FURTHER MAPPING OF THE NATALITY CHRONOME IN TODA CITY (JAPAN) MATERNITY HOSPITAL.

In order to investigate any circannual and/or circaseptan variations in birth incidence and birth weight in Toda City (Japan), data on 4,411 consecutive births were obtained from the city's Maternity Hospital between 1 Jan 1999 and 31 Dec 2001. Data were analysed by cosinor separately for babies with birth weights in given ranges, and separately for boys and girls born at different gestational ages. A circannual rhythm was detected with statistical significance (P=0.047) for birth incidence of all vaginal deliveries, with an acrophase in the fall. A similar result for caesarean sections was of borderline statistical significance. A circaseptan component with a relatively consistent acrophase around midweek was of borderline statistical significance for birth incidence in some of the groups investigated. About-yearly and about-weekly variations were also found to characterize birth weight in some of the groups investigated.

Heart rate variability in normotensive healthy children with aging.

Although the heart rate variability (HRV) values in adults decrease with aging, those in children show a variety of changes. The present study was designed to investigate the relationship between HRV and aging, physique and blood pressure in 70 healthy male school children, between 6 and 12 years of age. The subjects were divided into 3 age groups (6-7, 8-9 and 10-12 years) and 3 other groups according to physique (thin, under -10%; normal, -10-20% and obese, over 20% of obesity index). After recording a 24-h ambulatory electrocardiograph, HRV was determined spectrally, using 3 components: the total-frequency (TF) component (0.01 to 0.5 Hz), the low-frequency (LF) component (0.04 to 0.15 Hz), the high-frequency (HF) component (0.15 to 0.5 Hz) and also a two component ratio (LF/HF). The HRV values between the 3 age groups had a significant effect on TF, LF and LF/HF during the 24-h period, with the values increasing with age. The HRV values between the 3 physique groups had no significant effect. Therefore, changes in HRV in school children are affected by age and not physique. It is possible that the increase in HRV values with age is caused by the development of the autonomic nervous system.

Seasonal variation in 1/f fluctuations of heart rate in asthmatic children.

We have reported previously that asthmatic children have a seasonal variation in the power spectrum in the low frequency, LF (0.04-0.15 Hz) and high frequency, HF (0.15-0.6 Hz) bands of heart rate variability (HRV). In recent years, the l/f fluctuations of heart rate (HR) have been used as a novel index of autonomic function from a chronobiological viewpoint. As asthma is a disease with symptoms affected by seasonal chronobiological changes, we examined whether the l/f fluctuations of HR in asthmatic children changed by season. The subjects examined were 87 asthmatic and 104 healthy children. Using a Holter recorder, a 24-h ambulatory electrocardiogram (AECG) was obtained from each subject. The l/f fluctuations of HR during the time awake, the time asleep, and the 24-h period for each of the four seasons were analyzed by the MemCalc system (Suwa Trust). No seasonal variations of HR l/f fluctuations were detected in either the asthmatic or the control group for any of the three periods analyzed. There was a significant seasonal variation in the mean of the normal-to-normal R-R intervals during the 24-h period in the asthmatic children, but not in the healthy children. In the children with asthma, although their HR varied by season, the l/f fluctuations of HR did not.

Seasonal variation in heart rate variability in asthmatic children.

Asthma is a "seasonal disease" with symptoms either aggravated by environmental changes during specific seasons or prevalent at certain times of the year for other reasons. We examined whether the heart rate variability (HRV) of asthmatic children changes by season. The HRV during a portion of one night (00:00-04:00) and day (12:00-16:00) and the entire 24h period (00:00-24:00) during each of the four seasons was analyzed. The data of 95 children with asthma and 106 healthy children, as controls, were assessed. In children with asthma during the 24h period, seasonal variation in the low-frequency (LF) band (0.04-0.15 Hz) and the high-frequency (HF) band (0.15-0.4 Hz) were detected (HF: F=6.81, p=.0003; LF: F=4.18, p= .008). The HF value in the summer was significantly higher than in autumn and spring (Scheffe test: autumn vs. summer, s = 4.46, p < .001: spring vs. summer, s = 2.86, p < .05), while the LF value in autumn was significantly lower than in summer (s = 3.42, p < .01). In the control group, no seasonal variation in HF, LF, or LF/HF was detected. The findings infer the HRV, a surrogate measure of autonomic nervous system function, of asthmatic children is more susceptible to seasonal changes brought about by either endogenous annual rhythms or environmental weather phenomena.

Can heart rate variability predict sudden death? A case of sudden death in a child with severe coronary sequelae of Kawasaki disease.

We report the heart rate variability (HRV) of a child aged 11 years. Arrhythmia was the suspected cause of sudden death after 10 years of therapy for Kawasaki disease. The linear methods failed to show any features of the HRV that could have predicted the patient's sudden death, but the fractal scaling as a nonlinear method had suddenly decreased from 5.3 to 4.1 1 year before his death.

[Circadian rhythm of parasympathetic nervous function in asthmatic children].

