Taiyu Hayashi

Dissipative energy loss within the left ventricle detected by vector flow mapping in children: Normal values and effects of age and heart rate

BACKGROUND Vector flow mapping (VFM) is a novel echocardiographic technology which enables visualization of the intraventricular flow velocity vector. Dissipative energy loss (EL) derived from the velocity vector field of intraventricular blood flow is considered to reflect the efficiency of blood flow, and could be an indicator of left ventricular function. We aimed to determine the reference values of the EL derived from VFM within the left ventricle. METHODS VFM analysis was performed using echocardiography in 64 healthy children. The velocity vector fields of the intra-left ventricular blood flow were obtained from the apical 5-chamber view, and the EL values during systole and diastole were calculated. The measurements were averaged over three cardiac cycles, and indexed to body surface area (BSA). RESULTS The mean subject age was 6.8±4.3 years. The mean EL was 4.10±2.35mW/m/m(2) BSA during systole and 16.24±11.63mW/m/m(2) BSA during diastole. On multivariate analysis, age and heart rate (HR) were independent predictors of systolic EL, whereas age, HR, and E wave peak velocity were independent predictors of diastolic EL. The regression equations used to predict the BSA-indexed systolic and diastolic EL were as follows: log10 (systolic EL)=-0.0332-0.00213×age (months)+0.00789×HR (beats/min) (adjusted R(2), 0.833; p<0.0001); and log10 (diastolic EL)=0.277-0.00346×age (months)+0.00570×HR (beats/min)+0.00564×E wave peak velocity (cm/s) (adjusted R(2), 0.867; p<0.0001). CONCLUSIONS The systolic and diastolic EL were positively correlated with HR and negatively correlated with age. Moreover, the diastolic EL was positively correlated with the E wave peak velocity. The present study provides reference values for the systolic and diastolic EL that can be used in future studies examining patients with heart disease.

Prenatal diagnosis of coronary artery fistula: A case report and review of literature

to diagnosis was about 1 month from birth. Although our patient had a normal Apgar score, his respiratory condition rapidly worsened over the next 3 days. The patient’s respiratory disorder was so severe that he was kept in hospital for 5 weeks; however, endoscopic laryngeal surgery was performed on the day of diagnosis, and this immediate treatment may have resulted in the good neurological prognosis at 12 months. Eighteen infantile cases of epiglottic cyst or VC have been reported in the English literature from 1997 to 2006. No malignant change has so far been reported. Regarding the treatment of VC in infants, prognosis is good if cysts are removed completely. Several studies have reported no recurrence of VC; however, insufficient resection might result in recurrence. VC should be considered in the differential diagnosis of an infant presenting with respiratory distress, particularly with stridor. In the case of persistent stridor and feeding difficulty, VC should be suspected, and flexible nasopharyngoscopy should be performed. Surgery is the treatment of choice.

Fever pattern and C-reactive protein predict response to rescue therapy in Kawasaki disease

Evidence to guide rescue therapy in refractory Kawasaki disease (KD) is lacking. The aim of this study was to determine the most important variables in predicting non‐response to rescue therapy in refractory KD.

Novel Risk Assessment Tool for Immunoglobulin Resistance in Kawasaki Disease: Application Using a Random Forest Classifier

Background: Resistance to intravenous immunoglobulin (IVIG) therapy is a risk factor for coronary lesions in patients with Kawasaki disease (KD). Risk-adjusted initial therapy may improve coronary outcome in KD, but identification of high risk patients remains a challenge. This study aimed to develop a new risk assessment tool for IVIG resistance using advanced statistical techniques. Methods: Data were retrospectively collected from KD patients receiving IVIG therapy, including demographic characteristics, signs and symptoms of KD and laboratory results. A random forest (RF) classifier, a tree-based machine learning technique, was applied to these data. The correlation between each variable and risk of IVIG resistance was estimated. Results: Data were obtained from 767 patients with KD, including 170 (22.1%) who were refractory to initial IVIG therapy. The predictive tool based on the RF algorithm had an area under the receiver operating characteristic curve of 0.916, a sensitivity of 79.7% and a specificity of 87.3%. Its misclassification rate in the general patient population was estimated to be 15.5%. RF also identified markers related to IVIG resistance such as abnormal liver markers and percentage neutrophils, displaying relationships between these markers and predicted risk. Conclusions: The RF classifier reliably identified KD patients at high risk for IVIG resistance, presenting clinical markers relevant to treatment failure. Evaluation in other patient populations is required to determine whether this risk assessment tool relying on RF has clinical value.

