Correlation of Heart Rate Variability Parameters and QT Interval in Patients After PTCA of Infarct Related Coronary Artery as an Indicator of Improved Autonomic Regulation

The purpose of this study was to determine if PTCA of the infarct related coronary artery (IRA) in the late phase of myocardial infarction (MI) can improve autonomic regulation of sinus rhythm and electrical stability of the myocardium measured by heart rate variability (HRV), QT, QTc, and its dispersion (QTd) and if any correlation exists among these measures. The study was performed in 25 patients (21 male, age: 50 ± 9 years, EF: 52%± 11%) in the late phase of MI (2.5 ± 1.5 months). HRV parameters were calculated automatically. QT, QTc, and QTd were measured manually from a 12-lead surface ECG (50 mm/s). All measurements were made before and 3–5 days after PTCA. Day and night parameters of HRV were sampled over two periods: 2 pm to 10 pm (day) and 10 pm to 6 am (night). Parameters of HRV measured from whole recordings were significantly higher after successful PTCA: SDRR (116 31 vs 128 ± 38 ms), SD (55 ± 17 vs 62 ± 22 ms), rMSSD (30 ± 13 vs 36 ± 14 ms) and HF (246 ± 103 vs 417 ± 224 ms2). Significant differences were found during daytime for SD, rMSSD, and HF, and during nighttime for SDRR, SDANN. QT interval duration, QT corrected to the heart rate, and QT dispersion were significantly lower after PTCA (QTd: 54 ± 15 vs 39 ± 12 ms). There was no correlation between HRV and QT values before PTCA. High correlations were found after the procedure, particularly between QTd and nighttime HRV. Conclusions: PTCA of IRA in the late phase of MI enhances sympathovagal regulation of the cardiac rhythm and the electrical stability of the heart, which may be prognostically important.     

Presence of Streptococcus mutans and lactobacilli in saliva and on enamel, glass ionomer cement, and composite resin surfaces

Abstract— The quantity of S. mutans , total streptococci, and lactobacilli on sound enamel surfaces and 1-yr-old glass ionomer cement and composite resin fillings with the cervical margins placed subgingivally was compared intraindividually. The amount of bacteria was compared to their number in saliva. The evaluation was done in a cross sectional study, where the patients continued to use their customary oral hygiene procedures and during a 14-day period of experimental plaque formation. The number of lactobacilli and S. mutans recovered from the test surfaces indicated that the critical salivary concentrations necessary for the isolation of S. mutans and lactobacilli from glass ionomer cement and composite resin surfaces are the same as for the enamel surfaces. The fluoride levels in plaque adjacent to glass ionomer cement will not become high enough to inhibit the accumulation of the investigated bacteria.     

Well-being and future sick-leave: Multivariate analyses with regard to preceding sick-leave

Consistent associations between self-rated well-being and futuresick-leave have previously been noted in a selected group ofrepeated short-term sick-leavers. The object was to retest thoseassociations after ruling out expected influences of precedingsick-leave. Hypothetically the well-being-sick-leave linkagesinitially observed would thereby overlap with the behaviouralconformity over time. Accordingly, they would possibly be erasedin a hierarchical stepwise regression analysis. The study groupcomprised 61 females and 62 males with diffuse reasons for theirhigh repeated sick-leave. Instead of having to present a doctor'scertificate on every new sick-leave occasion, they chose totake part In a support programme. Altogether 8 hierarchicalmultiple regression analyses were run with sick-leave occasionsand days the first and second years after the contact as separatedependent variables. In the first step, long-term behaviouralproneness to sickness absence was evaluated, i.e. the correlationsbetween the sick-leave parameters the year before and each ofthe 2 years after the programme were computed. In the secondstep, the possible additional impact of well-being ascertainedat entrance Into as well as exit from the clinical contact wasestablished. Sick-leave correlated strongly over the study periodsas expected. Yet, fairly consistent associations between well-beingand future sick-leave remained. The well-being parameters accountedfor another 4–8% of the entire variance in 5 of the 8regression analyses performed. That increment corresponded tobetween 25 and 100% of the proportion initially explained bypreceding sick-leave. Thus the independent role of perceivedself-image for the long-term inclination to sickness absencein the current ‘risk’ group was underscored. Thiswas particularly so since the influence of several other backgroundand job-related factors have previously proven to be empiricallynegligible. Moreover, similar prospective correlations havebeen seen in other study groups.     

