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Biomedical subjects

I R Zucker

Publications and source records attributed to I R Zucker.

At least 19 recordsLinked to original sources
PubMed1984

A decade of nuclear pacing.

In April, 1973, a decade-long study was begun on nuclear-powered pacemakers. The first 15 of these were designed by the Numec Corporation under a contract from the United States Atomic Energy Commission. Altogether 151 units powered by the isotope plutonium 238 were implanted in 131 patients; the pacemakers of 4 different manufacturers were used. The last nuclear pacemaker was implanted in January, 1983. The actuarial survival at 10 years was 92%, meeting the original performance goal of the Commission of 90%. Ninety pulse generators are still in service today; 25 patients have died and 36 pulse generators have been replaced with non-nuclear units. The most common indication for replacement was an inappropriate pacing mode. This high reliability and superior performance suggest that continued use of a radioisotopic power source is justified, particularly if combined with the electronic circuits of today's dual-chambered, multiprogrammable, and multifunctional pacemakers.

Equipment Design↗
PubMed1978

Symptomatic unilateral cannon "a" waves in a patient with a ventricular pacemaker.

A 64-year-old woman was referred because of intermittent pulsations of the left side of the neck, face, and scalp that were first noticed after the insertion of a ventricular pacemaker. The pacemaker had been inserted because of symptomatic 2:1 atrioventricular block. Right cardiac catherization showed cannon "a" waves, and phlebographic studies revealed stenosis of the right innominate and internal jugular veins. The symptoms were abolished by conversion to an atrial synchronous pacing system. Comments are offered on the hemodynamic findings, the "pacemaking syndrome", and the use of atrial synchronous pacing.

Brachiocephalic Veins↗
PubMed1976

Idiopathic hirsutism--an ovarian abnormality.

We investigated increased production of testosterone and androstenedione in 44 women with unexplained adult-onset hirsutism, 41 of whom had normal-sized ovaries. Twenty women in this group had at least 50 per cent suppression of plasma testosterone and androstenedione after four to five days of dexamethasone. Testosterone and androstenedione values in ovarian-vein effluents were higher than those of their adrenal veins. We calculated adrenal secretion rates of both androgens in each patient by relating the adrenal gradients to those of cortisol. In 42 of the hirsute women, including those whose androgens were suppressed after dexamethasone, the ovaries were the predominant source of androgen production. The women with dexamethasone suppression had milder degrees of virilism and lower production rates of testosterone and androstenedione. We conclude that the ovaries are the source of excessive androgens in most women with unexplained hirsutism, and that corticoid-suppressible patients have milder forms of ovarian hyperandrogenism.

Adrenal Glands↗
PubMed1976

Concurrence of aldosterone, androgen, and cortisol secretion in adrenal venous effluents.

Adrenal effluent concentrations of aldosterone were measured along with testosterone, androstenedione, and cortisol in 17 women with idiopathic hirsutism. In the basal state, aldosterone secretion (higher concentrations vs peripheral blood) was demonstrated in 14 out of 16 of the women, in contrast to 8 out of 16 who demonstrated cortisol gradients. Nine women received 0.25 mgm beta 1-24 ACTH im and serial adrenal venous blood samples were obtained over the next 30 minutes. Parallel 30-40-fold increments were noted in aldosterone, androstenedione, and cortisol; testosterone increased only 8-fold. These marked changes in adrenal effluents were not observed in simultaneously monitored peripheral blood. Minimal changes in these steroid concentrations were noted in adrenal and peripheral blood in 7 women who received 2,000 IU hCG. One woman received a pressor dose of angiotensin II, resulting in a marked increase in adrenal vein aldosterone and a simultaneous decrease in cortisol. Since adrenal androgen secretion parallels cortisol, quantification of adrenal androgen secretion rates can be achieved by sampling the adrenal effluent and relating the androgen gradient to that of cortisol at any given time. In contrast, aldosterone secretion is often independent of cortisol, and thus cannot be estimated by comparison of adrenal gradients. ACTH administration, however, invariably stimulated aldosterone secretion, enabling us to quantify the "ACTH-related aldosterone secretion rate" from a comparison of maximal adrenal gradients of aldosterone vs cortisol. In 6 women, "ACTH-related aldosterone" secretion rate averaged 40 mug/day, roughly 20% of the total daily aldosterone secretion rate.

Adrenal Glands↗
PubMed1975

Followup of implanted pacemakers: an evaluation of surveillance methods.

A waveform analysis clinic augmented by telephone transmission of pacemaker interval in the late stages of pacemaker life will yield a considerable amount of information and will permit elective replacement of pacemakers in about 90 per cent of cases. The clinic has an advantage over other surveillance systems in the accuracy of the diagnosis, the identification of abnormalities that do not require pacemaker replacement, and the multiple benefits of a direct doctor-patient relationship. No system of surveillance can be recommended over all others in all circumstances. It is sufficient here to indicate the merits of each system and to allow the various centers to develop according to their own particular needs and desires. There is no objection to telephone monitoring alone as long as one realizes that only about 80 per cent of the problems can be detected and that there will be an irreducible percentage of false negative and false positive diagnoses. The danger of errors of this type is not great, but it does exist and should be avoided if possible. Other methods of pacemaker followup, such as simple examination and an electrocardiogram in a doctor's office or changing the pacemaker on the basis of the manufacturer's prediction, are relatively unsatisfactory. It should be stressed that pacemaker surveillance of some type is essential to satisfactory patient care because it provides for maximum utilization of the pacemaker, for replacement only if and when necessary, for detection of 90 per cent of pacemaker problems, and for protection of the patient against unexpected pacemaker failure.

Costs and Cost Analysis↗
PubMed1975

Clinical experience with nuclear pacemakers.

Approximately 1,400 nuclear pacemakers have been implanted in patients since April, 1970, without a single battery failure; 64 of these have been implanted at the Newark Beth Israel Medical Center. All except four of the 64 pulse generators were attached to transvenous electrodes, 39 to pacing wires already in place. Fifty-nine of the 64 units are in service and continue to function normally in a follow-up period of up to 2 years. In the total worldwide experience, 70 pacemakers are out of service, approximately half because of the patient's death, and the rest for infection or lead problems, and only three or four because of difficulties with components. The first 15 ARCO pacemakers implanted 2 years ago continue to function well. Of the 15 control pacemakers implanted at the same time, one unit has failed. We have concluded that a nuclear pacemaker should not be used in a patient with limited life expectancy or in an infant, but for the otherwise healthy young or middle-age individual, it should be the unit of choice.

Arrhythmias, Cardiac↗