Warning Symptoms Before Sudden Cardiac Arrest
Do victims of sudden cardiac arrest (SCA) have warning symptoms in the preceding 4 weeks, and is response to these symptoms associated with survival to hospital discharge?
The Oregon Sudden Unexpected Death Study is an ongoing community-based prospective study of out-of-hospital SCA. Among victims aged 35-65 years old, the researchers collected information about the 4 weeks before SCA from survivors, family members, friends, medical records, and emergency response records.
Of 839 patients with SCA (mean age, 53 years; 75% men), 430 (51%) had warning symptoms, mainly chest pain and dyspnea. In most symptomatic patients (93%), symptoms recurred within the 24 hours preceding SCA. Only 81 patients (19%) called emergency medical services to report symptoms before SCA; these persons were more likely to be patients with a history of heart disease or continuous chest pain. Survival when 911 was called in response to symptoms was 32.1% compared with 6.0% in those who did not call (p < 0.001).
The authors concluded that warning symptoms frequently occur before SCA. Emergent medical care was associated with survival in patients with symptoms.
SCA is traditionally thought of as ‘sudden,’ (i.e., without associated premonitory symptoms). Prior studies have shown that some patients do have symptoms hours before the arrest. The present study is important because it shows that a majority of victims of SCA experience symptoms in the weeks preceding their arrest. This is not entirely surprising given that two-thirds to three-quarters of SCAs are due to coronary artery disease. In the study, patients with continuous symptoms or with known heart disease were more likely to call 911, probably because of a better awareness of warning signs. This offers an opportunity to affect outcomes by engaging patients and the public at large. The next step would be to conduct a study to assess whether public education efforts might translate into improved survival among SCA victims.
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