The Department of Health warns some Medtronic Kappa and Sigma pacemakers may fail due to wire separation.

Medtronic International said the models in question might cause loss of rate response, premature battery depletion, or intermittent or total loss of signal. The models are Kappa 600/700/900 and Sigma 100/200/300.

Patients should consult their doctors immediately if they experience fainting or light-headedness.

No deaths or injuries associated with the failure have been reported in Hong Kong so far.

The Hospital Authority and private hospitals will inform all 189 patients in Hong Kong fitted with the device.