Today, Medtronic began notifying physicians and patients about a new advisory (pdf) on some of their Kappa and Sigma series of pacemakers manufactured between 2000 and 2002. The defect stems from certain "voids" created in the solder joint where the attachments are made with the circuit board, causing them to fail over time. This loss of connection could lead to premature battery depletion, loss of rate response, loss of telemetry, or even no output.
Although these pacemakers were one of Medtronic's most popular pacemaker lines in early 2000-2004 with over 1.7 million devices implanted worldwide, it is estimated that only 36,900 remain actively implanted in patients. There have been two reported deaths that, while it is uncertain, may have stemmed from this problem.
According to the advisory letter, Medtronic has observed 285 Kappa devices and 131 Sigma devices affected by this issue, representing 0.49% of all Kappa devices and 0.88% of all Sigma devices implanted. It is estimated that the failure rates of Kappa pacemakers is 1.1% and Sigma pacemakers is 4.8% over the remaining lifetime of these pacemakers (the higher failure rate in the Sigma device because of its longer estimated longevity).
Physicians and patients can find if their particular device is affected by logging on to http://www.KappaSigmaSNList.medtronic.com to look up their specific serial number to see if it's affected by this advisory.
Also according to the letter, another subset of Kappa pacemakers involving an additional 96,000 devices might be affected by this defect, but at a much lower failure rate of 0.04% of the devices.
Physicians should consider replacing devices in pacemaker-dependent patients (those dependent on the device for their heart to beat). Further recommendations and information about the advisory can be found on the advisory letter issued today.