Correspondence

A Lifetime Pacemaker Revisited

N Engl J Med 2007; 357:2638-2639December 20, 2007

Article

To the Editor:

The longevity of pulse-generator batteries for cardiac pacemakers is still of some interest. On April 10, 1973, my colleagues and I implanted a plutonium-238 radioisotope pacemaker in a 20-year-old woman who had complete atrioventricular block after repair of a ventricular septal defect 6 years earlier. The nuclear pacemaker (Numec NU-5), one of the first of such devices implanted in the United States, was attached to a unipolar, “thumb tack” electrode of our own design. When the lead fractured 11 years later, it was repaired by splicing it to a new connector, retaining the same pacemaker. The stimulation threshold was 1.2 V and 1.0 mA at a pulse duration of 1.5 msec. Thirty-four years have elapsed, with no subsequent untoward events. The patient's ejection fraction, which was not assessed at the time of implantation, is now 34%; the left ventricle is moderately dilated, and the right ventricle is normal; there is moderate mitral- and tricuspid-valve insufficiency. The patient, who is now 54 years old, has no physical intolerance and maintains a normal routine.

This patient is one of 139 who received the first versions of the nuclear pacemaker, which was developed in 1973 in an effort to find a lifelong power source for implanted pacemakers. It was originally determined that even when the half-life of the isotope (88 years) was reached, the power would still remain sufficient to drive the circuit. Nine of these devices are still in use.1 Many of the recipients have since died, some have been lost to follow-up, and some have undergone implantation of a replacement device in order to upgrade to more modern pacing modes. This specific device was projected to have 90% reliability at 20 years. That target has been exceeded.

The patient's tolerance of this pacemaker is also noteworthy. So far, there have been no local or systemic consequences of prolonged exposure to ionizing radiation, nor have there been any deleterious clinical effects of prolonged fixed-rate pacing or of pacing in the right ventricular apex.

Despite the expense of the initial device (about $5,000 in 1973), the amortized cost is less than it would be for a standard pacemaker. The follow-up cost would have been $19,000 for the nuclear unit, including hospitalization, medical fees, and follow-up, as compared with $55,000 for a standard device, a difference of $36,000 (or approximately $1,060 per year). Thus, the nuclear pacemaker has been cost-effective and has produced a most gratifying clinical response for the past 34 years, which, to our knowledge, is the longest survival of a pulse generator yet reported.2

Victor Parsonnet, M.D.
Newark Beth Israel Medical Center, Newark, NJ 07112
vpace1@gmail.com

2 References

1
Parsonnet V, Driller J, Cook D, Rizvi SA. Thirty-one years of clinical experience with “nuclear-powered” pacemakers. Pacing Clin Electrophysiol 2006;29:195-200
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2
Parsonnet V, Bernstein AD, Perry GY. The nuclear pacemaker: is renewed interest warranted? Am J Cardiol 1990;66:837-842
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