study Group. Efficacy of intravenous magnesium sulphate in supraventricular tachyarrhythmias. Propafenone versus amiodarone in field treatment of primary atrial tachydysrhythmias. Prophylaxis of supraventricular and ventricular arrhythmias after coronary artery bypass grafting with low-dose sotalol. The Midlands Trial of Empirical Amiodarone versus Electrophysiology-guided Interventions and Implantable Cardioverter-defibrillators (MAVERIC): a multi-centre prospective randomised clinical trial on the secondary prevention of sudden cardiac death. Electrophysiological mechanisms and determinants of vagal maneuvers for termination of paroxysmal supraventricular tachycardia. Efficacy and safety of low-dose propranolol versus diltiazem in the prophylaxis of supraventricular tachyarrhythmia after coronary artery bypass grafting. A randomized, placebo-controlled trial of propafenone in the prophylaxis of paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation. UK Propafenone PSVT Study Group. Intravenous amiodarone versus verapamil for acute conversion of paroxysmal atrial fibrillation to sinus rhythm. Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations. Japanese randomized trial for investigation of a combined therapy of amiodarone and implantable cardioverter defibrillator in patients with ventricular tachycardia and fibrillation: the Nippon ICD Plus Pharmachologic Option Necessity study design.
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 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 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 ) 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 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 . ] UNLABELLED The aim of the study was to investigate the efficacy of diltiazem bolus intravenous administration , compared to disopyramide , in the treatment of various types of paroxysmal supraventricular tachyarrhythmias . METHOD Fifty patients ( 23 males , 27 females , mean age 47.7 + /- 15.2 years ) with paroxysmal supraventricular tachyarrhythmia ( 20 with paroxysmal atrial tachycardia , 23 with paroxysmal atrial fibrillation and rapid ventricular response and 7 with atrial fluttering ) were studied . Diltiazem at a dose of 0.25 - 0.30 mg/kg BW or disopyramide at a dose of 50 mg were given bolus IV . If conversion of the arrhythmia to sinus rhythm could not be achieved with the initial drug , the alternate was given . The order of administration of the drugs was r and om , independent of the type of the arrhythmia . Before and during drug administration detailed clinical examination and frequent blood pressure ( BP ) measurements were performed . Twenty-four hour Holter monitoring was done in all patients , starting with the administration of the antiarrhythmic drug . RESULTS 1 ) Paroxysmal atrial tachycardia : diltiazem administration converted the arrhythmia to sinus rhythm in all patients while disopyramide in only 1 of 9 patients who received this drug . 2 ) Paroxysmal atrial fibrillation : disopyramide converted the arrhythmia in 5 patients without significant change in ventricular response in the others . Diltiazem did not convert the arrhythmia though it caused significant decrease in ventricular response ( < 100 bpm ) and in 1 patient an important bradycardia ( 45 bpm ) . 3 ) Atrial fluttering : disopyramide converted the arrhythmia to sinus rhythm in 1 patient without significant change in the ventricular response in the others . Diltiazem caused significant decrease in the ventricular response without conversion to sinus rhythm . During conversion to sinus rhythm an AV junctional rhythm of short duration ( < 1 min ) was noticed in 5 patients and a short pause ( < 2 sec ) with or without an initial premature contraction in the remaining 21 . Disopyramide administration was not associated with side effects .  Diltiazem administration cause small ( < 20 mm Hg ) , transient ( < 30 min ) decrease of BP without symptoms with the exception of the patient with bradycardia in whom the BP decrease was significant ( 90/60 from 160/80 mm Hg ) followed by intense symptoms which lasted for six hours . CONCLUSIONS Diltiazem administration is extremely effective in conversion of paroxysmal atrial tachycardia to sinus rhythm . In addition it retards ventricular response in patients with atrial fibrillation and fluttering . Compared to disopyramide these effects of diltiazem are more pronounced and clinical ly pertinent Diltiazem has electrophysiologic effects similar to those of verapamil . Its efficacy and safety in 4 doses for treatment of induced supraventricular tachycardia ( SVT ) were examined and compared with those of placebo in 87 patients ( 25 with atrioventricular [ AV ] nodal reentry tachycardia , 60 with AV reentry associated with an accessory AV connection , and 2 with atrial tachycardia ) .  Conversion to sinus rhythm occurred in 4 of 14 patients ( 29 % ) with 0.05 mg/kg of diltiazem , 16 of 19 ( 84 % ) with 0.15 mg/kg , 13 of 13 ( 100 % ) with 0.25 mg/kg , and 14 of 17 ( 82 % ) with 0.45 mg/kg compared with 6 of 24 ( 25 % ) treated with placebo .  