Paul Gérard

Cephalic and extracephalic pressure pain thresholds in chronic tension-type headache.

&NA; Pressure pain thresholds were assessed with an algometer (Sometic Inc.), over the forehead, temple and suboccipital region as well as over the Achilles tendon. A group of 32 patients suffering from chronic tension‐type headache was compared to 20 healthy controls and to 10 migraineurs without aura. Although individual values were widely scattered, pressure pain thresholds were on average significantly lower in chronic tension‐type headache, not only at pericranial sites but also over the Achilles tendon. Only 50% of these patients had one or more pericranial thresholds 1.5 S.D. below the mean of controls. After muscular biofeedback therapy, all pain thresholds were on average increased. Along with results obtained previously, the present data support the hypothesis that diffuse disruption of central pain‐modulating systems, possibly due to a modified limbic input to the brain‐stem, is pivotal in the pathophysiology of chronic tension‐type headache.

Computed tomographic pulmonary angiography and prognostic significance in patients with acute pulmonary embolism

Background: Patients with acute pulmonary embolism (APE) present with a broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) has progressively been established as a first line test in the APE diagnostic algorithm, but estimation of short term prognosis by this method remains to be explored. Methods: Eighty two patients admitted with APE were divided into three groups according to their clinical presentation: pulmonary infarction (n = 21), prominent dyspnoea (n = 29), and circulatory failure (n = 32). CTPA studies included assessment of both pulmonary obstruction index and right heart overload. Haemodynamic evaluation was based on systolic aortic blood pressure, heart rate, and systolic pulmonary arterial pressure obtained non-invasively by echocardiography at the time of diagnosis of pulmonary embolism. Results: The mortality rate was 0%, 13.8% and 25% in the three groups, respectively. Neither the pulmonary obstruction index nor the pulmonary artery pressure could predict patient outcome. In contrast, a significant correlation with mortality was found using the systolic blood pressure (p<0.001) and heart rate (p<0.05), as well as from imaging parameters including right to left ventricle minor axis ratio (p<0.005), proximal superior vena cava diameter (p<0.001), azygos vein diameter (p<0.001), and presence of contrast regurgitation into the inferior vena cava (p = 0.001). Analysis from logistic regression aimed at testing for mortality prediction revealed true reclassification of 89% using radiological variables. Conclusion: These results suggest that CTPA quantification of right ventricular strain is an accurate predictor of in-hospital death related to pulmonary embolism.

Exteroceptive suppression of temporalis muscle activity in chronic headache

Early (ES1) and late (ES2) exteroceptive suppression periods elicited by electrical stimulation of the labial commissure during teeth-clenching were recorded over the temporalis muscle in 45 headache patients (25 tension headaches and 20 migraines) and 22 controls. Mean duration of ES2 for single shocks was significantly reduced in tension headache when compared with migraine or controls. At a stimulation rate of 2 Hz, ES2 was abolished in 40% of tension headache sufferers, but in none of the migraineurs. EMG analysis of temporalis late exteroceptive suppression might be a helpful diagnostic tool in functional headaches. Reduction of ES2 suggests that there is deficient activation or excessive inhibition of pontobulbar inhibitory interneurons which receive a strong input from limbic structures. ES2 might thus represent an interface between psychogenic and myogenic factors putatively involved in the pathogenesis of tension headache.

Circadian rhythm of heart rate and heart rate variability

BACKGROUND Measurements of heart rate variability (HRV) are increasingly used as markers of cardiac autonomic activity. AIM To examine circadian variation in heart rate and HRV in children. SUBJECTS A total of 57 healthy infants and children, aged 2 months to 15 years, underwent ambulatory 24 hour Holter recording. Monitoring was also performed on five teenagers with diabetes mellitus and subclinical vagal neuropathy in order to identify the origin of the circadian variation in HRV. METHODS The following variables were determined hourly: mean RR interval, four time domain (SDNN, SDNNi, rMSSD, and pNN50) and four frequency domain indices (very low, low and high frequency indices, low to high frequency ratio). A chronobiological analysis was made by cosinor method for each variable. RESULTS A significant circadian variation in heart rate and HRV was present from late infancy or early childhood, characterised by a rise during sleep, except for the low to high frequency ratio that increased during daytime. The appearance of these circadian rhythms was associated with sleep maturation. Time of peak variability did not depend on age. Circadian variation was normal in patients with diabetes mellitus. CONCLUSION We have identified a circadian rhythm of heart rate and HRV in infants and children. Our data confirm a progressive maturation of the autonomic nervous system and support the hypothesis that the organisation of sleep, associated with sympathetic withdrawal, is responsible for these rhythms.

