Management of cardiac emergencies in children.

Children with heart disease may present to the Emergency Department in many stages of life, with a range of cardiovascular manifestions, from minimally irritating palpitations to the life-threatening derangements of shock or lethal dysrhythmia. Cardiac emergencies are rare in children in comparison to adults. The pathophysiology differs: ischemic heart disease is virtually unknown, whereas most cases occur secondary to congenital heart disease. Their successful management requires an accurate diagnosis and timely interventions to achieve optimal outcomes in this heterogeneous and complex patient population. The diagnosis, however, is not always straightforward, as evidenced by the non-specific clinical picture that can be presented by pediatric heart diseases. This article reviews pertinent issues concerning diagnosis and management of cardiac disorders with which children present to the emergency department. The initial diagnostic and specific therapeutic approach to these patients will be discussed.

Spectrum and workload of consultation activities in a Belgian tertiary paediatric cardiac centre.

BACKGROUND: Few data are available on the spectrum and frequency of issues addressed in the paediatric cardiology consultation service of tertiary academic hospitals. METHODS: Those activities were collected prospectively during 6 months. RESULTS: A total of 967 consultations were performed. The origin was mostly the medical ward (n = 535), the intensive care unit (n = 195), the neonatal unit (n = 97), the operating room (n = 84) and the nursery (n = 44). In 553 cases, a heart disease was previously known and the most common reasons of consultation were postoperative (n = 279) and preoperative evaluations (n = 129). Thirteen newborns had a prenatal suspicion of congenital heart disease, which was confirmed in 11 cases. For the other 401 consultations, the most common clinical concerns included cardiac function in oncological disease (n = 60), murmur (n = 48), syncope (n = 33), diabetes mellitus (n = 28), prematurity (n = 27), syndrome (n = 19), unexplained stridor or respiratory distress (n = 19) and unexplained fever (n = 15). There were new diagnoses of congenital heart disease, acquired heart disease and arrhythmias in 35, 17 and 5 cases, respectively. CONCLUSIONS: The workload of the paediatric cardiology consultation service is increasing alarmingly. These data may be helpful in future planning of consultant manpower and in curriculum development in cardiac training of students and residents.

Spectrum and frequency of illness presenting to a pediatric emergency department.

BACKGROUND: Knowledge of the spectrum and relative frequencies of pediatric emergencies is an important factor in developing appropriate training curricula for pediatric residents. MATERIAL AND METHODS: To provide these data, we indexed the 11,483 consecutive patients seen in our pediatric emergency department (PED) during the year 2003. RESULTS: Age ranged from 1 week to 27 years, with a mean age of 3.9+/-4.3 years. 52.7% of the visits were by children younger than 3 years, 9.5% by adolescents, and 0,1% by young adults with chronic conditions. 55.1% of the patients arrived on day shift, 32.5% on evening shift and 12.4% on night shift. 61.8% of the patients were seen during the evening/nighttime or on the weekends. 25.2%, 22.1% and 28.6% of the patients seen on night, day and evening shifts respectively were hospitalized. The most common chief complaints were fever (22.1%), upper respiratory tract infection (13.2%) and diarrhea (10%). The most common final diagnoses were upper respiratory tract infection (26.7%), viral syndrome (13.1%) and gastroenteritis (10.7%). The majority of chief complaints and final diagnoses were related to infection (63.9%). CONCLUSION: These data may contribute to curriculum development in training of PED physicians. We especially recommend an emphasis on management of fever and infections to optimize the quality of care delivered in the pediatric emergency department.

Delayed recognition of congenital heart disease.

