Relative efficacy of various physical manoeuvres in the termination of junctional tachycardia

Comparison of Various Vagal Maneuvers for Supraventricular Tachycardia by Network Meta-Analysis

BACKGROUND

Vagal maneuvers (VagMs) are recommended as the first-line treatment of supraventricular tachycardia (SVT). However, the optimal type of VagMs remains unproven.

AIM

This study aims to compare the effectiveness and adverse events amongst VagMs on SVT via network meta-analyses (NMAs).

METHODS

We systematically searched randomized controlled trials (RCTs) that involved adults with SVT and compared VagMs without language restrictions. We determined the initial and final responses of conversion rate to sinus rhythm and adverse events. Risk of bias (RoB) was appraised by Cochrane revised tool, and contribution matrix was calculated. NMAs were synthesized using frequentist random-effects model and presented as relative risk (RR) with 95% CI. The order of probability was presented as surface under the cumulative ranking curve analysis (SUCRA). Sensitivity analysis was performed using both Bayesian and frequentist approach with fixed- or random-effects models. Certainty of evidence (CoE) was rated by using the Grading of Recommendations, Assessment, Development, and Evaluations methodology.

RESULTS

Fourteen RCTs with 2,180 patients were enrolled. Small portion of mixed estimates was contributed from high overall RoB studies. Compared with carotid sinus massage (CSM), the modified Valsalva maneuver (MVM) was the most effective VagM after initial performance [SUCRA: 0.9992, RR: 5.47 (1.77-16.93)] and at the end of study [SUCRA: 1.0000, RR: 3.62 (2.04-6.39), CoE: high]. The standard VM did not elicit better conversion rate to the sinus rhythm than CSM at the initial response [SUCRA: 0.4395, RR: 1.97 (0.63-6.15)] and at the end of the study [SUCRA: 0.4795, RR: 1.64 (0.94-2.87), CoE: moderate]. The SUCRA value of CSM at the initial and final responses was the least one amongst three VagMs (0.0613 and 0.0205, respectively). Adverse events amongst three VagMs were similar (CoE: low). Sensitivity analyses yielded consistent results.

CONCLUSION

We recommended MVM as the first choice of VagM for rhythm conversion before the pharmacological management of SVT.

Effectiveness of the modified Valsalva manoeuvre in adults with supraventricular tachycardia: a systematic review and meta-analysis

BACKGROUND AND IMPORTANCE

Cardiac arrhythmia, specifically paroxysmal supraventricular tachycardia (SVT), accounts for a substantial proportion of emergency medical services resources utilisation. Reconversion requires increasing the atrioventricular node's refractoriness, which can be achieved by vagal manoeuvres, pharmacological agents or electrical cardioversion. There are multiple variants of vagal manoeuvres, including the Valsalva manoeuvre (VM). While the effectiveness of the standard VM has already been systematically reviewed, there has been no such analysis for the modified VM.

OBJECTIVES

Compare the effectiveness of the modified VM versus the standard VM in restoring the normal sinus rhythm in adult patients with supraventricular tachycardia.

DESIGN

Systematic review with meta-analysis of published randomised controlled trials.

OUTCOME MEASURES

The primary outcome was the reconversion to a sinus rhythm. Secondary outcomes included: medication use, adverse events, length of stay in the emergency department and hospital admission.

MAIN RESULTS

Five randomised controlled trials were included, with a combined total of 1181 participants. The meta-analysis demonstrated a significantly higher success rate for reconversion to sinus rhythm when using the modified VM compared to the standard VM in patients with an SVT (odds ratio = 4.36; 95% confidence interval, 3.30-5.76; P < 0.001). More adverse events were reported in the modified VM group, although this difference is NS (risk ratio = 1.48; 95% confidence interval, 0.91-2.42; P = 0.11). The available evidence suggests that medication use was lower in the modified VM group than the standard VM group. However, medication use could not be generalised across the different studies. None of the included studies showed a significant difference in length of stay in the emergency department. Only one study reported on hospital admission, with no significant difference between the two groups.

CONCLUSIONS

The available evidence is highly suggestive to support the use of the modified VM compared to the standard VM in the treatment of adult patients with SVT. Meta-analysis showed a higher success rate, required less medication use, and resulted in an equal number of adverse events. However, these results cannot be regarded as definitive in the absence of higher-quality studies.

Initial and Sustained Response Effects of 3 Vagal Maneuvers in Supraventricular Tachycardia: A Randomized, Clinical Trial

BACKGROUND

For acute termination of supraventricular tachycardia (SVT), vagal maneuvers, including the standard Valsalva maneuver (sVM), modified Valsalva (mVM) maneuver, and carotid sinus massage (CSM), are first-line interventions. There is no criterion standard technique.

OBJECTIVE

This prospective, randomized study was aimed at analyzing the success rates of these 3 vagal maneuvers as measured by sustaining sinus rhythm at the fifth minute and SVT termination.

METHODS

We conducted this prospective, randomized controlled study in an emergency department (ED). We enrolled all the patients who were admitted to the ED and diagnosed with SVT. We randomly assigned them to 3 groups receiving sVM, mVM, and CSM and recorded the patients' responses to the vagal maneuvers and SVT recurrence after vagal maneuvers.

