The efficacy of atropine in the treatment of hemodynamically unstable bradycardia and atrioventricular block: prehospital and emergency department considerations

Efficacy and Safety of Isoprenaline during Unstable Third-Degree Atrioventricular Block

Unstable and symptomatic complete atrioventricular block represents a potentially fatal condition that requires prompt therapy while waiting for definitive pacemaker implantation. Although transcutaneous pacing is included in acute management, it could be a difficult approach due to its painfulness and the occasional failure of mechanical capture. Drug therapy is a feasible choice, and current guidelines encompass the use of atropine, dopamine, or epinephrine. Isoprenaline has never been investigated in this setting, and no specific indication of its use has been provided despite its potentially more favorable pharmacological profile. The study population included a consecutive series of patients who presented to the emergency department because of unstable third-degree atrioventricular block and were treated with either isoprenaline or dopamine infusion while waiting for definitive pacemaker implantation. Asymptomatic patients or those with reversible causes of complete atrioventricular block were excluded. The clinical response to the drug was deemed poor if, despite achieving a full drug dose, patients remained symptomatic and/or with hemodynamic instability, ventricular rate and rhythm did not improve or worsened, including if ventricular arrhythmias or asystolic pauses and/or irrepressible nausea/vomiting occurred. Isoprenaline infusion has proved to be safe and tolerated with no arrhythmia induction or hypotensive issues. Isoprenaline has also proven to be more satisfactory in achieving an effective clinical response in 84% of patients rather than dopamine (31%, p < 0.001), reducing the need for temporary artificial pacing. Our data point out the efficacy and safety of isoprenaline infusion and its greater tolerability over dopamine in the acute management of unstable third-degree AV block while waiting for definitive pacemaker implantation.

Vasovagal Responses to Human Monomorphic Ventricular Tachycardia: Hemodynamic Implications From Sinus Rate Analysis

BACKGROUND

Factors determining hemodynamic stability during human ventricular tachycardia (VT) are incompletely understood.

OBJECTIVES

The purposes of this study were to characterize sinus rate (SR) responses during monomorphic VT in association with hemodynamic stability and to prospectively assess the effects of vagolytic therapy on VT tolerance.

METHODS

This is a retrospective analysis of patients undergoing scar-related VT ablation. Vasovagal responses were evaluated by analyzing sinus cycle length before VT induction and during VT. SR responses were classified into 3 groups: increasing (≥5 beats/min, sympathetic), decreasing (≥5 beats/min, vagal), and unchanged, with the latter 2 categorized as inappropriate SR. In a prospective cohort (n = 30) that exhibited a failure to increase SR, atropine was administered to improve hemodynamic tolerance to VT.

RESULTS

In 150 patients, 261 VT episodes were analyzed (29% untolerated, 71% tolerated) with median VT duration 1.6 minutes. A total of 52% of VT episodes were associated with a sympathetic response, 31% had unchanged SR, and 17% of VTs exhibited a vagal response. A significantly higher prevalence of inappropriate SR responses was observed during untolerated VT (sustained VT requiring cardioversion within 150 seconds) compared with tolerated VT (84% vs 34%; P < 0.001). Untolerated VT was significantly different between groups: 9% (sympathetic), 82% (vagal), and 32% (unchanged) (P < 0.001). Atropine administration improved hemodynamic tolerance to VT in 70%.

CONCLUSIONS

Nearly one-half of VT episodes are associated with failure to augment SR, indicative of an under-recognized pathophysiological vasovagal response to VT. Inappropriate SR responses were more predictive of hemodynamic instability than VT rate and ejection fraction. Vagolytic therapy may be a novel method to augment blood pressure during VT.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 2: Ventricular and bradyarrhythmias

PURPOSE

This is the second article in a 2-part series reviewing the pathophysiology and treatment considerations for arrhythmias. Part 1 of the series discussed aspects related to treating atrial arrhythmias. Here in part 2, the pathophysiology of ventricular arrhythmias and bradyarrhythmias and current evidence on treatment approaches are reviewed.

