Sudden out-of-hospital cardiac arrest in pediatric patients in Kyushu area in Japan.

BACKGROUND: It is well-known that a neurologically favorable outcome of out-of-hospital cardiac arrest (OHCA) is associated with the presence of bystander-initiated cardiopulmonary resuscitation (bystander CPR) and use of an automated external defibrillator. However, little is known about the effect of the presence of pre-existing conditions, prior activity, and locations on the outcome of pediatric OHCA. METHODS: We analyzed the data from questionnaires about pediatric patients with OHCA aged from 3 days to 19 years in the Kyushu area in Japan between 2012 and 2016. RESULTS: A total of 594 OHCA cases were collected. The numbers of OHCA cases and the rate of 1 month survival with a favorable neurological outcome during sleeping, swimming / bathing, and exercise were 192 (1.0%), 83 (32.5%), and 44 (65.9%), respectively. When an OHCA occurred at school (n = 56), 88% of children / adolescents received bystander CPR, but when it occurred at home (n = 390), 15% received bystander CPR. Cardiovascular (n = 61), suicide (n = 61), and neurological / neuromuscular (n = 44) diseases were three major pre-existing conditions. The OHCA of cardiovascular disease was associated with exercise (24/61) and mainly occurred at school (22/61). The OHCA of neurological / neuromuscular disease was associated with swimming/bathing (15/44) and mainly occurred during bathing at home (12/44). Multivariate regression analysis showed that the presence of bystander CPR (P < 0.001) and occurrence of OHCA at school (P < 0.001) were independently predictive of a favorable outcome in pediatric OHCA. CONCLUSION: The outcome was different among pre-existing conditions, prior activity, and location of OHCA. These findings might be useful for preventing OHCA and improving the outcome of pediatric OHCA.

QT Dynamics During Exercise in Asymptomatic Children with Long QT Syndrome Type 3.

Sympathetic provocative testing is commonly used to detect the abnormal QT dynamics in long QT syndrome (LQTS) patients, particularly LQTS type 1 and type 2. However, little is known about LQTS type 3 (LQT3). We investigated QT dynamics during exercise testing in LQTS patients, particularly LQT3. This study included 37 subjects, comprising 16 genotyped LQTS patients and 21 unrelated healthy subjects without QT prolongation. LQTS patients were divided into LQT3 and non-LQT3 groups. During exercise tests using a modified Bruce protocol, 12-lead electrocardiogram monitoring was performed using a novel multifunctional electrocardiograph. QT intervals were automatically measured. The QT/heart rate (HR) relationship was visualized by plotting the beat-to-beat confluence of the recorded data. A linear regression analysis was performed to determine the QT/HR slope and intercept. Estimated QT intervals at HR 60 bpm (QT60) were calculated by the regression line formula. QT/HR slopes were steeper for each LQTS group than for the control group (P < 0.001). QT60 values demonstrated a moderate correlation with QT intervals at rest (P < 0.0001) for both groups. The corrected QT intervals (QTc) at 4 min of recovery after exercise were significantly longer in the non-LQT3 group than in the control group but were not different between the LQT3 and the control groups. Abnormal QT dynamics during exercise testing were observed in both LQT3 patients and other LQTS subtypes. This method may be useful for directing genetic testing in subjects with borderline prolonged QT intervals.

QT dynamics evaluated on fully automated QT measurement in children.

BACKGROUND: The association between QT interval and heart rate (HR), QT dynamics, has been reported to vary greatly between individuals. We investigated QT dynamics using fully automated QT interval measurement with a commercially available multifunctional electrocardiogram (ECG) recorder. METHODS: The study group included 17 otherwise healthy subjects (mean age, 12.7 years; 11 girls, 6 boys), who were undergoing exercise test for arrhythmia evaluation. The subjects had single premature ventricular contraction. RESULTS: Mean corrected QT interval (Fridericia) at rest was 412 ± 19 ms (male, 408 ± 20 ms; female, 414 ± 19 ms), manually measured with a digitizer, using the tangent method. We assessed QT interval/HR slope during the whole exercise test, the exercise phase, and the recovery from exercise phase; the slopes were calculated offline after excluding wide QRS complex and were -1.15 ± 0.26 (r(2) = 0.65), -1.18 ± 0.30 (r(2) = 0.62), and -1.11 ± 0.25 (r(2) = 0.70), respectively. Estimated QT interval at HR 60 beats/min (QT60) was calculated using the regression line formula and was 383 ± 24 ms, 387 ± 28 ms, and 375 ± 21 ms, respectively. QT60 of the total exercise test correlated with the corrected QT interval at rest (P = 0.04, r(2) = 0.25). CONCLUSIONS: Assessment of QT dynamics is feasible on fully automated QT interval measurement with this ECG recorder. Further studies are required in larger populations to confirm the accuracy and precision of QT measurement and QT dynamics using this new multifunctional ECG.