Clinical implications of mitral valve geometric alterations in children with dilated cardiomyopathy.

We aimed to elucidate the relationship between severity of secondary mitral regurgitation and mitral valve geometry in children with dilated cardiomyopathy. The medical records of 16 children with dilated cardiomyopathy (median age, 1.2 years; range, 0.4-12.3 years) were reviewed. Mitral valve geometry was evaluated by measuring coaptation depth using echocardiographic apical four-chamber views at the initial presentation. Patients were dichotomised according to the mitral regurgitation severity: patients with moderate or severe secondary mitral regurgitation (n=6) and those with mild secondary mitral regurgitation (n=10). A total of 58 healthy children were considered as normal controls, and a regression equation to predict coaptation depth by body surface area was derived: coaptation depth [mm]=4.37+1.34×ln (body surface area [m2]) (residual standard error, 0.49; adjusted R2, 0.68; p<0.0001). Compared with patients with mild secondary mitral regurgitation, those with moderate or severe secondary mitral regurgitation had significantly larger coaptation depth z-scores (6.4±2.3 versus 1.9±1.4, p<0.005), larger mitral annulus diameter z-scores (3.6±2.6 versus 0.9±1.8, p<0.05), higher left ventricular sphericity index (0.89±0.07 versus 0.79±0.06, p<0.005), and greater left ventricular fraction shortening (0.15±0.05 versus 0.09±0.05, p<0.05). In conclusion, geometric alteration in the mitral valve and the left ventricle is associated with the severity of secondary mitral regurgitation in paediatric dilated cardiomyopathy, which would provide a theoretical background to surgical intervention for secondary mitral regurgitation in paediatric populations.

Total anomalous pulmonary venous connection with ccTGA and VSD: Can pulmonary artery banding avert pulmonary venous obstruction?

We describe a rare case of infracardiac total anomalous pulmonary venous connection (TAPVC), associated with congenitally corrected transposition of the great arteries (ccTGA) and ventricular septal defect, in which the patient had undergone pulmonary artery banding (PAB) at 16 days of age. She began to have episodes of severe cyanosis while crying, 2 weeks after PAB. Cardiac catheterization at 34 days of age showed severe pulmonary hypertension and a transhepatic pressure gradient of 7 mmHg. The infant underwent TAPVC repair and conventional repair for ccTGA at 35 days of age. Although PAB might have the provisional effect of delaying the manifestation of pulmonary venous obstruction (PVO), it is unable to prevent the development of PVO due to the high resistance of the hepatic sinusoids. Signs of PVO should be closely monitored so that TAPVC can be repaired in a timely fashion.

Isoproterenol stress test during catheterization of patients with coarctation of the aorta.

Background:  The exercise test is considered useful in selecting high‐risk patients with repaired coarctation of the aorta (CoA), but it is difficult to obtain the cooperation of pediatric patients. The present study determines the feasibility of the isoproterenol stress test (IST) among pediatric patients with CoA.

Effect of i.v. immunoglobulin in the first 4 days of illness in Kawasaki disease

Although early treatment of Kawasaki disease (KD) with i.v. immunoglobulin (IVIG) is expected to prevent coronary artery abnormalities, the effectiveness of IVIG by day 4 of illness remains to be determined.

Echocardiographic assessment of ventricular contraction and synchrony in children with isolated complete atrioventricular block and epicardial pacing: Implications of interventricular mechanical delay

To assess the correlations between interventricular mechanical delay (IVMD) and cardiac function in children with isolated complete atrioventricular block and epicardial pacing.

Echocardiographic assessment of prosthetic mitral valves in children

We studied how Doppler‐derived hemodynamic parameters in children change as the relative prosthetic mitral valve (PMV) size decreases with somatic growth and evaluated the diagnostic utility of the parameters for detecting PMV obstruction in children.