Conversion rates in groups receiving doses of 0.15 to 0.45 mg/kg of diltiazem were superior to that in the placebo group ( p less than 0.001 ) . Time to conversion was 3.0 + /- 2.6 minutes in responding diltiazem patients compared with 5.9 + /- 6.1 minutes in responding control patients . Diltiazem administration result ed in significant lengthening of SVT cycle length , AH interval , and AV nodal effective refractory period and block cycle length . The most frequent adverse response to diltiazem was hypotension ( 7 of 63 patients ) ; however , only 4 patients had symptoms related to hypotension . Thus , intravenous diltiazem in doses of 0.15 , 0.25 and 0.45 mg/kg is an effective and safe treatment for the acute management of SVT This study was conducted to evaluate the clinical efficacy of intravenous ( i.v . ) magnesium sulphate 2 gm bolus in sustained supraventricular tachycardia ( SVT ) and atrial flutter-fibrillation with fast ventricular rate of more than 160/min ( AF-FVR ) and to compare it with i.v . verapamil 5 mg . In this r and omised controlled trial , 68 cases of SVT and 86 cases of AF-FVR were studied . Patients with evidence of renal dysfunction and systolic blood pressure less then 90 mm Hg were excluded . Response was considered when the heart rate fell to less than 100/min . In SVT , 33.3 % ( 11 out of 33 ) responded to magnesium sulphate which was significantly less than verapamil ( 23 out of 35 , 65.7 % ) p = 0.007 . Similarly , in AF-FVR , response was more with verapamil ( 25 out of 45 , 55.6 % ) than magnesium sulphate ( 8 out of 41 , 19.5 % ) p < 0.0001 . Response to magnesium sulphate was better in patients with IHD . There were no significant side effects , except flushing and sense of warmth with i.v . magnesium sulphate .  Serum magnesium rose significantly after i.v . magnesium bolus . Though magnesium sulphate is a weaker antiarrhythmic drug than verapamil , further studies are needed to identify subgroups of supraventricular tachyarrhythmias which would respond to magnesium sulphate 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 BACKGROUND Supraventricular tachyarrhythmia ( SVT ) commonly occurs shortly after coronary artery bypass grafting ( CABG ) , but ventricular arrhythmias are less documented . METHODS On the 1st postoperative day , 206 consecutive eligible patients were prospect ively r and omized to a sotalol group ( 80 mg b.i.d . ; n = 103 ) or a control group without beta-blockade or antiarrhythmic drugs ( n = 103 ) . RESULTS The SVT incidence ( predominantly atrial fibrillation ) accounted for 16 % in the sotalol group versus 48 % ( p < 0.00001 ) . Multivariate analysis showed that sotalol reduced the SVT incidence ( p < 0.00001 , odds ratio , 0.20 ; 95 % confidence interval , 0.09 to 0.42 ) , whereas a lower preoperative left ventricular ejection fraction ( p = 0.019 ) and older age ( p = 0.031 ) were independent risk factors of SVT occurrence . The Holter electrocardiographic analysis ( 24 hours ) demonstrated that sotalol ( 32 versus 92 ; p = 0.031 ) decreased the median number of ventricular events , mostly isolated premature ventricular beats . Neither ventricular proarrhythmia effect nor " torsades de pointes " were detected . Despite strict hemodynamic-based selection , sotalol had to be discontinued in 8 patients ( 7.8 % ) , for reasons related to asthma in 3 or cardiac reasons in 5 . CONCLUSIONS Oral low-dose sotalol provided considerable and reliable protection in selected nondepressed cardiac function patients , reducing the occurrence of both supraventricular and ventricular arrhythmias after CABG AIMS MAVERIC was a r and omised clinical trial design ed to test the possibility of prospect ively identifying patients who would benefit most from the implantable cardioverter-defibrillator ( ICD ) by electrophysiology ( EP ) study in the context of secondary prevention of sudden cardiac death ( SCD ) through comparing EP-guided interventions ( anti-arrhythmic drugs , coronary revascularization , and ICD ) against empirical amiodarone therapy . METHODS Two hundred and fourteen survivors of sustained ventricular tachycardia ( VT ) , ventricular fibrillation ( VF ) or SCD were r and omized to either treatment strategy , pre-stratified for haemodynamic status at index event , and followed up for a median of 5 years . RESULTS Of the 106 amiodarone arm patients , 89 ( 84 % ) received the drug and 5 ( 5 % ) received an ICD after crossing over . Of the 108 EP  arm patients , 31 ( 29 % ) received an ICD , 46 ( 43 % ) received  anti-arrhythmic drugs only ( mainly amiodarone or sotalol ) and 18 ( 17 % ) received coronary revascularization but no ICD . No significant differences in survival or arrhythmia recurrence existed between the two treatment arms after 6 years . However , ICD recipients had a lower mortality than non-ICD recipients , regardless of allocated treatment ( hazard ratio=0.54 , p=0.0391 ) . CONCLUSIONS Prospect i ve selection of patients to receive the ICD by EP study did not improve survival compared with empirical amiodarone therapy among survivors of VT , VF or SCD , whereas ICD implantation improved survival regardless of allocated treatment . On this basis , routine EP study has no role in the management of such patients , who should be offered empirical ICD therapy according to the results of other secondary prevention ICD trials 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 OBJECTIVE Supraventricular tachyarrhythmias ( SVT ) complicate postoperative management after coronary bypass surgery in about 30 % of all patients . Though a prophylactic