News Release

Researchers determine best possible drug option for cardiac arrest

Peer-Reviewed Publication

University of Toronto

TORONTO -- Data published in the New England Journal of Medicine by St. Michael's Hospital/University of Toronto researchers demonstrates that the anti-arrhythmic agent IV amiodarone is almost twice as effective as lidocaine in keeping patients alive to hospital. As a result of this study, amiodarone is carried by Toronto ambulances responding to cardiac arrests and there are major implications for the recommended standard of treatment of cardiac arrest by paramedics and hospitals across North America.

Heart disease is the number one killer in North America. More than 25,000 Canadians and over 250,000 Americans suffer out-of-hospital cardiac arrest every year. Unfortunately, fewer than 10 per cent of these patients survive. Many of these cardiac arrests are caused by a potentially lethal heart rhythm disturbance called ventricular fibrillation, or VF. Patients suffering from VF will die unless they receive CPR and an electrical shock (defibrillation) within five to seven minutes to restore normal heart beating. Early CPR is essential, followed rapidly by defibrillation. If defibrillation does not work immediately, the next step is to use an anti-arrhythmic drug, followed by additional defibrillations.

Prior to this study, commonly-used anti-arrhythmic drugs had not been scientifically compared to determine which was most effective. Traditionally, lidocaine has been the drug used in these cardiac arrest situations. In 2000, the American Heart Association Advanced Life Support guidelines recommended a promising drug called amiodarone as an alternative. However, considerable controversy remained as to which drug was preferable.

The ALIVE (Amiodarone versus Lidocaine In pre-hospital Ventricular fibrillation Evaluation) trial, the first such trial to undertake a head-to-head comparison of anti-arrhythmic drugs, studied the effectiveness of lidocaine versus amiodarone. The trial followed 347 randomized patients who had suffered cardiac arrest, and who had one of the two drugs administered in a blinded fashion by Toronto Emergency Medical System (EMS) paramedics. The study found that almost twice as many patients survived to be admitted to hospital when they received amiodarone compared to those who received the traditional treatment of lidocaine.

"Although there have been major advancements in treating out-of-hospital cardiac arrest, the overall survival rate has been relatively low," says primary investigator Dr. Paul Dorian, staff cardiologist and director of the Arrhythmia Service at St. Michael's Hospital and professor, University of Toronto. "We knew that we might be able to improve those odds by determining the most effective possible drug available, as there has previously been no scientific evidence to distinguish one drug option from another. The results from ALIVE mean that we can now tell ambulance personnel and emergency departments that amiodarone appears to be the most effective drug, based on the evidence that we have to date."

"Cardiac arrest requires prompt action, both by ambulance personnel and emergency department staff and physicians," says study co-author Dr. Dan Cass, chief, Department of Emergency Medicine, St. Michael's Hospital and assistant professor, University of Toronto. "Our goal is to provide clear, scientifically-based guidelines as to the most effective possible drug treatment should electrical defibrillation fail."

The ALIVE trial paves the way for further investigations to determine the longer-term survival of cardiac arrest patients. This study followed patients up to the point of hospital admission, but a much larger trial is needed to verify whether more patients receiving amiodarone go on to survive to discharge from hospital.

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The ALIVE trial was supported by an unrestricted educational grant from Wyeth-Ayerst Laboratories, manufacturers of amiodarone. The company contributed funding and the amiodarone drug for the study, but had no input or influence over the research design or conduct.

St. Michael's Hospital is a Catholic teaching and research hospital, fully affiliated with the University of Toronto, specializing in heart and vascular disease, inner city health, trauma/neurosurgery, diabetes comprehensive care, minimal access therapeutics, and neurological and musculoskeletal disorders.

To arrange interviews please contact:
Tracy MacIsaac, Media Relations
St. Michael's Hospital
Telephone: 416-864-5047
Pager: 416-864-5431

Interviews are available with Dr. Dan Cass, chief, Department of Emergency Medicine, St. Michael's Hospital, Dr. Brian Schwartz, director, Sunnybrook and Women's Base Hospital Land Ambulance Program and Graham Munro, coordinator, Toronto Emergency Medical System (EMS) Education.


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