Increased abdominal fat mass and high fat consumption in young school children with congenital heart disease: results from a case-control study.

BACKGROUND: We have previously found that infants with complex congenital heart disease (CHD) experience growth failure despite high-energy dietary supplementation. This is a follow-up and comparison with healthy controls at 9 years of age regarding body composition and macronutrient intake, especially in relationship to the diet provided during infancy. METHODS: Anthropometric changes in 10 children with CHD at 12 months and at 4 and 9 years of age were analysed as Z-scores. To assess body composition and food intake at 9 years of age, a dual-energy X-ray absorptiometry scan and a 3-day food diary were completed and compared with age- and gender-matched controls using Wilcoxon's signed-rank test for matched pairs. RESULTS: Growth changes from 12 months to 9 years, converted to Z-scores for weight for height and height for age, were significantly different within the group of children with complex CHD, although no growth differences were seen in comparison with healthy controls at 9 years of age. However, the children with CHD had statistically higher abdominal fat mass index and higher daily intake of fat, particularly from saturated fatty acid in g kg-1 compared to controls. CONCLUSIONS: At 9 years of age, children with complex CHD with growth failure and high fat intake in infancy have normalised growth but increased abdominal fat mass and higher intake of saturated fatty acid compared to their peers. Nutritional monitoring in early childhood may detect unhealthy diet quality and prevent later health risks in this group.

Passive leg-lifting in heart failure patients predicts exercise-induced rise in left ventricular filling pressures.

AIM: The aim of this study was to assess PCWP with passive leg-lifting (PLL) and exercise, in two groups of patients presenting with normal left ventricular ejection fraction (LVEF); one group with elevated NT-proBNP (eBNP), and one with normal NT-proBNP (nBNP) plasma concentration. METHODS AND RESULTS: Fifty-one patients with eBNP (NT-proBNP ≥ 125 ng/l) and LVEF > 50%, were investigated and compared with 34 patients with nBNP (NT-proBNP < 125 ng/l) and LVEF > 50%. Both groups underwent right heart catheterization (RHC) at rest, PLL and exercise. From RHC, mean pulmonary arterial pressure (mPAP), cardiac output (CO), and PCWP were measured. All nBNP patients had PCWP < 15 mmHg at rest, and a PCWP of < 25 mmHg with PLL and during exercise. Patients with eBNP had higher (p < 0.01) resting mPAP, PCWP, and mPAP/CO. These values increased with exercise; however, CO increased less in comparison with nBNP patients (p = 0.001). 20% of patients with eBNP had a PCWP > 15 mmHg at rest, this percentage increased to 47% with PLL and 41% had a PCWP > 25 mmHg during exercise. Of those with PCWP > 25 mmHg during exercise, 91% had a PCWP > 15 mmHg with PLL. A PCWP > 15 mmHg on PLL had a 91% sensitivity and 92% specificity in predicting exercise-induced PCWP of > 25 mmHg. CONCLUSION: In patients presenting with eBNP, PLL can predict which patients will develop elevated PCWP with exercise. These findings highlight the role of stress assessment.

Gender and age effects on risk factor-based prediction of coronary artery calcium in symptomatic patients: A Euro-CCAD study.

BACKGROUND AND AIMS: The influence of gender and age on risk factor prediction of coronary artery calcification (CAC) in symptomatic patients is unclear. METHODS: From the European Calcific Coronary Artery Disease (EURO-CCAD) cohort, we retrospectively investigated 6309 symptomatic patients, 62% male, from Denmark, France, Germany, Italy, Spain and USA. All of them underwent risk factor assessment and CT scanning for CAC scoring. RESULTS: The prevalence of CAC among females was lower than among males in all age groups. Using multivariate logistic regression, age, dyslipidaemia, hypertension, diabetes and smoking were independently predictive of CAC presence in both genders. In addition to a progressive increase in CAC with age, the most important predictors of CAC presence were dyslipidaemia and diabetes (ß = 0.64 and 0.63, respectively) in males and diabetes (ß = 1.08) followed by smoking (ß = 0.68) in females; these same risk factors were also important in predicting increasing CAC scores. There was no difference in the predictive ability of diabetes, hypertension and dyslipidaemia in either gender for CAC presence in patients aged <50 and 50-70 years. However, in patients aged >70, only dyslipidaemia predicted CAC presence in males and only smoking and diabetes were predictive in females. CONCLUSIONS: In symptomatic patients, there are significant differences in the ability of conventional risk factors to predict CAC presence between genders and between patients aged <70 and ≥70, indicating the important role of age in predicting CAC presence.

