OHSU Heart Researchers Analyze Community Deaths to Determine Incidence of Sudden Cardiac Arrest

09/14/04    Portland, Ore.

This is the first study to look at deaths as they occurred to determine the extent of this disease

Oregon Health & Science University heart researchers have the first accurate picture of how many people die unexpectedly of sudden cardiac arrest by analyzing the deaths as they occurred.

The scientists found that 6 percent of all deaths, in a county of more than 660,000 people, die of sudden cardiac arrest. These results are part of continuing studies through OHSU's Oregon Sudden Unexplained Death Study (Ore-SUDS). The study, "Current Burden of Sudden Cardiac Death," will be published in the Sept. 15 issue of the Journal of the American College of Cardiology.

"These results are important to our ongoing studies of sudden cardiac arrest because when tackling the problem, we first needed to understand the extent of the problem," said Sumeet Chugh, M.D., principal investigator and associate professor of medicine (cardiology) in the OHSU School of Medicine. He also is an OHSU Heart Research Center scientist and director of OHSU's Heart Rhythm Research Laboratory. "This is a real public health issue. Ninety-five percent of people who experience sudden cardiac arrest die. No other condition that affects humans has such a high mortality rate."

Chugh's team studied all deaths caused by sudden cardiac arrest as they occurred in Multnomah County, Ore., between February 2002 and January 2003. During this time, 353 residents suffered sudden cardiac arrest in a population of more than 660,000. The researchers were surprised to find there were almost as many women (43 percent) as men (57 percent) who suffered from this disease. It was previously thought that three times as many men died of this condition than women. This indicates that future research should focus equally on men and women.

What wasn't surprising was that most people (82 percent) suffer sudden cardiac arrest in their homes. This highlights the dilemma that developments in emergency medical response, such as automatic external defibrillators (AEDs), focus on public places without much effect on cardiac arrests at home.

For the first time, Chugh's team also compared the results of their prospective data, an analysis as the deaths occurred, with retrospective results gained from death certificates completed during that same period. They found that the death certificates overestimated the incidence of sudden cardiac arrest three-fold, when compared to the analysis of actual deaths.

"The effort based in Multnomah County is the first community study to show that this prospective methodology utilizing multiple sources of information is feasible and should happen in other communities around the country," said Chugh.

This type of study was possible thanks to the collaborative efforts between OHSU's Heart Rhythm Research Laboratory - 10 full-time research personnel work on this project - emergency medicine responders, including 150 paramedics from American Medical Response, led by Jonathan Jui, M.D., professor of emergency medicine, OHSU School of Medicine and co-investigator, and the office of the Oregon State Medical Examiner, headed by co-investigator Karen Gunson, M.D. In all, there are 16 area hospitals that serve Multnomah County and all participated in this effort.

"It takes a community to study disease in a community," said Chugh. "Most importantly, this kind of research is made possible by survivors of sudden cardiac arrest and the families of those who didn't survive."

Chugh said studying sudden cardiac arrest is like weaving a tapestry. This study is one corner of the tapestry. Researchers continue to work their way toward the center with study results. Their ultimate goal is to fill in the center with specific factors that will predict who will suffer from sudden cardiac arrest before it happens. Those missing factors may be inherited disorders or gene defects that predispose people to this deadly condition and can be identified in time to save lives.

Chugh's research team will continue to analyze the circumstances of death, autopsy data and medical records of the Multnomah County residents who died of sudden cardiac arrest with the hope of finding more answers to this mysterious condition.

Funding for this work was provided by the national Centers for Disease Control and Prevention, the American Heart Association and the Doris Duke Charitable Foundation.