Sodium Bicarbonate and Calcium Chloride for the Treatment of Hyperkalemia-Induced Cardiac Arrest: A Randomized, Blinded, Placebo-Controlled Animal Study.

OBJECTIVES: Current international guidelines recommend administrating calcium chloride and sodium bicarbonate to patients with hyperkalemia-induced cardiac arrest, despite limited evidence. The aim of this study was to evaluate the efficacy of calcium chloride and sodium bicarbonate on return of spontaneous circulation (ROSC) in a pig model of hyperkalemia-induced cardiac arrest. DESIGN: A randomized, blinded, placebo-controlled experimental pig study. Hyperkalemia was induced by continuous infusion of potassium chloride over 45 minutes followed by a bolus. After a no flow period of 7 minutes, pigs first received 2 minutes of basic cardiopulmonary resuscitation and subsequently advanced life support. The first intervention dose was administered after the fifth rhythm analysis, followed by a defibrillation attempt at the sixth rhythm analysis. A second dose of the intervention was administered after the seventh rhythm analysis if ROSC was not achieved. In case of successful resuscitation, pigs received intensive care for 1 hour before termination of the study. SETTING: University hospital laboratory. SUBJECTS: Fifty-four female Landrace/Yorkshire/Duroc pigs (38-42 kg). INTERVENTIONS: The study used a 2 × 2 factorial design, with calcium chloride (0.1 mmol/kg) and sodium bicarbonate (1 mmol/kg) as the interventions. MEASUREMENTS AND MAIN RESULTS: Fifty-two pigs were included in the study. Sodium bicarbonate significantly increased the number of animals achieving ROSC (24/26 [92%] vs. 13/26 [50%]; odds ratio [OR], 12.0; 95% CI, 2.3-61.5; p = 0.003) and reduced time to ROSC (hazard ratio [HR] 3.6; 95% CI, 1.8-7.5; p < 0.001). There was no effect of calcium chloride on the number of animals achieving ROSC (19/26 [73%] vs. 18/26 [69%]; OR, 1.2; 95% CI, 0.4-4.0; p = 0.76) or time to ROSC (HR, 1.5; 95% CI, 0.8-2.9; p = 0.23). CONCLUSIONS: Administration of sodium bicarbonate significantly increased the number of animals achieving ROSC and decreased time to ROSC. There was no effect of calcium chloride on the number of animals achieving ROSC or time to ROSC.

Long-term use of everolimus for refractory arrhythmia in a child with tuberous sclerosis complex.

Tuberous sclerosis complex is associated with the occurrence of cardiac rhabdomyomas that may result in life-threatening arrhythmia unresponsive to standard antiarrhythmic therapy. We report the case of an infant with multiple cardiac rhabdomyomas who developed severe refractory supraventricular tachycardia (SVT) that was successfully treated with everolimus. Pharmacological mTOR inhibition rapidly improved arrhythmia within few weeks after treatment initiation and correlated with a reduction in tumor size. Intermediate attempts to discontinue everolimus resulted in rhabdomyoma size rebound and recurrence of arrhythmic episodes, which resolved on resumption of therapy. While everolimus treatment led to successful control of arrhythmia in the first years of life, episodes of SVT reoccurred at the age of 6 years. Electrophysiologic testing confirmed an accessory pathway that was successfully ablated, resulting in freedom of arrhythmic events. In summary we present an in-depth evaluation of the long-term use of everolimus in a child with TSC-associated SVT, including the correlation between drug use and arrhythmia outcome. This case report provides important information on the safety and efficacy of an mTOR inhibitor for the treatment of a potentially life-threatening cardiac disease manifestation in TSC for which the optimal treatment strategy is still not well established.

Evaluation of Right Ventricular Function in Patients with Propionic Acidemia-A Cross-Sectional Study.

