Several older generation implantable cardioverter defibrillators manufactured by St Jude Medical (Hong Kong) may be affected by cosmic rays and may not function properly, the Department of Health warns.

The affected models are:

* Photon DR (Model V-230HV) (certain serial numbers);

* Photon Micro VR/DR (Models V-194/V-232); and,

* Atlas VR/DR (Models V-199/V-240).

Thirty-four Hong Kong patients have the implants and will be contacted by their doctors. No serious patient injury or death has been reported so far.