OBJECTIVE: The aim of this prospective study was to evaluate the proportion of children with delayed recognition of congenital heart disease (CHD). METHODS: Of the 744 children with CHD primarily diagnosed during a 10 year period in one hospital, the patients were identified where the diagnosis of CHD was established with a significant delay. RESULTS: Sixty six patients (8.9%) had delayed diagnosis of CHD. Among patients with cyanotic CHD, 10.4% (7 of 67 cases) were referred after they had initially been discharged home from the birth clinic. Among patients with acyanotic CHD, 8.7% (59 of 677) of all children and 35.1% (59 of 168) of the children who required surgery or interventional catheterisation were referred at an age where elective repair should have already been performed or needed immediate treatment because of their haemodynamic status. Of the 66 patients with delayed diagnosis, one infant with cor triatriatum died at admission because of delayed referral and 10 children had severe complications: preoperative cardiogenic shock in seven cases of aortic coarctation and one case of endocardial fibroelastosis, pulmonary hypertensive crisis in one child after delayed repair of a ventricular septal defect, and infectious endocarditis after dental care in a teenager with undiagnosed moderate aortic stenosis, who required Ross operation a few months later. DISCUSSION AND CONCLUSION: A substantial proportion of CHD was detected with relevant delay. In all cases of late diagnosis, clinical cardiac findings were present that should have alerted the physician on the possible presence of underlying CHD.

Patterns of physical activity determined by heart rate monitoring among diabetic children.

BACKGROUND: Children with type 1 diabetes should be encouraged to participate in physical activity because exercise can benefit insulin sensitivity and improve known risk factors for atherosclerosis. METHODS: Physical activity patterns of 127 children and adolescents with stable type 1 diabetes were investigated by 24 hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of physical activity at different intensities. The results were compared with normative data. RESULTS: Diabetic preschoolchildren accumulated 192.7 (78.1), 39.1 (24.3), and 21.3 (9.4) minutes/day (mean (SD)) of light, moderate, and vigorous physical activity, respectively. At the same activity levels, diabetic schoolchildren accumulated 168.9 (76.7), 37.9 (15.9), and 19.0 (14.8) minutes/day, and diabetic teenagers accumulated 166.3 (67.5), 45.6 (26.9), and 25.2 (15.3) minutes/day. Diabetic schoolchildren were significantly more active than healthy peers when considering moderate activity; diabetic teenagers were significantly more active when considering moderate and vigorous activity. There was a negative correlation between the most recent glycated haemoglobin and the time spent in light activities in schoolchildren, and a negative correlation between mean glycated haemoglobin for one year and time spent in light and moderate activities in schoolchildren. CONCLUSION: The majority of our diabetic patients meet the classical paediatric guidelines for physical activity and compare favourably with their healthy peers.

Patterns of physical activity defined by continuous heart rate monitoring among children from Liège.

Health benefits of a physically active lifestyle are well documented. We therefore investigated the physical activity patterns of 200 children from Liège. They were monitored continuously using a 24-hour Holter monitoring system during normal weekdays and the percentage of heart rate reserve (%HRR) was used to measure the amounts of physical activity at different intensities. Preschool children attained 184.3+/-54.2, 40.7+/-16.1, 15.8+/-6.9 and 6.0+/-7.2 minutes/day (mean+/-SD) between 20% to 40%, 40% to 50%, 50% to 60%, and greater than 60% of HRR, respectively. At the same %HRR intensities, schoolchildren attained 165.6+/-74.6, 32.1+/-12.1, 15.8+/-6.7 and 7.0+/-5.9 minutes/day, and teenagers attained 159.2+/-68.3, 32.1+/-23.5, 13.1+/-6.0 and 6.1+/-6.3 minutes/day. Age was a significant predictor of the intercept and slope of the time spent in physical activity and %HRR relationship. In Liège the average youth accumulates +/-30 to 40 minutes/day of moderate-intensity physical activity and +/-20 minutes/day of high-intensity physical activity. Those children meet the classical revised guidelines for physical activity but do not compare favourably with children from elsewhere. On the other hand, they get more than 2 1/2 to 3 hours/day of low-intensity physical activity. Our findings suggest that children from Liège are not engaged in sedentary behaviour but do not experience the ideal amount and type of physical activity classically believed to benefit the cardiopulmonary system. Public health strategies should be adapted to our findings.

The influence of fetal and postnatal growth on heart rate variability in young infants.

