Keizo Tsuchida, Kazuhiko Tanabe
Background: The 2004 Mid Niigata Prefecture Earthquake struck the Chuetsu district of Niigata Prefecture in Japan on October 23, 2004 (6.8 on the Richter scale, 13 km in depth), following a lot of strong aftershocks for 20 days. This study investigated the change of plasma brain natriuretic peptide (BNP) on the earthquake, and the relationship between earthquake-induced stress and BNP.
Methods: This study included 529 outpatients (mean age: 69.8 years), whose BNP was measured within 4 weeks after the earthquake and additional 4 weeks after the former by immunoradiometric assay (Sionogi), and compared to BNP before the earthquake.
Results: The mean BNP 0-4 weeks after the earthquake was increased significantly by 18 pg/ml compared to BNP before the earthquake (?BNP), and fell to the former level 4-8 weeks after the earthquake (56→74→60 pg/ml, p<0.0001). BNP was increased significantly in patients with cardiac diseases (n=218) (101→129→109 pg/ml, p<0.0001) and also in patients without cardiac diseases (n=311) (25→35→25 pg/ml, p<0.0001) and furthermore in healthy persons (n=10) (9→29→8 pg/ml, p<0.0001). BNP was increased not significantly in patients taking beta-blocker (n=13) (?BNP 19 pg/ml: 19→39→20 pg/ ml, p=0.0685) but significantly in patients not taking it (n=61) (?BNP 25 pg/ml: 20→45→22 pg/ml, p<0.0001). Further, blood pressure, pulse rate and D-dimer were significantly increased right after the earthquake.
Conclusion: These results suggest that emotional and physical stress on earthquake stimulates sympathetic nerve system, and subsequently elevates blood pressure and heart rate, and so increases BNP levels. BNP is useful for evaluation of cardiac overload and dysfunction due to emotional and physical stress after the earthquake.
