An Alternative Approach to Determining Metabolic Syndrome Component Cutoffs in Children and Adolescents Using Segmental Regression Analysis.

Background: The prevalence of metabolic syndrome is increasing in children and adolescents. Although some diagnostic criteria for metabolic syndrome exist, further research is needed to determine appropriate age-, sex-, and race-specific cutoffs for each component. Methods and Results: Health examinations were conducted in 1,679 children aged 6-15 years in 9 regions of Japan. Participants were divided into 3 age groups for each sex: 6-8, 9-11, and 12-15 years. For metabolic syndrome components in each group, inverse cumulative percentile graphs were drawn and approximated by 3 regression lines using segmented regression analysis. The intersection of each regression line was defined as the breakpoint, and the measured value corresponding to the breakpoint percentile as the breakpoint value. Breakpoint values for waist circumference were age dependent at approximately 60, 70, and 80 cm for ages 6-8, 9-11, and 12-15 years, respectively. Breakpoint values for blood pressure were age- and/or sex dependent, while those for triglycerides, high-density lipoprotein cholesterol, and fasting blood glucose were neither age nor sex dependent. Based on these results, we proposed new cutoffs for diagnosing metabolic syndrome in Japanese children and adolescents. Conclusions: Breakpoint values obtained by segmented regression analysis on inverse cumulative percentile graphs can be useful for determining metabolic syndrome component cutoffs in children and adolescents.

Developmental trajectories at a high risk for childhood overweight/obesity.

BACKGROUND: The associations between developmental patterns (trajectories) in children and maternal factors have been widely investigated, but paternal effects on these trajectories are unclear. This study aimed to determine child and parental factors involved in developmental trajectories at high risk for causing adverse cardiovascular (CV) profiles in children. METHODS: We analyzed longitudinal anthropometric data from birth to the present and CV profiles of 1,832 healthy volunteers (51% girls) aged 3-15 years who participated in a nationwide study between July 2012 and January 2014. Six trajectory latent class growth models were developed using body mass index z- scores. Predictors for being in developmental trajectories at high risk for causing adverse CV profiles were determined by multivariate regression analysis. RESULTS: The mean±standard deviation number of anthropometric data points was 12±3 for both boys and girls. Among the six trajectories, the infantile onset and continual increase groups had significantly worse levels of many CV profiles than those in the remaining groups. Paternal overweight/obesity was an independent predictor for boys being in the infantile onset group and for girls being in the continual increase group. Additionally, maternal pre-pregnancy overweight/obesity in boys and maternal excessive gestational weight gain in girls were independent predictors for being in the infantile onset group. Having no sibling in boys and an older maternal age were independent predictors for being in the continual increase group. CONCLUSIONS: Interventions to prevent childhood obesity should include strategies that focus on fathers and mothers as well as those that focus on children with certain types of familial background.

A double heterozygous variant in MYH6 and MYH7 associated with hypertrophic cardiomyopathy in a Japanese Family.

Hypertrophic cardiomyopathy (HCM) is genetically heterogeneous. Different variants associated with HCM have been identified in several cardiac sarcomeric protein genes. We identified the heterozygous missense variant c.2191 C>A p. Pro 731 Thr in the MYH7 gene and the heterozygous frameshift variant c.1091-1092 insTGAA p.Lys364fs*in the MYH6 gene in a Japanese family. Family members with the double variants demonstrated severe phenotypes, such as sudden cardiac-related death and heart failure. These double variants were well segregated and might be responsible for the severity of cardiovascular events in affected family members. These double variants are potentially associated with specific phenotypes in HCM. Further studies are needed to analyze specific gene functions. .

Electrocardiographic Diagnosis of Hypertrophic Cardiomyopathy in the Pre- and Post-Diagnostic Phases in Children and Adolescents.

