Effect of the Atrial Blanking Time On the Detection of Atrial Fibrillation in Dual Chamber Pacing

NOWAK, B., et al. : Effect of the Atrial Blanking Time On the Detection of Atrial Fibrillation in Dual Chamber Pacing. Patients with paroxysmal atrial fibrillation (PAF) and dual chamber pacemakers frequently have short postventricular atrial blanking times and sensitive atrial sensing thresholds used to provide reliable detection and mode switching during AF. However, short atrial blanking times increase the risk of atrial sensing of ventricular far‐field signals. We evaluated if the length of the atrial blanking time influences the detection of AF. The study included ten patients with a VDDR (n = 7 ) or DDDR system (n = 3 ), who presented with AF at 18 follow‐up visits. Bipolar atrial sensing was programmed to the most sensitive value. Atrial blanking times were programmed from 100 to 200 ms in 25‐ms steps in each patient. Using marker annotation, the following parameters were measured at ten consecutive ventricular beats: VAF = the interval between ventricular stimulus and first sensing of AF; AFS = the number of atrial‐sensed events between two ventricular events; and XAF = the interpolated number of atrial‐sensed events during atrial blanking time. The intervals between ventricular events and between atrial‐sensed event markers showed no significant differences for the five blanking times tested. There was no significant influence of the atrial blanking time onto the measured parameters (least square means ± standard error) with VAF between 281 ± 12 and 300 ± 12 ms (P = NS ), AFs between 3.4 ± 0.2 and 3.6 ± 0.2 beats (P = NS ) and XAF between 1.84 ± 0.12 and 2.03 ± 0.12 beats (P = NS ). At ventricular rates < 100/min, the atrial sensing of AF in dual chamber pacemakers demonstrated no evidence for deterioration by an increase of the atrial blanking time from 100 to 200 ms. Thus, the risk of ventricular far‐field sensing may be reduced without compromising atrial sensing.     

Screening by nurses for aphasia in stroke- the Ullevaal Aphasia Screening (UAS) test

Purpose: In Norway, the speech therapist is responsible for the assessment of language impairment after stroke, but many hospitals have no speech therapist. This study therefore developed and evaluated a simple method to be used by nurses to detect aphasia in the acute stage of stroke; the Ullevaal Aphasia Screening (UAS) test. Method: The study was carried out among 37 stroke patients admitted to an acute stroke unit. They were assessed by nurses using the UAS, while the results of a comprehensive assessment by a speech therapist acted as the 'gold standard'. Results: The predictive value of a positive test was 0.67 and that of a negative test 0.93; only two out of 28 who screened negative on the UAS were diagnosed with mild aphasia by the speech therapist. The weighted kappa coefficient of agreement was 0.83, indicating a strong agreement between the nurses' and speech therapists' scoring. The screening took 5-15 minutes to complete. Conclusion: The Ullevaal Aphasia screening test seems to be a short and valid screening instrument for aphasia in the acute stage of stroke, but further studies would be needed to substantiate the efficacy of the UAS test.     

A follow-up study of patients with recurrent urticaria and hypersensitivity to aspirin, benzoates and azo dyes

We have studied seventy-five patients with recurrent urticaria and angio-oedema of more than 4 months duration and with positive provocation tests to aspirin, azo dyes, and/or benzoates. Crossreactions between the test compounds were common. The patients were recommended to be on a diet free from salicylates, benzoates, and azo dyes. They were then followed for 6–24 months. At the follow-up, 24% were free from symptoms, 57% considered themselves much better and 19% stated that they were slightly better or unchanged. All patients had followed the diet for at least 1–3 months. Most of those who became totally free of symptoms did not continue with the diet, while most of the patients who considered themselves much better found that it was necessary to continue on the recommended diet. They usually developed symptoms as soon as they ingested something containing azo dyes or benzoates. To be able to maintain such a diet, it is important that the content of additives in food and drugs be properly declared.     

Increased chemotactic activity of neutrophil leukocytes in psoriasis

The random and active migration of neutrophil leukocytes in agarose was studied in sixty-one patients with psoriasis and in healthy controls. E. coli filtrate was used as chemoattractant. The random as well as the active migration was increased in psoriasis. The increase was most pronounced in those cases with widespread psoriasis. In twenty patients who were followed for 1–3 years, the neutrophil chemotactic activity remained essentially unchanged.     

Age changes in the two-point discrimination threshold in human oral mucosa

Fifty young and fifty elderly subjects were tested by a two-point discrimination method applying an aesthesiometer to the mucous membrane of lips, cheeks and tongue. Two changes characteristic of ageing were disclosed: (1) higher threshold values were found in the older age group concomitant with (2) a greater range of variation in these values. The importance of the perception of tactile stimuli from the structures tested is discussed in relation to adaptation to full dentures. It is suggested that signals arising from lips, cheeks and tongue assist the process of adaptation, whereas signals from the denture foundation can, on occasion, prevent adaptation.     

Debrisoquine 4-hydroxylation and sulphamethazine N-acetylation in patients with schizophrenia and major depression

Debrisoquine 4-hydroxylation and sulphamethazine N -acetylation phenotypes were determined in 115 Czech drug-free in-patients with schizophrenia ( n =64) or major depressive disorder ( n =51). These data were compared with a control group of 321 healthy volunteers from the North-East German area of Greifswald. The distribution of debrisoquine hydroxylator phenotypes was almost identical in patients and healthy controls. Thus, there were 8.7% (95% CI 5.4–12.0%) of poor metabolizers (PM) among patients while 8.7% (95% CI 3.6–13.8%) PM among the control group. The prevalences of PM amongst patients with chronic schizophrenia and major depression were 10.9% (95% CI 4.5–21.3%) and 5.9 % (95% CI 1.24–16.3%), respectively (χ² schizophrenics vs control=0.315, NS; χ² depressive patients vs control=0.450, NS). However, within the group of EM patients there was a significant ( P <0.01) shift towards higher debrisoquine metabolic ratios, reflecting a lower hydroxylation capacity in EM patients compared with EM healthy controls. The proportion of slow acetylators (SA) was 60.0% (95% CI 51.0–68.9%) in the entire group of psychiatric patients and 57.5% (95% CI 52.1–62.9%) in the control group (χ² all patients vs control=0.195, NS). Furthermore, there were no significant differences in the prevalence of the SA phenotype between controls and schizophrenics or patients with major depression. Although the results of this modest study were negative, the presence of subtle differences in the metabolic capacity between psychiatric patients and a healthy population cannot be ruled out.     

STUDIES ON PHOTOTHERAPY IN NEWBORN INFANTS

ABSTRACT: Windorfer, A., Faxelius, G. and Boréus, L. O. (Departments of Clinical Pharmacology and Paediatrics, Karolinska Hospital, Stockholm, Sweden). Studies on phototherapy in newborn infants: Influence on protein binding of bilirubin and salicylate and on activity of acetylsalicylic acid esterase. Acta Paediatr Scand 64:293, 1975.– Phototherapy of newborn infants with hyperbilirubinemia was shown to result in an increase in hematocrit values and in the activity of the erythrocyte enzyme acetylsalicylic acid esterase. The elevation of the enzyme activity also could be produced in light-treated rabbits and in vitro after illumination of blood from adult volunteers. The binding of bilirubin to serum albumin and of salicylate to plasma proteins did not alter, nor did the concentrations of albumin or total proteins in plasma. It is concluded that light does not increase the unbound fraction of bilirubin in blood.