This study aimed to examine the long-term effects of the 2011 Japan earthquake and tsunami on the incidence of fatal and nonfatal myocardial infarction (MI). In the present study, the incidence of 2 types of cardiac events was comprehensively recorded. The study area was divided into 2 zones based on the severity of tsunami damage, which was determined by the percentage of the inundated area within the residential area (<10%, low-impact zone and ≥10%, high-impact zone). The standardized incidence ratio (SIR) and 95% CI for both types of cardiac events during the disaster year and the postdisaster years were determined in each zone. During the 4-year period after the disaster, the SIRs for nonfatal MI did not change to a statistically significant extent in either zones. For fatal MI, the SIR was stable during the study period in the low-impact zone. However, in the high-impact zone, the SIR was significantly elevated in the disaster year of 2011 (1.80 [95% CI 1.32 to 2.28]), and this increase was sustained for the following 3 years (2012, 2.06 [1.55 to 2.57]; 2013, 1.99 [1.49 to 2.48]; 2014, 2.12 [1.62 to 2.63]). The SIRs for fatal MI for the 4 postdisaster years in the municipal areas were significantly correlated with the percentage of the inundated area (r = 0.83; p <0.001) and the number of deaths due to the tsunami (r = 0.77; p <0.005) but not with the maximum seismic intensity (r = 0.43; p = 0.12). In conclusion, these results suggest that the devastating tsunami was associated with a continual increase in the incidence of fatal MI among disaster survivors.

This study investigated the long-term impact of the 2011 Japan earthquake and tsunami on the incidence of acute decompensated heart failure (HF) in the disaster area. This was a population-based study using comprehensive registration for all hospitals within the study area. The standardized incidence ratio (SIR) and 95% confidence interval (CI) for new onset of HF during the disaster year (2011) and postdisaster years (2012 to 2014) were determined. When SIR were compared between the low- and high-impact areas, as defined by the extent of tsunami inundation in residential areas, SIR showed a significant increase in high-impact areas in 2011 (1.67, 95% CI 1.45 to 1.88) and tended to return to baseline in 2012, the first postdisaster year (1.25, 95% CI 1.06 to 1.43). The rate again increased in 2013 (1.38, 95% CI 1.18 to 1.57) and 2014 (1.55, 95% CI 1.35 to 1.75). In low-impact areas, no such increase was apparent during either the disaster year or the postdisaster years. Mean postdisaster period SIR for municipalities significantly correlated with the percentage of tsunami flooding in residential areas (r = 0.52, p <0.05) and with the percentage of refugees within the population (r = 0.74, p <0.01). There was no significant relation between maximum seismic intensity and mean SIR in these municipalities. In conclusion, these results suggest that the catastrophic tsunami but not the earthquake per se resulted in a prolonged increase in the incidence of HF among the general population living in tsunami-stricken areas.