We examined the circadian rhythm of parasympathetic nervous function in asthmatic children. The subjects were 80 patients with asthma (mild 54 patients, moderate 15 patients and severe 11 patients) and 90 individuals in healthy children. All the patients underwent 24-electrocardiography in normal condition. We measured the %RR50 for hour and analyzed the rhythm using the single cosine fitting method, comparing the values of the Amplitude, the MESOR and the Acrophase in terms of the therapy and also the severity of asthma. Circadian rhythm disappeared in 9 of the 80 asthmatic children and was observed in all the individuals in the healthy children. The value of MESOR was lower in the asthmatic children than in the healthy children. There was no significant difference between the different severity or therapies in each group. In some asthmatic children, the circadian rhythm of parasympathetic nervous function disappeared, the parasympathetic nervous function was low in remission. It is suggested that the disorder of biologic rhythm is related to the pathogenesis of asthma.

Heart rate variability during 24 hours in asthmatic children.

The autonomic circadian rhythm plays an important role in asthma. In recent years it has become possible to evaluate autonomic nervous function (ANF) using analysis of heart rate variability (HRV). We analyzed the HRV in the 24h period following the state without an asthma attack in order to study the relationship between asthma and ANF. The HRV was analyzed in 94 asthmatic children (ages 5-15 years). These subjects were divided into groups according to the severity of their asthma. After recording a 24h ambulatory electrocardiograph (AECG), the HRV was analyzed by a computer. Evaluation of the HRV was carried out using time-domain and frequency-domain analyses. The ANF of asthma subjects was decreased in comparison to the normal group. The severity of asthma had a significant effect on the %RR50 (the proportion of cycles during which the difference is > 50 ms), the SD (standard deviation; mean of standard deviation of all normal RR intervals for all 5-minute periods), the low-frequency (LF) band (0.04 to 0.15 Hz), and the high-frequency (HF) band (0.15 to 0.4 Hz) (%RR50: F = 4.31, p = 0.01; SD: F = 3.48, p = 0.03; LF: F = 3.67, p = 0.02; HF: F = 3.41, p = 0.03). These values were lowest in the severe asthma group. With regard to the therapy grouping, the index that exhibited a significant difference was the NNA (mean of normal-to-normal RR intervals over 24h) (F = 4.43, p = 0.01). In conclusion, even in the normal condition in which the patient is free of an asthma attack, the ANF of asthma sufferers differs from that of normal children. It is possible that the different ANF of asthma sufferers is related to the severity of the asthma.

Cervical aortic arch associated with 22q11.2 deletion.

A 16-year-old boy had cervical aortic arch associated with 22q11.2 deletion. This case is the first one reported of cervical aortic arch in which deletion within the 22q11.2 band was detected by the fluorescent in situ hybridization (FISH) method.

Collateral circulation in Kawasaki disease with coronary occlusion or severe stenosis.

Forty patients with Kawasaki disease with severe coronary sequelae were investigated. All had at least a 90% reduction in the diameter of the major coronary artery. Collateral vessels were seen in 32 of 33 (97%) patients with total occlusion. All patients with severe stenosis but not total occlusion had no or poorly developed collateral vessels. Analysis according to the presence or absence of collateral vessels showed no significant differences in the results of treadmill stress testing and myocardial imaging between these two groups. In patients treated surgically, the abnormalities recognized by these tests were normalized or improved when the bypass was patent. These data indicate that collateral circulation in patients with Kawasaki disease cannot be seen angiographically unless there is total occlusion and the presence of collateral circulation cannot provide protection against stress-induced myocardial ischemia.

[Axilla-iliac bypass in a patient with aortic obstruction progressed from atypical coarctaion].

A case of a 13 year-old girl with abdominal aortic obstruction is presented. At the age of nine years she underwent an evaluation for a continuous murmur heard over the left costal margin. The blood pressure was 210/125 mmHg in the ascending aorta, and an aortography revealed a critical stenosis in the descending aorta proximal to the origin of the celiac artery. No surgical treatment was recommended at this time. At the age of 13 years she developed severe headache and was admitted for the second time. Upon catheterization the ascending aortic pressure was 242/150 mmHg, and an aortography revealed total obstruction of the abdominal aorta in the segment proximal to the celiac artery. An extraanatomical bypass was constructed between the right axillary artery and the right common iliac iliac artery with a 10 mm dacron graft. Two weeks after this procedure, the blood systolic pressure was 110 mmHg in the upper extremities. It has been 12 months since the patient had this procedure, and she continue to do well, i.e., she has no particular limitations of the hip joint movement, has no headache, and remains to be normotensive.

Long-term prognosis of Kawasaki disease patients with coronary artery obstruction.

The prognosis of coronary artery obstruction was studied in patients with Kawasaki disease. Between May 1973 and December 1987, coronary artery obstruction was diagnosed by coronary angiography in 30 patients (21 males, 9 females), of whom, only 8 (26.7%) had clinical symptoms. One patient died after 9 years of illness. Two complained of frequent chest pain, which disappeared after bypass surgery in one case and spontaneously in the other. Five had symptomatic myocardial infarction. Myocardial ischemia was diagnosed in 31.8% by treadmill stress testing, but was well demonstrated in 85.7% by thallium-201 myocardial tomography. Frequent ventricular premature beats, Wenckebach-type atrioventricular block, and ST-segment depression accompanied by chest pain were recognized by 24-h Holter monitoring. In the past, the methods used to determine the prognosis of Kawasaki disease patients with coronary artery obstruction were not adequate. However, the examinations used in this study revealed an improved ability to determine the prognosis in this disease. Myocardial tomography, in particular, provided a more accurate evaluation of myocardial damage. Ventricular arrhythmias seem to be a serious problem in these patients. Therefore, careful observation using these tests, especially myocardial tomography and Holter monitoring, should be done even if the patients are free of symptoms.