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. 2021 May;18(5):778-784.
doi: 10.1016/j.hrthm.2020.12.035. Epub 2021 Jan 20.

Sudden cardiac death during nighttime hours

Archana Ramireddy  1 , Harpriya S Chugh  1 , Kyndaron Reinier  1 , Audrey Uy-Evanado  1 , Eric C Stecker  2 , Jonathan Jui  3 , Sumeet S Chugh  4
Affiliations

Sudden cardiac death during nighttime hours

Archana Ramireddy et al. Heart Rhythm. 2021 May.

Abstract

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 < .001). In a multivariate regression model, female sex (odds ratio [OR] 1.3 [confidence interval (CI) 1.1-1.5]; P = .001), medications associated with somnolence/respiratory depression (OR 1.2 [CI 1.1-1.4]; P = .008) and chronic obstructive pulmonary disease/asthma (OR 1.4 [CI 1.1-1.6]; P < .001) were independently associated with nighttime SCD. Women were taking more central nervous system-affecting medications than men (1.9 ± 1.7 vs 1.4 ± 1.4; P = .001).

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.

Keywords: Cardiac arrest; Risk; Sex; Sleep; Sudden death; Women.

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Conflict of interest statement

The authors have no conflicts of interest

Figures

Figure 1:
Figure 1:
Comparisons of the clinical profile of nighttime vs daytime SCD Cases. Prevalence of female sex, COPD/asthma, and depression was significantly higher (p<0.05 for all) in nighttime SCD. In addition, COPD medications and CNS-affecting medications were used to a significantly greater extent in nighttime SCD (p<0.05). CNS = central nervous system; COPD = chronic obstructive pulmonary disease; SCA = sudden cardiac disease.
Figure 2:
Figure 2:
Results of the multivariable logistic regression model for nighttime SCD. OR = odds ratio; LCL= lower confidence level; UCL = upper confidence level.
Figure 3:
Figure 3:
Sex-specific analysis of clinical profile in nighttime vs daytime SCD. In women with nighttime SCD, only COPD/asthma was significant (p=0.001). In men with nighttime SCD, depression, COPD/asthma, and prior/current smoking were significant (p<0.05 for both). CNS=central nervous system; COPD= chronic obstructive pulmonary disease; SCA= sudden cardiac arrest; SCD= sudden cardiac death.
Figure 4:
Figure 4:
Overall distribution of CNS-affecting medications by sex. More women were prescribed ≥ 2 CNS-affecting medications compared with men in both nighttime and daytime SCD (p=0.004 for 2 medications and p<0.001 for ≥ 3 medications). CNS= central nervous system; SCD= sudden cardiac death
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