(1) Background: In propionic acidemia (PA), myocardial involvement often leads to progressive cardiac dysfunction of the left ventricle (LV). Cardiomyopathy (CM) is an important contributor to mortality. Although known to be of prognostic value in CM, there are no published data on right ventricular (RV) function in PA patients. (2) Methods: In this cross-sectional single-center study, systolic and diastolic RV function of PA patients was assessed by echocardiography, including frequency, onset, and combinations of echocardiographic parameters, as well as correlations to LV size and function. (3) Results: N = 18 patients were enrolled. Tricuspid annulus S' was abnormal in 16.7%, RV-longitudinal strain in 11.1%, tricuspid annular plane systolic excursion (TAPSE) in 11.1%, Tricuspid valve (TV) E/e' in 33.3%, and TV E/A in 16.7%. The most prevalent combinations of pathological parameters were TV E/A + TV E/e' and TAPSE + TV S'. With age, the probability of developing abnormal RV function increases according to age-dependent normative data. There is a significant correlation between TAPSE and mitral annular plane systolic excursion (MAPSE), and RV/LV-longitudinal strain (p ≤ 0.05). N = 5 individuals died 1.94 years (mean) after cardiac evaluation for this study, and all had abnormal RV functional parameters. (4) Conclusions: Signs of diastolic RV dysfunction can be found in up to one third of individuals, and systolic RV dysfunction in 16.7% of individuals in our cohort. RV function is impaired in PA patients with a poor outcome. RV functional parameters should be used to complement clinical and left ventricular echocardiographic findings.

Anxiety and Depression Levels in Parents after Counselling for Fetal Heart Disease.

The progress in fetal cardiology allows for the early diagnosis of congenital heart defects, but there is still a lack of data on the psychological situation of parents expecting a child with a congenital heart defect. In this cross-sectional study, 77 parents (45 women and 32 men) expecting a child with a heart defect were interviewed with different questionnaires. The standardized Hospital Anxiety and Depression Scale (HADS) questionnaire was used to assess the psychological state of the parents. Various statistical procedures were performed to determine the prevalence, risk factors, and predictors of anxiety and depression. The prevalence for prenatal anxiety was 11.8% and for depressed mood 6.6%, whereas the postnatal prevalence was 25% for anxiety and 16.7% for depressed mood. The mother is influential in protecting against depression as a contact person (p = 0.035). Women were more affected by anxiety and depression than men (p = 0.036). A significant and positive correlation was observed between anxiety and depression before birth (ρ = 0.649, p < 0.001) and after birth (ρ = 0.808, p < 0.001). The level of education correlated negatively with depression (p = 0.016) and anxiety (p = 0.017) before birth. Significantly higher anxiety and depression scores were not observed among health and social workers (p = 0.084), first-time mothers (p = 0.190), and parents whose pregnancies were due to medical assistance (p = 0.051). Close collaboration between maternal-fetal care units, pediatric cardiologists and psychiatric/psychosomatic disciplines is a possible strategy to reduce stress in parents. Therefore, an expert team of professionals, educating with understandable terms and sufficient knowledge about fetal heart disease in parenting counseling, is required. The support of affected parents can positively impact the treatment of the child and should be integrated into the daily routine of the clinic.

Detection of early cardiac disease manifestation in propionic acidemia - Results of a monocentric cross-sectional study.