RESULTS

The study was completed with 98 patients. A total of 25 (25.5%) instances of SVT were initially treated successfully with vagal maneuvers. The success rate was 43.7% (14/32 cases) from mVM, 24.2% (8/33) for sVM, and 9.1 % (3/33) for CSM (p < 0.05). At the end of the fifth minute, only 12.2% (12/98) of all patients had sinus rhythm. Sinus rhythm persisted in 28.1% (9/32) of patients in the mVM group, 6.1% (2/33) of patients in the sVM group, and 3% (1/33) in the CSM group at the fifth minute (p < 0.05).

CONCLUSION

mVM is superior to the CSM maneuver in terminating SVT and maintaining rhythm. We conclude that it is beneficial to use mVM, which is more effective and lacks side effects.

Valsalva maneuver techniques for supraventricular tachycardias: Which and how?

Study objective:

While some research has been done on Valsalva maneuvers in treating supraventricular tachycardia, there is no standardized algorithm on which technique has been the most effective for the termination of supraventricular tachycardias. In this study, we compare different Valsalva maneuver techniques in order to determine the exact technique needed for maximal vagal response.

Methods:

This was a repeated measures clinical study, which enlisted a sample of healthy adult volunteers. Participants performed four different Valsalva maneuver techniques (40 mm Hg—10 s, 40 mm Hg—15 s, 50 mm Hg—10 s, and 50 mm Hg—15 s) while lying in a supine position. The maneuvers were repeated three times. An electrocardiography printout was obtained during each trial, and heart rate differences between pre-maneuver and post-maneuver were measured.

Results:

Among the 97 volunteers who participated in the study, 7 were excluded because the target Valsalva maneuver pressures were not reached, and 1 volunteer was excluded due to T-wave inversion that developed after Valsalva maneuver. We enrolled 89 participants. There was no significant difference in the heart rate decrease among the four techniques. In addition, there was no difference between the vagal responses in terms of age, gender, and body mass index.

Conclusion:

This study shows that the four different Valsalva maneuver techniques were not superior to one another in terms of decreased heart rate.

Leg Lift Valsalva Maneuver for Treatment of Supraventricular Tachycardias

Clinical question Can conversion to sinus rhythm for a supraventricular tachycardia be enhanced by a postural modification to the Valsalva maneuver? Article chosen Appelboam A, Reuben A, Mann C, et al. Postural modification of the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet 2015;386(10005):1747-53. 1 OBJECTIVE: To determine effectiveness of a postural modification of the Valsalva involving leg elevation and supine positioning.

Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial

BACKGROUND

The Valsalva manoeuvre is an internationally recommended treatment for supraventricular tachycardia, but cardioversion is rare in practice (5-20%), necessitating the use of other treatments including adenosine, which patients often find unpleasant. We assessed whether a postural modification to the Valsalva manoeuvre could improve its effectiveness.

METHODS

We did a randomised controlled, parallel-group trial at emergency departments in England. We randomly allocated adults presenting with supraventricular tachycardia (excluding atrial fibrillation and flutter) in a 1:1 ratio to undergo a modified Valsalva manoeuvre (done semi-recumbent with supine repositioning and passive leg raise immediately after the Valsalva strain), or a standard semi-recumbent Valsalva manoeuvre. A 40 mm Hg pressure, 15 s standardised strain was used in both groups. Randomisation, stratified by centre, was done centrally and independently, with allocation with serially numbered, opaque, sealed, tamper-evident envelopes. Patients and treating clinicians were not masked to allocation. The primary outcome was return to sinus rhythm at 1 min after intervention, determined by the treating clinician and electrocardiogram and confirmed by an investigator masked to treatment allocation. This study is registered with Current Controlled Trials (ISRCTN67937027).

FINDINGS

We enrolled 433 participants between Jan 11, 2013, and Dec 29, 2014. Excluding second attendance by five participants, 214 participants in each group were included in the intention-to-treat analysis. 37 (17%) of 214 participants assigned to standard Valsalva manoeuvre achieved sinus rhythm compared with 93 (43%) of 214 in the modified Valsalva manoeuvre group (adjusted odds ratio 3·7 (95% CI 2·3-5·8; p<0·0001). We recorded no serious adverse events.

INTERPRETATION

In patients with supraventricular tachycardia, a modified Valsalva manoeuvre with leg elevation and supine positioning at the end of the strain should be considered as a routine first treatment, and can be taught to patients.

FUNDING

National Institute for Health Research.

Reconsidering the effectiveness and safety of carotid sinus massage as a therapeutic intervention in patients with supraventricular tachycardia

OBJECTIVE

The objectives of our investigation were to review the evidence for the efficacy and safety of carotid sinus massage in terminating supraventricular tachycardia and to determine if other potentially less harmful interventions have been established to be safer and more effective.

METHODS

A search using PubMed, Ovid, and COCHRANE databases was performed using the terms supraventricular tachycardia, carotid sinus massage, SVT, and CSM. Articles not written in English were excluded. There was a paucity of randomized controlled trials comparing various supraventricular tachycardia (SVT) interventions. However, articles of highest quality were selected for review and inclusion. In addition, articles examining potential hazards of carotid sinus massage in case report format were reviewed, even when performed for other indications other than SVT, as the maneuver is identically performed. Selected articles were reviewed by both authors for relevance to the topic.

