New universal strain software accurately assesses cardiac systolic and diastolic function using speckle tracking echocardiography.

BACKGROUND: We have developed new universal strain software (USS) that can be used to perform speckle tracking of any Digital Imaging and Communications in Medicine (DICOM) image, regardless of the ultrasound system used to obtain it. METHODS: Fifty patients prospectively underwent echocardiography immediately prior to cardiac catheterization. Biplane peak global longitudinal strain (GLS), peak systolic longitudinal strain rate (SSR), peak early diastolic longitudinal strain rate (DSR), and peak early diastolic circumferential strain rate (DCSR) were determined using conventional strain software (CSS) that uses raw data, and using the new USS applied to DICOM images. RESULTS: Universal strain software correlated with CSS for GLS (r = 0.78, P < 0.001), SSR (r = 0.78, P < 0.001), DSR (r = 0.54, P < 0.001), and DCSR (r = 0.43, P = 0.019). GLS and SSR using USS correlated with left ventricular ejection fraction (LVEF) (r = -0.67 and -0.71, respectively) as well as using CSS (r = -0.66 and -0.71). Patients with diastolic dysfunction had significantly lower DSR (0.61 vs. 0.87/sec, P = 0.02) and DCSR (0.89 vs. 1.23/sec, P = 0.03), and less negative GLS (-10.8 vs. -16.1%, P = 0.002) using USS in all patients, as well as among those with LVEF ≥ 50%. Receiver-operating characteristic (ROC) analysis for detection of diastolic dysfunction revealed a sensitivity and specificity of 82% and 83% for DCSR < 1.09/sec (area under the curve [AUC = 0.80]) and 85% and 83% for GLS > -13.7% (AUC = 0.84) using USS. CONCLUSION: Universal strain software can be used to accurately assess LV systolic and diastolic function using speckle tracking echocardiography.

Physical deconditioning as a cause of breathlessness among obese adolescents with a diagnosis of asthma.

BACKGROUND: Obese children frequently complain of breathlessness. Asthma and obesity can both contribute to the symptoms during exercise, and this symptom can contribute to a diagnosis of asthma in these children. Despite the high prevalence of obesity few studies have investigated the cardiopulmonary physiology of breathlessness in obese children with a diagnosis of asthma. METHODS: In this case-control study, thirty adolescents between age 12 and 19 were studied with baseline spirometry and a cardiopulmonary exercise test. Ten adolescents were normal controls, ten had obesity without a diagnosis of asthma, and ten had obesity with a history of physician-diagnosed asthma. RESULTS: Baseline characteristics including complete blood count and spirometry were comparable between obese adolescents with and without a diagnosis of asthma. During exercise, obese asthmatic and obese non-asthmatic adolescents had significantly reduced physical fitness compared to healthy controls as evidenced by decreased peak oxygen uptake after adjusting for actual body weight (21.7 ± 4.5 vs. 21.4 ± 5.4 vs. 35.3 ± 5.8 ml/kg/min, respectively). However, pulmonary capacity at the peak of exercise was comparable among all three groups as evidenced by similar pulmonary reserve. CONCLUSION: In this study, breathlessness was primarily due to cardiopulmonary deconditioning in the majority of obese adolescents with or without a diagnosis of asthma.

What is the primary source of discordance in strain measurement between vendors: imaging or analysis?

Strain imaging quantifies myocardial deformation in both overt and subclinical myocardial diseases. Strain values have been shown to vary between vendors. The aim of this study was to investigate whether this variation reflects differences of image characteristics or analysis software. We enrolled 45 patients (age 54 ± 14 years, 26 males) who underwent two echocardiograms on the same day with two different commercially available ultrasound systems. Three apical views were analyzed by two vendor-specific and two digital imaging and communications in medicine (DICOM)-based software packages. The results were compared in two ways; comparison of global longitudinal strain (GLS) by nine different combinations of ultrasound systems and strain software, and comparison of strains by wall, view and global levels. Comparison of GLS between two vendor-specific software packages yielded poor correlation (ρ = 0.35). The use of the same software on the images from different vendors was concordant (ρ = 0.74 and 0.64; bias = 0.0 and -0.5). There were no significant differences in correlation coefficients among the comparisons with DICOM-based software. There was no significant difference in correlation coefficients among three views (4CV vs. 3CV, p = 0.44; 4CV vs. 2CV, p = 0.47). Comparison of walls showed the septum to have the best correlation (ρ = 0.73), and the posterior wall (ρ = 0.31; p = 0.005 vs. septum) had the worst. Use of the same software to measure strain in images from different vendors minimizes the variation of GLS. Post-processing is the most important determinant in inter-vendor variation, with differences in acquisition having a small effect. These findings should be examined and confirmed with other combinations of ultrasound machines and deformation software.

Perioperative anaphylaxis in a 44-year-old man.