BACKGROUND: In propionic acidemia (PA) myocardial involvement is common and includes development of cardiomyopathy, life-threatening acute heart failure, and acquired long-QT syndrome. We sought to investigate which echocardiographic parameters of left ventricular systolic and diastolic function indicate early cardiac disease manifestation in PA. METHODS: This is a prospective observational study (cross-sectional design) in a Tertiary Medical Care Center. Individuals with confirmed PA were enrolled and the following cardiac investigations were performed in all study individuals: echocardiographic measurements of systolic and diastolic left ventricular (LV) function (LV fractional shortening (LV-FS), LV ejection fraction by biplane modified Simpson's (LV-EF), mitral annular plane systolic excursion (MAPSE), LV global longitudinal strain (LV-GLS) by speckle tracking echocardiography (STE), pulsed Doppler analyses of mitral valve (MV) inflow velocities (MV E/A) and MV deceleration time (DT-E), tissue doppler imaging (TDI) of the mitral annulus (MV E/e'), and LV myocardial performance index (LV-MPI)). LV and left atrial (LA) diameters were assessed. 12­lead electrocardiograms (ECG) were recorded and corrected QT intervals (QTc) calculated. Clinical phenotype and laboratory parameters at the time of cardiac investigation were assessed. Besides descriptive analyses we analyzed frequency, onset, and combinations of echocardiographic and ECG data as well as their correlations with clinical and biochemical findings. The effects of 'age at visit' and LV functional parameters on QTc were analyzed with multiple regression. RESULTS: A total of 18 patients with confirmed PA were enrolled. Median age at PA onset was 6 days (range 1-357 days). Median age at visit for cardiac evaluation was 13.1 years (range 0.6-28.1 years). LV-GLS was abnormal in 72.2%, LV-EF in 61.1%, MAPSE in 50%, MV E/e' in 44.4%, LV-MPI in 33.3%, LV-FS in 33.3%, and MV E/A in 27.8%. In cases with normal or near normal LV-FS, LV-GLS was pathological in 5/10, LV-EF in 4/10, and MAPSE in 3/10. The probability of developing LV dysfunction - systolic and diastolic - increases with age. LV-MPI is a reliable parameter to indicate systolic LV-dysfunction in combination with a dilated LV, i. e. dilated cardiomyopathy (DCM) in PA. Multiple regression reveals a significant positive association between LV diameters and QTc. Abnormal LV-GLS significantly correlates with reduced muscle strength, muscle tone and/or abnormal gross motor function. CONCLUSIONS: Our data suggests a high prevalence of cardiac disease manifestation in PA, considerably higher than in previous studies, where only LV-FS was used to assess LV function. Usage of advanced echocardiographic techniques, such as LV-GLS assessment, may allow for early detection of subtle LV dysfunction in PA, and may lead to timely cardiac treatment but also consideration of liver transplantation to prevent development of manifest cardiac complications.

Parents' Perspectives on Counseling for Fetal Heart Disease: What Matters Most?

After diagnosis of congenital heart disease (CHD) in the fetus, effective counseling is considered mandatory. We sought to investigate which factors, including parental social variables, significantly affect counseling outcome. A total of n = 226 parents were recruited prospectively from four national tertiary medical care centers. A validated questionnaire was used to measure counseling success and the effects of modifiers. Multiple linear regression was used to assess the data. Parental perception of interpersonal support by the physician (ß = 0.616 ***, p = 0.000), counseling in easy-to-understand terms (ß = 0.249 ***, p = 0.000), and a short period of time between suspicion of fetal CHD, seeing a specialist and subsequent counseling (ß = 0.135 **, p = 0.006) significantly improve "overall counseling success". Additional modifiers (e.g., parental native language and age) influence certain subdimensions of counseling such as "trust in medical staff" (language effect: ß = 0.131 *, p = 0.011) or "perceived situational control" (age effect: ß = 0.166 *, p = 0.010). This study identifies independent factors that significantly affect counseling outcome overall and its subdimensions. In combination with existing recommendations our findings may contribute to more effective parental counseling. We further conclude that implementing communication skills training for specialists should be considered essential.

Counseling for fetal heart disease-current standards and best practice.

Congenital heart disease (CHD) is the most common cause of major congenital anomalies affecting newborns. Prenatal detection of CHD has been improving continuously during the last two decades due to technical advances and thus optimized fetal cardiac imaging. Besides the in-utero diagnosis of CHD effective parental counseling is an integral part of any Fetal Cardiology Program. However, studies on the most effective techniques are scarce, as well as data on empirical assessment of counseling and its effectiveness. In this review article, we summarize current guidelines from different international associations and societies. We provide an updated literature overview evaluating current standards of counseling with regard to parental needs. This includes ethical aspects, counseling for univentricular disease and in-utero cardiac interventions. We discuss our method to assess counseling success for fetal heart defects by exploring different analytical dimensions that may be considered helpful in order to improve efficacy. Finally, we present a proposal of how to optimize a setting for counseling based on the current literature and our own data. In summary, parental counseling for fetal heart disease is complex and multidimensional. Significant expertise in fetal cardiology and physiology, potential progression of CHD, postnatal treatment strategies and knowledge of long-term sequelae is necessary. A structured approach, together with continuous improvement of communicative skills, may lead to more effective counseling for parents following a diagnosis of CHD in the fetus.