The coronary calcium score is a more accurate predictor of significant coronary stenosis than conventional risk factors in symptomatic patients: Euro-CCAD study.

AIMS: In this retrospective study we assessed the predictive value of the coronary calcium score for significant (>50%) stenosis relative to conventional risk factors. METHODS AND RESULTS: We investigated 5515 symptomatic patients from Denmark, France, Germany, Italy, Spain and the USA. All had risk factor assessment, computed tomographic coronary angiogram (CTCA) or conventional angiography and a CT scan for coronary artery calcium (CAC) scoring. 1539 (27.9%) patients had significant stenosis, 5.5% of whom had zero CAC. In 5074 patients, multiple binary regression showed the most important predictor of significant stenosis to be male gender (B=1.07) followed by diabetes mellitus (B=0.70) smoking, hypercholesterolaemia, hypertension, family history of CAD and age but not obesity. When the log transformed CAC score was included, it became the most powerful predictor (B=1.25), followed by male gender (B=0.48), diabetes, smoking, family history and age but hypercholesterolaemia and hypertension lost significance. The CAC score is a more accurate predictor of >50% stenosis than risk factors regardless of the means of assessment of stenosis. The sensitivity of risk factors, CAC score and the combination for prediction of >50% stenosis when measured by conventional angiogram was considerably higher than when assessed by CTCA but the specificity was considerably higher when assessed by CTCA. The accuracy of CTCA for predicting >50% stenosis using the CAC score alone was higher (AUC=0.85) than using a combination of the CAC score and risk factors with conventional angiography (AUC=0.81). CONCLUSION: In symptomatic patients, the CAC score is a more accurate predictor of significant coronary stenosis than conventional risk factors.

Regional changes in cerebral blood flow oxygenation can indicate global changes in cerebral blood flow during coronary artery occlusion in juvenile pigs.

Near infrared spectroscopy (NIRS) is a widely employed method for assessment of regional cerebral oxygenation (RcStO2). RcStO2 values are expected to vary with changes in the relative amount of oxyhaemoglobin. The present experimental study aimed to assess the response of RcStO2 to controlled alterations of carotid blood flow (CQ). Landrace pigs were anesthetized followed by surgical preparation. Cyclic variations in cardiac output were accomplished by intermittently occluding the main stem of the left coronary artery. A flow measurement probe for assessing CQ was placed around the left carotid artery. One NIRS probe was placed on the left ipsilateral forehead to assess regional cerebral oximetry. Simultaneous registration of CQ and RcStO2 was conducted. There was a strong correlation for variation in CQ and RcStO2 signal values. Based on coherence analysis the fraction of power of the RcStO2 that was coherent with the CQ signal reached 0.84 ± 0.12 (P < 0.05) for frequencies lower than 0.1 Hz. The agreement of the sample-to-sample co-variation, as assessed by the Pearson correlation coefficient, was 0.83 ± 0.08 (P < 0.05). One explanatory component for variations in cerebral oxygenation verified by NIRS should be attributed to variations in the cerebral blood flow.

Gastric emptying in hereditary transthyretin amyloidosis: the impact of autonomic neuropathy.