Reference values of body composition obtained by dual energy X-ray absorptiometry in preterm and term neonates

BACKGROUND As previously reported, dual-energy x-ray absorptiometry provides reliable and accurate values for bone mineralization in piglets and infants, but overestimates fat content in small infants. The purpose of the current study was to determine an appropriate equation of correction for fat mass measurement and to establish reference values of body composition of preterm and term neonates. METHODS Fat mass and chemical whole-body fat content were evaluated by dual-energy x-ray absorptiometry in eight piglets with a body weight between 1408 and 5151 g. The results were combined with previous data obtained in 13 piglets, and two correction equations were determined according to fat mass content. Close to birth, 106 healthy appropriate-for-gestational-age preterm and term infants were scanned by dual-energy x-ray absorptiometry to determine bone mineral content, bone area, and fat mass. Fat mass content determined by dual-energy x-ray absorptiometry was corrected using the equations obtained in piglets after which lean body mass was recalculated. RESULTS Multivariate analysis showed that dual-energy x-ray absorptiometry body weight was the best predictor of bone mineral content (r2 = 0.94), bone area (r2 = 0.95), lean body mass (r2 = 0.98), and fat mass (r2 = 0.84). Gender was an additional significant independent variable for fat mass and lean body mass. Body weight related curves of percentiles for bone mineral content, bone area, fat mass, and lean body mass, were constructed. In vivo dual-energy x-ray absorptiometry values of fat mass and calcium content estimated from bone mineral content were in accordance with previously reported whole-body carcass reference values in preterm and term neonates. CONCLUSION Normative data of dual-energy x-ray absorptiometry body composition for healthy preterm and term infants are provided and can therefore be used in research and in clinical practice.

Aortic valve replacement in the octogenarians: perioperative outcome and clinical follow-up

OBJECTIVES To determine long-term results of aortic valve replacement (AVR) in patients 80 years old or older, and assess the factors influencing perioperative outcome. METHODS Data were reviewed on 83 consecutive octogenarians, undergoing aortic valve replacement between 1992 and 1997. There were 66 women and 17 men (mean age: 82.8 years). Fifty-seven patients (69%) were in New York Heart Association (NYHA) class III-IV and six had previous myocardial infarction. Three patients had previous percutaneous aortic valvuloplasty. There were 19 urgent procedures (23%). Coronary artery bypass grafting (CABG) was performed on 21 patients (25%). Possible influence of preoperative and operative variables on early and late mortality was performed with univariate and multivariate statistical analysis, and survival was estimated with the Kaplan-Meier method. RESULTS Operative mortality was 13% (9% for AVR, 24% for AVR-CABG). Postoperative complications were respiratory failure in 19 patients, atrial fibrillation in 19, hemodialysis in four, myocardial infarction in four and stroke in two patients. Five patients required pacemaker insertion for permanent atrioventricular block. Median hospital stay and intensive care unit stay were 19.8 +/- 12.2 days and 7.9 +/- 3.4 days, respectively. Multivariate predictors of hospital death (P < 0.05) were percutaneous aortic valvuloplasty, NYHA class IV, and urgent procedure. Mean follow-up was 26.5 months. Survival at 1, 2, and 5 years was 98.5 +/- 1.4% (63 patients at risk), 93.4 +/- 3.2% (47 patients at risk), and 78.2 +/- 6.9% (six patients at risk), respectively. Preoperative myocardial infarction and urgent procedure were independent predictors of late death. At most recent follow-up, 91% were angina free and 81% were in class I-II. CONCLUSIONS Aortic valve replacement in octogenarians can be performed with acceptable mortality. These results stress the importance of early operation on elderly patients with aortic valve disease. Both long-term survival and functional recovery are excellent.

Weight gain composition in preterm infants with dual energy X-ray absorptiometry.