BACKGROUND: The usefulness of electrocardiographic (ECG) voltage criteria for diagnosing hypertrophic cardiomyopathy (HCM) in pediatric patients is poorly defined.Methods and Results:ECGs at the 1st grade (mean [±SD] age 6.6±0.3 years) were available for 11 patients diagnosed with HCM at around the 7th grade (13.2±0.3 years). ECGs were available for another 64 patients diagnosed with HCM in the 1st (n=15), 7th (n=32), and 10th (n=17) grades. Fifty-one voltage criteria were developed by grade and sex using 62,841 ECGs from the general population. Voltage criteria were set at the 99.95th percentile (1/2,000) point based on the estimated prevalence of childhood HCM (2.9 per 100,000 [1/34,483]) to decrease false negatives. Conventional criteria were from guidelines for school-aged children in Japan. Of 11 patients before diagnosis, 2 satisfied conventional criteria in 1st grade; 5 (56%) of the remaining 9 patients fulfilled 2 voltage criteria (R wave in limb-lead I [RI]+S wave in lead V3 [SV3] and R wave in lead V3 [RV3]+SV3). Robustness analysis for sensitivity showed RV3+SV3 was superior to RI+SV3. For all patients after diagnosis, RI+SV4 was the main candidate. However, conventional criteria were more useful than voltage criteria. CONCLUSIONS: Early HCM prediction was possible using RV3+SV3 in >50% of patients in 1st grade. Voltage criteria may help diagnose prediagnostic or early HCM, and prevent tragic accidents, although further prospective studies are required.

Novel electrocardiographic criteria for short QT syndrome in children and adolescents.

AIMS: Although shortening of the corrected QT interval (QTc) is a key finding in the diagnosis of short QT syndrome (SQTS), there may be overlap of the QTc between SQTS patients and normal subjects in childhood and adolescence. We aimed to investigate electrocardiographic findings for differentiation of SQTS patients. METHODS AND RESULTS: The SQTS group comprised 34 SQTS patients <20 years old, including 9 from our institutions and 25 from previous reports. The control group comprised 61 apparently healthy subjects with an QTc of <360 ms who were selected from 13 314 participants in a school-based screening programme. We compared electrocardiographic findings, including QT and Jpoint-Tpeak intervals (QT and J-Tpeak, respectively), those corrected by using the Bazett's and Fridericia's formulae (cB and cF, respectively) and early repolarization (ER) between the groups. QT, QTc by using Bazett's formula (QTcB), QTc by using Fridericia's formula (QTcF), J-Tpeak, J-Tpeak cB, and J-Tpeak cF were significantly shorter in the SQTS group than in the control group. On receiver operating characteristic curve analysis, the area under the curve (AUC) was largest for QTcB (0.888) among QT, QTcB, and QTcF, with a cut-off value of 316 ms (sensitivity: 79.4% and specificity: 96.7%). The AUC was largest for J-Tpeak cB (0.848) among J-Tpeak, J-Tpeak cB, and J-Tpeak cF, with a cut-off value of 181 ms (sensitivity: 80.8% and specificity: 91.8%). Early repolarization was found more frequently in the SQTS group than in the control group (67% vs. 23%, P = 0.001). CONCLUSION: A QTcB <316 ms, J-Tpeak cB < 181 ms, and the presence of ER may indicate SQTS patients in childhood and adolescence.

Diagnostic value of P-waves in children with idiopathic restrictive cardiomyopathy.

Restrictive cardiomyopathy (RCM) is a rare myocardial disease with an impaired diastolic function and poor prognosis. Almost all RCM patients are reported to have abnormal P-waves due to atrial overloading. This study aimed to reveal the characteristics of the P-waves in RCM patients and to suggest the diagnostic index of RCM in children with a 12-lead electrocardiogram (ECG). We retrospectively investigated 17 ECGs of children with idiopathic RCM during the initial visit at 15 institutes in Japan between 1979 and 2013. The RCM group was divided into four groups based on the age (elementary school [ES] and junior high school [JHS] students) and inception of the diagnosis (abnormal ECG on school-heart-screening [e-RCM] and some cardiovascular symptoms [s-RCM]), the ES/e-RCM (n = 5), ES/s-RCM (n = 4), JHS/e-RCM (n = 4), and JHS/s-RCM (n = 4) groups. As an aged-match control group, school-heart-screening ECGs of 1st-grade ES students (16,770 students) and 1st-grade JHS students (18,126 students) from Kagoshima in 2016 were adopted. For a comparison between the groups, we used the effect size "Hedge's g" by calculating the mean and standard deviation of the two groups. An effect size of 0.8 (or above) had an overlap of 53% (or less). The effect sizes of the sum of the absolute values of the forward and backward amplitudes in lead V1 (P1 + P2 V1) was the largest, and the ES/e-RCM, ES/s-RCM, JHS/e-RCM, and JHS/s-RCM were 15.8, 22.1, 9.4, and 10.3, respectively. A P1 + P2 V1 > 200 µV was able to rule in all RCM patients, thus, we proposed 200 µV as the cutoff value for screening purposes. In conclusion, the P1 + P2 V1 in the school-heart-screening may be useful for detecting asymptomatic or early-stage RCM in school-age children.

