Verapamil or adenosine for the immediate treatment of supraventricular tachycardia

A comparison of verapamil with adenosine for the immediate treatment of supraventricular tachycardia was made from a retrospective review of 164 spontaneous episodes of paroxysmal tachycardia in 43 patients. Verapamil administered to 33 patients restored sinus rhythm in 91 of 112 episodes (81 per cent). Hypotension occurred in 9 per cent of episodes. Adenosine terminated 94 per cent of episodes of supraventricular tachycardia in 25 patients. The arrhythmia recurred shortly after adenosine restored sinus rhythm in 20 episodes. Transient side effects were common. Fifteen patients were treated with both agents. Adenosine was successful in all, but verapamil failed to restore sinus rhythm at least once in seven of the 15 patients. Early recurrence of tachycardia occurred in five of these after adenosine, but in only one after verapamil. Verapamil and adenosine are both effective in the treatment of supraventricular tachycardia; adenosine has the higher success rate and is safer, but transient symptoms are common and arrhythmias may recur.     

Use of adenosine in the management of perioperative arrhythmias in the pediatric cardiac intensive care unit.

OBJECTIVE: To assess the safety, efficacy, and diagnostic usefulness of iv adenosine in treating acute episodes of paroxysmal supraventricular tachycardia in critically ill infants and children with congenital heart disease. DESIGN: A consecutive sample study over a 1-yr period. SETTING: A six-bed pediatric cardiac ICU at a tertiary care center. PATIENTS: Nine consecutive critically ill infants and children with congenital heart disease, either awaiting emergent surgery or in the immediate postoperative period, who had at least one episode of tachyarrhythmia treated with iv adenosine. INTERVENTIONS: In children less than 50 kg, adenosine was administered in incremental doses of 100, 200, and 300 micrograms/kg every 3 mins. Patients weighing greater than 50 kg were given doses of 6, 12, and 18 mg iv. The adenosine protocol was stopped when the arrhythmia was terminated or a mechanism of the arrhythmia was shown that would not respond to adenosine administration. MEASUREMENTS AND MAIN RESULTS: Adenosine was used 14 times in nine patients, all of whom were hemodynamically unstable before or after the development of the tachyarrhythmia. Adenosine was effective in rapidly terminating all nine episodes of paroxysmal supraventricular tachycardia, six of which occurred in patients known to have Wolff-Parkinson-White syndrome. All patients had marked hemodynamic improvement after conversion to normal sinus rhythm. In five episodes of tachyarrhythmia that did not respond to adenosine, the transient block at the atrioventricular (A-V) node helped determine the underlying arrhythmia without clinically important side-effects. CONCLUSIONS: Adenosine can be used safely and effectively in critically ill infants and children with congenital heart disease and perioperative tachyarrhythmia. More investigation into the "chemical conversion" of paroxysmal supraventricular tachycardias as well as its diagnostic value in this subset of critically ill patients is warranted.     

Treatment of Out-of-hospital Supraventricular Tachycardia: Adenosine vs Verapamil

