Disaster events and the risk of sudden cardiac death: a Washington State investigation.

Background: Psychological distress following disaster events may increase the risk of sudden cardiac death. In 2001, the Nisqually earthquake and the 11 September terrorist attacks profoundly affected Washington state residents.
Hypothesis: This research investigated the theory that the incidence of sudden cardiac death would increase following these disaster events.
Methods: Death certificates were abstracted using a uniform case definition to determine the number of sudden cardiac deaths for the 48-hour and one-week periods following the two disaster events. Sudden cardiac deaths from the corresponding 48-hour and one-week periods in the three weeks before the events, and the analogous periods in 1999 and 2000 were designated as control times. Using t-tests, the number of sudden cardiac deaths for the periods following the disaster events was compared to those of the control periods.
Results: In total, 32 sudden cardiac deaths occurred in the four counties affected by the Nisqually earthquake during the 48 hours after the event, compared to an average of 22 +/- 3.5 (standard deviation) in the same counties during the control periods (p = 0.02). No difference was observed for the one-week period (94 compared to 79.2 +/- 12.4, p = 0.28). No difference was observed in the number of sudden cardiac deaths in the 48-hours or one-week following the terrorist attacks compared to control periods.
Conclusions: A local disaster caused by a naturally occurring hazard, but not a geographically remote human disaster, was associated with an increased risk of sudden cardiac death. A better understanding of the underlying mechanisms may have implications for prevention of sudden cardiac death.