RESULTS

Summarizing the findings of this review leads to these 3 fundamental conclusions. First, a therapeutic intervention should only be performed when the benefit of the procedure outweighs its risk. Carotid sinus massage exposes the patient to rare but potentially devastating iatrogenic harm. Second, a therapeutic intervention should be efficacious. The efficacy of carotid sinus massage in terminating supraventricular tachycardia appears to be modest at best. Third, other readily available, easily mastered, and potentially safer and more efficacious alternative interventions are available such as Valsalva maneuver and pharmacologic therapy.

CONCLUSION

Based on the limited evidence available, we believe that carotid sinus massage should be reconsidered as a first-line therapeutic intervention in the termination of SVT.

Effectiveness of the Valsalva Manoeuvre for reversion of supraventricular tachycardia

BACKGROUND

People with the cardiac arrhythmia supraventricular tachycardia (SVT) frequently present to clinicians in the prehospital and emergency medicine settings. Restoring sinus rhythm by terminating the SVT involves increasing the refractoriness of atrioventricular nodal tissue within the myocardium by means of vagal manoeuvres, pharmacological agents, or electrical cardioversion. A commonly used first-line technique to restore the normal sinus rhythm (reversion) is the Valsalva Manoeuvre (VM). This is a non-invasive means of increasing myocardial refractoriness by increasing intrathoracic pressure for a brief period, thus stimulating baroreceptor activity in the aortic arch and carotid bodies, resulting in increased parasympathetic (vagus nerve) tone.

OBJECTIVES

To assess the evidence of effectiveness of the VM in terminating SVT.

SEARCH METHODS

We updated the electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 7); MEDLINE Ovid (1946 to August week 3, 2014); EMBASE Classic and EMBASE Ovid (1947 to 27 August 2014); Web of Science (1970 to 27 August 2014); and BIOSIS Previews (1969 to 22 August 2014). We also checked trials registries, the Index to Theses, and the bibliographies of all relevant publications identified by these strategies.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that examined the effectiveness of VM in terminating SVT.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data using a standardised form. We assessed each trial for internal validity, resolving any differences by discussion. We then extracted and entered data into Review Manager 5.

MAIN RESULTS

In this update, we did not identify any new RCT studies for inclusion. We identified two RCT studies as ongoing that we are likely to include in future updates. Accordingly, our results are unchanged and include three RCTs with a total of 316 participants. All three studies compared the effectiveness of VM in reverting SVT with that of other vagal manoeuvres in a cross-over design. Two studies induced SVT within a controlled laboratory environment. Participants had ceased all medications prior to engaging in these studies. The third study reported on people presenting to a hospital emergency department with an episode of SVT. These participants were not controlled for medications or other factors prior to intervention.The two laboratory studies demonstrated reversion rates of 45.9% and 54.3%, whilst the clinical study demonstrated reversion success of 19.4%. This discrepancy may be due to methodological differences between studies, the effect of induced SVT versus spontaneous episodic SVT, and participant factors such as medications and comorbidities. We were unable to assess any of these factors, or adverse effects, further, since they were either not described in enough detail or not reported at all.Statistical pooling was not possible due to heterogeneity between the included studies.

AUTHORS' CONCLUSIONS

We did not find sufficient evidence to support or refute the effectiveness of VM for termination of SVT. Further research is needed, and this research should include a standardised approach to performance technique and methodology.

Effectiveness of the Valsalva Manoeuvre for reversion of supraventricular tachycardia

BACKGROUND

Patients with the cardiac arrhythmia supraventricular tachycardia (SVT) frequently present to clinicians in the prehospital and emergency medicine settings. Restoring sinus rhythm by terminating the SVT involves increasing the refractoriness of AV nodal tissue within the myocardium by means of vagal manoeuvres, pharmacological agents or electrical cardioversion. A commonly used first-line technique to restore the normal sinus rhythm (reversion) is the Valsalva Manoeuvre (VM). This is a non-invasive means of increasing myocardial refractoriness by increasing intrathoracic pressure for a brief period, thus stimulating baroreceptor activity in the aortic arch and carotid bodies, resulting in increased parasympathetic (vagus nerve) tone.

OBJECTIVES

To assess the evidence of effectiveness of the Valsalva Manoeuvre in terminating supraventricular tachycardia.

SEARCH METHODS

We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1 of 12, 2012); MEDLINE Ovid (1946 to January 2012); EMBASE Ovid (1947 to January 2012); Web of Science (1970 to 27 January 2012); and BIOSIS Previews (1969 to 27 January 2012). Trials registries, the Index to Theses and the bibliographies of all relevant publications identified by these strategies were also checked.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that examined the effectiveness of the Valsalva Manoeuvre in terminating SVT.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data using a standardised form. Each trial was assessed for internal validity with differences resolved by discussion. Data were then extracted and entered into Review Manager 5.1 (RevMan).