Impact of the T-wave characteristics on distinguishing arrhythmogenic right ventricular cardiomyopathy from healthy children.

BACKGROUND: T-wave inversion (TWI) is not considered useful for diagnosing pediatric arrhythmogenic right ventricular cardiomyopathy (ARVC), because right precordial TWI in ARVC resembles a normal juvenile pattern. OBJECTIVES: The aims of this study were to clarify the electrocardiographic (ECG) characteristics of pediatric ARVC to distinguish those patients from healthy children. METHODS: Between 1979 and 2017, 11 ARVC patients under 18 years old were registered and compared with school screening ECGs from 48,401 healthy children. RESULTS: The mean age at the first arrhythmic event or diagnosis was 13.3 ± 4.7 years. Nine patients were asymptomatic initially and were found by ECG screening, but 6 developed severe symptoms during the follow-up. Healthy children had a normal juvenile pattern, while ARVC children, especially symptomatic patients, had a significant tendency to have inferior and anterior TWI. The phenomenon of T-wave discontinuity (TWD) in which the TWI became deeper from V1 to V3 and suddenly turned positive in V5 was significantly more frequent in ARVC (60%) than healthy children (0.55%). Anterior TWI and TWD were also significantly more frequent in those who developed severe symptoms. The sensitivity and specificity of TWD were 60% (95% CI, 31-83%), and 99% (95% CI, 99-99%) to distinguish ARVC from healthy children, as well as 100% (95% CI, 71-100%) and 80% (95% CI, 51-80%), respectively, to predict severe symptoms in the future. CONCLUSIONS: The ECG is useful to distinguish ARVC children, even in the early phase. Anterior TWI and TWD could detect ARVC children and to predict the possible serious conditions.

Promoting physical activity through walking to treat childhood obesity, mainly for mild to moderate obesity.

BACKGROUND: There are no randomized controlled trials examining the effect of walking on childhood obesity. METHODS: A randomized controlled trial was conducted between August 2014 and April 2015 in Japan. Elementary school children aged 6 to 12 years with a percentage overweight (%OW) of ≥20% were recruited. One hundred and ninety children wanted to participate in the program, and all were accepted. After viewing a video that promoted physical activity through walking, participants were randomly assigned to three groups: walking (≥10 000 steps on school holidays), limiting screen time (<90 min on weekdays and <150 min on school holidays), and a control group (no intervention). The primary outcome was a decrease in %OW after 3 months' intervention. Per protocol analysis was performed using 156 participants who fulfilled the inclusion criteria of a %OW ≥20%. RESULTS: The mean %OW was 35 ± 7% before intervention. The mean reduction in %OW after intervention in the walking (n = 59), limiting ST (n = 46), and control (n = 51) groups were -4.06 ± 4.84, -1.97 ± 4.62, and -1.81 ± 3.64 percentage points, respectively. Reduction in %OW was significantly larger in the walking group than in the control group: adjusted mean difference, -2.18 percentage points (95% confidence interval, -3.85 to -0.52), P = 0.002. The intervention in children also had favorable effects on the lifestyles of their parents. The intention-to-treat analysis of all 190 participants showed comparable results. CONCLUSION: Promoting physical activity through walking on school holidays may be an additional strategy for treating elementary school children with obesity.

A significance of school screening electrocardiogram in the patients with ventricular noncompaction.

