The Department of Health has issued an alert over a batch of defective implanted cardiac pacemakers manufactured by Guidant Corporation.

The devices may experience premature battery depletion without warning, inappropriate pacing and early display of replacement indicators. The affected pacemakers are PULSAR MAX, PULSAR, DISCOVERY, MERIDIAN, PULSAR MAX II, DISCOVERY II, VIRTUS PLUS II, INTELIS II and CONTAK TR manufactured between November 25, 1997 and October 26, 2000.

If these devices exhibit failure modes, patients may notice prolonged rapid heart beating and they could become dizzy. In serious circumstances, though uncommon, they may develop heart failure symptoms such as shortness of breath and unconsciousness.

The department called on affected patients to contact their doctors for advice. It has also alerted the Hospital Authority, private hospitals and medical associations of the corrective action undertaken by Guidant on some of their pacemakers.

The manufacturer has informed doctors of the situation through letters, and advised them to replace the pacemakers where necessary. It has also set up hotlines 2593 2210 and 6292 2308 for enquiries.