Studies on the Mechanism of the Increased Dose-Response of Erythropoietin After Stimulation with Erythropoietin

The responsiveness to ESF of the erythremic mouse is increased one to fourdays after a previous stimulation with ESF. The formation of nucleated redcells by the priming ESF stimulation was suppressed either by simultaneousinjections of ESF and Actinomycin D, or by giving the priming ESF challengeto erythremic mice shortly after they had been exposed to 400 R. total bodyirradiation with X-rays. By these techniques it was demonstrated that thepresence of nucleated red cells within the erythron is not important for theobserved increase in dose response of ESF after ESF stimulation. It was concluded that the recruitment of primitive erythropoietin-responding cells isenhanced by ESF.

Submitted on May 12, 1969 Accepted on December 22, 1969     

Task Complexity and Visual Acuity in Senile Macular Degeneration

ABSTRACT The effects of choice of test object and inter-symbol spacing (contour interaction) on the measurement of low visual acuities was investigated. Visual acuities of sixteen subjects with senile macular degeneration and five age-matched normal subjects were measured using different test targets of varying complexities. Visual acuity of both groups of subjects decreased with increasing task complexity but the trend was more marked for the low vision subjects. However, within the low vision group, the complexity effect was not dependent on the level of visual acuity. This study showed that visual acuity of persons with senile macular degeneration can be measured equally well with single letters, constant contour interaction Landolt rings, or the Bailey-Lovie letter chart but the test used should be specified. Grating targets and word charts measure different visual functions from standard visual acuity tests.     

L-THYROXINE TREATMENT OF DIFFUSE NON-TOXIC GOITRE EVALUATED BY ULTRASONIC DETERMINATION OF THYROID VOLUME

The effect of a daily dose of 150 micrograms l-thyroxine for one year was studied in forty-five patients with diffuse non-toxic goitre. Thyroid volume was evaluated by ultrasonic scanning. A decrease in the median value of the thyroid volume of about 20% was found after 3 months of therapy and no further change in the median value was observed in the following 9 months of treatment. About 50% of the patients showed a response to therapy and about 30% obtained normal size of the thyroid gland. Median value of the thyroid volume returned to pretreatment value 3 months after thyroxine therapy was stopped. A considerable increase in serum T4 and free T4 index was noted after 3 months of therapy and these elevated values persisted unaltered during the following 9 months of treatment. Serum T3 was studied before and after 3 months of thyroxine therapy in eleven of the patients. A small and insignificant increase in serum T3 and free T3 index was observed.     

How to calculate human muscle fibre areas in biopsy samples—methodological considerations

Cross-sectional muscle fibre areas (type I, IIA and IIB) were determined in duplicate biopsies from the left vastus lateralis (n=11) and in biopsies from right and left vastus lateralis (n=8).The SD for the difference in means between duplicate biopsies was 510 μm² for type I, 1020 μm² for type II A and 860 μm² for type II B.Expressed as coefficient of variation (CV) these SD constituted 10, 15 and 15%, respectively. The variation in fibre size within a sample was considerably less than the variation between samples on the assumption that at least 15–20 areas of each fibre type were measured per sample. No difference in mean fibre area for type I, IIA and IIB fibres was obtained between the right and left muscle. Several artefacts due to the sampling and preparing procedures are discussed and a method for determining muscle fibre areas in biopsy samples is suggested.     

Genetic and Environmental Determinants for Lipoprotein Concentrations in Blood

ABSTRACT Path and segregation analyses have been performed on cholesterol and triglyceride contents of serum as well as on very low, low and high density lipoproteins in 78 Swedish nuclear families. The effect of environmental variables like alcohol and smoking on the concentrations of the different lipoproteins has been studied. Genetic heritability was 0.16-0.68 for the cholesterol fractions and 0-0.56 for the triglyceride fractions. No major gene was evident for any of the variables studied.     

Intra-arterial Blood Pressure Monitoring in the Neonate

Management of the critically ill neonate requires accurate and continuous pressure monitoring of intra-arterial blood pressure. An overview of arterial pressure monitoring is presented, including indications for monitoring, sites, normal values, technique, clinical observations, risks, and problems inherent in this procedure.