Cardiac Arrest Often Preceded by Specific Warning Signs; Researchers Looking for Ways to Improve Risk Assessment

Researchers with the Oregon Sudden Unexpected Death Study are working to understand the mechanisms of sudden cardiac arrest by "searching for novel determinants of this condition that will facilitate the identification of subjects at risk, with the overall goal of improving prevention of sudden cardiac arrest" and improving the current low rate of successful resuscitation.

Sumeet Chugh, MD, Associate Director for Genomic Cardiology at the Cedars-Sinai Heart Institute and his colleagues have spent the past 12 years studying factors that contribute to sudden cardiac arrest.

The benchmark study thus far has been the Framingham Study, but there are many questions still unanswered. Approximately 350,000 people die each year in the US from sudden cardiac arrest (SCA); more than 1,000 people die each day from SCA. Approximately 95% die within 10 minutes.

Chugh and his research associates formed the Oregon Sudden Unexpected Death Study 12 years ago, encompassing 1 million people in Portland, OR.

“The goal is to try to predict who is at risk for sudden cardiac arrest and to try to increase prevention,” said Chugh. “We found factors that consistently enable us to predict death in this population. Many people think that sudden cardiac death happens without warning, but we have been able to identify 10 different contributing factors.”

Those resulting factors are the basis of research findings that Chugh discussed during a poster session at the 2013 American Heart Association Scientific Sessions, currently ongoing in Dallas, TX. Highlights included:

  • 53% of the study group had some kind of warning sign that represents an opportunity for preventative care. These warning sings include shortness of breath and chest pain.
  • In the “Warning Symptoms Precede Sudden Cardiac Death in the Majority of Men” study, the researchers hypothesized that despite significant enhancements in resuscitation methodology, survival after sudden cardiac arrest (SCA) remains low. Improved knowledge of warning signs may assist the process of early intervention for SCA.
  • The methodology of the warning symptom study looked at the 1 million patients in Oregon and the researchers systematically evaluated the frequency characteristics and temporal trends of all symptomatology in the four weeks prior to the SCA among middle-aged men (ages 35-65.) The researchers performed a detailed and comprehensive assessment of the accounts of family members, witnesses, emergency medical personnel during this time period.
  • Of the 825 SCA cases, 258 (31 percen)t did not have sufficient information to ascertain symptoms. Of the 567 cases with appropriate assessment, symptoms such as chest pain, dizziness, and palpitations preceded the SCA episode within one hour beforehand. Symptoms were more frequent among patients who had a past history of coronary artery disease.
  • The researchers also studied sports-related cardiac arrest, reporting that 4% of the study group exhibited sports-related cardiac death, which represents 14.7 per million in Oregon. The most common sports with patients exhibiting cardiac arrest are running (27%), basketball (15%), and cycling (15%).
  • Researchers also analyzed cardiac deaths in patients who had a psychiatric diagnosis like depression or schizophrenia. Evidence shows that some antipsychotic medications may triple the risk of a cardiac incident.