Anticoagulation in atrial fibrillation

Herz - Atrial fibrillation (AF) is the most frequently encountered sustained arrhythmia with a prevalence of 0.5–10%, depending predominantly on age. The arrhythmia is associated...     

Restrictive cardiomyopathy in an infant with massive biatrial enlargement and normal ventricular size and pump function.

Restrictive cardiomyopathy in an infant with massive biatrial enlargement and normal ventricular size has been reported only once previously [3]. We now present a 13-month-old patient with severe and progressive congestive heart failure who demonstrated normal ventricular cavity size with biatrial enlargement. Ejection fraction and echocardiographic ventricular function studies were normal.     

Parasympathetic nervous system activity and children's sleep

We examined indices of children's parasympathetic nervous system activity (PNS), including respiratory sinus arrhythmia during baseline (RSAB) and RSA reactivity (RSAR), to a laboratory challenge, and importantly the interaction between RSAB and RSAR as predictors of multiple parameters of children's sleep. Lower RSAR denotes increased vagal withdrawal (reductions in RSA between baseline and task) and higher RSAR represents decreased vagal withdrawal or augmentation (increases in RSA between baseline and task). A community sample of school‐attending children (121 boys and 103 girls) participated [mean age = 10.41 years; standard deviation (SD) = 0.67]. Children's sleep parameters were examined through actigraphy for 7 consecutive nights. Findings demonstrate that RSAB and RSAR interact to predict multiple sleep quality parameters (activity, minutes awake after sleep onset and long wake episodes). The overall pattern of effects illustrates that children who exhibit more disrupted sleep (increased activity, more minutes awake after sleep onset and more frequent long wake episodes) are those with lower RSAB in conjunction with lower RSAR. This combination of low RSAB and low RSAR probably reflects increased autonomic nervous system arousal, which interferes with sleep. Results illustrate the importance of individual differences in physiological regulation indexed by interactions between PNS baseline activity and PNS reactivity for a better understanding of children's sleep quality.     

Myocardial anaerobic metabolism during isoprenaline infusion in a cyanotic animal model: possible cause of myocardial dysfunction in cyanotic congential heart disease.

Mongrel dogs were made acutely cyanotic by anastomosis of the inferior vena cava to the left atrium and measurements of high fidelity left ventricular pressure, arterial pressure, blood gases, and myocardial lactate arteriovenous differences were determined before pacing, with atrial pacing at a rate of approximately 240 per minute, and during an infusion of isoprenaline to increase myocardial oxygen demands. The animals were divided into two groups on the basis of the arterial PO2 during isoprenaline: acyanotic or control dogs (n = 4, PO2 greater than or equal to 6.7 kPa [50 mmHg], mean = 52) and cyanotic dogs (n = 5, PO2 less than or equal to 4.7 kPa (35 mmHg), mean = 32). Myocardial lactate arterio-venous difference showed no significant changes in the control dogs with pacing or isoprenaline, but myocardial lactate production occurred in all five cyanotic dogs with isoprenaline infusion. These studies demonstrate that myocardial anaerobic metabolism can be produced during times of stress with isoprenaline infusion in a cyanotic animal model at systemic oxygen levels that can occur clinically.     

Evaluation of automated basophil counting by using fluorescence-labelled monoclonal antibodies

The shortcomings of current methods of basophil enumeration detract from the clinical value of the basophil count. Moreover, sophisticated and costly techniques of automated basophil counting hardly can be validated for lack of a suitable reference method. We investigated whether a flow cytometric technique using double staining with fluorescence-labelled monoclonal antibodies (mAb) CD45-FITC and CD14-PE on a Coulter Epics Profile II could be used to evaluate basophil counting performance of hematology analyzers. The technique was compared with the 800-cell manual differential, the Coulter STKS, and the Cobas Argos 5 Diff. Precision: STKS, Argos and Profile II showed a precision analogous to a 2,173, 2,250-, and 14,705-cell differential, respectively, illustrating the superiority of automated methods. Accuracy (150 normal and abnormal samples): Using the Profile II as reference the STKS showed a notably weaker correlation than the Argos (r = 0.581 and 0.718, respectively), although this difference was nearly concealed when the imprecise manual differential served as reference (r = 0.517 and 0.562, respectively). The Profile 11 correlated relatively well with the manual differential (r = 0.730). Analyzing 137 healthy adult subjects, we obtained a reference range of 0.33 to 1.35% (0.020 to 0.102 × 10⁹, basophils/L) for the mAb-based method. These data would recommend mAb-based basophil counting as a valuable tool for instrument evaluation. However, an observed bias of 0.09% against the manual differential suggests that modifications are necessary before this technique can be considered as new reference method. © 1996 Wiley-Liss, Inc.     

Balloon catheter occlusion of the ascending aorta

Dense calcification of the ascending aorta predisposes to aortic injury and distal embolization when the aorta is cross-clamped or partially clamped in the performance of cardiac operations. We occluded the ascending aorta with a Foley balloon catheter in 2 patients undergoing aortocoronary bypass grafting. The technique used is described in this report.     

Making distance education accessible for students who are deaf and hard-of-hearing

Distance education is based on providing learning "anytime, anywhere." The design of many distance education courses, however, may actually erect barriers to the full participation of some students with disabilities, particularly those with hearing impairments. Without careful consideration, distance education could become learning anytime, anywhere, but not for anybody. It is not only unethical, but also illegal to ignore the special needs of these learners. The specific impact of such legislation on distance education for those students with hearing impairments will be addressed. Students with disabilities are often faced with a double digital divide that must be bridged. Universal design uses an excellent proactive approach to closing this digital divide caused by inaccessible courses. Each medium of transmission in distance education poses unique access barriers. Even within the same medium, what is best for one student or class may not be the most ideal accommodation in another situation. Individualized accommodation methods will be examined, and specific technologies and software will be discussed.     

Children's internalizing symptoms: the role of interactions between cortisol and respiratory sinus arrhythmia

We examined interactions between children's physiological activity across two systems, the hypothalamic-pituitary-adrenal (HPA)-axis and the parasympathetic nervous system (PNS), as predictors of child-reported internalizing symptoms (depression, anxiety). HPA activity was indexed by baseline salivary cortisol, and PNS activity was indexed by baseline respiratory sinus arrhythmia (RSA). Study 1 consisted of 57 children (54% girls; M age = 8.81 years ±.34), and Study 2 included 219 children (51% girls; M age = 9.31 years ±.79). Cortisol interacted with RSA to explain unique variance in children's internalizing symptoms. Across the two studies, children with higher cortisol levels in conjunction with higher RSA levels tended to exhibit the lowest levels of depression and anxiety symptoms. Findings demonstrate that contemporaneous consideration of physiological activity across multiple systems can advance understanding of internalizing symptoms in children.