The Canterbury earthquake appears to have triggered a surge in heart attacks, including some fatal ones.
Christchurch Hospital's clinical director of cardiology says heart attacks are much more common during disasters, and earthquakes may be particularly dangerous.
Dr David Smyth says six to eight people a day were admitted in the wake of the initial 7.1 magnitude quake on 4 September and the major aftershock four days later - three times the usual rate.
No one has died in hospital, but Dr Smyth says the quake and its aftermath will have caused fatal heart attacks that the coroner will deal with.
The cardiac ward is now getting back to normal, although two more people were admitted on Friday morning after the dozen aftershocks overnight.
Health concerns remain in other areas: Canterbury's Medical Officer of Health, Dr Alistair Humphrey, says he is surprised and disappointed people are ignoring warning signs on rivers.
He says anyone who come into contact with the river water is putting themselves at risk of illnesses such as gastroenteritis and hepatitis.