MAIN RESULTS

We identified three randomised controlled trials including 316 participants. All three studies compared the effectiveness of VM in reverting SVT with that of other vagal manoeuvres in a cross-over design. Two studies induced SVT within a controlled laboratory environment. Participants had ceased all medications prior to engaging in these studies. The third study reported on patients presenting to a hospital emergency department with an episode of SVT. These patients were not controlled for medications or other factors prior to intervention.The two laboratory studies demonstrated reversion rates of 45.9% and 54.3%, whilst the clinical study demonstrated reversion success of 19.4%. This discrepancy may be due to methodological differences between studies, the effect of induced SVT versus spontaneous episodic SVT, and participant factors such as medications and comorbidities. We were unable to assess any of these factors further, nor adverse effects, since they were either not described in enough detail or not reported at all.Statistical pooling was not possible due to heterogeneity between the included studies.

AUTHORS' CONCLUSIONS

We did not find sufficient evidence to support or refute the effectiveness of the Valsalva Manoeuvre for termination of SVT. Further research is needed and this should include a standardised approach to performance technique and methodology.

Elucidating nature's solutions to heart, lung, and blood diseases and sleep disorders

Evolution has provided a number of animal species with extraordinary phenotypes. Several of these phenotypes allow species to survive and thrive in environmental conditions that mimic disease states in humans. The study of evolved mechanisms responsible for these phenotypes may provide insights into the basis of human disease and guide the design of new therapeutic approaches. Examples include species that tolerate acute or chronic hypoxemia like deep-diving mammals and high-altitude inhabitants, as well as those that hibernate and interrupt their development when exposed to adverse environments. The evolved traits exhibited by these animal species involve modifications of common biological pathways that affect metabolic regulation, organ function, antioxidant defenses, and oxygen transport. In 2006, the National Heart, Lung, and Blood Institute released a funding opportunity announcement to support studies that were designed to elucidate the natural molecular and cellular mechanisms of adaptation in species that tolerate extreme environmental conditions. The rationale for this funding opportunity is detailed in this article, and the specific evolved mechanisms examined in the supported research are described. Also highlighted are past medical advances achieved through the study of animal species that have evolved extraordinary phenotypes as well as the expectations for new understanding of nature's solutions to heart, lung, blood, and sleep disorders through future research in this area.

Deep nasopharyngeal aspiration as a treatment option for conversion of supraventricular paroxysmal tachycardia in infants: First experiences

OBJECTIVE

Supraventricular paroxysmal tachycardias are the most common paroxysmal rhythm disorders in childhood. Atypical clinical presentations as well as their ability to induce hemodynamic deterioration imply necessity for arrhythmia rapid termination during the first months of life. The objective of this article was to evaluate the efficiency of deep nasopharyngeal aspiration as a potential vagal maneuver for supraventricular paroxysmal tachycardias termination.

DESIGN

Clinical trial.

PATIENTS AND METHODS

From June 2005 to October 2009, a total of eight infants, who were admitted at our institutions and diagnosed to have supraventricular paroxysmal tachycardias, were analyzed. To terminate supraventricular paroxysmal tachycardias "diving" reflex was initially tried and in the cases of its inefficacy, deep nasopharyngeal aspiration was performed.

MAIN RESULTS

Nasopharyngeal aspiration successfully converted arrhythmia in three infants (37.5%).

CONCLUSIONS

Deep nasopharyngeal aspiration could be an alternative vagal maneuver for infants with supraventricular paroxysmal tachycardia.

A cross-sectional study of Victorian Mobile Intensive Care Ambulance Paramedics knowledge of the Valsalva Manoeuvre

BACKGROUND

The Valsalva Manoeuvre (VM) is a primary measure for terminating haemodynamically stable supraventricular tachycardia (SVT) in the emergency care setting. The clinical use and termination success of the VM in the prehospital setting has not been investigated to date. The objective of this study was to determine Melbourne Mobile Intensive Care Ambulance (MICA) Paramedic knowledge of the VM, and to compare this understanding with an evidence-based model of VM performance.

METHODS

A cross-sectional study in the form of a face-to-face interview was used to determine Melbourne MICA Paramedic understanding of VM instruction between January and February, 2008. The results were then compared with an evidence-based model of VM performance to ascertain compliance with the three criteria of position, pressure and duration. Ethics approval was granted.

RESULTS

There were 28 participants (60.9%) who elected a form of supine posturing, some 23 participants (50%) selected the syringe method of pressure generation, with 16 participants (34.8%) selecting the "as long as you can" option for duration. On comparison, one out of 46 MICA Paramedics correctly identified the three evidence-based criteria.

CONCLUSIONS

The formal education of Melbourne's MICA Paramedics would benefit from the introduction of an evidence based model of VM performance, which would impact positively on patient care and may improve reversion success in the prehospital setting. The results of this study also demonstrate that an opportunity exists to promote the evidence-based VM criteria across the primary emergency care field.

Treatment of paroxysmal supraventricular tachycardia using instrument-assisted manipulation of the fourth rib: a 6-year case study

OBJECTIVE

The purpose of this case report was to describe the observation of the manipulation of the fourth rib followed by the reproducible, rapid return of heart rate to normal in a patient with paroxysmal supraventricular tachycardia.

CLINICAL FEATURES

A male patient had paroxysmal supraventricular tachycardia. He was evaluated using standard methods of palpation. He was followed over a 6-year period.