Heart rate variability (HRV), a measure of cardiac autonomic control, was analyzed in infants to assess the hypothesis that early undernutrition may induce autonomic dysfunction that could play a role in the programming of later cardiovascular disease. HRV data were collected during a night session in 546 healthy infants at 5-12 weeks of adjusted age, and statistical associations with fetal and postnatal growth indices were established. A significant positive correlation between birth weight, the ratio of neonatal weight to head circumference and postnatal weight gain, and HRV indices mostly influenced by sympathetic activity was demonstrated in 11- and 12-week-old infants. A slight correlation (p > 0.05) was also found in younger infants. These data suggest the influence of fetal and postnatal growth on the programming of the autonomic nervous system beyond the neonatal period. This influence may be one of the important mechanisms that link impaired growth in fetal and infant life to high blood pressure and other cardiovascular disease during childhood and adulthood (the Barker hypothesis).

Normal ranges for the variability in heart rate in young infants while sleeping.

OBJECTIVE: Measurements of the variability in heart rate are increasingly used as markers of cardiac autonomic activity. We sought to establish the development this variability in healthy young infants while sleeping. PATIENTS: We carried out polygraphic studies with electrocardiographic recording in 587 healthy infants aged from 5 to 26 weeks. METHODS: We determined several variables over a period of 400 minutes sleeping: mean RR interval, 5 time-domain (SDNN, SDNNi, SDANNi, RMSSD, and pNN50) and 5 frequency-domain indexes (spectral power over 3 regions of interest, total power and low-to-high frequency ratio). Frequency-domain indexes were also assessed separately for the periods of quiet sleep and those of rapid eye movement sleep. RESULTS: Our data showed a significant correlation between the indexes of heart rate variability and the mean RR interval, the breathing rate, and the corrected age of the infants. We also demonstrated the importance of the maturation of the sleeping patterns. CONCLUSION: These data in a large cohort of healthy infants confirm a progressive maturation of the autonomic nervous system during sleep, and may be used to examine the influence of physiological and pathophysiological factors on autonomic control during polygraphic studies.

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.

Heart rate variability and the outcome of head-up tilt in syncopal children.

OBJECTIVE: This study evaluated autonomic nervous system function in 5 young (6-10 years old) and 5 older (10-15 years) children with recurrent episodes of neurally mediated syncope and a positive tilt-test result, 10 with syncope but a negative test result and 30 age-matched healthy volunteers. METHODS: Time- (SDNN, SDNNi, SDANNi, rMSSD, pNN50) and frequency-domain indices (LF, HF, LF/HF) of heart rate variability (HRV) were measured during a 24-hour Holter recording and for 5 min. segments before and during 90 degrees head-up tilt (tests lasted 30 min. or until syncope occurred). RESULTS: 24-hour HRV-indices were within the normal range for all syncopal patients. Mean RR interval and HRV-indices, except LF/HF, were higher in the older children with a positive test result before they were tilted and during the first 5 min. of head-up tilt. HRV-indices tended to be lower after tilt in the younger children with a positive test result. SDNN and LF in older children with a positive test result and LF/HF in the younger ones increased during the 5 min preceding the syncope. No difference was observed between syncopal children with a negative test result and controls. CONCLUSION: This study confirms that patients with vasovagal syncope have no chronic differences from normal subjects in autonomic nervous system activity. The modulation of the autonomic tone during head-up tilt is abnormal in children who faint during the test, but younger and older patients respond differently to the orthostatic stimulus.

Dependency of premature ventricular contractions on heart rate and circadian rhythms during childhood.

The aim of the present study was to identify and quantify the rate dependence of premature ventricular contractions (PVC) during childhood. A 24-hour Holter recording was performed in 16 consecutive children, aged 22 days to 11 years (mean age 5.6 years), with frequent (>5,000/day), isolated monomorphic PVC. Those PVC were identified and the length of the preceding sinus cycle was measured. The values were ordered into 50-ms class intervals, and the percentage of PVC for each class was calculated and then analyzed by linear regression analysis. On the basis of the significance of the p value, and the positive or negative value of the slope, we identified a tachycardia-enhanced, a bradycardia-enhanced, and an indifferent pattern. Chronobiologic analysis was made by the cosinor method. All the patients had upper and lower limits of cycle length beyond which PVC disappeared. A tachycardia-enhanced pattern was present in 7 patients and an indifferent one in 9 patients. In the latter a second-degree polynomial correlation was systematically found. Children but not infants had a significant circadian variation in the frequency of PVC with a very variable time of highest incidence. In conclusion, it is possible to identify a circadian rhythm of PVC and a spontaneous trend between their incidence and the length of the preceding cardiac cycle in children.

