Acute management of paroxysmal atrioventricular junctional reentrant supraventricular tachycardia: pharmacologic strategies

Esmolol Compared with Amiodarone in the Treatment of Recent-Onset Atrial Fibrillation (RAF): An Emergency Medicine External Validity Study

BACKGROUND

Recent-onset atrial fibrillation (RAF) is the most frequent supraventricular dysrhythmia in emergency medicine. Severely compromised patients require acute treatment with injectable drugs OBJECTIVE: The main purpose of this external validity study was to compare the short-term efficacy of esmolol with that of amiodarone to treat severe RAF in an emergency setting.

METHODS

This retrospective survey was conducted in mobile intensive care units by analyzing patient records between 2002 and 2013. We included RAF with (one or more) severity factors including: clinical shock, angina pectoris, ST shift, and very rapid ventricular rate. A blind matching procedure was used to constitute esmolol group (n = 100) and amiodarone group (n = 200), with similar profiles for age, gender, initial blood pressure, heart rate, severity factors, and treatment delay. The main outcome measure was the percentage of patients with a ventricular rate control defined as heart frequency ≤ 100 beats/min. More stringent (rhythm control) and more humble indicators (20% heart rate reduction) were analyzed at from 10 to 120 min after treatment initiation.

RESULTS

Patient characteristics were comparable for both groups: age 66 ± 16 years, male 71%, treatment delay < 1 h 36%, 1-2 h 29%, > 2 h 35%, chest pain 61%, ST shift 62%, ventricular rate 154 ± 26 beats/min, and blood pressure 126/73 mm Hg. The superiority of esmolol was significant at 40 min (64% rate control with esmolol vs. 25% with amiodarone) and for all indicators from 10 to 120 min after treatment onset.

CONCLUSION

In "real life emergency medicine," esmolol is better than amiodarone in the treatment of RAF.

ATPace™: injectable adenosine 5'-triphosphate : Diagnostic and therapeutic indications

ATPace™, a novel injectable formulation of adenosine 5'-triphosphate (ATP), is developed by Cordex Pharma, Inc. (Cordex) as a diagnostic and therapeutic drug for the management of cardiac bradyarrhythmias. Extracellular ATP exerts multiple effects in various cell types by activating cell-surface receptors known as P2 receptors. In the heart, ATP suppresses the automaticity of cardiac pacemakers and atrioventricular (AV) nodal conduction via adenosine, the product of its degradation by ecto-enzymes, as well as by triggering a cardio-cardiac vagal reflex. ATP, given as a rapid intravenous bolus injection, has been used since the late 1940s as a highly effective and safe therapeutic agent for the acute termination of reentrant paroxysmal supraventricular tachycardia (PSVT) involving the AV node. In addition, preliminary studies have shown that ATP can also be used as a diagnostic agent for the identification of several cardiac disorders including sinus node dysfunction (sick sinus syndrome), dual AV nodal pathways, long QT syndrome, and bradycardic syncope. The US Food and Drug Administration has approved Cordex formulation for ATP as an Investigational New Drug and two pathways for its marketing approval; one therapeutic, i.e., acute termination of paroxysmal PSVT, and the other diagnostic, i.e., the identification of patients with bradycardic syncope who can benefit from pacemaker therapy. The scientific rationale for the development of ATPace™ is discussed.

The adenosine triphosphate test: a bedside diagnostic tool for identifying the mechanism of supraventricular tachycardia in patients with palpitations

OBJECTIVES

This study assesses the value of the "ATP test" (injection of adenosine triphosphate [ATP] during sinus rhythm) for identifying patients with palpitations of unclear etiology who actually have atrioventricular (AV) nodal re-entry tachycardia (AVNRT) or AV re-entry tachycardia (AVRT).

BACKGROUND

Because AVNRT and AVRT can be cured with radiofrequency ablation, documentation of spontaneous AVNRT or AVRT usually prompts referral for electrophysiologic (EP) evaluation. However, these paroxysmal arrhythmias may elude clinical diagnosis. We recently showed that administration of ATP during sinus rhythm often reveals dual AV node physiology or a concealed accessory pathway (AP) in patients with documented AVNRT or AVRT. Thus, we postulated that the ATP test could identify patients with palpitations who actually have AVNRT or AVRT and would therefore benefit from EP evaluation.

METHODS

One hundred forty-six patients (54 with "palpitations without documented arrhythmias" and 92 with "documentation of arrhythmias of unclear mechanism") underwent a noninvasive ATP test. ATP was injected during sinus rhythm using 10 mg increments. The ATP test was considered positive when prospectively defined signs of dual AV node physiology or concealed AP were disclosed in the electrocardiogram. These findings were correlated with the results of EP evaluation.

