Background: On March 11, 2011, the Tohoku district was struck by the most powerful known earthquake to hit Japan. Although stress-induced heart diseases rise after strong psychosocial stress, little is known about the characteristics of heart failure (HF) caused by psychosocial stress related to earthquakes. Methods: We examined patients admitted to our hospital for HF during a three-week period between March 11 and March 31, 2011 (Disaster group) and compared them to patients during the corresponding period of 2010 (Non-Disaster group). Results: The number of patients was larger in the Disaster group (n = 30, 18 men, 12 women; mean age 77.3 +/- 9.8 years) than in the Non-Disaster group (n = 16, 8 men, 8 women; mean age 77.3 +/- 11.6 years). A total of 14 of 30 patients (46.7%) in the Disaster group did not have past history of admission for HF, compared to 2 patients (12.5%) in the Non-Disaster group (p = 0.02). The number of patients with hypertension was larger in the Disaster group than in the Non-Disaster group (53.3% vs. 37.5%, p = 0.04). The number of patients with atrial fibrillation was also larger in the Disaster group than in the Non-Disaster group (56.7% vs. 25.0%, p = 0.03). Left ventricular systolic ejection fraction (EF) did not differ between the Disaster and Non-Disaster groups (45.2 +/- 17.8% vs. 45.6 +/- 14.0%, p = 0.46), however, the proportion of patients whose EF was more than 45% were significantly higher in the Disaster group more than in the Non-Disaster group (56.7% vs. 43.8%, p = 0.04). The in-hospital mortality rate for patients in the Disaster group was higher than in the Non-Disaster group (20.0% vs. 6.3%, p = 0.04). Conclusion: The incidence and in-hospital mortality rate of HF increased after the Great East Japan Earthquake, suggesting that psychosocial stress brought on by such a disaster could lead to the development of HF with preserved EF more than that with reduced EF. (C) 2013 Published by Elsevier Ltd on behalf of Japanese College of Cardiology.