Wang Jk

Electrophysiological properties of dual atrioventricular nodes in patients with right atrial isomerism.

There are reports that in right atrial isomerism the conduction system has paired sinus nodes and paired atrioventricular nodes. Electrophysiological studies were performed in two patients with right atrial isomerism. One patient had a delta wave on the surface electrocardiogram without tachycardia attacks. The other, who did not have manifest pre-excitation, had recurrent narrow QRS tachycardia. Electrophysiological studies suggested the presence of dual atrioventricular nodes. Only unidirectional atrioventricular or ventriculoatrial conduction was demonstrated for these dual atrioventricular nodes even after infusion of isoprenaline. It is suggested that unidirectional conduction may be a common property of the dual atrioventricular nodes in right atrial isomerism and that the absence of retrograde ventriculoatrial conduction protects the patients against tachycardia.

A variant of long QT syndrome manifested as fetal tachycardia and associated with ventricular septal defect

Two patients with a novel variant of long QT syndrome are described. The clinical course was characterised by an in utero onset of ventricular tachycardia and atrioventricular block (at 26 and 30 weeks’ gestational age, respectively), and an association with a ventricular septal defect. Studies of both patients’ families identified relatives with prolonged QT interval, syncope, or sudden death. One patient died of intractable ventricular tachycardia at 4 days old. The other received β blocker treatment and a pacemaker. She died suddenly at the age of 10 months. The unique association with ventricular septal defect and the malignant clinical course warrants further molecular diagnosis of this novel variant of long QT syndrome.

Percutaneous transluminal angioplasty of renal artery stenosis in a 9-month-old hypertensive girl with congestive heart failure

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Association of hiatus hernia with asplenia syndrome

During a 13-month period, 13 patients with asplenia syndrome were evaluated with MRI for cardiovascular and visceral anomalies. The MR images were reviewed for the presence of hiatus hernia which was found in three patients. One of the remaining ten patients with no MRI evidence of hiatus hernia was diagnosed as having gastro-oesophageal reflux and hiatus hernia by an oesophagogram and 24-h pH monitoring. This patient had undergone fundoplication prior to MRI. Out of the 13 patients (31%) with asplenia syndrome, 4 had hiatus hernia. It appears that among patients with the asplenia syndrome, hiatus hernia is a frequent finding. Recurrent pneumonia or bronchiolitis in patients with asplenia syndrome requires evaluation for the presence of hiatus hernia and gastro-oesophageal reflux.

Outcome in Children Bridged and Nonbridged to Cardiac Transplantation

BACKGROUND Heart transplantation (HTx) in children with end-stage heart disease has become an accepted treatment option. OBJECTIVE To evaluate our results of pediatric cardiac transplantation with vs without bridge methods. PATIENTS AND METHODS The study included 31 patients (34 transplantations) younger than 18 years who underwent orthotopic HTx between March 1995 and December 2008. Ten patients were girls, and 21 were boys. Preoperative diagnoses included cardiomyopathy (n=20), congenital heart disease (n=7), hypertrophic cardiomyopathy (n=2), restrictive cardiomyopathy (n=1), and ischemic cardiomyopathy (n=1). Mean (SD) ischemia time was 185 (72) minutes. Thirty-day mortality was 6%, and was due to primary graft failure (n=2). Overall follow-up was 4.36 (3.93) years. Eleven patients underwent bridge techniques before HTx, and 11 patients required perioperative extracorporeal membrane oxygenation or ventricular assist device support. RESULTS In the group that received extracorporeal membrane oxygenation, 8 patients (73%) were successfully weaned and discharged with excellent functional class. There were no differences in operative mortality, functional class, survival, rejection, and infection rates between the bridged and nonbridged groups. Overall actuarial 1- and 5-year survival rates were 93% and 83%, respectively. All survivors had good functional class. CONCLUSION Our findings demonstrate satisfactory medium-term outcome of HTx in selected pediatric patients with end-stage heart disease. Using bridge methods in children at high risk can increase the opportunity to receive a donor heart. These bridge methods achieve similar postoperative outcomes.

An accurate time-domain current waveform simulator for VLSI circuits

A new charge-based current model for CMOS gates is presented in this paper. The current during a transition consists of three components: one occurs when the input changes and the others exist only when the output changes. So, this model can generate current waveform with negative values, like SPICE. These three components are characterized by triangular functions with four parameters which can be easily obtained after timing simulation. When comparing the results obtained by using SPICE with those by our model, we find agreement, especially on the time points at which maximum current occurs.<<ETX>>

Esophageal varices in congenital heart disease with total anomalous pulmonary venous connection

Total anomalous pulmonary venous connection (TAPVC) is an uncommon congenital anomaly in which the anatomical presentations vary widely among patients. We hereby present two newborns with TAPVC associated with asplenia syndrome; both had severe esophageal varices due to infradiaphragmatic pulmonary venous drainage. Ultrafast computed tomography (CT) scanning was superior to color Doppler echocardiography and cardiac catheterization as it provided a detailed portrait of the pulmonary drainage. The remarkable radiographic manifestations are presented.

CT AND MRI FINDINGS IN A CHILD WITH CONSTRICTIVE PERICARDITIS

Abstract. Constrictive pericarditis is rare in children. We report computed tomography (CT) and magnetic resonance imaging (MRI) findings in a 3-year-old girl. She had a swollen abdomen that increased in two months. CT and MRI showed a thickened pericardium (5.2 mm) without calcification. Both atria were enlarged and ventricles were relatively small. The engorged inferior vena cava had 2.8× the diameter of the descending aorta at the same level. Symptoms were dramatically improved after pericardiectomy. The histopathological features confirmed chronic pericarditis.

Unusual form of total anomalous pulmonary venous connection with double drainage

A patient with complex congenital heart disease was diagnosed by two-dimensional echocardiography. Total anomalous pulmonary venous connection (TAPVC) was suspected because of the results of two-dimensional echocardiography, but the exact anatomy was delineated by cineangiocardiography as an unusual form of TAPVC with double drainage or connections to the left superior vena cava at nearly the same level. The clinical implications and possible embryogenesis for such a condition are discussed.

An unusual cause of chylothorax after Norwood stage one reconstruction.

We report an unusual cause of prolonged chylothorax drainage after Norwood stage one reconstruction. This 1-month-old girls chylous drainage was refractory to medical treatment. Echocardiography revealed thrombosis of the superior vena cava. Upon sternotomy to remove the thrombus, we were surprised to find the ePTFE (expanded polytetrafluoroethylene) tube previously used for selective cerebral perfusion compressing the innominate vein and the pericardium-based aortic arch. We performed a superior vena cava thrombectomy and shortened the ePTFE tube. Her chylothorax subsided gradually. We suggest that external compression of the venous drainage system should be considered in patients with prolonged chylothorax drainage. Once medical treatment fails, early surgical exploration may be helpful to stop the chylothorax.