Warning symptoms are associated with survival from sudden cardiac arrest

Background: Survival after sudden cardiac arrest (SCA) remains low, and tools for improved prediction of patients at long-term risk for SCA are lacking. Alternative short-term approaches aimed at preemptive risk stratification and prevention are needed. Objective: To assess characteristics of symptoms in the 4 weeks before SCA and whether response to these symptoms is associated with better outcomes. Design: Ongoing prospective population-based study. Setting: Northwestern United States (2002 to 2012). Patients: Residents aged 35 to 65 years with SCA. Measurement: Assessment of symptoms in the 4 weeks preceding SCA and association with survival to hospital discharge. Results: Of 839 patients with SCA and comprehensive assessment of symptoms (mean age, 52.6 years [SD, 8]; 75% men), 430 (51%) had warning symptoms (50% of men vs. 53% of women; P = 0.59), 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 (911) to report symptoms before SCA; these persons were more likely to be patients with a history of heart disease (P < 0.001) or continuous chest pain (P < 0.001). Survival when 911 was called in response to symptoms was 32.1% (95% CI, 21.8% to 42.4%) compared with 6.0% (CI, 3.5% to 8.5%) in those who did not call (P < 0.001). Limitation: Potential for recall and response bias, symptom assessment not available in 24% of patients, and missing data for some patients and SCA characteristics. Conclusion: Warning symptoms frequently occur before SCA, but most are ignored. Emergent medical care was associated with survival in patients with symptoms, so new approaches are needed for short-term prevention of SCA. Primary Funding Source: National Heart, Lung, and Blood Institute.