Intravenous amiodarone for ventricular arrhythmias: overview and clinical use

Trends Over Time in Drug Administration During Adult In-Hospital Cardiac Arrest

OBJECTIVES

Clinical providers have access to a number of pharmacologic agents during in-hospital cardiac arrest. Few studies have explored medication administration patterns during in-hospital cardiac arrest. Herein, we examine trends in use of pharmacologic interventions during in-hospital cardiac arrest both over time and with respect to the American Heart Association Advanced Cardiac Life Support guideline updates.

DESIGN

Observational cohort study.

SETTING

Hospitals contributing data to the American Heart Association Get With The Guidelines-Resuscitation database between 2001 and 2016.

PATIENTS

Adult in-hospital cardiac arrest patients.

INTERVENTIONS

The percentage of patients receiving epinephrine, vasopressin, amiodarone, lidocaine, atropine, bicarbonate, calcium, magnesium, and dextrose each year were calculated in patients with shockable and nonshockable initial rhythms. Hierarchical multivariable logistic regression was used to determine the annual adjusted odds of medication administration. An interrupted time series analysis was performed to assess change in atropine use after the 2010 American Heart Association guideline update.

MEASUREMENTS AND MAIN RESULTS

A total of 268,031 index in-hospital cardiac arrests were included. As compared to 2001, the adjusted odds ratio of receiving each medication in 2016 were epinephrine (adjusted odds ratio, 1.5; 95% CI, 1.3-1.8), vasopressin (adjusted odds ratio, 1.5; 95% CI, 1.1-2.1), amiodarone (adjusted odds ratio, 3.4; 95% CI, 2.9-4.0), lidocaine (adjusted odds ratio, 0.2; 95% CI, 0.2-0.2), atropine (adjusted odds ratio, 0.07; 95% CI, 0.06-0.08), bicarbonate (adjusted odds ratio, 2.0; 95% CI, 1.8-2.3), calcium (adjusted odds ratio, 2.0; 95% CI, 1.7-2.3), magnesium (adjusted odds ratio, 2.2; 95% CI, 1.9-2.7; p < 0.0001), and dextrose (adjusted odds ratio, 2.8; 95% CI, 2.3-3.4). Following the 2010 American Heart Association guideline update, there was a downward step change in the intercept and slope change in atropine use (p < 0.0001).

CONCLUSIONS

Prescribing patterns during in-hospital cardiac arrest have changed significantly over time. Changes to American Heart Association Advanced Cardiac Life Support guidelines have had a rapid and substantial effect on the use of a number of commonly used in-hospital cardiac arrest medications.

Amiodarone for the emergency care of children

Amiodarone is a class 3 antiarrhythmic agent used for a broad range of arrhythmias including adenosine-resistant supraventricular tachycardia, junctional ectopic tachycardia, and ventricular tachycardia. Compared with adults, there are few data on its use in children with arrhythmias resistant to conventional therapy. National and international guidelines for cardiopulmonary resuscitation and emergency cardiovascular care recommend its use for a variety of arrhythmias based on case reports, cohort studies, and extrapolation from adult data. This article will review the historical development, chemical properties, metabolism, indications and contraindications, and adverse effects of amiodarone in infants and children. After completing this CME activity, the reader should be able to utilize amiodarone in the pediatric population for arrhythmias and identify complications associated with its use.

Amiodarone inhibits arterial thrombus formation and tissue factor translation

BACKGROUND

In patients with coronary artery disease and reduced ejection fraction, amiodarone reduces mortality by decreasing sudden death. Because the latter may be triggered by coronary artery thrombosis as much as ventricular arrhythmias, amiodarone might interfere with tissue factor (TF) expression and thrombus formation.

METHODS AND RESULTS

Clinically relevant plasma concentrations of amiodarone reduced TF activity and impaired carotid artery thrombus formation in a mouse photochemical injury model in vivo. PTT, aPTT, and tail bleeding time were not affected; platelet number was slightly decreased. In human endothelial and vascular smooth muscle cells, amiodarone inhibited tumor necrosis factor (TNF)-alpha and thrombin-induced TF expression as well as surface activity. Amiodarone lacking iodine and the main metabolite of amiodarone, N-monodesethylamiodarone, inhibited TF expression. Amiodarone did not affect mitogen-activated protein kinase activation, TF mRNA expression, and TF protein degradation. Metabolic labeling confirmed that amiodarone inhibited TF protein translation.

CONCLUSIONS

Amiodarone impairs thrombus formation in vivo; in line with this, it inhibits TF protein expression and surface activity in human vascular cells. These pleiotropic actions occur within the range of amiodarone concentrations measured in patients, and thus may account at least in part for its beneficial effects in patients with coronary artery disease.

Antioxidant activity and sex differences of acute vascular effects of amiodarone in advanced atherosclerosis

Sexual dimorphisms of atherosclerosis and the susceptibility to arrhythmias and antiarrhythmic treatment have been reported. This study investigated acute effects of amiodarone on endothelium-dependent relaxation in the aorta of male and female apoE0 mice with advanced atherosclerosis. Amiodarone tissue uptake was quantified by high-performance liquid chromatography, and xanthine oxidase-dependent superoxide anion formation was investigated in vitro in presence or absence of amiodarone. Incubation with amiodarone for 30 min improved endothelium-dependent relaxation, which was associated with rapid vascular accumulation of amiodarone (P < 0.001) that was sex-dependent. In males, reduced endothelium-dependent relaxation was improved by amiodarone (from 88 +/- 3% to 100 +/- 2%, P < 0.01). Spontaneous phasic contractions, which were greater in females than in males (P < 0.001), were completely abolished by amiodarone (P < 0.0001). Amiodarone also inhibited generation of superoxide anion (P < 0.0001). These data show that amiodarone rapidly accumulates in atherosclerotic vascular tissue, abolishes vascular autorhythmicity, and improves endothelium-dependent function in atherosclerotic arteries. Antioxidant and vasodilator effects following amiodarone administration may contribute to its antiarrhythmic effects.