INTERVENTION AND OUTCOME

The patient was treated during episodes of supraventricular tachycardia (SVT) with instrument-assisted manipulation of the fourth rib without treatment of any other segments. Tachycardia was eliminated after rib manipulation within less than 2 minutes. Over a 6-year period, effective control of episodes of SVT was consistently achieved associated with manipulation of the fourth rib.

CONCLUSIONS

This case study is suggestive of a relationship between SVT and misalignment of the fourth rib. Controlled studies are necessary to validate this observation.

The International Liaison Committee on Resuscitation (ILCOR) consensus on science with treatment recommendations for pediatric and neonatal patients: pediatric basic and advanced life support

This publication contains the pediatric and neonatal sections of the 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations (COSTR). The consensus process that produced this document was sponsored by the International Liaison Committee on Resuscitation (ILCOR). ILCOR was formed in 1993 and consists of representatives of resuscitation councils from all over the world. Its mission is to identify and review international science and knowledge relevant to cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) and to generate consensus on treatment recommendations. ECC includes all responses necessary to treat life-threatening cardiovascular and respiratory events. The COSTR document presents international consensus statements on the science of resuscitation. ILCOR member organizations are each publishing resuscitation guidelines that are consistent with the science in this consensus document, but they also take into consideration geographic, economic, and system differences in practice and the regional availability of medical devices and drugs. The American Heart Association (AHA) pediatric and the American Academy of Pediatrics/AHA neonatal sections of the resuscitation guidelines are reprinted in this issue of Pediatrics (see pages e978-e988). The 2005 evidence evaluation process began shortly after publication of the 2000 International Guidelines for CPR and ECC. The process included topic identification, expert topic review, discussion and debate at 6 international meetings, further review, and debate within ILCOR member organizations and ultimate approval by the member organizations, an Editorial Board, and peer reviewers. The complete COSTR document was published simultaneously in Circulation (International Liaison Committee on Resuscitation. 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Circulation. 2005;112(suppl):73-90) and Resuscitation (International Liaison Committee on Resuscitation. 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Resuscitation. 2005;67:271-291). Readers are encouraged to review the 2005 COSTR document in its entirety. It can be accessed through the CPR and ECC link at the AHA Web site: www.americanheart.org. The complete publication represents the largest evaluation of resuscitation literature ever published and contains electronic links to more detailed information about the international collaborative process. To organize the evidence evaluation, ILCOR representatives established 6 task forces: basic life support, advanced life support, acute coronary syndromes, pediatric life support, neonatal life support, and an interdisciplinary task force to consider overlapping topics such as educational issues. The AHA established additional task forces on stroke and, in collaboration with the American Red Cross, a task force on first aid. Each task force identified topics requiring evaluation and appointed international experts to review them. A detailed worksheet template was created to help the experts document their literature review, evaluate studies, determine levels of evidence, develop treatment recommendations, and disclose conflicts of interest. Two evidence evaluation experts reviewed all worksheets and assisted the worksheet reviewers to ensure that the worksheets met a consistently high standard. A total of 281 experts completed 403 worksheets on 275 topics, reviewing more than 22000 published studies. In December 2004 the evidence review and summary portions of the evidence evaluation worksheets, with worksheet author conflict of interest statements, were posted on the Internet at www.C2005.org, where readers can continue to access them. Journal advertisements and e-mails invited public comment. Two hundred forty-nine worksheet authors (141 from the United States and 108 from 17 other countries) and additional invited experts and reviewers attended the 2005 International Consensus Conference for presentation, discussion, and debate of the evidence. All 380 participants at the conference received electronic copies of the worksheets. Internet access was available to all conference participants during the conference to facilitate real-time verification of the literature. Expert reviewers presented topics in plenary, concurrent, and poster conference sessions with strict adherence to a novel and rigorous conflict of interest process. Presenters and participants then debated the evidence, conclusions, and draft summary statements. Wording of science statements and treatment recommendations was refined after further review by ILCOR member organizations and the international editorial board. This format ensured that the final document represented a truly international consensus process. The COSTR manuscript was ultimately approved by all ILCOR member organizations and by an international editorial board. The AHA Science Advisory and Coordinating Committee and the editor of Circulation obtained peer reviews of this document before it was accepted for publication. The most important changes in recommendations for pediatric resuscitation since the last ILCOR review in 2000 include: Increased emphasis on performing high quality CPR: "Push hard, push fast, minimize interruptions of chest compression; allow full chest recoil, and don't provide excessive ventilation" Recommended chest compression-ventilation ratio: For lone rescuers with victims of all ages: 30:2 For health care providers performing 2-rescuer CPR for infants and children: 15:2 (except 3:1 for neonates) Either a 2- or 1-hand technique is acceptable for chest compressions in children Use of 1 shock followed by immediate CPR is recommended for each defibrillation attempt, instead of 3 stacked shocks Biphasic shocks with an automated external defibrillator (AED) are acceptable for children 1 year of age. Attenuated shocks using child cables or activation of a key or switch are recommended in children <8 years old. Routine use of high-dose intravenous (IV) epinephrine is no longer recommended. Intravascular (IV and intraosseous) route of drug administration is preferred to the endotracheal route. Cuffed endotracheal tubes can be used in infants and children provided correct tube size and cuff inflation pressure are used. Exhaled CO2 detection is recommended for confirmation of endotracheal tube placement. Consider induced hypothermia for 12 to 24 hours in patients who remain comatose following resuscitation. Some of the most important changes in recommendations for neonatal resuscitation since the last ILCOR review in 2000 include less emphasis on using 100% oxygen when initiating resuscitation, de-emphasis of the need for routine intrapartum oropharyngeal and nasopharyngeal suctioning for infants born to mothers with meconium staining of amniotic fluid, proven value of occlusive wrapping of very low birth weight infants <28 weeks' gestation to reduce heat loss, preference for the IV versus the endotracheal route for epinephrine, and an increased emphasis on parental autonomy at the threshold of viability. The scientific evidence supporting these recommendations is summarized in the neonatal document (see pages e978-e988).