SUMMARY

Ventricular arrhythmias can arise suddenly and are a common cause of sudden cardiac death. Several antiarrhythmics may be effective in management of ventricular arrhythmias, but there is robust evidence to support the use of only a few of these agents, and such evidence was largely derived from trials involving patients with out-of-hospital cardiac arrest. Bradyarrhythmias range from asymptomatic mild prolongation of nodal conduction to severe conduction delays and impending cardiac arrest. Vasopressors, chronotropes, and pacing strategies require careful attention and titration to minimize adverse effects and patient harm.

CONCLUSION

Ventricular arrhythmias and bradyarrhythmias can be consequential and require acute intervention. As experts in pharmacotherapy, acute care pharmacists can participate in providing high-level intervention by aiding in diagnostic workup and medication selection.

Bradycardia in Older Patients in a Single-Center Emergency Department: Incidence, Characteristics and Outcomes

Objective

This study aimed to explore data associated with the characteristics, incidence, and outcomes of older patients with symptomatic bradycardia presenting to the emergency department (ED).

Methods

We prospectively reviewed data of all patients aged 60 years and older who visited our ED with symptomatic bradycardia during 8AM-12PM between June 4, 2018, and June 10, 2019. The outcomes were the incidence of symptomatic bradycardia and adverse events (recurrent bradycardia, rate of ED revisits, subsequent hospitalization, mortality rate, and composite outcomes) at 30 days and 180 days.

Results

A total of 3297 patients visited the ED. Of these, 205 patients had symptomatic bradycardia. The incidence of symptomatic bradycardia was 6.2% (205/3297). One hundred fourteen patients (55.7%) were female, and the mean age was 74.9 (SD, 9) years. One-third of bradycardia patients (80 patients [39.0%]) were admitted to the hospital, 32 of whom because of unstable bradycardia. Ten of these 32 (30%) patients died during hospitalization from causes unrelated to bradycardia. One-third of unstable bradycardia patients had dyspnea (10/32 patients [31.3%]) followed by chest pain and altered mental status, respectively. ED revisit was the most common adverse event after 30 days (10.8%) and 180 days (20.3%). End-stage renal disease with hemodialysis was associated with adverse outcomes at 30 days (odds ratio, 2.34; 95% confidence interval, 1.30–20.87).

Conclusion

The incidence of symptomatic bradycardia among older adults was 6.2% in one urban ED. End-stage renal disease with hemodialysis was associated with adverse outcomes at 30 days. Larger studies should confirm this association and investigate methods of minimizing adverse outcomes.

Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity

Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.

Dysrhythmias and heart failure complicating acute myocardial infarction: An emergency medicine review

INTRODUCTION

Patients with acute myocardial infarction (AMI) may suffer several complications after the acute event, including dysrhythmias and heart failure (HF). These complications place patients at risk for morbidity and mortality.

OBJECTIVE

This narrative review evaluates literature and guideline recommendations relevant to the acute emergency department (ED) management of AMI complicated by dysrhythmia or HF, with a focus on evidence-based considerations for ED interventions.

DISCUSSION

Limited evidence exists for ED management of dysrhythmias in AMI due to relatively low prevalence and frequent exclusion of patients with active cardiac ischemia from clinical studies. Management decisions for bradycardia in the setting of AMI are determined by location of infarction, timing of the dysrhythmia, rhythm assessment, and hemodynamic status of the patient. Atrial fibrillation is common in the setting of AMI, and caution is warranted in acute rate control for rapid ventricular rate given the possibility of compensation for decreased ventricular function. Regular wide complex tachycardia in the setting of AMI should be managed as ventricular tachycardia with electrocardioversion in the majority of cases. Management directed towards HF from left ventricular dysfunction in AMI consists of noninvasive positive pressure ventilation, nitroglycerin therapy, and early cardiac catheterization. Norepinephrine is the first line vasopressor for patients with cardiogenic shock and hypoperfusion on clinical examination. Early involvement of a multi-disciplinary team is recommended when caring for patients in cardiogenic shock.