Amiodarone has anti-inflammatory and anti-oxidative properties: An experimental study in rats with carrageenan-induced paw edema

Amiodarone is a widely used anti-arrhythmic agent. We have investigated alterations in the glutathione (GSH) level and the activities of anti-oxidative enzymes (superoxide dismutase, catalase, glutathione s-transferase and glutathione reductase) and myeloperoxidase, as marker of acute inflammation, following oral administration of amiodarone and diclofenac in rats with carrageenan-induced paw edema. In the present study, we found that 1) Amiodarone reduced the development of carrageenan-induced paw edema, to a greater degree than diclofenac; 2) Amiodarone and diclofenac alleviated increases in the activities of catalase and glutathione s-transferase enzymes resulting from edema; 3) Amiodarone and diclofenac ameliorated depressions in the GSH level and the activities of superoxide dismutase and glutathione reductase enzymes caused by carrageenan injection; and 4) All doses of amiodarone and diclofenac caused an amplification in myeloperoxidase activity resulting from induced paw edema. These results suggest that the anti-inflammatory effect of amiodarone on carrageenan-induced acute inflammation can be attributed to its ameliorating effect on the oxidative damage.

Advanced life support drugs: do they really work?

Basic life support and rapid defibrillation for ventricular fibrillation or pulseless ventricular tachycardia are the only two interventions that have been shown unequivocally to improve survival after cardiac arrest. Several drugs are advocated to treat cardiac arrest, but despite very encouraging animal data, no drug has been reliably proven to increase survival to hospital discharge after cardiac arrest. This review focuses on recent experimental and clinical data concerning the use of vasopressin, amiodarone, magnesium, and fibrinolytics during advanced life support (ALS). Animal data indicate that, in comparison with epinephrine (adrenaline), vasopressin produces better vital organ blood flow during cardiopulmonary resuscitation (CPR). These apparent advantages have yet to be converted into improved survival in large-scale trials of cardiac arrest in humans. Data from two prospective, randomized trials suggest that amiodarone may improve short-term survival after out-of-hospital ventricular fibrillation cardiac arrest. On the basis of anecdotal data, magnesium is recommended therapy for torsades de pointes and for shock-resistant ventricular fibrillation associated with hypomagnesemia. In the past, CPR has been a contraindication to giving fibrinolytics, but several studies have demonstrated the relative safety of fibrinolysis during and after CPR. Fibrinolytics are likely to be beneficial when cardiac arrest is associated with plaque rupture and fresh coronary thrombus or massive pulmonary embolism. Fibrinolysis may also improve cerebral microcirculatory perfusion once a spontaneous circulation has been restored. A planned, prospective, randomized trial may help to define the role of fibrinolysis during out-of-hospital CPR.

Advanced cardiac life support for the new millennium

The American Heart Association has been the recognized source for Advanced Cardiac Life Support (ACLS) education for the past three decades. Since the first ACLS course, numerous revisions have been made to the management algorithms based on evolving scientific evidence. The last revisions made in August 2000 were the first international guidelines published. These guidelines reflect the intense review and analysis of scientific work and emphasize the importance of evidence-based therapies. This article outlines the major changes to ACLS guidelines for dysrhythmias, acute coronary syndromes, and acute stroke management.

Recent advances in emergency life support

With additional international input, recent changes in emergency life support are reflected in updated guidelines for Advanced Cardiac Life Support (ACLS) from the American Heart Association and new technology in the arena of vascular access and emergency airway management. These changes will expand nurses' ability to provide advanced levels of care, even in the prehospital situation, and represent a more rigorous evidence-based approach than ever before. As early morbidity and mortality in emergency situations are frequently associated with complications associated with airway management and vascular access, recent development in these areas are reviewed along with evolution in ACLS guidelines.

Cardiac arrhythmias: drugs and devices

This review focuses on the important role played by the various types of remedial therapy in the prevention and treatment of perioperative cardiac arrhythmias. It discusses the new concepts of arrhythmogenesis and pro-arrhythmia; the long QT interval syndrome; newer, more selective class 3 antiarrhythmic drugs; cardiac rhythm management devices; drugs or devices used as prophylaxis for postoperative atrial arrhythmias; intravenous amiodarone for destabilizing ventricular arrhythmias; and preoperative potassium imbalance.

Recent progress in advanced cardiac life support

The revised guidelines for advanced cardiac life support (ACLS) from the American Heart Association are anticipated in the fall of 2000. Although dramatic changes in the approach to adult basic and ACLS are not anticipated, several controversies and new drugs on the horizon may radically change our approach to emergent cardiac resuscitation. This article features some of the evolving thinking on the emergent treatment of the adult with ventricular fibrillation or ventricular tachycardia, the critical rhythms seen in most cases of acute cardiac distress. Approaches to airway therapy drug administration and new agents also are described.