Last year's earthquakes in Niigata, Japan, have opened the window on a dramatic heart problem.

It's called Takotsubo cardiomyopathy. Translation: stress-induced heart failure.

This wasn't common stress, which can chip away at you over time. Instead, it was sudden, violent, and totally uncontrollable: three strong earthquakes and about 90 large aftershocks.

Local heart problems spiked in the following days and weeks, Japanese doctors report in The Journal of the American Medical Association.

"We conclude that physicians should be aware of the potential for Takotsubo cardiomyopathy following catastrophic events," they write.

Read WebMD's "Staying Healthy in Times of Stress"

Before & After the Quakes

Researchers working on the study included cardiologist Hiroshi Watanabe, MD, PhD, of Niigata University.

They counted the number of heart "events" — including stress-induced heart failure and sudden cardiac death — before and after the earthquakes. All of those problems jumped right after the quakes, the researchers report.

Here's a look at the number of those "events":

— Average daily events in the week after the quakes: 6 (52 in the first week)

— Average daily events in the previous four weeks: 2

— Average daily number of sudden deaths in the week after the quakes: 3

— Average daily number of sudden deaths in the previous four weeks: 1

Read WebMD's "How to Respond and Cope in an Emergency"

Stress-Induced Heart Failure

Here are the numbers for stress-induced heart failure:

— Cases of stress-induced heart failure in the month after the quakes: 25

— Cases of stress-induced heart failure in the previous month: 1

— Cases of stress-induced heart failure a year earlier: 0

— Cases of stress-induced heart failure two years earlier: 1

"The first case occurred immediately after the first shock," write the researchers. "Ten further cases began within a few hours."

New cases were seen until the 19th day after the quakes. Cases tapered off with time.

There were 16 cases in the first week, five in the second week, and four in the third week as the aftershocks continued, write the researchers.

Stress-induced heart failure may be due to elevated levels of stress hormones, such as adrenalin, following such an event, write the researchers.

By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCE: Watanabe, H. The Journal of the American Medical Association, July 20, 2005; vol 294: pp 305-307.