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Thursday 22nd August 2019

Japan sees spike in heart failures

2nd October 2012

Japan recorded a large increase in cases of heart failure in the wake of the devastating earthquake and tsunami of March, 2011, a new study has found.


In Miyagi prefecture, the area where the earthquake occurred, cases of heart failure spiked and remained higher than normal for six weeks after the disaster, which is known in Japan as the Great Earthquake of East Japan.

More than 15,000 people died in the earthquake, which measured a 9.0 on the Richter scale, and the resulting tsunami.

Cases of cardiac arrest and other heart problems also showed a sharp rise in the weeks following the earthquake, but returned to normal levels after three weeks.

According to Hiroaki Shimokawa, one of the authors of the study and a professor at Tohoku University Graduate School of Medicine, the prolonged mental and physical stress caused by the ordeal could have been a major factor.

He said people were more likely to have discontinued crucial medication in the aftermath of the earthquake, to have endured low temperatures, and to have eaten large quantities of salt from preserved food.

The researchers gathered together all the medical records of people admitted by ambulance to a single hospital in Miyagi Prefecture in the months running up to the earthquake, and compared them with the records for the months that followed.

The numbers of cases of heart failure, stroke, cardiac arrest and pneumonia were calculated, and then compared to figures for the same period in 2010, 2009 and 2008.

They found a sharp spike in cardiac arrest cases on the day of the earthquake, March 11, when 17 cases were brought to the hospital by ambulance, compared with just five on the previous day, and 2-4 for the same period in the previous years.

Shimokawa speculated that the cause of the sudden increase could be that the heart is sensitive to sudden stress factors.

Heart failure cases showed no immediate increase, but had increased by March 15, four days after the earthquake.

While the rate of cardiac arrests returned to previous levels within two weeks, heart failure rates remained unusually high for longer.

Writing in the European Heart Journal, Shimokawa and fellow researchers said that more than 9,500 of the earthquake-related deaths had taken place in Miyagi Prefecture, which was closest to the epicenter.

Previous studies have also shown a link between short-term rises in cardiovascular problems and earthquakes, Shimokawa said.

High rates of depression and stress were recorded among workers at other nuclear power plants in the region in the months following the disaster.

Experts said it was unclear what the causes of the change in disease rates were, however.

Gerhard Steinbeck, a professor at the University of Munich in Germany, who was not involved in the Japanese study, said it was hard to tell from the data provided whether the stress of the earthquake caused the increase in heart problems, or whether it was the result of the after-effects of the earthquake.

He also pointed out some possible inaccuracies in the way the heart failure and cardiac arrest cases were counted, partly because the researchers did not define heart failure, nor give details of how it was diagnosed.

A heart failure diagnosis is time-consuming and difficult, especially in the midst of a catastrophe, Steinbeck said in an editorial accompanying the study.

But he said that the study clearly showed that a disaster of such proportions was a real challenge to any healthcare system.

The team's findings should be useful in helping preparedness teams in healthcare systems around the world ensure they are ready to respond after natural disasters.

He said that natural disasters like the Japanese earthquake put an added strain on healthcare systems in the form of increased emergencies and cardiovascular disease for months, not just days or hours, after the event.


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