BACKGROUND: Gastrointestinal (GI) complications are common in hereditary transthyretin amyloidosis and an autonomic dysfunction has been considered to explain these symptoms. The aim of this study was to investigate the impact of autonomic neuropathy on gastric emptying in hereditary transthyretin amyloidosis and to relate these findings to nutritional status, GI symptoms, gender, and age at disease onset. METHODS: Gastric emptying was evaluated with gastric emptying scintigraphy. Spectral analysis of the heart rate variability and cardiovascular responses after tilt test were used to assess the autonomic function. The nutritional status was evaluated with the modified body mass index (s-albumine × BMI). KEY RESULTS: Gastric retention was found in about one-third of the patients. A weak correlation was found between the scintigraphic gastric emptying rate and both the sympathetic (rs = -0.397, P < 0.001) and parasympathetic function (rs = -0.282, P = 0.002). The gastric emptying rate was slower in those with lower or both upper and lower GI symptoms compared with those without symptoms (median T(50) 123 vs 113 min, P = 0.042 and 192 vs 113 min, P = 0.003, respectively). Multiple logistic regression analysis showed that age of onset (OR 0.10, CI 0.02-0.52) and sympathetic dysfunction (OR 0.23, CI 0.10-0.51), but not gender (OR 0.76, CI 0.31-1.84) and parasympathetic dysfunction (OR 1.81, CI 0.72-4.56), contributed to gastric retention. CONCLUSIONS AND INFERENCES: Gastric retention is common in hereditary transthyretin amyloidosis early after onset. Autonomic neuropathy only weakly correlates with gastric retention and therefore additional factors must be involved.

Physiological responses to touch massage in healthy volunteers.

OBJECTIVES: To evaluate effects of touch massage (TM) on stress responses in healthy volunteers. METHODS: A crossover design including twenty-two (mean age=28.2) healthy volunteers (11 male and 11 female) cardiac autonomic tone was measured by heart rate (HR) and heart rate variability (HRV). Stress hormone levels (cortisol) were followed in saliva. We also measured blood glucose and serum insulin. Extracellular (ECV) levels of glucose, lactate, pyruvate and glycerol were followed using the microdialysis technique (MD). TM was performed on hands and feet for 80 min, during control, participants rested in the same setting. Data were collected before, during, and after TM and at rest. Saliva cortisol, serum glucose, and serum insulin were collected before, immediately following, and 1 h after intervention or control, respectively. RESULTS: After 5 min TM, HR decreased significantly, indicating a reduced stress response. Total HRV and all HRV components decreased during intervention. Saliva cortisol and insulin levels decreased significantly after intervention, while serum glucose levels remained stable. A similar, though less prominent, pattern was seen during the control situation. Only minor changes were observed in ECV levels of glucose (a decrease) and lactate (an increase). No significant alterations were observed in glycerol or pyruvate levels throughout the study. There were no significant differences between groups in ECV concentrations of analyzed substances. CONCLUSIONS: In healthy volunteers, TM decreased sympathetic nervous activity, leading to decreased overall autonomic activity where parasympathetic nervous activity also decreased, thereby maintaining the autonomic balance.

Investigation of boundary conditions for biomimetic HA deposition on titanium oxide surfaces.

To improve the clinical outcome of metal implants, i.e. earlier loading and reduction of the incidence of revision surgery, better bone bonding ability is wanted. One method to achieve this is to change the surface chemistry to give a surface that facilitates bone bonding in vivo, i.e. a bioactive surface. Crystalline titanium oxide has recently been proven to be bioactive in vitro and is an interesting option to the more common hydroxylapatite (HA) coatings on implants. A materials possible in vitro bioactivity is tested through soaking in simulated body fluid and studies of possible HA formation on the surface. For bioactive materials, the formed HA layer can also be used as a coating. The aim of the current paper is to investigate some boundary conditions for HA formation on crystalline titanium oxide surfaces regarding influence from coating thickness, soaking time and soaking temperature. The influence from soaking time and temperature on the HA growth were investigated on oxidised Ti samples, (24 h at 800 degrees C) resulting in a rutile surface structure. The oxidised samples were tested at three temperatures (4, 37 and 65 degrees C) and four times (1 h, 1 day, 1 week and 4 weeks). The influence from titanium coating thickness on the HA growth was investigated via depositing thin films of crystalline titanium dioxide on Ti plates using a reactive magnetron sputtering process. Four different PVD runs with coating thicknesses between 19 and 74 nm were tested. The soaking temperature had an effect on the HA formation and growth on both rutile surfaces and native oxide on Ti substrates. Higher temperatures lead to easier formation of HA. It was even possible, at 65 degrees C, to grow HA on native titanium oxide from soaking in PBS. The coating quality was better for HA formed at 65 degrees C compared to 37 degrees C. All PVD-coatings showed HA growth after 1 week in PBS at 37 degrees C, thus even very thin coatings of crystalline titanium oxide coatings are bioactive.

