Sudden Cardiac Death During Nighttime Hours.

Background In the absence of apparent triggers, sudden cardiac death (SCD) during nighttime hours is a perplexing and devastating phenomenon. There are few published reports in the general population with insufficient numbers to perform sex-specific analyses. Smaller studies of rare nocturnal SCD syndromes suggest a male predominance and implicate sleep-disordered breathing. Objective The purpose of this study was to identify mechanisms of nighttime SCD in the general population. Methods From the population-based Oregon Sudden Unexpected Death Study, we evaluated SCD cases that occurred in the community between 10 PM and 6 AM (nighttime) and compared them with daytime cases. Univariate comparisons were evaluated using Pearson χ2 tests and independent samples t tests. Logistic regression was used to further assess independent SCD risk. Results A total of 4126 SCD cases (66.2% male, 33.8% female) met criteria for analysis and 22.3% (n = 918) occurred during nighttime hours. Women were more likely to present with nighttime SCD than men (25.4% vs 20.6%; P Conclusion In the general population, women were more likely than men to suffer SCD during nighttime hours and female sex was an independent predictor of nighttime events. Respiratory suppression is a concern, and caution is advisable when prescribing central nervous system–affecting medications to patients at an increased risk of SCD, especially women.