Lower Proportion of Fatal Arrhythmia in Sudden Cardiac Arrest Among Patients With Severe Mental Illness Than Nonpsychiatric Patients

Background: Sudden unexpected deaths occur more frequently among patients with severe mental illness (SMI), but direct evidence on the causes is still scarce. Objective: The objective of this study is to investigate initial rhythms and characteristics of out-of-hospital cardiac arrest among patients with SMI. Methods: We conducted a systematic chart review of adult patients who suffered from out-of-hospital cardiac arrest and transferred to Tokyo Metropolitan Bokutoh Hospital in Japan between January 2011 and December 2017. The initial rhythms, clinical characteristics, and outcomes were compared between patients with schizophrenia or mood disorders (i.e., SMI) and nonpsychiatric control patients. Values of interest were compared using Fisher's exact test or Mann-Whitney U-test, as appropriate. Multiple regression analysis was also conducted to investigate the effect of SMI on the initial rhythms. Results: A total of 2631 patients were included in this study. Of these, 157 patients had SMI. Fatal arrhythmias (i.e., ventricular fibrillation and ventricular tachycardia) were less frequently noted as the initial rhythms among patients with SMI than among controls (5.7% vs. 18.8%, adjusted odds ratio = 0.27, 95% confidence interval = 0.13–0.55, P < 0.001). Patients with SMI were significantly younger (median [range], 58 years [22–85] vs. 72 years [18–108], P < 0.001) and less frequently had comorbid physical illnesses than controls (the proportion of patients without comorbidities; 58.6% vs. 37.1%, P < 0.001). Survival and neurological function at discharge were not different between the 2 groups. Conclusion: Fatal arrhythmia may account for a relatively small portion in excess of sudden death among patients with SMI. Furthermore, appropriate medical checkups for the patients with SMI at earlier ages would be important to prevent sudden cardiac death.