CONCLUSIONS

This review discusses considerations of ED management of dysrhythmias and HF associated with AMI.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Pre-hospital management of patients with chest pain and/or dyspnoea of cardiac origin. A position paper of the Acute Cardiovascular Care Association (ACCA) of the ESC

Chest pain and acute dyspnoea are frequent causes of emergency medical services activation. The pre-hospital management of these conditions is heterogeneous across different regions of the world and Europe, as a consequence of the variety of emergency medical services and absence of specific practical guidelines. This position paper focuses on the practical aspects of the pre-hospital treatment on board and transfer of patients taken in charge by emergency medical services for chest pain and dyspnoea of suspected cardiac aetiology after the initial assessment and diagnostic work-up. The objective of the paper is to provide guidance, based on evidence, where available, or on experts’ opinions, for all emergency medical services’ health providers involved in the pre-hospital management of acute cardiovascular care.

Effect of pulse width on transesophageal atrial pacing in dogs

OBJECTIVE

To determine the impact of stimulus pulse width (PW) on pacing threshold (PT), zone of capture (ZOC) and extraneous muscular stimulation (EMS).

STUDY DESIGN

Experimental trial in client-owned dogs.

ANIMALS

Seventeen dogs, median weight 16.1 kg (interquartile range: 11.4-21.5).

METHODS

Transesophageal atrial pacing (TAP) involved a 6 Fr pacing catheter inserted trans-orally into the esophagus to a position aboral to the heart in anesthetized dogs. The catheter was slowly withdrawn until atrial pacing was noted on an electrocardiogram. The catheter was withdrawn in 1 cm increments until TAP could not be achieved. PTs were recorded at each pacing site using PWs of 10.0, 5.0, 2.0 and 1.8 ms, always in that order.

RESULTS

The overall lowest mean PTs for all dogs were 6 ± 3 mA, 9 ± 4 mA, 11 ± 5 mA and 13 ± 5 mA at PWs of 10.0, 5.0, 2.0 and 1.8 ms, respectively. A significant decrease in overall minimum PT was noted using a PW of 10.0 ms compared with either 2.0 or 1.8 ms (p = 0.043 and p = 0.001, respectively) and pacing using 5.0 ms compared with 1.8 ms (p = 0.028). A significant increase in ZOC was noted using a PW of 10.0 ms compared with PWs of 5.0, 2.0 and 1.8 ms (p = 0.0047, p = 0.0006 and p = 0.0003, respectively), using a PW of 5.0 ms compared with PWs of 2.0 and 1.8 ms (p = 0.0011 and p = 0.0003, respectively) and using a PW of 2.0 compared with one of 1.8 ms (p = 0.0084).

CONCLUSIONS AND CLINICAL RELEVANCE

Use of 10.0 or 5.0 ms PW to perform TAP minimized the power required to pace the atria, while a PW of 10.0 ms maximized the size of the ZOC.

Reevaluation of arrhythmias and alterations of the autonomic nervous activity induced by T-2 toxin through telemetric measurements in unrestrained rats

This study was conducted to clarify and reevaluate the cardiac and autonomic nervous effects of T-2 toxin, which had been previously examined by several acute experiments, in unrestrained and conscious rats implanted with telemetric transmitters. Two groups of rats were given two subcutaneous injections of 0.1 and 0.5 mg/kg of T-2 toxin with an interval of 3 days. Two other groups of rat were pre-implanted with osmotic minipumps by which atropine (20 mg/kg/day) or propranolol (100 mg/kg/day) was continuously administered preceding subcutaneous injection of T-2 toxin (0.5 mg/kg). The present study demonstrated that T-2 toxin caused marked arrhythmias, such as second-degree atrioventricular (AV) block, sinus bradycardia, supraventricular extrasystole, and ventricular extrasystole, which were accompanied by a significant increase in heart rate and a significant decrease in total power and low- and high-frequency power of heart rate variability, during 3 days of observation after the toxin administration. However, the occurrence of arrhythmia with conduction disturbance such as second-degree atrioventricular blocks was markedly diminished by pretreatment with atropine, while the occurrence of ventricular extrasystole was augmented by atropine. The present study with the telemetric measurement elucidated and confirmed that T-2 toxin produced significant cardiac dysfunctions involving disturbance of the conduction pathway influenced by the autonomic nervous activity and also possible direct effects on cardiac myocytes.

