True Incidence of Pacemaker Syndrome

HELDMAN, D., ET AL.: True Incidence of Pacemaker Syndrome. Although the purported incidence of pacemaker syndrome according to the literature is only 5%–15%, this is based on a series of patients with VVI pacing. Increasing numbers of studies are being reported in which patients prefer the dual chamber mode despite little benefit being demonstrated on objective testing, suggesting that pacemaker syndrome may be more common than is generally reported. This study was designed to evaluate the reported symptoms in a series of patients programmed to both the VVI and one or more dual chamber modes. Forty unselected patients with dual chamber pacemakers were entered into a blind, randomized trial comparing the symptoms associated with VVI pacing to those associated with dual chamber pacing. Patients were randomized to either WI or dual chamber pacing. At the end of 1 week, questionnaires rating 16 different symptoms were completed. Blood pressure, LV function, presence of ventriculoatrial conduction, and ability to override the pacemaker were evaluated. The pacemaker was then programmed to the other mode. Overall, 12 of 16 symptoms were significantly worse in the VVI as compared to dual chamber mode. The most highly significant (p < 0.005) were shortness of breath, dizziness, fatigue, pulsations in the neck or abdomen, cough, and apprehension. Pacemaker syndrome was clinically recognized in 83% of patients paced in the WI mode with 65% of patients experiencing moderate to severe symptoms. There were no readily identified clinical, hemodynamic, or electrophysiological parameters that predicted which patients would develop pacemaker syndrome. Thus, when patients have an opportunity to experience both pacing modes in close proximity to one another, there is a high incidence of pacemaker syndrome in the VVI mode.     

Molecular analysis of HLA DR4-/β1 gene in malaria vaccinees. Typing and subtyping by PCR technique and oligonucleotides

The combination of the PCR technique and the synthetic oligonucleotides has proved to be a useful tool in the molecular analysis of HLA class II genes, allowing recognition of as little as a single nucleotide modification in the sequence of the gene. The molecules encoded by these genes have been associated with genetic control of the immune response and with susceptibility to certain diseases. Studies carried out in our laboratory have shown three patterns of humoral immune response in the human volunteers vaccinated with the synthetic protein SPf 66; high, intermediate and low responders. Approximately 73.3% of the low responders were serologically typed as HLA DR4 and 42% as DQw6. These results moved us to look for a subtype (Dw) correlation between the DR4 positive individuals and the different humoral immune response patterns. Using oligo-typing methods after previous amplification of the DR4 B1 exon, we subtyped 20 DR4 volunteers, classified as high, intermediate and low responders. We did not find any direct association between the HLA DR4 Dw special subtype in the high or low responders immunized with the SPf 66 vaccine.     

Early Discharge with Home Follow-up: Impacts on Low-Income Mothers and Infants

Low-income mothers and infants discharged at 24 to 47 hours after birth were compared to two control groups: early discharge with infant separation and conventional discharge. No differences among the three groups in maternal or infant morbidity at seven to 15 days postdelivery were recorded. Simultaneous early discharge was associated with higher maternal attachment scores, fewer maternal concerns, and greater maternal satisfaction with discharge type than early discharge with infant separation. All three groups had substantial morbidity in the first two weeks of life. A shorter hospital stay and more health monitoring postdischarge may be a better use of health resources than a conventional hospital stay for low-income mothers and their infants.     

What Pregnant Women Want to Know: A Comparison of Client and Provider Perceptions

Objective: To compare client and health-care provider perceptions concerning health topics.
Design: A survey conducted at the first prenatal visit asked women to indicate levels of interest in 38 topics. Providers answered the same survey, indicating perceptions of clients' interests.
Setting: A prenatal clinic and a private office, both in an inner city area.
Participants: Two groups of prenatal clients (n = 135 private care and n = 250 public care) and their health-care providers (n = 32 nurses and physicians ).
Results: Significant differences were found (p < .01 for four topics , p < .05 for six topics) between the clients' interests and the providers' perceptions. Women in private and public care differed significantly (p < .01) in their levels of interest. Interest was significantly affected by parity, but not maternal education.
Conclusions: Nurses and other health professionals should be aware of the range of topics in which clients express interest. This study suggests that site of care and parity should be considered when developing prenatal health education.     

The Effect of Continuous Light on Refractive Error and the Ocular Components of the Rat