Fetal Cardiac Services during the COVID-19 Pandemic: How Does It Affect Parental Counseling?

The COVID-19 pandemic impacts health care providers in multiple ways, even specialties that do not seem to be affected primarily, such as fetal cardiac services. We aimed to assess the effects on parental counseling for fetal congenital heart disease (CHD). In this multicenter study, we used a validated questionnaire. Parents were recruited from four national tertiary medical care centers (n = 226); n = 169 had been counseled before and n = 57 during the pandemic. Overall counseling success including its dimensions did not differ between the two groups (p = n.s.). However, by applying the sorrow scale, we could demonstrate that parents counseled during the pandemic were significantly more concerned (p = 0.025) and unsure (p = 0.044) about their child's diagnosis, therapy and outcome. Furthermore, parents expressed a significantly increased need for written and/or online information on fetal heart disease (p = 0.034). Other modifiers did not affect counseling success (p = n.s.). We demonstrate that the COVID-19 pandemic impacts effectiveness of parental counseling for fetal CHD, possibly by altering parental perceptions. This needs to be taken into consideration when counseling. Implementing alternative and innovative approaches (e.g., online conference or virtual reality tools) may aid in facilitating high-quality services in critical times such as in the present pandemic.

Counseling for Prenatal Congenital Heart Disease-Recommendations Based on Empirical Assessment of Counseling Success.

Objectives: Empirical assessment of parental needs and affecting factors for counseling success after prenatal diagnosis of congenital heart disease (CHD). Methods:Counseling success after fetal diagnosis of CHD was assessed by a validated standardized questionnaire. The dependent variable "Effective Counseling" was measured in five created analytical dimensions (1. "Transfer of Medical Knowledge-ToMK"; 2. "Trust in Medical Staff-TiMS"; 3. "Transparency Regarding the Treatment Process-TrtTP"; 4. "Coping Resources-CR"; 5. "Perceived Situational Control-PSC"). Analyses were conducted with regard to influencing factors and correlations. Results: Sixty-one individuals (n = 40 females, n = 21 males) were interviewed in a tertiary medical care center. Median gestational age at first parental counseling was 28 + 6 weeks. Parental counseling was performed four times (median), mostly by pediatric cardiologists (83.6%). Overall counseling was successful in 46.3%, satisfying in 51.9%, and unsuccessful in 1.9%. Analyses of the analytical dimensions show that counseling was less successful for TOMK (38.3%) and PSC (39%); success rates were higher if additional written information or links to web sources were provided (60 and 70%, respectively). Length of consultation was positively correlated to counseling success for ToMK (r = 0.458), TrtTP (r = 0.636), PSC (r = 0.341), and TiMS (r = 0.501). Interruptions were negatively correlated to the dimensions TiMS (r = -0.263), and TrtTP (r = -0.210). In the presence of high-risk CHD (37.5%) overall counseling success was lower (26.1%). By cross table analysis and to a low degree of positive correlation in one dimension (ToMK; r = 0.202), counseling tends to be less successful for ToMK, TrtTP, and TiMS if parents have not been counseled by cardiologists. Analyses regarding premises show a parental need for a separate counseling room, which significantly impacts ToMK (r = -0,390) and overall counseling success (r = -0.333). A language barrier was associated with lower success rates for ToMK, TiMS, and CR (21.4, 42.9, and 30.8%). Conclusions: Data from this multidisciplinary study indicate that parents after fetal diagnosis of CHD need uninterrupted counseling of adequate duration and quality in a separate counseling room. Providing additional written information or links to adequate web sources after initial counseling seems necessary. High-risk CHD needs more attention for counseling. There is a trend towards more counseling success if provided by cardiologists.