Left ventricular noncompaction (LVNC) is a hereditary cardiomyopathy and is associated with high morbidity and mortality. However, the role and significance of school screening for LVNC have not been fully elucidated. In this multicenter, retrospective cohort study, a total of 105 children with LVNC were included from 2000 to 2017. At the initial presentation, 44 patients (41.9%) were diagnosed by school screening. One (1.0%) patient underwent heart transplantation and four (3.8%) patients died during the study. Electrocardiogram data showed a high prevalence of fragmented QRS (33.4%) and J wave (15.7%). Treatments were needed in eight (18.2%) patients who were detected by school screening. The multivariable proportional hazards model showed T-wave abnormality on electrocardiogram in first graders was independent risk factors for major adverse cardiac events (odds ratio 4.94, p value = 0.0007). Moreover, dilation of the left atrium on chest X-ray and low ejection fraction on echocardiogram at the initial treatment were independent risk factors for treatment (odds ratio 1.7 × 107 and 22.3, p = 0.0362 and 0.0028, respectively). This study is the first report focusing on school screening in a large pediatric cohort with LVNC. With the use of abnormalities in electrocardiogram, school screening may be a good detector of and predictor for LVNC.

Multivariate analysis of TU wave complex on electrocardiogram in Andersen-Tawil syndrome with KCNJ2 mutations.

BACKGROUND: The exact differences between the TU wave complex of ATS1 and that of healthy individuals remain to be investigated. We sought to characterize the TU wave complex of Andersen-Tawil syndrome type 1 (ATS1) using high frequency electrocardiogram (ECG) data. METHODS: Electrocardiograms were recorded as time series data with a 2 kHz frequency ECG amplifier in 13 patients with ATS1 (positive for KCNJ2 mutation, ATS1 group) and age-matched healthy individuals (control group). Conventional ECG parameters were measured, and principal component analysis (PCA) and independent component analysis (ICA) were applied to the TU wave complex. RESULTS: Time from T peak (Tp) to U peak (Up), time from bottom (B) to Up, and time from B to U end (BUe, U duration) (0.232 ± 0.018 vs. 0.165 ± 0.017, p < .0001), where B is the lowest point between T and U waves, were all longer in the ATS1 group than the control group. Multivariate logistic regression analysis revealed that BUe could completely differentiate the two groups. PCA ratios in the ATS1 group were significantly larger than the control group (26.5 ± 12.3 vs. 10.4 ± 6.2, p = .0005). ICA revealed 1 or 2 U-wave-specific independent components (ICs) that exclusively comprise the U wave in ATS1, whereas U waves in the control group were composed of some ICs that also comprised T waves. CONCLUSIONS: U-wave-related temporal parameters, particularly BUe, and the existence of U-wave-specific ICs, extracted in the ICA, are useful for differentiation of U waves in ATS1 from those in healthy individuals.

Standard Values and Characteristics of Electrocardiographic Findings in Children and Adolescents.

BACKGROUND: Reference values and the characteristics of the electrocardiographic (ECG) findings using a large number of subjects are lacking for children and adolescents.Methods and Results:A total of 56,753 digitally stored ECGs of participants in a school-based ECG screening system were obtained between 2006 and 2009 in Kagoshima, Japan. Each ECG was manually reviewed by 2 pediatric cardiologists and only ECGs with sinus rhythm were included. A final total of 48,401 ECGs from 16,773 1st (6 years old, 50% girls), 18,126 7th (12 years old, 51% girls), and 13,502 10th graders (15 years old, 52% girls) were selected. ECG variables showed differences in age and sex. However, the effects of age and sex on ECG variables such as the PQ interval, QRS voltage, and STJ segment were also different. The 98th percentile values of well-known surrogate parameters for ventricular hypertrophy in the present study were much higher than the conventional criteria. CONCLUSIONS: The present study of a large number of pediatric subjects showed that the effects of age and sex on ECG parameters are different, and that criteria for ventricular hypertrophy should be newly determined by age and sex. We have developed reference data for STJ segment elevation for children and adolescents. These findings are useful for creating guidelines and recommendations for interpretation of pediatric ECG.