Can analysis of heart rate variability predict arrhythmia in children with Fontan circulation?

The aim of this study was to examine whether changes in heart rate variability (HRV) can predict arrhythmias in children who have undergone the Fontan procedure. The study included 15 children with total cavopulmonary connection. All examinations included echocardiography and 24-h ambulatory electrocardiogram with power spectral analysis of HRV and Poincaré plots (plots of each R-R interval as a function of the previous R-R interval). Six patients developed supraventricular tachycardia (four or more consecutive supraventricular beats). One patient was excluded from the study due to the development of bradycardia, necessitating placement of a pacemaker. Compared to the arrhythmia group, the patients without arrhythmias (n = 8) exhibited a significant difference in the standard deviation of instantaneous beat-to-beat R-R interval variability (p = 0.02). Poincaré plots of patients without arrhythmias showed a typical torpedo- or comet-shaped pattern, whereas the arrhythmia group showed a more complex pattern. Although this study examined only a few subjects, needing confirmation by larger studies, it does indicate that patients who develop arrhythmias after receiving the Fontan procedure show a different Poincaré pattern compared to the nonarrhythmic group-even before the arrhythmia can be detected using the conventional Holter procedure. Routine follow-up using the Holter procedure and Poincaré plot analysis could help detect early arrhythmias.

Wireless system for real-time recording of heart rate variability for home nursing.

Modern wireless communication technologies offer new possibilities for patient monitoring in hospitals, as well as at home or in outdoor environments. In this paper, we present a wireless system for ECG recordings and real-time analysis of heart rate variability (HRV). The system also makes it possible for distance consultation, for example with a specialist in cardiology, with the help of a WEB-solution.

Adaptive spatio-temporal filtration of bioelectrical signals.

In this paper we show how independent component analysis (ICA) algorithms can be used to perform spatio-temporal filtration of electromyographic (EMG) and electrocardiographic (ECG) signals. The technique was used to decompose the EMG signals into motor unit action potential (MUAP) trains. From the 88 outputs of the adaptive spatio-temporal filtration, three groups of different MUAP train patterns were found. The technique was also used to obtain a fetus' ECG and showed better result compared to using ICA.

Does the autonomic nervous system play a role in the development of insulin resistance? A study on heart rate variability in first-degree relatives of Type 2 diabetes patients and control subjects.

AIMS: To investigate dysregulation of the autonomic nervous system as a potential mechanism for early insulin resistance in the development of Type 2 diabetes. METHODS: Thirteen healthy individuals with first-degree relatives with Type 2 diabetes (R) were compared with 14 control subjects without family history of diabetes (C), matched for age, body mass index and sex. An oral glucose tolerance test and a hyperinsulinaemic euglycaemic clamp were performed. Analysis of heart rate variability during rest, controlled breathing, an orthostatic manoeuvre and a standardized physical stress (cold pressor test (CPT)), were used to evaluate the activity of the autonomic nervous system. RESULTS: Fasting blood glucose, HbA1c and serum insulin were similar in the R and C groups. The M-value, reflecting insulin sensitivity, did not differ significantly between the groups. Total spectral power and high-frequency power were lower in R during controlled breathing (P = 0.05 and P = 0.07, respectively), otherwise there were no significant differences between R and C in heart rate variability. However, low-frequency (LF)/high-frequency (HF) spectral power ratio during CPT, reflecting sympathetic/parasympathetic balance, was negatively associated with insulin sensitivity (r = -0.53, P = 0.006). When all subjects were divided into two groups by the mean M-value, the low M-value group displayed an overall higher LF/HF ratio (P = 0.04). HF power was lower in the low M-value group during controlled breathing and CPT (P = 0.01 and P = 0.03, respectively). CONCLUSION: An altered balance of the parasympathetic and sympathetic nervous activity, mainly explained by an attenuated parasympathetic activity, might contribute to the development of insulin resistance and Type 2 diabetes.