Objective Assessment of Counselling for Fetal Heart Defects: An Interdisciplinary Multicenter Study.

The objective of this study was to analyze parental counselling for fetal heart disease in an interdisciplinary and multicenter setting using a validated questionnaire covering medical, sociodemographic, and psychological aspects. n = 168 individuals were recruited from two pediatric heart centers and two obstetrics units. Overall, counselling was combined successful and satisfying in >99%; only 0.7% of parents were dissatisfied. "Perceived situational control" was impaired in 22.6%. Adequate duration of counselling leads to more overall counselling success (r = 0.368 ***), as well as providing written or online information (57.7% vs. 41.5%), which is also correlated to more "Transfer of Medical Knowledge" (r = 0.261 ***). Interruptions of consultation are negatively correlated to overall counselling success (r = -0.247 **) and to "Transparency regarding the Treatment Process" (r = -0.227 **). Lacking a separate counselling room is associated with lower counselling success for "Transfer of Medical Knowledge" (r = 0.210 ***). High-risk congenital heart disease (CHD) is correlated to lower counselling success (42.7% vs. 71.4% in low-risk CHD). A lack of parental language skills leads to less overall counselling success. There is a trend towards more counselling success for "Transfer of Medical Knowledge" after being counselled solely by cardiologists in one center (r = 0.208). Our results indicate that a structured approach may lead to more counselling success in selected dimensions. For complex cardiac malformations, counselling by cardiologists is essential. Parental "Perceived Situational Control" is often impaired, highlighting the need for further support throughout the pregnancy.

Impaired Systolic and Diastolic Left Ventricular Function in Children with Chronic Kidney Disease - Results from the 4C Study.

Children with chronic kidney disease suffer from excessive cardiovascular mortality and early alterations of the cardiovascular system. Tissue doppler imaging is a validated echocardiographic tool to assess early systolic and diastolic cardiac dysfunction. We hypothesized that tissue Doppler velocities would reveal reduced cardiac function in children with chronic kidney disease compared to healthy children. A standardized echocardiographic exam was performed in 128 patients of the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) Study aged 6-17 years with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73 m2. Tissue Doppler measurements included early (E') and late (A') diastolic and systolic (S') velocity at the mitral and septal annulus of the left ventricle. Measured values were normalized to z-scores using published reference data. Predictors of E'/A', E/E', S' and left ventricular mass index (LVMI) were assessed by multiple linear regression analyses. Tissue Doppler E' was reduced and tissue Doppler A' increased, resulting in a reduced tissue Doppler E'/A' ratio (z-score -0.14, p < 0.0001) indicating reduced diastolic function compared to healthy children. Reduced tissue Doppler E'/A' Z-Scores were independently associated with lower eGFR (p = 0.002) and increased systolic blood pressure (p = 0.02). While E/E' Z-Scores were increased (Z-score 0.57, p < 0.0001), patients treated with pharmacological RAS blockade but not with other antihypertensive treatments had significantly lower E/E' and higher E'/A' Z-Scores. Systolic tissue Doppler velocities were significantly decreased (Z-score -0.24, p = 0.001) and inversely correlated with E/E' Z-Scores (r = -0.41, p < 0.0001). LVMI was not associated with systolic or diastolic tissue Doppler velocities. Concentric left ventricular hypertrophy showed a tendency to lower S' in multivariate analysis (p = 0.13) but no association to diastolic function. Concentric left ventricular geometry was significantly associated with lower midwall fractional shortening. In summary, systolic and diastolic function assessed by tissue Doppler is impaired. eGFR, systolic blood pressure and the type of antihypertensive medications are significant predictors of diastolic function in children with CKD. Left ventricular morphology is largely independent of tissue Doppler velocities. Tissue Doppler velocities provide sensitive information about early left ventricular dysfunction in this population.

Assessment of Needs for Counseling After Prenatal Diagnosis of Congenital Heart Disease - A Multidisciplinary Approach.