Environmental risk factors for sudden infant death syndrome in Japan.

While the prevalence of sudden infant death syndrome (SIDS) has decreased worldwide, this decline has plateaued recently. Strategies are needed to resume the constant decrease of SIDS in Japan. A prospective electrocardiographic screening program for infants was performed between July 2010 and March 2011. Parents of 4319 infants were asked about environmental factors related to SIDS through questionnaires at a one-month medical checkup and one year. Parental awareness of prone position, smoke exposure, and breast feeding as environmental factors were 81.4 %, 69.0 %, and 47.8 %, respectively. The prevalence of laying infants exclusively in a supine position was 96.7 %. At the one-month medical checkup, smoking prevalence was 41.7 % in fathers and 2.1 % in mothers. Maternal smoking prevalence was significantly increased at one year after (p < 0.001). Multivariate regression analysis showed that risk factors for new or continued maternal smoking habits were maternal smoking habits at one month (p < 0.001), paternal smoking habits one year later (p < 0.001), and younger maternal age (p = 0.02). CONCLUSION: Most parents already avoid laying infants in the prone position, and parental smoking is still a SIDS risk concern in Japan. Smoking cessation programs should be further implemented for parents to decrease risks of SIDS in Japan. What is Known: • The prevalence of sudden infant death syndrome (SIDS) has decreased worldwide, however, this decline has plateaued recently. What is New: • Most infants were laid sleeping in the supine position (96.7 %) and were fed breast milk or a mix of expressed milk and formula (92.7 %), and 2.1 % of mothers smoked at the one-month medical checkup. • Maternal smoking prevalence significantly increased from the one-month medical checkup to one year later, and smoking mothers were more likely to feed infants by formula rather than breast milk. • Independent risk factors for new or continued maternal smoking habits included younger maternal age, maternal smoking habits at one month, and paternal smoking habits one year later.

Circumstances and outcomes of out-of-hospital cardiac arrest in elementary and middle school students in the era of public-access defibrillation.

BACKGROUND: Circumstances and outcomes of out-of-hospital cardiac arrest (OHCA) in elementary and middle school students while at school in the era of public-access defibrillation are unknown. METHODS AND RESULTS: We conducted a nationwide hospital-based survey of elementary and middle school students who had had OHCA of cardiac origin and received prehospital resuscitation in 2005-2009. Among 58 cases recruited, 90% were witnessed by bystanders; 86% had ventricular fibrillation as the initial rhythm; 74% were resuscitated by bystanders; 24% were defibrillated by bystanders; 55% occurred at school; 66% were exercise-related; 48% were followed up before the event; 67% had structural heart disease. In total, 53% of overall patients and 79% of those initially defibrillated by bystanders had a favorable neurological outcome. Patients were more likely to be defibrillated by bystanders (38% vs. 8%, P=0.012) and had a more favorable neurological outcome in schools (69% vs. 35%, P=0.017) than in other locations. The majority of arrests in schools were exercise-related (84% vs. 42%, P=0.001), occurred at sports venues, and students were resuscitated by teachers; half of the cases at school occurred in patients with a pre-event follow-up. CONCLUSIONS: After OHCA, children were more likely to be defibrillated by bystanders and had a better outcome in schools than in other locations, which may be relevant to the circumstances of events.

Electrocardiographic screening of 1-month-old infants for identifying prolonged QT intervals.

BACKGROUND: Neonatal electrocardiographic screening is used to screen infants with prolonged QT intervals, as previously shown in whites. However, this procedure needs to be confirmed in other ethnic groups. METHODS AND RESULTS: In 8 areas in Japan, an ECG was recorded in 4285 infants at 1-month medical checkup. A prospective study showed that a provisional criterion of QTc≥470 ms was appropriate for infants. To assess the validity of the criterion, all infants with a QTc between 460 and 470 ms were followed up. Five infants had a QTc≥470 ms. Four infants were diagnosed with prolonged QT intervals from follow-up ECGs. Four infants showed no symptoms and did not have a family history of long-QT syndrome. Two infants showed progressive prolongation of QT intervals, and medication was started. Genetic testing was performed in 3 of 4 infants with prolonged QT intervals, and it revealed a KCNH2 mutation (3065 delT, L1021fs+34X) in 1 infant. One infant with a QTc≥470 ms and 2 infants with a QTc between 460 and 470 ms showed a decline in their QTc values during follow-up. The study screened another infant with Wolff-Parkinson-White syndrome who was diagnosed with noncompaction before symptoms appeared. CONCLUSIONS: Neonatal electrocardiographic screening can identify infants likely to be affected by long-QT syndrome in the Japanese population, as already shown in whites. This screening may also be useful in identifying other important cardiac diseases.