This article presents a case report of perioperative anaphylaxis in a previously nonallergic 44-year-old man undergoing cervical spine surgery. After receiving general anesthesia with midazolam, propofol, lidocaine, fentanyl, rocuronium, and sevoflurane and cefazolin for prophylaxis, the patient developed hypotension, tachycardia, bronchospasm, and generalized erythema. A serum tryptase concentration was markedly elevated 2 hours after the anaphylactic episode. Initial prick and intradermal skin tests (excluding skin testing for unavailable benzylpenicilloyl polylysine) and IgE immunoassays for penicillin and cefazolin were negative. However, repeat prick skin testing for cefazolin 6 weeks after anaphylaxis was positive. Although anaphylaxis to cephalosporins is rare, it remains a potential cause of perioperative anaphylaxis. All cases of perioperative anaphylaxis require a workup to identify the offending agent and to avoid future reactions. Skin testing regimens for several commonly implicated drugs used for general anesthesia are available and are described.

Paediatric asthma and obesity.

None of the explanations proposed for the increase in paediatric asthma have been adequate. It is becoming apparent that the cause of the increase in asthma must be multi-factorial. Increasing attention has been focused on the role of lifestyle in the development of asthma. Lifestyle changes that have occurred in children are those in diet and decreased physical activity, with obesity being the product of these changes. The increase in asthma, obesity and a sedentary lifestyle have occurred together. However, a temporal relationship between asthma, obesity and decreased physical activity has not been determined in the paediatric literature. Limited data suggest that decreased physical activity could be playing a role in the aetiology of asthma independent of obesity. Furthermore, there has been substantial research on the benefits of exercise programmes for paediatric patients with asthma. Longitudinal trials monitoring physical activity, obesity and the development of asthma are needed.

Physical activity and exercise in asthma: relevance to etiology and treatment.

There is little doubt that the cause of the increased prevalence and severity of asthma is multifactorial. Although the factors of allergen exposure and hygiene are almost certainly necessary for its development, there is a growing body of literature that implicates lifestyle change, specifically decreased physical activity, as a contributor to the increase in asthma prevalence and severity. Several literature reviews of exercise conditioning in patients with asthma have been published. These reviews and recent controlled trials emphasize that although many of the studies of exercise conditioning in asthmatic patients involved different methods and outcome measures, the overwhelming majority of studies demonstrated the capacity for asthmatic subjects to exercise safely and significantly improve their cardiovascular fitness and quality of life. There are several proposed pathophysiologic mechanisms responsible for the effects of decreased activity on the lung function of patients with asthma. A prescription for exercise has been endorsed for all asthmatic subjects by the American College of Sports Medicine and the American Thoracic Society. The allergy community has placed emphasis on medical therapy and allergen avoidance; in addition, exercise [correction] has not been formally incorporated into the National Asthma Education and Prevention Program guidelines. It is our belief that an exercise prescription should be part of the treatment for all cases of asthma. The real question is whether prolonged physical activity and, in particular, outdoor play of children plays a role in prophylaxis against persistent wheezing. If so, the decrease in physical activity might have played a major role in recent increases in asthma prevalence and severity.

Update on allergy immunotherapy.

This article summarizes and provides commentary regarding guidelines on the administration of immunotherapy (IT) for allergic airway disease. Recent investigations have provided important insights into the immunologic mechanism of IT and the prominent role of interleukin-10-producing regulatory T lymphocytes. The most important aspect of successful IT is the administration of an appropriate dose of an extract containing a sufficient concentration of the relevant allergen. This is largely possible now only with standardized extracts. When the major allergen content of successful IT extracts was quantified, efficacy was demonstrated across a surprisingly narrow concentration range (approximately 5-24 mug per injection), irrespective of the extract. This presumably reflects the concentration of an antigen that drives an immune response toward tolerance. It may be predicted that as major allergen content is quantified in currently nonstandardized extracts, effective IT will also be achieved by administering a dose in this range, in contrast to current practices involving fairly arbitrary dosing decisions. With the availability of nonsedating antihistamines, intranasal corticosteroids, and the leukotriene modifiers, inadequate pharmacologic response or intolerable side effects are less commonly the major indications for starting IT for allergic rhinitis (AR). However, with the recognition that a relatively short course (3-5 years) of IT can provide long-term immunomodulation and clinical benefit, a desire to avoid long-term pharmacotherapy and the associated high costs may be the primary indication for IT in AR cases. While evidence overwhelmingly supports the beneficial influences of IT in asthma cases, the positioning of IT for this disorder is not established. The observed prevention of asthma in children who have AR is intriguing, but further studies are required to assess the extent to which the prevalence and severity of chronic asthma will be reduced when these children reach adulthood. Similarly, safety issues overwhelmingly suggest that uncontrolled asthma is the greatest risk factor for mortality associated with IT and that IT therefore may be contraindicated for most patients who have inadequate pharmacologic responses or are unable to tolerate useful pharmacologic agents. Paradoxically, these are the patients for whom a response to IT may be most desirable.