Comparison of the Incidence of Acute Decompensated Heart Failure Before and After the Major Tsunami in Northeast Japan

On March 11, 2011, a huge tsunami attacked the northeastern coast of Japan after a magnitude 9 earthquake. No reports have investigated the impact of tsunamis on the incidence of cardiovascular disease, especially heart failure (HF). We investigated the number and clinical characteristics of hospitalized patients with acute decompensated HF (ADHF) in the east coast of Iwate hit by the tsunami (tsunami area) for a 12-week period around the disaster. For comparison with previous years, numbers of ADHF were surveyed in the corresponding area in 2009 and 2010. In addition, to elucidate the impact of the tsunami, a similar study was performed in a remote area where the tsunami had minimal effect (control area). After the disaster, the number of patients with ADHF in the tsunami area was significantly increased compared to the predisaster period (relative risk 1.97, 95% confidence interval 1.50 to 2.59). The peak was found 3 to 4 weeks after the disaster. In contrast, in the control area, no significant change in ADHF events was observed (relative risk 1.29, 95% confidence interval 0.94 to 1.78). There was a significant correlation between changes in the number of ADHF admissions and percent tsunami flood area (r = 0.73, p <0.001) or the number of shelter evacuees (r = 0.83, p <0.001). In conclusion, these findings suggest that large and sudden changes in daily life and the trauma associated with a devastating tsunami have a significant impact on the incidence of ADHF.