Phototoxic induced degeneration of the rat retina is a well-documented phenomenon resulting in losses of photoreceptors and their cell bodies, and an overall retinal thinning. This process may serve as a test of the hypothesis that the retinoscopic reflex originates from the inner limiting membrane of the retina. Retinal thinning should produce myopia in the absence of any other ocular component changes in a stable, mature eye if the inner limiting membrane model is correct. Phototoxic retinal degeneration was induced in 10 albino rats by exposure to 19 days of continuous light (1,800 cd m⁻²). Another 10 albino rats exposed to 12-hr on/12-hr off cycled light served as controls. Before and after the exposure to constant light, measures were made of refractive state by cycloplegic retinoscopy, corneal curvature and lens curvature by Purkinje image photography, and axial length of the globe by A-scan ultrasonography.Comparing pre- to post-exposure values, phototoxic degeneration resulted in a mean (±s.d.) myopic shift of −5.10±2.12 D (P<0.002). The corneal curvature also steepened significantly (0.17±0.11 mm, equivalent to −6.0 D;P<0.004), while the posterior curvature of the crystalline lens flattened by 0.21±0.22 equivalent mm (P<0.027), and the axial length shortened by 0.11±0.11 equivalent mm (all tests Wilcoxon signed-rank;P<0.025). Phototoxic rats underwent a mean retinal thinning of 49.6 μcompared to controls (Kruskal-Wallis test;P<0.0008). No refractive or ocular parameters changed significantly in the controls. Phototoxic degeneration in the rat has optical consequences beyond simple retinal thinning. The size of the eye and the curvature of refractive surfaces can be altered in a mature eye well after the completion of development. The multiple changes which occur prevent phototoxic retinal thinning from serving as a test of the inner limiting membrane model for retinoscopic reflections.     

Echocardiographic Detection of a Congenital Diverticulum of the Right Ventricular Outflow Tract

Congenital diverticula of the right ventricle are extremely rare and may be life threatening. The ultrasound demonstration and recognition of such an abnormality and the important differential features are discussed.     

Physical Determinants of the Endocardial P Wave

SHANDLING, A.H., ET AL.: Physical Determinants of the Endocardial P Wave. Reliable atrial sensing of intrinsic P wave activity is important to ensure optimal atrial or dual chamber pacemaker function. Various physical factors (e.g., posture, respiration, exercise) may influence P wave characteristics and impair adequate sensing. To investigate this phenomenon, we measured the average of three P wave amplitudes (PWA) and calculated slew rates from telemetered printouts acquired from Pacesetter pacemakers in 32 patients. These measurements were performed in various body positions, with upright exercise and in varying stages of respiration. Results: the mean supine PWA increased on full inspiration (3.56 ± 1.3 mV versus 3.25 ± 1.2 mV during quiet respiration, p < 0.001), and also increased significantly with full expiration. The mean PWA increased on assuming the erect position (3.25 ± 1.2 mV increasing to 3.49 ± 2.3 mV, p < 0.001); in the upright position, the mean erect PWA during quiet respiration was not significantly influenced by the stage of respiration. The mean upright exercise PWA did not differ significantly from the preexercise erect PWA (3.50 f 1.2 with exercise, and 3.47 ± 1.5 before exercise; P = NS). Calculated slew rates were not different lying versus standing. Conclusions: the mean supine PWA increases significantly at the extremes of respiration and on assuming the erect body position; upright exercise results in no appreciable change in the erect PWA. Atrial sensitivity adjustments based on standard supine testing should be adequate for all body positions. (PACE, Vol. 13, December, Part I 1990)     

What Do Pregnant Women Know about preventing preterm Birth?

Approximately 75% of all perinatal mortality is attributable to preterm birth and its sequelae; therefore, the prevention of preterm birth is a major public health priority. In an effort to determine what pregnant women need to be taught about this subject, 211 pregnant women in an inner-city clinic were given a questionnaire to ascertain their basic knowledge about the subject. Among the results were that almost one-half of the women surveyed did not know how many weeks constituted a normal pregnancy and one-third did not know that neonates born preterm could have health problems. The importance of teaching these and other basic facts (which nurses might think are already known by pregnant women) is a notable finding of this research. If perinatal nurses are to effectively teach pregnant women about the prevention of preterm birth, they must target the appropriate facts and build their patients' knowledge base.     

Chromophobe renal cell carcinoma with neuroendocrine differentiation

Chromophobe renal cell carcinoma was described by Thoenes et al. in 1986, and associations with carcinoma of collecting ducts, conventional renal cell carcinoma and sarcomatoid renal cell carcinoma have been described. We report a case of chromophobe renal cell carcinoma which showed neuroendocrine differentiation. This is the first known case to be clearly identified as such. The patient was a 56‐year‐old man with constant right flank pain and hematuria; CT scan revealed an 8.5 cm non‐homogeneous mass involving the right kidney. Right radical nephrectomy was performed. The tumor showed a mixture of classical and eosinophilic patterns of chromophobe cell carcinoma. Additionally, it showed insular, glandular and rosetoid‐like formations embedded in a dense eosinophilic hyaline stroma. The cells were cuboid or cylindrical with well‐defined boundaries, finely stippled chromatin and a small nucleolus. The appearance of the cytoplasm varied from faintly eosinophilic to coarsely granular eosinophilic. Immunohistochemically, the neuroendocrine areas were reactive for C‐kit, epithelial membrane antigen, cytokeratin, cytokeratin 7, chromogranin A, neuron‐specific enolase, CD56 and S‐100 protein. Our case represents a typical chromophobe carcinoma with neuroendocrine differentiation. Additionally, the immunohistochemical profile in both types of lesion suggests a common origin from renal tubular cells.