The impact of the code drugs: cardioactive medications in cardiac arrest resuscitation

The goal of treating patients who present with cardiac arrest is to intervene as quickly as possible to affect the best possible outcome. The mainstays of these interventions, including early activation of the emergency response team, early initiation of cardiopulmonary resuscitation, and early defibrillation, are essential components with demonstrated positive impact on resuscitation outcomes. Conversely, the use of the code drugs as a component of advanced life support has not benefited these patients to the same extent as the basic interventions in a general. Although short-term outcomes are improved as a function of these medications, the final outcome has not been altered significantly in most instances.

Rhythm disturbances

Patients with cardiac rhythm disturbances may present in a variety of conditions. Patients may be unstable, requiring immediate interventions, or stable, allowing for a more deliberate approach. Rapid assessment of patient stability, underlying rhythm, and determination of appropriate interventions guides timely therapy. This article discusses the differential diagnosis and treatment of adult patients presenting with primary bradyarrhythmias and tachyarrhythmias, with the exception of atrial fibrillation and atrial flutter, covered elsewhere in this issue. A concise approach to diagnosis and determination of appropriate therapy is presented.

Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

The goal of therapy for bradycardia or tachycardia is to rapidly identify and treat patients who are hemodynamically unstable or symptomatic due to the arrhythmia. Drugs or, when appropriate, pacing may be used to control unstable or symptomatic bradycardia. Cardioversion or drugs or both may be used to control unstable or symptomatic tachycardia. ACLS providers should closely monitor stable patients pending expert consultation and should be prepared to aggressively treat those with evidence of decompensation.

Part 10: Pediatric basic and advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Note From the Writing Group: Throughout this article, the reader will notice combinations of superscripted letters and numbers (eg, “Family Presence During ResuscitationPeds-003”). These callouts are hyperlinked to evidence-based worksheets, which were used in the development of this article. An appendix of worksheets, applicable to this article, is located at the end of the text. The worksheets are available in PDF format and are open access.

Vascular access and drug therapy in pediatric resuscitation

Using the evidence brought together through the 2005 International Liaison Committee on Resuscitation evidence evaluation process and the subsequent 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, the role for specific drug therapy in pediatric cardiac arrest is outlined. The drugs discussed include epinephrine, vasopressin, calcium, sodium bicarbonate, atropine, magnesium, and glucose. The literature addressing how best to deliver these drugs to the critically ill child is also presented, specifically looking at the use of intraosseous and endotracheal drug therapy.

Compromising bradycardia: management in the emergency department

AIM OF THE STUDY

Bradycardia may represent a serious emergency. The need for temporary and permanent pacing is unknown.

METHODS

We analysed a registry for the incidence, symptoms, presenting rhythm, underlying mechanism, management and outcome of patients presenting with compromising bradycardia to the emergency department of a university hospital retrospectively during a 10-year period.