Public access defibrillation improved the outcome after out-of-hospital cardiac arrest in school-age children: a nationwide, population-based, Utstein registry study in Japan.

AIMS: The purpose of this study was to determine whether implementation of public access defibrillation (PAD) improves the outcome after out-of-hospital cardiac arrest (OHCA) in school-age children at national level. METHODS AND RESULTS: We conducted a prospective, nationwide, population-based Japanese Utstein registry study of consecutive OHCA cases in elementary and middle school children (7-15 years of age) who had a bystander-witnessed arrest of presumed cardiac origin during 2005-09 and received pre-hospital resuscitation by emergency responders. The primary endpoint was a favourable neurological outcome 1 month after an arrest. Among 230 eligible patients enrolled, 128 had ventricular fibrillation (VF) as an initial rhythm. Among these 128 patients, 29 (23%) children received a first shock by a bystander. Among these 29 patients, the proportion of the favourable neurological outcome after OHCA was 55%. During the study period, the proportion of patients initially shocked by a bystander among eligible patients increased from 2 to 21% (P = 0.002 for trend). The proportion of patients with a favourable neurological outcome after OHCA increased from 12 to 36% overall (P = 0.006). The collapse to defibrillation time was shorter in bystander-initiated defibrillation when compared with defibrillation by emergency responders (3.3 ± 3.7 vs. 12.9 ± 5.8 min, P < 0.001), and was independently associated with a favourable neurological outcome after OHCA [P = 0.03, odds ratio (OR) per 1 min increase, 0.90 (95% confidence interval 0.82-0.99)]. A non-family member's witness was independently associated with VF as the initial rhythm [P < 0.001, OR 4.03 (2.08-7.80)]. CONCLUSION: Implementation of PAD improved the outcome after OHCA in school-age children at national level in Japan.

Role of insulin resistance in non-obese adolescents.

Insulin resistance in the obese is closely related with cardiovascular diseases and their risk factors not only in adults but also in children and adolescents. We aimed to elucidate whether insulin resistance in non-obese adolescents is related with these conditions. A total of 74 non-obese high-school students (38 boys and 36 girls) were recruited. Anthropometry, blood pressure, fasting serum chemistry and insulin activity were measured. Subjects with a homeostasis model assessment-insulin resistance (HOMA-IR) level greater than the 75th percentile (> 2.25 for boys and > 2.89 for girls) were defined as insulin resistant. Non-obese boys with impaired insulin sensitivity had higher systolic blood pressure, lower HDL-cholesterol concentration, and fewer hours of vigorous exercise during weekdays, while non-obese girls with impaired insulin sensitivity had higher systolic blood pressure than their peers with normal insulin sensitivity. By multiple stepwise regression analysis, systolic blood pressure (p < 0.001) and the hours of vigorous exercise during weekdays (p < 0.03) were independently associated with HOMA-IR in boys, while systolic blood pressure (p < 0.0001) and serum concentrations of HDL-cholesterol (p < 0.01) were found in girls. In nonobese adolescents, insulin sensitivity is related with cardiovascular risk factors.

Cut-offs for screening prolonged QT intervals from Fridericia's formula in children and adolescents.