Management of Arrhythmias in the Emergency Department

The authors present practical and concise advice on initial diagnosis and management of arrhythmias, on arrhythmia devices, and on syncope. There is discussion of tachyarrhythmias, both wide and narrow, bradyarrhythmias, and management of pacemakers and defibrillators. Common pitfalls and concerns are addressed.

Vagal response varies with Valsalva maneuver technique: a repeated-measures clinical trial in healthy subjects

STUDY OBJECTIVE

Variable success rates of the Valsalva maneuver in treatment of paroxysmal supraventricular tachycardia may be due to variations in performance technique. This study aimed to compare the magnitude of the vagal reflexes initiated by 5 variations of the Valsalva maneuver technique (supine, supine with epigastric pressure, supine with leg raise, semirecumbent position, and sitting position).

METHODS

This was a single-blinded, repeated-measures, clinical trial of 65 subjects in sinus rhythm. Subjects performed each Valsalva maneuver technique 5 times in random order. The means of the longest ECG R-R intervals during the relaxation phase (postmaneuver R-R interval) and the postmaneuver pulse rates for each technique were compared. The mean differences between the pre- and postmaneuver R-R intervals for each technique were also compared.

RESULTS

The supine with epigastric pressure and supine techniques resulted in longer mean postmaneuver R-R intervals (1.082 seconds [95% confidence interval (CI) 1.045 to 1.119 seconds] and 1.075 seconds [95% CI 1.035 to 1.114 seconds], respectively) than the leg raise, semirecumbent, and sitting position techniques (1.053 seconds [95% CI 1.019 to 1.086 seconds], 1.044 seconds [95% CI 1.006 to 1.081 seconds], and 1.024 seconds [95% CI 0.990 to 1.059 seconds], respectively), which equates to slower mean postmaneuver pulse rates for the supine with epigastric pressure and supine techniques (55.5 and 55.8 beats/min, respectively) than the leg raise, semirecumbent, and sitting position techniques (57.0, 57.5, and 58.6 beats/min, respectively). The supine with epigastric pressure and supine techniques also resulted in the largest premaneuver versus postmaneuver differences.

CONCLUSION

For healthy subjects in sinus rhythm, the supine with epigastric pressure and supine techniques generated stronger vagal responses, as measured by R-R intervals and pulse rates, than the other techniques examined. However, the vagal responses of these 2 techniques were similar, and the addition of epigastric pressure may confer little advantage.

Incorrect instruction in the use of the Valsalva manoeuvre for paroxysmal supra-ventricular tachycardia is common

OBJECTIVE

Success rates for the Valsalva manoeuvre (VM) in treatment of paroxysmal supraventricular tachycardia (SVT) vary with performance technique. This study aimed to assess whether ED doctors instruct their patients to perform the recommended VM technique (supine position for 15 s).

METHODS

A multicentre, observational study of 35 ED registrars and 17 emergency physicians. Each doctor was asked to describe how he/she would instruct a patient in SVT to perform the VM.

RESULTS

Only five (9.6%) doctors would position their patient correctly and 31 (59.6%) would incorrectly instruct their patient to assume a sitting or semirecumbent position. Only five (9.6%) doctors would give specific instructions to blow for at least 15 s and 34 (65.4%) would instruct their patient to blow 'as long as you can'. Only four (7.4%) doctors would use a sphygmomanometer to measure intrathoracic pressure during the VM. There were no significant differences (P > 0.05) between the registrar and physician group responses for any study endpoint.

CONCLUSION

Few ED doctors correctly instruct their patients in the VM technique recommended for management of SVT. Hence, maximal vagal tone and SVT conversion rates may not be achieved in many cases. The use of the recommended VM technique is encouraged.

Postoperative arrhythmias and conduction disorders

Cardiac arrhythmias are common in the perioperative period. Most arrhythmias are clinically benign. Occasionally, cardiac arrhythmias and conduction disturbances can pose a major additional risk to the patient in the perioperative and postoperative periods. The current availability of a wide array of techniques for controlling serious arrhythmias--pharmacologic, electrical, and interventional--enable the physician to manage most arrhythmias and conduction disturbances successfully. The added risks posed by arrhythmias and conduction disturbances in the perioperative period now can be minimized.