Objective: To compare the use of adenosine and the use of verapamil as out-of-hospital therapy for supraventricular tachycardia (SVT). Methods: A period of prospective adenosine use (March 1993 to February 1994) was compared with a historical control period of verapamil use (March 1990 to February 1991) for SVT. Data were obtained for SVT patients treated in a metropolitan, fire-department-based paramedic system serving a population of approximately 1 million persons. Standard drug protocols were used and patient outcomes (i.e., conversion rates, complications, and recurrences) were monitored. Results: During the adenosine treatment period, 105 patients had SVT; 87 (83%) received adenosine, of whom 60(69%) converted to a sinus rhythm (SR). Vagal maneuvers (VM) resulted in restoration of SR in 8 patients (7.6%). Some patients received adenosine for non-SVT rhythms: 7 sinus tachycardia, 18 atrial fibrillation, 7 wide-complex tachycardia (WCT), and 2 ventricular tachycardia; no non-SVT rhythm converted to SR and none of these patients experienced an adverse effect. Twenty-five patients were hemodynamically unstable (systolic blood pressure < 90 mm Hg), with 20 receiving drug and 13 converting to SR; 8 patients required electrical cardioversion. Four patients experienced adverse effects related to adenosine (chest pain, dyspnea, prolonged bradycardia, and ventricular tachycardia). In the verapamil period, 106 patients had SVT; 52 (49%) received verapamil (p < 0.001, compared with the adenosine period), of whom 43 (88%) converted to SR (p = 0.11). Two patients received verapamil for WCT; neither converted to SR and both experienced cardiovascular collapse. VM resulted in restoration of SR in 12 patients (11.0%) (p = 0.52). Sixteen patients were hemodynamically unstable, with 5 receiving drug (p = 0.005) and 5 converting to SR; 9 patients required electrical cardioversion (p = 0.48). Four patients experienced adverse effects related to verapamil (hypotension, ventricular tachycardia, ventricular fibrillation). Recurrence of SVT was noted in 2 adenosine patients and 2 verapamil patients in the out-of-hospital setting and in 23 adenosine patients and 15 verapamil patients after ED arrival, necessitating additional therapy (p = 0.48 and 0.88, for recurrence rates and types of additional merapies, respectively). Hospital diagnoses, outcomes, and ED dispositions were similar for the 2 groups. Conclusion: Adenosine and verapamil were equally successful in converting out-of-hospital SVT in patients with similar etiologies responsible for the SVT. Recurrence of SVT occurred at similar rates for the 2 medications. Rhythm misidentification remains a common issue in out-of-hospital cardiac care in this emergency medical services system.     

Effect of Adenosine and Verapamil in Catecholamine-Induced Accelerated Atrioventricular Junctional Rhythm: Insights into the Underlying Mechanism

Accelerated AV junctional rhythm is postulated to he due to enhanced automaticity of a high AV junctional focus. The adenosine response of this rhythm was tested in 17 patients (7 males, 12-83 years). The indications of electrophysiology study were nonspecific palpitation (n = 5), unexplained syncope (n = 6), postablation of accessory pathways (n = 4), and postmodification of AV nodal reentry tachycardia (n = 2). The sinus node and AV nodal functions were normal. Pacing and programmed electrical stimulation failed to induce anv arrhythmia at baseline. The accelerated junctional rhythm (cycle length = 553 ± 134 ms) was initiated spontaneously in all patients after isoproterenol infusion (1-2 μg/min). It was not suppressible bv overdrive pacing. Cessation of isoproterenol infusion terminated the rhythm in all patients. Adenosine (6 mg) reproducibly terminated the accelerated functional rhythm in all patients. In six patients, adenosine suppressed the junctional rhythm without producing AV nodal block. In the other 11 patients, the junctional rhythm was terminated prior to the occurrence of AV nodal block. Verapamil was tested in ten patients and 5 mg of intravenous verapamil terminated the junctional rhythm in all patients. In conclusion, the mechanism of catecholamine-induced accelerated AV junctional rhythm is most likely enhanced automaticity, and catecholamine-induced accelerated AV functional automaticity is sensitive to adenosine and verapamil. Adenosine appears to have differential effects on catecholamine-enhanced AV junctional automaticity and AV nodal conduction. This suggests that, under catecholamine stimulation, adenosine may have different mechanisms of action on AV nodal conduction and automaticity.     

Intravenous adenosine therapy accelerating rate of paroxysmal supraventricular tachycardia.

Two cases of paroxysmal supraventricular tachycardia are reported in which the administration of adenosine produced sustained elevation of the rate of paroxysmal supraventricular tachycardia. In each case, sinus rhythm was restored readily through the use of intravenous verapamil. This adverse reaction to adenosine has not been previously described.     

Verapamil in the treatment of ventricular tachycardia

Verapamil, the drug of choice for conversion of most cases of paroxysmal supraventricular tachycardia, has also displayed some efficacy in the treatment of ventricular tachycardia. A case in which the administration of intravenous verapamil resulted in conversion of ventricular tachycardia to sinus rhythm is presented. Experimental and clinical studies of verapamil in the treatment of this arrhythmia have revealed markedly variable results. Verapamil does not appear to be consistently effective in converting ventricular tachycardia. It has, however, demonstrated utility in some instances, especially in cases resistant to more traditional therapeutic agents, as well as relatively unusual forms of ventricular tachycardia. Verapamil may be most effective in suppressing ventricular tachycardia initiated by certain mechanisms.     

Adenosine as a therapeutic agent.