RESULTS

We identified 277 patients, 173 male (62%), median age 68 (IQR 58-78), median ventricular rate 33 min(-1) (IQR 30-40). The leading symptoms were syncope [94 (33%)], dizziness [61 (22%)], collapse [46 (17%)], angina [46 (17%)] and dyspnoea/heart failure [30 (11%)]. The initial ECG showed high grade AV block [134 (48%)], sinus bradycardia/AV block [46 (17%)], sinuatrial arrest [42 (15%)], bradycardic atrial fibrillation [39 (14%)] and pacemaker-failure [16 (6%)]. The underlying mechanisms were primary disturbance of cardiac automaticity and/or conduction [135 (49%)], adverse drug effect [58 (21%)], acute myocardial infarction [40 (14%)], pacemaker failure [16 (6%)], intoxication [16 (6%)] and electrolyte disorder [12 patients (4%)]. In 107 (39%) patients bed rest resolved the symptoms. Intravenous drugs to increase ventricular rate were given to 170 (61%) patients, 54 (20%) required additional temporary transvenous/transcutaneous pacing. Two severely intoxicated patients could be stabilised only by cardiopulmonary bypass. A permanent pacemaker was implanted in 137 patients (50%). Mortality was 5% at 30 days.

CONCLUSION

In our cohort, about 20% of the patients presenting with compromising bradycardia required temporary emergency pacing for initial stabilisation, in 50% permanent pacing had to be established.

Prehospital transcutaneous cardiac pacing for symptomatic bradycardia or bradyasystolic cardiac arrest: A systematic review

BACKGROUND

Advanced cardiac life support (ACLS) guidelines suggest transcutaneous cardiac pacing (TCP) for the treatment of symptomatic bradycardia (SB) and bradyasystolic cardiac arrest (BACA). Many EMS systems are extrapolating these guidelines and employing TCP in the prehospital setting. Our objective was to conduct a systematic review to determine the efficacy of prehospital TCP in the management of these two conditions.

METHODS

MEDLINE (1966-2004), EMBase and Science Citation Index (1980-2004) were searched using: prehospital/emergency medical services; external/transcutaneous; pacing. Two reviewer teams blinded to the source and author conducted a hierarchical selection (title, abstract, article) and quality assessment using a validated scale. Kappa agreement at each level of review was measured. Data abstraction was done by consensus.

RESULTS

Thirty-four articles were identified and seven selected (Kappa agreement; title: 0.85, abstract: 0.78, full article: 0.82). Article quality was poor in all trials. There were three case series (BACA, n=215), three unblinded randomised controlled trials (one BACA, two BACA+SB), and one subgroup (SB) analysis. In the case series of paced BACA patients, 0/215 survived to hospital discharge. In the BACA trials 16/509 (paced) versus14/497 (control) survived to discharge. In a subgroup of one SB trial 5/6 (paced) versus 1/7 (control) survived to discharge (p=0.01). When a SB trial subgroup was combined with a case series 4/27 (paced) versus 0/24 (control) survived to discharge (p=0.07).

CONCLUSIONS

In the prehospital setting, there is no evidence to support the use of TCP in bradyasystolic cardiac arrest. There is inadequate evidence to determine the efficacy of prehospital TCP in the treatment of symptomatic bradycardia.

Cardiovascular Emergencies in the Elderly

Already the major cause of mortality in the United States, cardio-vascular emergencies will become increasingly prevalent in the future as the geriatric population doubles. This article discusses five cardiovascular emergencies: acute coronary syndrome, congestive heart failure, dysrythmias, aortic dissection, and ruptured abdominal aortic aneurysm. The discussion focuses on the differences in presentation, management, and outcomes that characterize each disease amongst the elderly. As a rule, the elderly have significantly worse outcomes than younger patients.

Cardiopulmonary resuscitation algorithms, defibrillation and optimized ventilation during resuscitation

PURPOSE OF REVIEW

In 2005, the American Heart Association released its Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. This article reviews the treatment algorithms for Advanced Cardiac Life Support, citing the evidence on which the Guidelines are based. Additional focus is placed on defibrillation and optimized ventilation.

RECENT FINDINGS

Major changes include a reorganization of the algorithms for cardiac arrest. Emphasis on effective cardiopulmonary resuscitation is placed as the key to improved survival. Single defibrillation shocks are recommended (compared with three 'stacked' shocks) with immediate provision of cardiopulmonary resuscitation and minimal interruptions in chest compressions. The recommended chest compression : ventilation rate for single rescuers has been changed to 30:2.