Supraventricular tachycardia

Supraventricular tachycardias (SVT) comprise those tachycardias that originate above the bifurcation of the bundle of His. They can be classified broadly as AV node dependent and AV node independent. The mechanism and clinical manifestation of SVTs, which is essential to their correct diagnosis, is reviewed. The therapeutic management of SVTs, including acute and chronic drug therapy and catheter ablation, is discussed also.

Electrophysiological mechanisms and determinants of vagal maneuvers for termination of paroxysmal supraventricular tachycardia

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 antegrade limb and 17 (20%) terminated in the retrograde limb. Out of 48 patients with atrioventricular nodal reentrant tachycardia (AVNRT), vagal maneuvers terminated the tachycardia in the antegrade slow pathway (14%) or in the retrograde fast pathway (19%). Baroreflex sensitivity was poorer but isoproterenol sensitivity test better in patients with AVNRT. Poorer antegrade atrioventricular node conduction properties and better vagal response determined successful antegrade termination of AVRT by vagal maneuvers. Poorer retrograde accessory pathway conduction property but better vagal response determined successful retrograde termination of AVRT. Better sympathetic and vagal response associated with poorer retrograde atrioventricular node conduction determined retrograde 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 understanding of the interaction of autonomic and electrophysiological mechanisms in maintaining or terminating PSVT may provide important insight into the pathophysiology of these two tachycardias.

Hemodynamic and Inotropic Effects of Antiarrhythmic Drugs Used to Treat Paroxysmal Supraventricular Arrhythmias

Episodes of sustained paroxysmal supraventricular tachycardias can be terminated by antiarrhythmic drugs given intravenously. The cardiodepressive effects of these drugs are an important limitation of this therapeutic procedure. The dose-dependent circulatory and myocardial effects of the nucleoside adenosine (0.5, 2.0, 5.0 mg/kg/minute) and the class I antiarrhythmic drug ajmaline (1.0, 2.0, 4.0 mg/kg) were investigated in 73 open-chest rats. Hemodynamic measurements in the intact circulation and isovolumic registrations (peak isovolumic left ventricular systolic pressure and peak isovolumic dP/dtmax) were compared with saline controls. Adenosine has a short-lasting, negative, chronotropic effect that causes a dose-dependent reduction of cardiac output (-34%, -54%, -65% vs control). The peak isovolumic left ventricular systolic pressure (LVSP) is not changed significantly by adenosine (-6%, -4%, +5% vs control). The negative chronotropic effect of ajmaline with consecutive reduction of cardiac output is less pronounced (cardiac output: -18%, -20%, -38% vs control). The highest dose of ajmaline causes a significant reduction of peak isovolumic LVSP (-2%, -1%, -7% vs control). Adenosine has an impressive negative chronotropic effect with a consequent marked decrease of cardiac output. The reduction of cardiac output by adenosine is more pronounced compared with ajmaline. Nevertheless, adenosine has-in contrast to ajmaline-no cardiodepressive effects in vivo.

Effects of enhanced parasympathetic tone on atrioventricular nodal conduction during atrioventricular nodal reentrant tachycardia

The effects of various physiologic and pharmacologic stimuli on the anterograde slow pathway in patients with atrioventricular nodal reentrant tachycardia are well characterized. We sought to further characterize the nature of anterograde and retrograde conduction during tachycardia and to define the differential input of the parasympathetic nervous system to these pathways. A custom-made neck suction collar was placed to stimulate the carotid body baroreceptors during supraventricular tachycardia. Neck suction at -60 mm Hg was applied and changes in tachycardia cycle length, AH, and ventriculoatrial intervals were measured in 20 patients. These measurements were repeated after intravenous administration of 10 mg of edrophonium to enhance vagal tone. We observed a 15 +/- 6 ms increase in tachycardia cycle length from baseline (p <0.0001) and a 14 +/- 6 ms increase in AH interval (p <0.0001), but no change in the VA interval with neck suction alone. The tachycardia cycle length prolonged 26 +/- 55 ms (p <0.0001) with edrophonium and an additional 12 +/- 43 ms (p <0.001) with neck suction after edrophonium. There was no change in the VA interval before or after edrophonium during neck suction. There were 10 tachycardia terminations in 8 patients during anterograde slow pathway block during neck suction, with tachycardia cycle length prolongation and mean AH prolongation before termination of 45 +/- 37 ms (vs 15 +/- 7 ms increase in AH interval without tachycardia termination, p = 0.10). There were 12 tachycardia terminations in 4 patients with retrograde block during neck suction, only after edrophonium, without any preceding change in tachycardia cycle length during 11 episodes. We conclude that anterograde slow pathway demonstrates gradual conduction slowing with parasympathetic enhancement, whereas retrograde fast pathway responds with abrupt block.

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 fibrilation, 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 therapies, 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.