Adenosine, an endogenous nucleoside has been recently approved for use in the treatment of paroxysmal supraventricular tachycardia. Adenosine is nearly 100% effective in terminating tachycardia in which the atrioventricular node forms part of the reentrant circuit. Although most ventricular tachycardias are insensitive to adenosine, this substance is effective in ventricular tachycardia induced by catecholamines or exercise. An intravenous bolus dose of 6 mg is the initial dose. If no effect is noted a further bolus of 12 mg can be given. The most common side effects are dyspnea, chest pressure and facial flushing. This article reviews, in addition, some of the comparative trials with verapamil and adenosine triphosphate, some of the additional therapeutic indications, the possible mechanisms of action in cardiac tissue, and the type of purinergic receptors involved in the antiarrhythmic effects of adenosine.     

Adenosine for paroxysmal supraventricular tachycardia

Adenosine is the most recent drug approved for the treatment of paroxysmal supraventricular tachycardia. Its advantage is that it is just as effective as verapamil and is far less toxic. The lack of toxicity is due to the extremely short half-life (one to seven seconds). The mechanism of action of adenosine is different from that of other antiarrhythmic agents. For the specific purpose of ameliorating paroxysmal supraventricular tachycardia, adenosine appears to be an ideal antiarrhythmic drug.     

Adenosine for the treatment of supraventricular tachycardia in the ED

To determine the safety and efficacy of intravenous adenosine as used in the emergency department (ED) for the treatment of presumed supraventricular tachycardia, the investigators performed a retrospective chart review in an urban, university-affiliated ED. Seventy-two consecutive patients were treated with intravenous adenosine for presumed supraventricular tachycardia. Of the 72 patients who were treated with adenosine, 46 patients had a confirmed diagnosis of supraventricular tachycardia. Of these, 39 or 46 (84.8%) converted to sinus rhythm after treatment. Of patients who successfully converted to sinus rhythm, none had recurrent tachycardia or required additional pharmacotherapy. Arrhythmias not successfully treated among the initially misdiagnosed patients were atrial fibrillation (n = 11), atrial flutter (n = 7), tachycardia of other origin (n = 5), and ventricular tachycardia (n = 2). No clinically significant adverse effects were noted among the stydy population. Intravenous adenosine is a safe and efficacious treatment for the emergent treatment of supraventricular tachycardia, including unstable patients (with hypotension and/or chest pain). It is also safe among patients initially presumed to have supraventricular tachycardia, who are later diagnosed with other arrhythmias.     

Adenosine-Sensitive Atrial Tachycardia

Limited data suggest that adenosine termination of atrial tachycardia is uncommon. To investigate further the effect of adenosine on atrial tachycardia, adenosine (6–12 mg) was administered during sustained atrial tachycardia in 17 patients. All patients underwent electrophysiological study to exclude other mechanisms of supraventricular tachycardia. Mean patient age was 51 ± 20 years (range 18–82 years). Seven patients had no structural heart disease. The mean atrial tachycardia cycle length was 390 ± 80 msecs (range 260–580). Sustained atrial tachycardia was induced with atrial extrastimuli in 8 patients, and was either incessant at baseline or developed spontaneously during isoproterenol infusion in 9 patients. Adenosine terminated atrial tachycardia in 3 patients (18%), transiently suppressed atrial tachycardia in 4 patients (23%), and produced AV block without affecting tachycardia cycle length in the remaining 10 patients. Adenosine sensitivity was observed in 3 of 8 patients with tachycardias initiated and terminated by atrial extrastimuli, and in 4 of 9 patients with spontaneous, but not inducible tachycardias including 3 of 4 patients with isoproterenol facilitated tachycardias. Of multiple clinical and electrophysiological variables examined as potential predictors of adenosine sensitivity, only isoproterenol facilitation of spontaneous or inducible sustained tachycardia predicted adenosine sensitivity (P = 0.02). These observations suggest that adenosine-sensitive atrial tachycardia may be more common than previously recognized. Adenosine sensitivity does not appear to be specific for tachycardia mechanism and cannot be predicted by response to pacing. Atrial tachycardias dependent on β-adrenergic stimulation are most likely to be terminated by adenosine.     