BACKGROUND: The corrected QT interval (QTc) according to Bazett's formula (QTc = QT/RR(1/2)) has been used in clinical practice. Bazett's formula, however, overcorrects the QT interval at fast heart rates and undercorrects it at low heart rates. Guidelines and some investigators have recommended using Fridericia's formula (QTc = QT/RR(1/3)) in these cases, especially in tachycardic subjects. The aim of the present study was to determine cut-offs for QTc suitable for screening pediatric subjects with prolonged QT intervals, based on manually measured values corrected by Fridericia's formula in a large number of subjects. METHODS AND RESULTS: Three consecutive QT and RR intervals were measured in 4,655, 4,655, and 5,273 1st, 7th, and 10th graders, aged 6, 12, and 15 years, respectively. Each QT interval was corrected by Fridericia's formula, and mean values were calculated. Determination of the cut-offs for screening was based on the prevalence of abnormal electrocardiographic phenotypes of 1:1,164 and on the upper 0.025 percentile in the QTc distribution derived from previous studies. The tentative cut-offs suitable for screening subjects with prolonged QT intervals were 430 ms for 1st graders, 445 ms for 7th graders, and 440 and 455 ms for 10th grade boys and girls, respectively. CONCLUSIONS: These tentative cut-offs can be used to screen subjects with prolonged QT intervals in the clinical setting. Further studies are needed to confirm their validity.

Clinical characteristics and genetic background of congenital long-QT syndrome diagnosed in fetal, neonatal, and infantile life: a nationwide questionnaire survey in Japan.

BACKGROUND: Data on the clinical presentation and genotype-phenotype correlation of patients with congenital long-QT syndrome (LQTS) diagnosed at perinatal through infantile period are limited. A nationwide survey was conducted to characterize how LQTS detected during those periods is different from that in childhood or adolescence. METHODS AND RESULTS: Using questionnaires, 58 cases were registered from 33 institutions. Diagnosis (or suspicion) of LQTS was made during fetal life (n=18), the neonatal period (n=31, 18 of them at 0 to 2 days of life), and beyond the neonatal period (n=9). Clinical presentation of LQTS included sinus bradycardia (n=37), ventricular tachycardia/torsades de pointes (n=27), atrioventricular block (n=23), family history of LQTS (n=21), sudden cardiac death/aborted cardiac arrest (n=14), convulsion (n=5), syncope (n=5), and others. Genetic testing was available in 41 (71%) cases, and the genotype was confirmed in 29 (71%) cases, consisting of LQT1 (n=11), LQT2 (n=11), LQT3 (n=6), and LQT8 (n=1). Ventricular tachycardia/torsades de pointes and atrioventricular block were almost exclusively observed in patients with LQT2, LQT3, and LQT8, as well as in those with no known mutation. In LQT1 patients, clues to diagnosis were mostly sinus bradycardia or family history of LQTS. Sudden cardiac death/aborted cardiac arrest (n=14) was noted in 4 cases with no known mutations as well as in 4 genotyped cases, although the remaining 6 did not undergo genotyping. Their subsequent clinical course after aborted cardiac arrest was favorable with administration of beta-blockers and mexiletine and with pacemaker implantation/implantable cardioverter-defibrillator. CONCLUSIONS: Patients with LQTS who showed life-threatening arrhythmias at perinatal periods were mostly those with LQT2, LQT3, or no known mutations. Independent of the genotype, aggressive intervention resulted in effective suppression of arrhythmias, with only 7 deaths recorded.

Role of exercise in the prevention of obesity and hemodynamic abnormalities in adolescents.

BACKGROUND: Poor physical activity plays a key role in the development of obesity. Little is known, however, about how much or the level of intensity of exercise that is needed to prevent obesity and hemodynamic abnormalities in adolescents. METHODS AND RESULTS: Height, bodyweight, resting heart rate (HR), and systolic and diastolic blood pressure was measured in 17,523 male and 16,906 female high school students. Self-reported exercise intensity was related to percentage of overweight (POW), diastolic blood pressure, and resting HR in boys, and to bodyweight and resting HR in girls. Self-reported exercise amount was associated with POW, diastolic blood pressure, and resting HR in both boys and girls. Also, high intensity or adequate amount of exercise was associated with a lower prevalence of obesity and resting tachycardia in both sexes, and slightly associated with the prevalence of systolic high blood pressure in boys. CONCLUSION: Both intensity and amount of exercise are associated with the prevalence of obesity and hemodynamic abnormalities in adolescents.