Paroxysmal supraventricular tachycardias

Paroxysmal supraventricular tachycardia (PSVT) is a distinct clinical syndrome. Most patients present with the abrupt onset of palpitations, dizziness, dyspnea, or chest pain. The electrocardiogram (ECG) demonstrates a fast heart rate (150-250 beats per min), a regular rhythm, and most often, a narrow QRS complex. The P wave is usually hidden within the QRS complex. PSVT is caused by reentry, and the tachycardias are classified, electrophysiologically, according to the anatomic location of the reentry circuit. Atrioventricular nodal reentry is the most common form of PSVT. In A-V nodal reentry, there are two conducting pathways (alpha and beta) that have different conduction times and refractory periods; both pathways are confined to the A-V nodal and perinodal atrial tissue. The other common form of PSVT, termed atrioventricular reciprocating tachycardia, depends on an anatomically distinct, or "accessory," pathway that may conduct impulses between the atria and the ventricles, while bypassing the AV node. The two forms of PSVT may be distinguished in many cases by examining the 12-lead electrocardiogram. In the majority of cases of A-V nodal reentry, the atria and ventricles are depolarized simultaneously, and the P waves are hidden in the QRS complex. If the reentry circuit includes an accessory pathway, the P wave always follows the QRS, and usually the R-P interval exceeds 70 msec. Several principles should guide the management of PSVT: (a) Unstable patients require emergent electrical cardioversion; (b) A 12-lead ECG should be obtained immediately to confirm that the tachycardia has a narrow complex (ventricular tachycardia may masquerade as PSVT if only a single lead is examined); (c) Vagal maneuvers may be attempted (the Valsalva maneuver is safer and more efficacious, especially in the elderly); and (4) In most patients, adenosine is the first-line agent to treat PSVT. Contraindications to adenosine and drug interactions are noted in this article. In addition, the use of adenosine in wide complex tachycardias and the indications for admission and referral for electrophysiologic evaluation are discussed.

Initial onset of accessory pathway-mediated and atrioventricular node reentrant tachycardia after age 65: clinical features, electrophysiologic characteristics, and possible facilitating factors

OBJECTIVE

To evaluate the clinical features electrophysiologic characteristics, and possible facilitating factors in older patients (> or = 65 years) with initial onset of accessory pathway-mediated and atrioventricular (AV) node reentrant tachycardia.

DESIGN

Of the patients undergoing electrophysiologic study and radiofrequency catheter ablation of accessory pathway-mediated and AV node reentrant tachycardia at this institution, patients with initial tachyarrhythmia after age 65 years were compared with those presenting initially before age 30.

SETTING

A tertiary medical center for the general public.

PARTICIPANTS

Sixty-six patients had their initial symptoms after age 65: Group I, 32 patients with accessory pathway-mediated tachycardia, and Group II, 34 patients with AV node reentrant tachycardia. Four-hundred forty patients had their initial symptoms before age 30: Group III, 283 with accessory pathway mediated tachyarrhythmia, and Group IV, 157 with AV node reentrant tachycardia.

INTERVENTION

All patients underwent electrophysiological study to determine the mechanisms of tachyarrhythmia, and radiofrequency catheter ablation for treatment of tachycardia.

RESULTS

(1) Older patients with initial arrhythmia had incidence of critical clinical manifestations, including tachyarrhythmia-related syncope and cardioversion, similar to those with initial arrhythmia at a younger age. (2) Patients in Group III, showed anterograde effective refractory period (ERP) of the AV node (P = .432), longer anterograde ERP of the accessory pathway (P = .004), and greater difference of the anterograde ERP between the AV node and the accessory pathway (D-ERP) (P = .003) similar to patients in group I. In Group II, the ERP and Wenckebach cycle length of the retrograde fast pathway was significantly longer than in Group IV (P = .037 and P < .001, respectively), and a greater percentage of patients in Group II than in Group IV AV node reentrant tachycardia needed isoproteronol to facilitate the induction of reentrant tachycardia (P = .034). (3) Patients in Group I and Group II had a higher incidence of supraventricular and ventricular ectopic activity than those in Group III (P = .002 and P = .005, respectively) and Group IV (P = .024 and P = .012, respectively) in 24-hour ambulatory electrocardiograms.

CONCLUSION

The initial onset of accessory pathway-mediated tachycardia after age 65 may be caused by changes of electrophysiologic properties (greater D-ERP) as well as increased supraventricular and ventricular ectopic activity. Influence of the autonomic nervous system, rather than changes of conduction properties in the AV node, and increase in ectopic activity may contribute to the new onset of AV node reentrant tachycardia in older adults. The choice of antiarrhythmic drugs and radiofrequency ablation require attention to the clinical profile and facilitating factors of reentrant tachycardia in this group of patients.

Life-threatening alterations in heart rate after the use of adenosine in atrial flutter

Adenosine has become the preferred treatment for common types of supraventricular tachycardia because it is extremely effective and rarely associated with with serious side effects. It has also been advocated as an intervention for diagnostic use to assess uncommon types of tachycardia. Evidence is shown in this report that adenosine was associated with dangerous worsening of arrhythmia in patients with atrial flutter. In two patients, adenosine precipitated acceleration of ventricular response, in one case necessitating emergent cardioversion. Both patients had atrial flutter with 2 to 1 atrioventricular block that evolved into 1 to 1 atrioventricular conduction. In three other patients, adenosine was associated with prolonged bradyasystole and hypotension. In each of the five patients, adenosine was given in a standard fashion (6 or 12 mg). In summary, adenosine should be recognized as a potentially dangerous intervention in patients with atrial flutter. If it is used for diagnostic purposes, resuscitative equipment should be readily available.