Intravenous calcium chloride in the conversion of paroxysmal supraventricular tachycardia to normal sinus rhythm

This brief report describes several cases of paroxysmal supraventricular tachycardia that converted promptly to normal sinus rhythm within 1 to 2 minutes of receiving intravenous calcium salts as pretreatment in anticipation of verapamil therapy. A review of calcium's hemodynamic and dromotropic effects suggests that this probably was due to electrophysiological effects rather than mere coincidence. Calcium raises blood pressure, which may reflexively increase cardiac parasympathetic tone, and also has a direct slowing effect on atrioventricular conduction. Adenosine remains the drug of choice in the treatment of paroxysmal supraventricular tachycardia. However, in addition to preventing hypotension when used as pretreatment to overapamil, intravenous calcium itself may terminate supraventricular tachycardia.     

Adenosine: novel antiarrhythmic therapy for supraventricular tachycardia.

Adenosine (Adenocard) is a unique new agent for the acute treatment of paroxysmal supraventricular tachycardia (PSVT). Administered by intravenous bolus, it has an onset and duration measured in seconds and greater than 90% efficacy. Its primary effect is to slow atrioventricular nodal conduction, thus converting reentrant forms of PSVT to normal sinus rhythm. Side effects quickly dissipate without treatment because of the short duration of action. Other uses include diagnosis of broad or wide QRS complex tachycardias and controlled intraoperative hypotension. Its short duration and high efficacy in converting select forms of PSVT make adenosine an excellent alternative to verapamil in patients with compromised hemodynamics. This article will review the clinical use and anesthetic implications for the administration of this drug.     

Untoward reaction to adenosine therapy for supraventricular tachycardia

Adenosine, a naturally occurring nucleoside that slows conduction through the atrioventricular node, has recently been approved for the treatment of supraventricular tachycardia. It has been shown to convert patients with supraventricular tachycardia to sinus rhythm in up to 92% of cases. Its intravascular half-life of only 10 seconds and absence of reported serious side effects have made adenosine an attractive antiarrhythmic agent. This report describes two cases in which significant side effects from the administration of adenosine were encountered including: (1) prolonged sinus arrest with syncope, and (2) syncope with prolonged bradycardia and hypotension. Emergency physicians should be cognizant of the potential complications resulting from adenosine administration, and should be prepared to deal with them when using this newly available agent.     

Anaphylactoid reaction to adenosine

Adenosine (Adenocard) is an endogenous purine nucleoside that has been approved recently for intravenous treatment of paroxysmal supraventricular tachycardia. With a serum half-life of 10 seconds, reported side effects including facial flushing, dyspnea, and chest pressure are common, but very transient. An elderly woman who received adenosine for paroxysmal supraventricular tachycardia had a prolonged anaphylactoid reaction that required pharmacological treatment. This is the first reported case of a prolonged anaphylactoid reaction to adenosine.     

Adenosine use in pregnancy: Lack of effect on fetal heart rate

The treatment for supraventricular tachycardia in pregnancy is somewhat controversial. Although a variety of medications have been used to terminate this rhythm during pregnancy, all have actual or theoretical drawbacks. Adenosine is a relatively new medication with an extremely short half-life and is effective in the treatment of supraventricular tachycardia. We report a case in which this medication was used successfully during pregnancy. In addition, we found that adenosine had no effect on fetal heart rate in this case.     

Distinct pharmacologic substrate in lidocaine-sensitive, repetitive atrial tachycardia

Lidocaine-sensitive, repetitive atrial tachycardia is an uncommon arrhythmia. The electrophysiologic substrate is still unknown, and the pharmacologic responses have not been fully explored. The aim of this study was to investigate the effects of intravenous adenosine and verapamil in patients with lidocaine-sensitive atrial tachycardia. In 9 patients with repetitive uniform atrial tachycardia, the response to intravenous adenosine (12 mg), lidocaine (1 mg/kg body weight), and verapamil (10 mg) were sequentially investigated. Simultaneous 12-lead electrocardiogram (ECG) was recorded at baseline and continuously monitored thereafter. Tracings were obtained at regularly timed intervals right after the administration of each drug to evaluate changes in the arrhythmia characteristics. Repetitive atrial tachycardia was abolished by intravenous lidocaine in the 9 patients within the first 2 minutes after the end of injection. Adenosine suppressed the arrhythmia in 2 patients and shortened the runs of atrial ectopic activity in 1 patient, while verapamil was effective in 2 patients, 1 of them insensitive to adenosine and the other 1 sensitive to this agent. In 5 patients, the arrhythmia was abolished by radiofrequency ablation at different sites of the right atrium. Lidocaine-sensitive atrial tachycardia may eventually be also suppressed by adenosine and/or verapamil. This suggests that this enigmatic arrhythmia may be caused by different underlying electrophysiologic substrates and that at least in some cases, delayed afterdepolarizations seem to play a determining role.     