BACKGROUND: Congenital heart disease is the most common cause of major congenital anomalies. After prenatal diagnosis effective counseling is crucial. However, little research has been undertaken in determining the most effective techniques. OBJECTIVES: To develop a questionnaire suitable to assess parental needs for counseling. MATERIAL AND METHODS: A questionnaire was developed by pediatric cardiologists, maternal-fetal-medicine specialists and sociologists. Likert scaled and open-ended questions are combined with socio-demographical data. The questionnaire was prospectively pilot-tested on 17 parents. We present first analyses of n=41 parents. RESULTS: Response rate was 89.5%. The dependent variable "effective counseling" was measured in 5 dimensions (transfer of medical information, trust in medical staff, transparency of treatment process, coping resources and perceived situational control). The questionnaire's internal consistency is high (Cronbach's alpha>0.7). First analyses show that 44.7% perceived counseling as successful. Transfer of medical information seems difficult (36.6% success rate). Trust in medical staff was high with 75%. CONCLUSIONS: This newly developed tool measures counseling success in five dimensions. A multidisciplinary approach is recommended as methodological expertise is essential for constructing adequate tests. Preliminary data indicate that transfer of medical information is not easily achieved. Further analyses are needed to identify factors that determine counseling success.

Malonic aciduria: long-term follow-up of new patients detected by newborn screening.

UNLABELLED: Malonic aciduria is an extremely rare autosomal recessive inborn error of metabolism. We present clinical, biochemical and genetic information for several years of follow-up of new malonic aciduria patients who were diagnosed by newborn screening. These data are discussed with regard to treatment options and possible diagnostic pitfalls. The cases presented here show that the course of malonic aciduria is unpredictable and can even significantly differ in two siblings harbouring identical mutations. Early treatment can lead to the rapid improvement of cardiomyopathy in the course of malonic aciduria. Biochemical parameters seem to be variable and can intermittently be undetectable in the blood or urine samples of affected patients. Therefore, confirmatory tests following a positive newborn screening should be taken with caution and include both malonyl carnitine detection in dried blood spots and urinary organic acid analysis as initial measures. CONCLUSION: Patients with a suspected or confirmed diagnosis of malonic aciduria should undergo thorough diagnostic procedures and be regularly screened for complications such as cardiomyopathy even when they are asymptomatic in order to ensure early therapy of treatable complications.

Prenatal screening for major congenital heart disease: assessing performance by combining national cardiac audit with maternity data.

OBJECTIVE: Determine maternity hospital and lesion-specific prenatal detection rates of major congenital heart disease (mCHD) for hospitals referring prenatally and postnatally to one Congenital Cardiac Centre, and assess interhospital relative performance (relative risk, RR). METHODS: We manually linked maternity data (3 hospitals prospectively and another 16 retrospectively) with admissions, fetal diagnostic and surgical cardiac data from one Congenital Cardiac Centre. This Centre submits verified information to National Institute for Cardiovascular Outcomes Research (NICOR-Congenital), which publishes aggregate antenatal diagnosis data from infant surgical procedures. We included 120 198 unselected women screened prospectively over 11 years in 3 maternity hospitals (A, B, C). Hospital A: colocated with fetal medicine, proactive superintendent, on-site training, case-review and audit, hospital B: on-site training, proactive superintendent, monthly telemedicine clinics, and hospital C: sonographers supported by local obstetrician. We then studied 321 infants undergoing surgery for complete transposition (transposition of the great arteries (TGA), n=157) and isolated aortic coarctation (CoA, n=164) screened in hospitals A, B, C prospectively, and 16 hospitals retrospectively. RESULTS: 385 mCHD recorded prospectively from 120 198 (3.2/1000) screened women in 3 hospitals. Interhospital relative performance (RR) in Hospital A:1.68 (1.4 to 2.0), B:0.70 (0.54 to 0.91), C:0.65 (0.5 to 0.8). Standardised prenatal detection rates (funnel plots) demonstrating inter-hospital variation across 19 hospitals for TGA (37%, 0.00 to 0.81) and CoA (34%, 0.00 to 1.06). CONCLUSIONS: Manually linking data sources produced hospital-specific and lesion-specific prenatal mCHD detection rates. More granular, rather than aggregate, data provides meaningful feedback to improve screening performance. Automatic maternal and infant record linkage on a national scale, requires verified, prospective maternity audit and integration of health information systems.