Whole body composition was investigated using dual energy x-ray absorptiometry in 54 healthy preterm infants, birth weight < 1750 g, who were fed fortified human milk (n = 20) and preterm formula (n = 34) when full enteral feeding was attained and then again 3 wk later at around the time of discharge. Weight gain composition was calculated from the difference between the earlier and later measurement. The minimal detectable changes in whole body composition over time according to the variance of the population (within groups of 20 infants) and the minimal detectable changes according to the dietary intervention (between two groups of 20 infants) were determined at 5% significance and 80% power. Whole body composition was similar in the two groups at the initial measurement, but all the measured variables differed at the time of the second measurement. Formula-fed infants showed a greater weight gain (19.9 ± 3.2 versus 15.9 ± 2.2 g·kg-1·d-1, p < 0.05), fat mass deposition (5.1 ± 1.9 versus 3.3 ± 1.3 g·kg-1·d-1, p < 0.05), bone mineral content gain (289 ± 99 versus 214 ± 64 mg·kg-1·d-1, p < 0.05), and increase in bone area (1.6 ± 0.4 versus 1.3 ± 0.3 cm2·kg-1·d-1, p < 0.05) compared with the fortified human milk group. From these data, a minimal increase from the first measurement of 111 g lean body mass, 68 g fat mass, and 3.1 g bone mineral content is needed to be detectable in a longitudinal study that includes 20 infants. For significance between two groups of 20 infants around the time of discharge, dietary intervention needs to achieve minimal differences of 160 g lean body mass, 86 g fat mass, and 4.1 g bone mineral content. With respect to weight gain composition, the minimal differences required to reach significance are 2.1 g·kg-1·d-1 for gain in lean body mass, 1.2 g·kg-1·d-1 for gain in fat mass, and 76 mg·kg-1·d-1 for gain in bone mineral content. We conclude that dual energy x-ray absorptiometry allows evaluation of the effects of dietary intervention on whole body and weight gain composition in preterm infants during the first weeks of life.

Chest Pain in Pediatric Patients Presenting to an Emergency Department or to a Cardiac Clinic

The aim of this study was to assess the epidemiology of chest pain among unselected Belgian children referred to an emergency department or to a cardiology clinic. Material and methods - We analyzed the etiology to chest pain and the diagnostic workup of 168 consecutive pediatric patients, seen in our emergency department with the primary diagnosis of chest pain over a 5-year period (group A). Simultaneously a sample of 69 consecutive pediatric patients referred to the cardiology clinic by primary care physicians with the same chief complaint was prospectively included in the study (group B). Results - Chest wall pain was the most common diagnosis in the group A (64%). Other causes included pulmonary (13%), psychological (9%), cardiac (5%), traumatic (5%), and gastrointestinal problems (4%). The organic causes were easily identified or suspected by history and physical examination. Chest radiography, electrocardiography, and blood analysis were performed in most patients with suspected nonorganic chest pain but in no case were organic diseases diagnosed by those ancillary studies. In group B, chest wall pain was also the most common diagnosis (89%). Supraventricular tachyarrhythmia and exercise-induced asthma were demonstrated in 5 (7%) and 3 patients (4%), respectively. The most important tools in assessing a child with acute chest pain in an emergency department are thorough history and physical examination. Assessment of recurrent chest pain is more difficult; arrhythmia, and allergic and exercise-induced asthma may be underestimated when investigations are not performed.

Effects of endotoxic shock on right ventricular systolic function and mechanical efficiency

OBJECTIVE To investigate the effects of endotoxin infusion on right ventricular (RV) systolic function and mechanical efficiency. METHODS Six anesthetized pigs (Endo group) received a 0.5 mg/kg endotoxin infusion over 30 min and were compared with six other anesthetized pigs (Control group) receiving placebo for 5 h. RV pressure-volume (PV) loops were obtained by the conductance catheter technique and pulmonary artery flow and pressure were measured with high-fidelity transducers. RESULTS RV adaptation to increased afterload during the early phase of endotoxin-induced pulmonary hypertension (T30) was obtained by both homeometric and hetereometric regulations: the slope of the end-systolic PV relationship of the right ventricle increased from 1.4+/-0.2 mmHg/ml to 2.9+/-0.4 mmHg/ml (P<0.05) and RV end-diastolic volume increased from 56+/-6 ml to 64+/-11 ml (P<0.05). Consequently, right ventricular-vascular coupling was maintained at a maximum efficiency. Ninety minutes later (T120), facing the same increased afterload, the right ventricle failed to maintain its contractility to such an elevated level and, as a consequence, right ventricular-vascular uncoupling occurred. PV loop area, which is known to be highly correlated with oxygen myocardial consumption, increased from 1154+/-127 mmHg/ml (T0) to 1798+/-122 mmHg/ml (T180) (P<0.05) while RV mechanical efficiency decreased from 63+/-2% (T0) to 45+/-5% (T270) (P<0.05). CONCLUSIONS In the very early phase of endotoxinic shock, right ventricular-vascular coupling is preserved by an increase in RV contractility. Later, myocardial oxygen consumption and energetic cost of RV contractility are increased, as evidenced by the decrease in RV efficiency, and right ventricular-vascular uncoupling occurs. Therefore, therapies aiming at restoring right ventricular-vascular coupling in endotoxic shock should attempt to increase RV contractility and to decrease RV afterload but also to preserve RV mechanical efficiency.

Nonlinear analysis of cardiac rhythm fluctuations using DFA method

After a brief overview of classical techniques used to explore cardiac rhythm variability, we show how the DFA method can help diagnose heart failure.