Efficacy of flecainide in patients with supraventricular arrhythmias and respiratory insufficiency

Objective Evaluation of efficacy of intravenous flecainide to revert supraventricular arrhythmias to sinus rhythm in patients with respiratory insufficiency. Design Comparative randomized prospective trial. Setting ICU in a University Hospital Patients 30 patients with acute respiratory insufficiency or acute exscerbation of chronic respiratory insufficiency and supraventricular arrhythmias. Intravenous flecainide was administered to 15 patients (Group A) (2 mg/kg for 10 min and continuous perfusion of 1.5 mg/kg for 1 h). Intravenous verapamil was administered to 15 patients (Group B) (0.15 mg/kg for 5 min and continuous perfusion of 0.005 mg/kg/min for 1 h). Measurements and results The categories of patients' arrhythmias were: Group A — atrial fibrillation (AF) in 5 cases, atrial flutter (AFl) in 2, multifocal atrial tachycardia (MAT) in 4 and other supraventricular tachycardia (SVT) in 4. Group B — AF in 6 cases, AFL in 2, MAT in 2 and SVT in 5 cases. Flecainide reverted arrhythmias to sinus rhythm in 12 out of 15 cases (80%); of these 12, 11 reverted with the initial bolus. Verapamil reverted 5 out of 12 cases (33.3%,p<0.01). No significant secondary adverse effects were detected. Conclusion Intravenous flecainide is an effective antiarrhythmic drug to treat acute supraventricular arrhythmias in patients with respiratory insufficiency.     

Antiarrhythmic effects of adenosine on ischemia-induced ventricular fibrillation

PURPOSE: The antiarrhythmic efficacy of adenosine during states of AV-nodal reentrant tachycardias is well known and clinically established. Adenosine is also able to reduce ventricular arrhythmias when applied before coronary ligation in rats. Hypoxia or ischemia leads to an increased production of adenosine by cardiac myocytes.The purpose of this study was to evaluate if adenosine also has a direct antiarrhythmic effect on ischemia-induced ventricular fibrillation. MATERIALS AND METHODS: In this study, the antiarrhythmic effects of adenosine on ventricular fibrillation during global (low flow) ischemia were evaluated in isolated guinea pig hearts perfused by the method of Langendorff. RESULTS: Adenosine showed a dose-dependent prolongation of the peak to peak interval of the ventricular ECG signal during ventricular fibrillation until ventricular flutter or tachycardia occurred at a concentration of 2 mmol/L. At a concentration of 20 mmol/L, adenosine converted ventricular fibrillation into ventricular tachycardia with intermittent periods of asystole. This conversion of ventricular fibrillation to asystole was antagonised by 200 micromol/L theophylline. CONCLUSION: Adenosine appears to have an antiarrhythmogenic effect both in supraventricular and ventricular rhythm disturbances. During myocardial infarction, where huge amounts of adenosine are present in ischemic regions, asystole may respond to adenosine antagonists.     

Adenosine-induced complete heart block: not so transient

Adenosine is a purine nucleoside widely used to terminate supraventricular tachycardias, and as a diagnostic adjunct in narrow complex regular tachycardia of uncertain origin. Atrioventricular blockade and bradyarrhythmias following administration are common but generally short-lived. We report a case of prolonged complete heart block requiring intubation and temporary pacing, following adenosine administration in atrial flutter treated with combination metoprolol and diltiazem.     

Supraventricular tachycardia. Changes in management

The various forms of supraventricular tachycardia can be differentiated by careful review of a patient's electrocardiogram. If reentrant tachycardia involves the atrioventricular node, intravenous adenosine (Adenocard) provides a rapid means of converting the tachycardia to sinus rhythm. Adverse effects of adenosine, though common, are mild and of brief duration. Wide QRS complex tachycardia of ventricular origin is usually not affected by the drug.