treatment both with beta-adrenergic blocking agents and the calcium antagonist diltiazem has been used for the prevention of post-operative SVT , no study yet has performed a prospect i ve comparison of the efficacy of these therapies . METHODS To investigate the prophylactic effect of either a calcium antagonist ( diltiazem , 0.1 mg/kg per h i.v . ) or a beta-adrenergic blocking agent ( propranolol , 10 mg every 6 h postoperatively ) , we r and omized prospect ively 103 consecutive patients into three groups , the third one serving as a control group . Anti-arrhythmic medication was started with the procedure and was continued until the 3rd postoperative day . RESULTS Preoperative conditions were the same for the three groups concerning age , extent of coronary heart disease , ventricular function and heart-related medication . There were no differences in intraoperative parameters or postoperative enzyme patterns . Diltiazem was ineffective in preventing SVT , the incidence being exactly the same as in the control group ( 35 % ) . Propranolol reduced the occurrence of SVT significantly ( 7 % , P < 0.05 ) . Furthermore , patients treated with diltiazem needed positive inotropic support more often in the first hours after surgery than patients of the control group ( 30 % vs 5 % , P < 0.01 ) . CONCLUSIONS The perioperative administration of low-dose propranolol is considered a safe and effective drug prophylaxis to avoid the occurrence of SVT after bypass surgery 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 Abstract Amiodarone and verapamil are well-known antiarrhythmic drugs used for treatment of ventricular and supraventricular arrhythmias . Although verapamil is the drug of choice for control of the atrioventricular node , it has also been reported to terminate atrial fibrillation . 1–3 Amiodarone has been used extensively for drug-refractory ventricular tachycardia but seldom for termination of paroxysmal atrial fibrillation . 4–6 To our knowledge , no comparative study with amiodarone and verapamil has been reported . Because of this , we compared the efficacy of intravenous amiodarone versus verapamil for conversion of paroxysmal atrial fibrillation to sinus rhythm in a single-blind r and omized study BACKGROUND Postoperative tachyarrhythmias remain a common complication after congenital cardiac operations .  Dexmedetomidine ( DEX ) , an α-2 adrenoreceptor agonist , can have a therapeutic role in supraventricular tachyarrhythmias for cardioversion to sinus rhythm or heart rate control . Whether routine perioperative use of DEX decreases the incidence of supraventricular and ventricular tachyarrhythmias was studied . METHODS In this prospect i ve cohort study , 32 pediatric patients undergoing cardiothoracic operations received DEX  and were compared with 20 control patients who did not receive DEX .  RESULTS Dexmedetomidine was started after anesthesia induction and continued intraoperatively and postoperatively for 38±4 hours ( mean dose , 0.76±0.04 μg/kg/h ) . Ten control patients and 2 DEX patients sustained 16 episodes of tachyarrhythmias ( p=0.001 ) , including a 25 % vs 0 % ( p=0.01 ) incidence of ventricular tachycardia and 25 % vs 6 % ( p=0.05 ) of supraventricular arrhythmias in the control and DEX group , respectively . Transient complete heart block occurred in 2 control patients and in 1 DEX patient . Control patients had a higher heart rate ( 141±5 vs 127±3 beats/min , p=0.03 ) , more sinus tachycardia episodes ( 40 % vs 6 % ; p=0.008 ) , required more antihypertensive drugs with nitroprusside ( 20±7 vs 4±1 μg/kg ; p=0.004 ) and nicardipine ( 13±5 vs 2±1 μg/kg ; p=0.02 ) , and required more fentanyl ( 39±8 vs 19±3 μg/kg ; p=0.005 ) . CONCLUSIONS Perioperative use of dexmedetomidine is associated with a significantly decreased incidence of ventricular and supraventricular tachyarrhythmias , without significant adverse effects BACKGROUND Implantable cardioverter-defibrillators ( ICDs ) are the most effective therapy in reducing the mortality of patients with life-threatening ventricular tachyarrhythmias . However , the ICD can not prevent the recurrence of tachycarida attacks and that limits the clinical usefulness of them . The Nippon ICD Plus Pharmachologic Option Necessity ( NIPPON ) trial was design ed as the first prospect i ve r and omized study to test the hypothesis whether amiodarone could improve the patient 's clinical outcome by reducing the amount of ICD therapy in the Japanese patient population . METHODS AND RESULTS Approximately 400 patients with organic heart disease and spontaneous episode(s ) of sustained ventricular tachycardia/fibrillation ( VT/VF ) will be r and omly assigned to one of 2 groups ; the amiodarone group and non-amiodarone group . Both groups of patients will be followed at least for 24 months . The end-point committee will adjudicate events in a blinded fashion . The primary end-points of this study are determination of the appropriate therapy from the ICD and alteration of the assigned treatment because of its harmful effects and /or frequent ICD therapies . CONCLUSION The NIPPON study is expected to confirm our underst and ing of the prognostic and therapeutic usefulness of adjuvant amiodarone therapy for patients with an ICD and with a history of sustained VT/VF
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 .