Sleep-disordered breathing and coronary artery disease: long-term prognosis.

The evidence linking sleep-disordered breathing to increased mortality and cardiovascular morbidity has been conflicting and inconclusive. We hypothesized that a potential adverse effect of disordered breathing would be more obvious in patients with established vascular disease. In a prospective cohort study 408 patients aged 70 yr or younger with verified coronary disease were followed for a median period of 5.1 yr. An apnea-hypopnea index (AHI) of > or = 10 and an oxygen desaturation index (ODI) of > or = 5 were used as the diagnostic criteria for sleep-disordered breathing. The primary end point was a composite of death, cerebrovascular events, and myocardial infarction. There was a 70% relative increase and a 10.7% absolute increase in the primary composite end point in patients with disordered breathing defined as an ODI of > or = 5 (risk ratio 1.70, 95% confidence interval [CI] 1.15-2.52, p = 0.008). Similarly, patients with an AHI of > or = 10 had a 62% relative increase and a 10.1% absolute increase in the composite endpoint (risk ratio 1.62, 95% CI 1.09-2.41, p = 0.017). An ODI of > or = 5 and an AHI of > or = 10 were both independently associated with cerebrovascular events (hazard ratio 2.62, 95% CI 1.26-5.46, p = 0.01, and hazard ratio 2.98, 95% CI 1.43-6.20, p = 0.004, respectively). We conclude that sleep-disordered breathing in patients with coronary artery disease is associated with a worse long-term prognosis and has an independent association with cerebrovascular events.

Pre- and post-season heart rate variability in adolescent cross-country skiers.

To investigate the effects on cardiac autonomic control after a competitive cross-country skiing season, 9 females and 8 males, 16-19 years old, performed tilt-table heart rate variability (HRV) recordings and incremental treadmill tests before (August), and after (April the following year) the most intensive period of training and competition. Spectral analysis of HRV showed increased total variability at rest and reduced low frequency variability in the tilted position (LFtilt) at the second test (P<0.05). The female subgroup showed consistently higher high frequency (HF) and total heart rate variability than males. Total run time (RunT) increased from 18.5+/-1.9 min to 19.4+/-1.7 min (mean+/-SD) in the entire group (P<0.05), while VO2max only showed a non-significant increase (0.05

Cardiac autonomic imbalance in an overtrained athlete.

PURPOSE: In order to investigate overtraining-related adaptations in the autonomic nervous system, cardiac autonomic activity was examined in a junior cross-country skier who presented with reduced performance in competitions, early breathlessness during training sessions, and accumulated central fatigue. METHODS: Power spectral analysis of heart rate variability (HRV) was performed before, when overtrained (OT), and after recovery (Rec). RESULTS: In the overtrained state, high frequency (HF) and total powers in the lying position were higher compared with before and after. In normalized units, the increased HF in OT was even more prominent and clearly higher than in any control subject, and it was reversed in Rec. Resting heart rate was slightly reduced in OT and returned to baseline in Rec. CONCLUSIONS: The shift toward increased heart rate variability, particularly in the HF range, together with a reduced resting heart rate suggest a cardiac autonomic imbalance with extensive parasympathetic modulation in this athlete when overtrained.

Endoscopic transthoracic sympathicotomy affects the autonomic modulation of heart rate in patients with palmar hyperhidrosis.