Gas exchange and heart rate kinetics during binary sequence exercise in cystic fibrosis.

MATERIAL AND METHODS: Gas exchange and heart rate (HR) kinetics were investigated in 20 patients with cystic fibrosis (CF) by using a pseudorandom binary sequence (PRBS)-technique. Electrocardiogram was continuously recorded, and VO2, VCO2 and ventilation/min (VE) responses to a multifrequent input signal were measured by means of breath-by-breath analysis. Lag time and peak value in the time-domain, and amplitude ratios in the frequency-domain were calculated to characterize the crosscorrelation functions between input and responses, and compared to normal ranges. RESULTS: Time and frequency domain parameters are abnormal for VO2, VCO2 and VE responses in moderately and severely ill patients, and for the HR response only in severely ill patients. Correlations are shown between those parameters, the severity of the illness evaluated by the Shwachman score and the level of impairment of the pulmonary function. CONCLUSION: The PRBS-technique is a useful tool to investigate the gas exchange and HR kinetics in CF patients, that offers many advantages: (1) no explicit mathematical models are assumed, (2) it is a walking test that may be used even in very young or severely ill patients, and (3) it challenges the ability to adapt to non-steady state exercise and is therefore representative for daily activities.

Cardiac autonomic dysfunction in diabetic children.

OBJECTIVE: Adults with type 1 diabetes may have abnormal alterations in heart rate variability (HRV) due to cardiac autonomic neuropathy. This prospective study was performed to determine whether HRV can be used to detect subclinical autonomic neuropathy in diabetic children. RESEARCH DESIGN AND METHODS: We examined five time domain and three frequency domain HRV indices determined from 24-h Holter recordings in 73 diabetic children and adolescents aged 3-18 years (mean 12.1 years) with a mean duration of diabetes of 55 months. The measures were compared with normal ranges. Z scores were established for each parameter and were compared with classic risk factors of other diabetic complications. RESULTS: Most HRV indices were significantly depressed in children aged > or = 11 years, and the levels of HRV abnormalities were significantly correlated with long-term metabolic control (mean GHb for 4 years) in that age-group. In younger patients, HRV indices were within the normal range and were not correlated with the level of metabolic control. Illness duration and microalbuminuria but not short-term metabolic control (most recent GHb) were also independently predictive of HRV abnormalities. CONCLUSIONS: These results suggest that early puberty is a critical period for the development of diabetic cardiac autonomic dysfunction. Therefore, all type 1 diabetic patients should be screened for this complication by HRV analysis beginning at the first stage of puberty regardless of illness duration, microalbuminuria, and level of metabolic control.

Midterm results of the neonatal arterial switch operation. A review.

Complete transposition of the great arteries is a relatively common anomaly, which comprises 5 to 7% of all instances of cardiac malformations. Given the decreasing mortality rates associated with a neonatal arterial switch operation and the unacceptable morbidity associated with atrial baffle operations, it is reasonable to accept this operation as the procedure of choice for the treatment of the complete transposition of the great arteries. It represents a major improvement since it does not introduce any additional intracardiac anomaly, restores the left ventricle to its natural systemic function, and maintains the sinus node function. Long-term survival exceeds 90%. Midterm general health status is encouraging. To date, there have been limited long-term follow-up studies after a neonatal arterial switch operation, although the intermediate data are promising. It will be necessary to determine whether the theorized benefits of the anatomic repair are realized, since experience is limited to the last 15 years. Translocation of the coronary arteries remains one of the most difficult aspects of the operation and late mortality appears to coincide with coronary artery events with sudden death secondary to acute myocardial infarction being reported in 1-2% of hospital survivors. Supravalvar pulmonary stenosis, neoaortic root dilation and valvar regurgitation, bronchopulmonary collateral arteries, coronary insufficiency, and myocardial perfusion abnormalities are other specific areas which require close observation and further investigation.