High prevalence of the SCN5A E1784K mutation in school children with long QT syndrome living on the Okinawa islands.

BACKGROUND: Genetic testing for long QT syndrome (LQTS) is now in clinical practice. We conducted molecular genetic analyses to definitively diagnose LQTS and to determine its subtypes for gene-specific treatment. We conducted a retrospective study to determine the characteristics of schoolchildren with LQTS living on the Okinawa Islands. METHODS AND RESULTS: The study population included children identified in a school-based electrocardiographic (ECG) screening program for cardiovascular diseases who were referred to Okinawa Children's Medical Center between 2007 and 2012; 23 children met the diagnostic criteria for LQTS. Of them, 17 were genotype-positive and 14 were found to harbor theSCN5AE1784K mutation exclusively among the LQTS genotype-positive children. The children were divided into genotype-positive and -negative groups. Clinical characteristics and ECG data were analyzed and compared. The median Schwartz score was 3. The median QT interval was 521 ms. CONCLUSIONS: The major finding is that the prevalent subtype of LQTS in Okinawa is discordant with other cohorts living in other regions of Japan or overseas. We cannot exclude the possibility of the presence of a specific founder mutation in this geographically clustered population, particularly considering that the hospital is the only tertiary heart center for children in Okinawa. However, this uniquely high prevalence of theSCN5AE1784K mutation serves as a compelling justification to conduct a larger study.

Diagnosis of epilepsy using an implantable loop recorder in a child with long-QT syndrome type 3.

We describe a case of a 10-year-old girl with genetically confirmed LQTS type 3 developed recurrent episodes of loss of consciousness due to epilepsy that was diagnosed by using an implantable loop recorder (ILR).

Dual atrioventricular nodal non-reentrant tachycardia in a child undergoing repair of ventricular septal defect.

Paroxysmal non-reentrant supraventricular tachycardia due to double ventricular response through antegrade dual atrioventricular nodal pathways by a single atrial excitation has been reported in limited adult cases but not in pediatric patients with structurally normal hearts or with congenital heart defects. We report the case of a 5-year-old boy with non-reentrant double-ventricular response (DVR) supraventricular tachycardia (SVT) after repair of ventricular septal defect. To the best of our knowledge, this is the first pediatric report about an electrophysiologic study and successful selective radiofrequency (RF) catheter ablation for the slow pathway leading to tachyarrhythmia that is difficult to manage medically. In conclusion, non-reentrant DVR SVT is a rare form of tachycardia that should be considered in the differential diagnosis of SVT in children after repair of congenital heart diseases. It is amenable to mapping and RF catheter ablation.

Surgical treatment of spontaneous intracerebral hemorrhage in a full-term infant with coagulopathy--case report.

An 11-week-old male infant presented with intracerebral hemorrhage associated with coagulopathy manifesting as left hemiparesis, lethargy, and vomiting. Computed tomography demonstrated extensive right frontoparietal intracerebral hemorrhage extending into the ventricular system. Liver function tests revealed abnormal values of transaminases and bilirubin. Blood coagulation studies showed prolonged prothrombin time (PT) and activated partial thromboplastin time (APPT). PT and APTT immediately normalized after the administration of vitamin K and fresh frozen plasma. Right parietal craniotomy and evacuation of the hematoma were performed because of the deterioration in consciousness and left hemiparesis. No vascular abnormality was observed in the hematoma cavity. After surgery, he became alert and the left hemiparesis improved. There is a risk of intracerebral hemorrhage due to vitamin K deficiency even if prophylactic administration of vitamin K was given. Surgical treatment should be considered for the treatment of infantile spontaneous intracerebral hemorrhage, especially if neurological deterioration is present.