An analysis of emergency medical services-treated cardiac arrest outcomes in 10 areas in North America finds a five-fold difference in survival rates, according to a study in the September 24 issue of JAMA.

Approximately 166,000 to 310,000 Americans per year experience an out-of-hospital cardiac arrest (OHCA), although resuscitation is not attempted in many of these cases. "Accurate estimation of the burden of OHCA is essential to evaluate progress toward improving public health by reducing cardiovascular disease," the authors write. "Knowledge of regional variation in outcomes after cardiac arrest could guide identification of effective interventions that are used in some communities but have not been implemented in others."

Graham Nichol, M.D., M.P.H., of the University of Washington, Seattle, and colleagues conducted a study to determine whether cardiac arrest incidence and outcome differed across geographic regions. The study included data on all out-of-hospital cardiac arrests in 10 North American sites (8 U.S. and 2 Canadian) from May 2006 to April 30, 2007, followed up to hospital discharge, and including data available as of June 28, 2008. Cases were assessed by organized emergency medical services (EMS) personnel. The ten sites were participants in the Resuscitation Outcomes Consortium, and were located in: Alabama; Dallas; Iowa; Milwaukee; Ottawa, Ontario; Pittsburgh; Portland, Ore.; Seattle; Toronto; and Vancouver, British Columbia.

Among the 10 sites, with a total population of 21.4 million for the areas studied, there were 20,520 cardiac arrests assessed by EMS personnel. Resuscitation was attempted in 11,898 cases (58.0 percent of total); 2,729 (22.9 percent of treated) had initial rhythm of ventricular fibrillation or ventricular tachycardia (unstable, rapid heart rhythm) or rhythms that were shockable by an automated external defibrillator; and 954 (4.6 percent) were discharged alive. The incidence of EMS-treated cardiac arrest per 100,000 population ranged from 40.3 to 86.7; for ventricular fibrillation, the incidence per 100,000 population ranged from 9.3 to 19.0. The EMS-treated cardiac arrest survival across sites ranged from 3.0 percent to 16.3 percent; ventricular fibrillation survival ranged from 7.7 percent to 39.9 percent, with significant differences across sites for incidence and survival.

"These findings have implications for prehospital emergency care. The 5-fold variation in survival after EMS-treated cardiac arrest and 5-fold variation in survival after ventricular fibrillation demonstrate that cardiac arrest is a treatable condition," the authors write.

"Out-of-hospital cardiac arrest is a common and lethal event. There are significant and important regional variations in the incidence and outcome of cardiac arrest. Additional investigation is necessary to understand the causes of this variation in an effort to better understand implications for allocation of resources to prehospital emergency care clinical practice and translational cardiac arrest research to reduce the magnitude of this variation and improve cardiovascular health."

(JAMA. 2008;300[12]:1423-1431. Available pre-embargo to the media at http://www.jamamedia.org/)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Editorial: Surviving Cardiac Arrest - Location, Location, Location

"... it is time to recognize the importance of EMS systems to the health of a community," writes Arthur B. Sanders, M.D., and Karl B. Kern, M.D., of the University of Arizona, Tucson, in an accompanying editorial in this week's JAMA.

"Physicians and the public should demand data on survival from cardiac arrest from every community. Publications and organizations should use these survival data when rating cities for livability and health indices, and businesses and individuals should take these public health data into account when deciding whether to relocate or expand to a new city. It is time to work to overcome barriers in each community, devote appropriate resources, and optimize survival of all patients so that location by city becomes a minor factor in survival of cardiac arrest."

(JAMA. 2008;300[12]:1462-1463. Available pre-embargo to the media at http://www.jamamedia.org/)

Editor's Note: Please see the article for additional information, including financial disclosures, funding and support, etc.

Cardiovascular disease is a broad term that includes several more specific cardiovascular conditions. Cardiovascular disease is the leading killer in the US. 

Common heart conditions include: 

• Arrhythmias. Irregular, or abnormally fast or slow, beating of the heart. The heart beat is controlled by electrical impulses. When the timing or frequency of these electrical impulses are disrupted, arrhythmias develop. Some arrhythmias are quite serious. An example is ventricular fibrillation, a severely abnormal heart rhythm that causes death unless treated right away by providing an electrical shock to the heart (called defibrillation). Others are less severe but can develop into more serious conditions over time. A particular concern is atrial fibrillation. Atrial fibrillation is rapid, irregular beating of the upper chambers of the heart. The chambers can quiver instead of beating in a regular pattern. Blood is not fully pumped out of them and may pool and clot.
• Cardiomyopathy. A weakening of the heart muscle or a change in heart muscle structure. It often results in inadequate heart pumping or other heart function abnormalities. These can result from various causes, including prior heart attacks, viral or bacterial infections, and others.
• Congenital Heart Disease. Malformations of heart structures, present during pregnancy or at birth. These may be caused by genetic factors or by adverse exposures during pregnancy. Examples include holes in the walls that divide the heart chambers, abnormal heart valves, and others. Congenital heart defects can disrupt the normal flow of blood through the heart. Congenital heart defects are the most common type of major birth defect.
• Coronary Heart Disease (CHD). CHD is the most common type of heart disease. CHD occurs when the coronary arteries, that supply blood to the heart muscle, become hardened and narrowed due to the plaque buildup. The plaque buildup and the narrowing and hardening of the arteries is called atherosclerosis. Plaques are a mixture of fatty substances including cholesterol and other lipids. Blood flow and oxygen supply to the heart can be reduced or even fully blocked with a growing plaque. Plaques may also rupture and cause blood clots that block arteries. CHD can lead to a heart attack. Angina, the most common symptom of CHD can also occur. Angina is chest pain or discomfort that occurs when the heart muscle is not getting enough blood. Irregular heart beats, called arrhythmias, can develop.Over time, CHD can weaken the heart muscle and lead to heart failure, a serious problem where the heart cannot pump blood the way that it should.
• Heart Attack. A heart attack , also called a myocardial infarction may occur when blood supply to the heart is severely reduced or completely blocked. When blood flow is restricted the heart muscle cells do not receive enough oxygen and begin to die. The more time that passes without treatment to restore blood flow, the greater the damage to the heart. This damage can cause irregular heart rhythms or even sudden cardiac arrest or stopping of the heart beat. Death can result. Coronary artery disease is the chief underlying cause of a heart attack. A less common cause of a heart attack is a severe spasm of a coronary artery that reduces the blood supply to the heart.
• Heart Failure. This may also be called congestive heart failure or chronic heart failure. Heart failure is a condition where the heart cannot pump enough blood and oxygen to meet the needs of other body organs. Heart failure does not mean that the heart has stopped, but that it cannot pump blood the way that it should. Heart failure is a serious condition. There is no cure for heart failure at this time, except a heart transplant. Once diagnosed, medicines are needed for the rest of the person's life.
• Peripheral Arterial Disease (PAD). Hardening of the arteries that supply blood to the arms and legs. PAD is usually the result of atherosclerosis, the buildup of plaque and narrowing of the arteries. Blood flow and oxygen to the muscles in the arms and legs can be reduced or even fully blocked. Painful leg muscles, numbness, swelling in the ankles and feet, and weak pulse in the feet are some of the signs and symptoms of PAD.
• Rheumatic Heart Disease.This condition is damage to the heart valves and other heart structures due to inflammation and scarring caused by rheumatic fever, which occurs from streptococcal infection.Heart disease is an umbrella term for a number of different diseases affecting the heart.Heart disease is a number of abnormal conditions affecting the heart and the blood vessels in the heart.