The Department of Health warns of potentially life-threatening software problems in six Medtronic International implantable cardiac devices.

The affected models are Consulta CRT-D (D234TRK), Secura DR/VR (D234DRG, D234VRC), Maximo II CRT-D (D284TRK) and Maximo II DR/VR (D284DRC, D284VRC). All except Maximo II VR (D284VRC) are distributed in Hong Kong.

The firm said 40 of the devices have been implanted in Hong Kong patients.

Recommending no change to current patient management, it is contacting the physicians concerned individually. The devices will receive software updating upon the patients' next scheduled clinic follow-up. Patients can call 2919 6413 for details.

Up to April 19, the manufacturer has received five confirmed reports of defects out of 144,000 devices sold worldwide. However, it said no patient injury or death arising from the affected devices has been reported so far.

The department has informed hospitals and medical associations of the issue, and will follow up with the firm on any further development.

If patients who have the deficient implants experience cardiac symptoms or hear alerts from the devices, they should seek medical attention immediately.