BACKGROUND: Palmar hyperhidrosis has been associated with an increased activity of the sympathetic nervous system. The objective of this study was to assess the immediate and long-term effects of endoscopic transthoracic sympathicotomy on the autonomic modulation of the heart rate in patients with palmar hyperhidrosis. METHODS: Power spectrum analysis of heart rate variability in the lying position and after passive tilt to the upright position was performed in thirteen patients the day before and after sympathicotomy. A follow-up recording was performed in ten patients approximately six months later. Recordings from 26 healthy subjects were used as a reference group. FINDINGS: The patients had a tendency to higher power of the low-frequency (LF: 0.04-0.15 Hz) and high-frequency (HF; above 0.15 Hz) components than controls in the upright position. After sympathicotomy LF power was reduced, but HF power was unchanged. At follow-up LF power remained at a lower level, but now HF power was reduced. INTERPRETATION: Patients with palmar hyperhidrosis have a sympathetic overactivity but also a compensatory high parasympathetic activity. Sympathicotomy results in an initial sympathovagal imbalance with a parasympathetic predominance, which is restored on a long-term basis.

Cardiac rhythm in patients with sleep-disordered breathing and coronary artery disease.

We examined the effect of sleep-disordered breathing on heart rates and arrhythmias in men and women with disabling angina pectoris and verified coronary artery disease by an overnight sleep study and Holter recording. The number of oxyhaemoglobin desaturations > or =4% (ODI) and number of apnoea-hypopnoeas per hour of sleep (AHI) were recorded. ODI > or =5 and AHI > or =10 were used as measures of disordered breathing and patients below these limits formed the control groups. One-hundred and forty-one men and 98 women < or =70 years of age were randomly included. Thirty-eight percent of the men and 36% of the women had an ODI > or =5. No serious ventricular arrhythmias occurred. Women with disordered breathing (ODI > or =5) had higher heart rates (mean 63.3 vs 59.1, p < 0.05) and a higher occurrence of ventricular premature contractions (VPCs) during sleep (75th percentiles 2.5 vs 0.5 per hour, p < 0.01). In men, however, no significant association between disordered breathing and heart rates or arrhythmias was found. We conclude that serious arrhythmias are infrequent in unselected patients with coronary artery disease and mild to moderate sleep-disordered breathing. Disordered breathing in women is associated with higher heart rates and a higher occurrence of VPCs during sleep.

Short-term overtraining: effects on performance, circulatory responses, and heart rate variability.

PURPOSE AND METHODS: Nine elite canoeists were investigated concerning changes in performance, heart rate variability (HRV), and blood-chemical parameters over a 6-d training camp. The training regimen consisted of cross-country skiing and strength training, in total 13.0+/-1.6 h, corresponding to a 50% increase in training load. RESULTS: Time to exhaustion (RunT) decreased from 19.1+/-1.0 to 18.0+/-1.2 min (P < 0.05). VO2max and max lactate (La(max)) both decreased significantly (P < 0.05) over the training period (4.99+/-0.97 to 4.74+/-0.98 L x min(-1) and from 10.08+/-1.25 to 8.98+/-1.03 mmol x L(-1) respectively). Heart rates (HR) decreased significantly at all workloads. Plasma volume increased by 7+/-7% (P < 0.05). Resting cortisol, decreased from 677+/-244 to 492+/-222 nmol x L(-1) (P < 0.05), whereas resting levels of adrenaline and noradrenaline remained unchanged. The change between tests in RunT correlated significantly with the change in HRmax (r = 0.79; P = 0.01). There were no group changes in high or low frequency HRV, neither at rest nor following a tilt. CONCLUSIONS: The reduced maximal performance indicates a state of fatigue/overreaching and peripheral factors are suggested to limit performance even though HRmax and La(max) both were reduced. The reduced submaximal heart rates are probably a result of increased plasma volume. HRV in this group didn't seem to be affected by short-term overtraining.