SUMMARY

Despite advances in resuscitation science, basic life support remains the key to improving survival outcomes. Ultimately, as new knowledge is gained, we believe resuscitation therapies will be more individualized, on the basis of pathophysiology and etiology of the initial cardiac arrest.

Electrocardiographic manifestations: diagnosis of atrioventricular block in the Emergency Department

Patients with bradycardia are commonly encountered by the Emergency Physician. Of the possible bradydysrhythmias, atrioventricular blocks (AVB) represent a significant portion of these presentations. In this article, we provide four illustrative cases of patients presenting to the Emergency Department (ED) with AVB. We review the various types of AV block dysrhythmias (1st, 2nd, and 3rd degrees) and their underlying etiologies. This discussion also focuses on the presentation, clinical considerations, management and acute treatment of AVB dysrhythmias in the emergent setting.

Use of advanced life support skills

BACKGROUND

The Advanced Life Support (ALS) Provider Course trains healthcare professionals in a standardised approach to the management of a cardiac arrest. In the setting of limited resources for healthcare training, it is important that courses are fit for purpose in addressing the needs of both the individual and healthcare system. This study investigated the use of ALS skills in clinical practice after training on an ALS course amongst members of the cardiac arrest team compared to first responders.

METHODS

Questionnaires measuring skill use after an ALS course were distributed to 130 doctors and nurses.

RESULTS

91 replies were returned. Basic life support, basic airway management, manual defibrillation, rhythm recognition, drug administration, team leadership, peri- and post-arrest management and resuscitation in special circumstances were used significantly more often by cardiac arrest team members than first responders. There was no difference in skill use between medically and nursing qualified first responders or arrest team members.

CONCLUSION

We believe that the ALS course is more appropriately targeted to members of a cardiac arrest team. In our opinion the recently launched Immediate Life Support course, in parallel with training in the recognition and intervention in the early stages of critical illness, are more appropriate for the occasional or first responder to a cardiac arrest.

How do Belgian mobile intensive care units deal with cardiovascular emergencies?

OBJECTIVES

To assess the availability and use of diagnostic tools, therapeutic equipment and drugs for the prehospital treatment of acute coronary syndromes, cardiopulmonary arrest and other cardiovascular emergencies in Belgian physician-staffed and hospital-based mobile intensive care units.

METHODS

In April 2001, a questionnaire was sent to all Belgian mobile intensive care unit centres.

RESULTS

The response rate was 90%. There was a 100% availability of many drugs and therapeutic equipment, with a well-established role in the care of cardiovascular emergencies: defibrillators, nitrates, epinephrine, atropine and diuretics. Important emergency drugs and tools were not ubiquitously available: external pacemakers (90%), aspirin (90%), bicarbonate (99%), amiodarone (87%), and intravenous beta-blockers (75%). Twelve-lead electrocardiogram recorders and thrombolytics had a rather low availability (46 and 20%, respectively) and were rarely used. There was a high availability of some drugs with limited data to support their use: oral calcium antagonists (61%), bretylium (65%) and isoproterenol (92%).

CONCLUSIONS

In Belgian mobile intensive care units the availability and use of technical and diagnostic equipment and cardiac drugs varied to an important extent. A local multidisciplinary evaluation may improve prehospital cardiovascular care by implementing current guidelines.

Diagnosis and management of bradycardia and atrioventricular block associated with acute coronary ischemia

Bradyarrhythmias arising in the setting of myocardial infarction occur in a significant minority of patients with AMI. In the majority of cases, these abnormalities are owing to myocardial ischemia or infarction with necrosis of the cardiac pacemaker sites and/or conduction system. Other factors responsible for these bradyarrhythmias include altered autonomic influence, systemic hypoxia, electrolyte disturbances, acid-based disorders, and complications of various medical therapies. This article will focus on not only the diagnosis and management of these rhythm disturbances, but also on the pathophysiology of the arrhythmias.