Functional role of TASK-1 in the heart: studies in TASK-1-deficient mice show prolonged cardiac repolarization and reduced heart rate variability.

TASK-1, a member of the recently identified K2P channel family, is mainly expressed in the heart and the nervous system. TASK-1 is regulated by several physiological and pathological conditions and functions as a background potassium channel. However, there are limited data concerning the significance of TASK-1 in cardiac physiology. We studied the functional role of TASK-1 in the heart by cardiac phenotyping the TASK-1-deficient mouse (TASK-1(-/-)). TASK-1 was predominantly expressed in the ventricles of control animals. Real-time PCR and immunoblot demonstrated that the expression of seven other K2P channels was unchanged in TASK-1(-/-) mice. No structural or functional abnormalities were found by histology and echocardiography. Electrophysiological studies recording monophasic action potentials (MAPs) showed a significant prolongation of action potential duration in spontaneously beating and atrially paced hearts, respectively. Surface ECGs of TASK-1(-/-) mice revealed a significant prolongation of the rate corrected QT interval. Telemetric ECG recordings for 24 h, during physical and pharmacological stress testing and after ischemia/reperfusion injury did not result in a higher incidence of arrhythmias. Infarct size was comparable in both genotypes. However, TASK-1(-/-) mice had a higher mean heart rate and significantly reduced heart rate variability (HRV). Time and frequency domain measurements as well as baroreceptor reflex testing revealed a sympathovagal imbalance with a shift to an increase in sympathetic influence in TASK-1(-/-) mice. In conclusion, TASK-1 plays a functional role in the repolarization of the cardiac action potential in vivo and contributes to the maintenance of HRV.

Palivizumab-resistant human respiratory syncytial virus infection in infancy.

Palivizumab-resistant respiratory syncytial virus was isolated from an infant treated with palivizumab. A stable mutation at codon 276 led to a nearly complete resistance to palivizumab. Additional studies revealed a second mutation at codon 272. Further passage of the virus led to a complete loss of binding of palivizumab.

Value of surrogate tests to predict exercise-induced bronchoconstriction in atopic childhood asthma.

Exercise challenge tests are helpful in the diagnosis and management of childhood asthma, but methodology is complex and time-consuming. The aim of this study was to investigate whether exercise-induced bronchoconstriction (EIB) can be predicted by the results of different surrogate tests in a pediatric population. Eighty-five children (mean age: 11 years, range: 5-16 years) with atopic asthma were studied. Measurements of exhaled nitric oxide (eNO), spirometry and whole body plethysmography were performed followed by a standardized exercise testing. Questionnaires were completed asking for respiratory symptoms within 2 weeks preceding the study protocol. In 12/85 children (14%), forced expiratory volume in 1 sec (FEV1) was significantly reduced by > or = 15% after exercise testing. eNO was significantly elevated in this group of 12 patients as compared to patients without EIB (51.3 (31.1-67.3) parts per billion (ppb) versus 20.2 (10.9-42.3) ppb; P = 0.003). All children with normal eNO levels (< or = 25 ppb) had normal lung function results after exercise; hence the negative predictive value (NPV) of elevated eNO levels for prediction of EIB was 100%. However, the positive predictive value (PPV) was only 28%. The NPV and PPV for reported asthma symptoms within 2 weeks preceding the study were 96% and 26%, respectively. Considering recent symptom history in addition to elevated eNO improved the PPV to 40%, and resulted in the best combination of sensitivity and specificity. No baseline lung function parameter predicted whether a patient would develop EIB or not. In conclusion, eNO measurements, symptom questionnaires and most efficiently a combination of both surrogate tests can be used as time-saving methods to exclude EIB in atopic childhood asthma.