Longitudinal Dissociation in the His Bundle: A Possible Mechanism of Two Distinct Cycle Lengths in Atrioventricular Reentrant Tachycardia

Two wide QRS tachycardias with identical morphology but different cycle lengths (CLs) developed in a 63-year-old man. Electrophysiological study demonstrated inducible atrioventricular reentrant tachycardia (AVRT) due to a concealed left posterior accessory pathway (AP), which was successfully ablated by radiofrequency application. Neither dual AV nodal pathways nor other APs were documented. Splitting of the His-bundle electrogram was shown, and programmed stimulation induced sudden prolongation of intra-hisian conduction time. These results suggest longitudinal dissociation in the His bundle may be responsible for two distinct CLs in AVRT without dualAV nodal physiology.     

Epidural air associated with spontaneous pneumomediastinum in children: Uncommon complication?

BACKGROUND: The purpose of the present study was to evaluate the incidence of epidural air associated with spontaneous pneumomediastinum in children. METHODS: The subjects consisted of 25 boys and 17 girls with an age range of 3-14 years (mean age: 8.5 years) who underwent chest computed tomography (CT) for evaluation of spontaneous pneumomediastinum. The CT scans and medical records were reviewed retrospectively. RESULTS: Of the 42 patients, four (9.5%) had intraspinal air on CT. The air was interpreted as epidural in every patient. The small number of patients with epidural air meant that there was no significant difference in age, gender, or clinical manifestations between groups with and without epidural air. Subcutaneous emphysema was identified in all four patients with epidural air versus 18 out of 38 patients (47%) without epidural air. The patients with epidural air did not have any neurologic symptoms. Irrespective of the presence or absence of epidural air, every patient had a favorable outcome without any serious complications. CONCLUSION: In patients with spontaneous pneumomediastinum, epidural air may be more common than was previously realized. It is suggested that an air leak may spread from the mediastinum into the epidural space via the cervical fascial planes and neural foramina.     

Clinical utility of a simple quantitative determination of hepatitis B e antigen

The titre of serum hepatitis B e antigen (HBeAg) was determined by using a simple quantitative system which is a slight modification of a commercially available enzyme immunoassay, and the relationship of serum HBeAg titre, hepatitis B virus (HBV)-associated DNA polymerase activity and HBV DNA level was evaluated. The HBeAg titre was found to have a significant correlation with DNA polymerase activity (r= 0.8153) and HBV DNA level (r= 0.8001). In 12 acute exacerbations of hepatitis in 10 patients with chronic type B hepatitis, these three parameters were found to be elevated either prior to or concurrent with the elevation of serum alanine aminotransferase, and the HBeAg titre peaked either simultaneously with or 1–4 weeks after the peaks of DNA polymerase activity and HBV DNA level, with average time lags of 1.00 weeks (s.d. = 1.29) and 1.08 weeks (s.d. = 1.25), respectively. Quantified HBeAg can be considered as a serum marker indicative of HBV replication, as is the case with DNA polymerase and HBV DNA. Furthermore, the HBeAg assay has the advantages of simplicity and low cost and it does not require special equipment. Therefore, quantification of HBeAg should be employed widely in clinical practice.     

Ultrasonic Diagnosis of Early Breast Cancer: Clinical Significance of Gray Scale Expanded Echography

Differential diagnosis of early breast cancer was performedby various echographic display techniques such as a sensitivitygraded method, gray scale echography and the expanded echographyof two dimensional (B-scan) ultrasonography on 541 cases. Theclinical significance of gray scale expanded echography fortarget enlargement was evaluated for early breast cancer on37 cases histologically verified. Differential criteria forthis technique is reported and bio-acoustic mechanisms for theappearance of such differential points are discussed. Diagnosticaccuracy rate improved for early breast cancer below 2.0 cmin size, while the false positive rate remained the same.     

Magnetic resonance imaging of clival marow in patients with anorexia nervosa

Hematological abnormalities, commonly associated with anorexia nervosa (AN) patients, are thought to be the results of serous atrophy in the bone marrow. Magnetic resonance imaging (MRI) has been utilized to ascertain T1 and T2 prolongation of marrow intensity in the lumbar spine, pelvis and proximal femora. The results correlate well with the severity of hematological abnormalities and body mass index. More importantly, the propensity for peripheral marrow involvement of T2 prolongation contrasts with the axial involvement in other marrow disorders. MRI undertaken in patients with AN to exclude hypothalamic tumor showed that the clival marrow was equivalent to the peripheral marrow. The signal pattern of clival marrow on sagittal T1 weighted MR images was evaluated in four teenage female patients with AN complicated by hematological abnormalities. Although the clival marrow intensity should be uniformly high in teenagers, three patients, two with pancytopenia and one with leukopenia and anemia, exhibited homogenous low intensity. One patient who had leukopenia only and the highest body mass index, showed inhomogeneous low intensity. The signal changes returned to normal in all patients but one, who died before examination after 6–11 months, at which time the others had almost recovered their original weight and normal hemogram. T1 prolongation in the clival marrow represents bone marrow dysfunction and the inhomogeneity of the signal change may imply relative preservation of hematopoiesis and body fat composition. Lack of knowledge of this phenomenon may lead to diagnostic confusion with other marrow disorders on cranial MRI.