RESULTS

A positive ATP test predicted induction of AVNRT or AVRT with a positive predictive value of 93% (sensitivity 71%) but a negative predictive value of 37% (specificity 76%).

CONCLUSIONS

A bedside ATP test identifies patients with palpitations who are likely to have AVNRT or AVRT (and who are therefore likely to benefit from EP evaluation) with a high positive predictive value.

The clinical utility of adenosine in difficult to diagnose tachyarrhythmias

BACKGROUND

The use of intravenous adenosine to help differentiate the origin of tachyarrhythmias has been suggested to be beneficial. However, the benefit of this intervention to physicians with different levels of training in electrocardiographic (ECG) interpretation is unknown.

HYPOTHESIS

The purpose of the study was to determine whether intravenous adenosine improved the diagnostic accuracy of difficult to diagnose tachyarrhythmias when used by physicians with different levels of training in ECG interpretation.

METHODS

We studied 28 consecutive patients presenting with wide and narrow complex tachyarrhythmias, in whom adenosine was given specifically for diagnostic purposes. Two groups of physicians, attending (n = 14) and housestaff (n = 10), reviewed each ECG before and after the administration of adenosine.

RESULTS

For narrow complex tachyarrhythmias, neither physician group derived diagnostic benefit from the use of adenosine. However, for wide complex tachyarrhythmias, the diagnostic accuracy of the housestaff group significantly improved with the use of adenosine (pre = 54%, post = 70%, p < 0.01), while the attending physician group had no significant improvement (pre = 61%, post = 71%, p = NS).

CONCLUSION

This study suggests that adenosine provides useful diagnostic information to physicians less experienced in ECG interpretation when presented with patients having wide complex tachyarrhythmias of uncertain origin.

Intravenous adenosine as first-line prehospital management of narrow-complex tachycardias by EMS personnel without direct physician control

This study was conducted to evaluate the safety and efficacy of intravenous adenosine therapy for prehospital treatment of narrow-complex tachycardias with a presumptive field diagnosis of paroxysmal supraventricular tachycardia (PSVT) by paramedics without direct physician control. A ten-month prospective case series was designed in an urban EMS system that has paramedics operating under standing orders before physician radio contact. All patients with PSVT field diagnosis were included. Diagnosis of PSVT was made by regular, narrow-complex tachycardia with a heart rate greater than 160 beats/min by field ECG. Interpretation was performed solely by paramedics; ECG transmission was not available. In hemodynamically stable patients, vagal maneuvers were followed by intravenous placement and administration of adenosine was recommended by the manufacturer. If three adenosine boluses failed to convert the arrhythmia, patients were monitored and transported, with electrical cardioversion available. Data collection included demographic, history, medications, vital signs, and EGG tracings. Of 14 included patients, 31 were correctly diagnosed with PSVT (75.6%), with mean ventricular rate of 205 beats/min (SD 7 beats/min); one had sinus tachycardia; nine had atrial fibrillation (AF) (22%). Of the 31 cases correctly diagnosed as PSVT, 28 converted to sinus rhythm after adenosine (90.3%). Of those converted, 16 required a single dose (57.1%), nine required one additional dose (32.1%), and three required two additional doses (10.8%). None reverted to PSVT after adenosine conversion during the study period (conversion to arrival at emergency department). No significant difference in length of asystolic pause or in outcome was detected between the true PSVT cases and the AF cases receiving adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful conversion of unstable supraventricular tachycardia to sinus rhythm with adenosine

STUDY PURPOSE

To evaluate the efficacy of adenosine in the treatment of emergency department patients with unstable paroxysmal supraventricular tachycardia (PSVT).

DESIGN

A retrospective chart review conducted over two years.

SETTING

A university-affiliated hospital ED.

PARTICIPANTS

Patients with unstable PSVT (systolic blood pressure of less than 90 mm Hg, chest pain, pulmonary edema, and/or altered mental status) who were treated with adenosine.

INTERVENTIONS

Patients' preadenosine and postadenosine heart rates, symptoms, and blood pressure were recorded, as were complications and recurrence of PSVT. PSVT was diagnosed by surface ECG.

RESULTS

Twelve patients were identified (three men and nine women with a mean age of 47.6 years). Nine patients presented with hypotension (mean systolic blood pressure, 79 mm Hg), ten with chest pain, and six with both chest pain and hypotension. There were no patients with altered mental status or pulmonary edema. Eight patients converted to sinus rhythm with a single 6-mg bolus of adenosine; the remaining four required an additional 12-mg bolus. In all cases, chest pain and hypotension resolved within minutes of conversion to sinus rhythm. There were no clinically significant adverse effects or recurrence of PSVT during ED observation (mean, 1.8 hours). All patients responded to adenosine; none required electrical cardioversion.

CONCLUSION

In the unstable patient with PSVT, adenosine appears to be a safe and effective alternative to current advanced cardiac life support-recommended immediate electrical cardioversion.

Clinical and electrophysiologic effects of magnesium sulfate on paroxysmal supraventricular tachycardia and comparison with adenosine triphosphate

Electrophysiologic studies have shown that intravenous magnesium sulfate prolongs atrioventricular (AV) nodal conduction and refractoriness and thus could play a role in the management of patients with paroxysmal AV reentrant supraventricular tachycardia (SVT). The present study evaluates the clinical and electrophysiologic effects of intravenous magnesium sulfate in patients with SVT and compares them with those of adenosine triphosphate (ATP), one of the most potent drugs in the treatment of this arrhythmia. Patients with inducible sustained SVT were treated with ATP (10 or 20 mg) and magnesium sulfate (2 g over 15 seconds) during electrophysiologic study. If the tachycardia failed to terminate by the sixth minute, an additional 2 g dose of magnesium was given. ATP (10 or 20 mg) was significantly better than magnesium for terminating induced tachycardias (14 of 14 vs 6 of 14, p less than 0.0001). Arrhythmia termination with ATP was due to anterograde AV nodal blockade in all but 1 patient who developed retrograde block over an accessory pathway with decremental conduction. Arrhythmia termination by magnesium was due to retrograde block over an accessory pathway in 3 patients (including the patient with accessory pathway exhibiting decremental conduction), anterograde AV nodal conduction block in 2 patients and premature ventricular complexes in 1 patient. During induced tachycardias, only AH intervals were prolonged by ATP, whereas magnesium significantly prolonged AH and QRS intervals. Short-lasting side effects (chest pain, flushing, nausea) occurred after both drugs were administered but were more severe after magnesium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine and the treatment of supraventricular tachycardia

Adenosine has recently become widely available for the treatment of paroxysmal supraventricular tachycardia. In order to evaluate its role in the management of arrhythmias, we have reviewed the literature on the cellular mechanisms, metabolism, potential for adverse effects, and clinical experience of the efficacy and safety of intravenous adenosine. Adenosine produces transient atrioventricular nodal block when injected as an intravenous bolus. This is of therapeutic value in the conversion to sinus rhythm of the majority of paroxysmal supraventricular tachycardias, which involve the atrioventricular node in a re-entrant circuit. The mean success rate was 93% from over 600 reported episodes. Compared with other antiarrhythmic agents, adenosine is remarkable for its rapid metabolism and brevity of action, with a half-life of a few seconds. It commonly produces subjective symptoms, particularly chest discomfort, dyspnea, and flushing, which are of short duration only. No serious adverse effect has been reported. Arrhythmias may recur within minutes in a minority of patients. Comparative studies have shown that adenosine is as effective as verapamil in the treatment of supraventricular tachycardia, and has less potential for adverse effects. Patients with supraventricular tachycardia should initially be treated using vagotonic physical maneuvers. Immediate electrical cardioversion is indicated if the arrhythmia is associated with hemodynamic collapse. Adenosine is the preferred drug in those patients in whom verapamil has failed or may cause adverse effects, such as those with heart failure or wide-complex tachycardia. The safety profile of adenosine suggests that it should be the drug of first choice for the treatment of supraventricular tachycardia, but only limited comparative data to support this view are available at present.

Verapamil administration to patients with contraindications: is it associated with adverse outcomes?

STUDY OBJECTIVES

To determine if the use of verapamil in patients with contraindications is associated with adverse sequelae, thereby assessing whether process measures of the quality of care are correlated with patient outcomes.

DESIGN

Retrospective chart review comparing the incidence of adverse outcomes and drug failure in patients with and without contraindications to verapamil administration.

SETTING

University hospital emergency department.

PARTICIPANTS

All patients more than 12 years old who received IV verapamil during the study period.

MEASUREMENTS

The presence or absence of contraindications to verapamil, the occurrence of complications, and the frequency of drug failure were determined by chart review.

MAIN RESULTS

Patients with contraindications to verapamil experienced a significantly higher incidence of adverse outcomes and drug failures than those without contraindications. The presence of contraindicated rhythms, low pretreatment blood pressure, and signs of congestive heart failure were each specifically associated with an increased risk of adverse sequelae.

CONCLUSION

Verapamil should not be administered to patients with contraindications to its use. In this instance, quality assurance process measures correlate with patient outcomes.