Unexpected Discharge from an Implanted Automatic Defibrillator

The occurrence of inappropriate discharge from an implanted cardioverter-defibrillator is reported. The device was triggered by an episode of induced nonsustained ventricular tachycardia, and the shock was delivered 10 sec after spontaneous termination of the arrhythmia.
This observation demonstrates that unexpected discharges from an implanted cardiaverter/defibrillator can occur while the patient is asymptomatic. In order to avoid such an adverse effect, improvement of the detection system of the device is advisable.     

Koch's Triangle in Pediatric Age: Correlation with Extra- and Intracardiac Parameters

The atrioventricular node is situated in the lower atrial septum, at the apex of the Koch's triangle. The dimensions of the Koch's triangle are studied in adult humans, while no data exist about tbem in pediatric age. the knowledge of the dimensions of Koch's triangle in childhood is very important for safe and correct application of radiofrequency energy during transcatheter ablation. The dimensions of Koch's triangle were determined in 69 human pediatric hearts. the median age of the children was 3 months. with a range from 1 day to 14 years, 30 were female and 39 were male. Relations between body weight (extracardiac parameter) and tricuspid valve diameter (intracardiac parameter) were determined in all hearts to sbow morpbometric modifications with growth. the distribution of body weight was not Gaussian and no correlation could be obtained between Koch's triangle dimensions and body weight. However, it was possible to identify that the mean ratio between the cathetus of the Koch's triangle corresponding to the annulus of the tricuspid valve and the tricuspid valve diameter was 0.45 ± 0.16, with a highly significant correlation coefficient (r = 0.653, P < 0.001). Therefore, by knowing: (1) the diameter of the tricuspid valve, and (2) the constant ratio between the cathetus of the Koch's triangle and the tricuspid valve diameter, it is possible to calculate the lengtb of the segment of the tricuspid annulus along wbich the transcatheter application of radiofrequency current can be applied to ablate the slow-pathway, tbus reducing the risks of damage of the atrioventricular node.     

Detection of homozygotes and heterozygotes for metachromatic leukodystrophy in lymphoid cell lines and peripheral leukocytes

Assays of arylsulphatase A have been performed on peripheral leukocytes and lymphoid cell lines from normal subjects and heterozygotes and homozygotes for metachromatic leukodystrophy (MLD) by utilizing an improved procedure based on the removal of excess protein from the final digest. No overlap of arylsulphatase A activity was observed between peripheral leukocytes obtained from 11 normal donors, 8 heterozygotes and 5 homozygotes for MLD. Absence of enzyme activity was demonstrated in the patients' leukocytes, when the modified assay procedure was employed. Arylsulphatase A activity (mean +/- S.D.) in 30 lymphoid lines and sublines established from 18 normal donors, 2 heterozygotes and 1 homozygote for MLD was 54-5 +/- 23-1, 24-1 +/- 3-2 and 0-9, respectively. The enzymic activity of arylsulphatase A and B remained stable over a period of several months. These findings indicate that long-term lymphoid lines express the genotype of the donor and maintain enzyme stability over long periods in culture. Moreover, it appears that peripheral leukocytes are a reliable system for the identification of the carrier state of MLD.     

Familial adult-onset Pompe disease associated with unusual clinical and histological features

The adult-onset form of Pompe disease had a wide clinical spectrum, ranging from asymptomatic patients with increased CK to muscle cramps and pain syndrome or rigid-spine syndrome. In addition clinical severity and disease progression are greatly variable. We report on a family with 3 siblings characterized by an unusual adult-onset Pompe disease including dysphagia and weakness of tongue, axial and limb-girdle muscles, in association with atypical globular inclusions in muscle fibres. Our study confirms the great clinical and histological variability of adult-onset Pompe disease and further supports the need of careful evaluation of bulbar function in patients affected by this pathology.Key words: Pompe disease, globular inclusions, bulbar symptomsGlycogen storage disease type II (Pompe disease or acid maltase deficiency) is a rare autosomal recessive muscular disorder characterized by deficiency of acidalfa glucosidase (GAA), determining accumulation of glycogen in the lysosomes, mainly in cardiac and skeletal muscle cells. Typical phenotypes of glycogenosis type II include the severe classic infantile form, characterized by severe muscle weakness and hypertrophic cardiomyopathy, almost invariably fatal by 12 months, a "non-classic" form presenting between 1 and 2 years of age and the lateonset form, presenting at any time after the age of 1 year, including juvenile and adult-onset subtypes, which are considered as part of a continuous clinical spectrum (1). In particular the adult-onset form presents with slowly progressive proximal lower limb and/or paraspinal muscle weakness, often followed by restrictive respiratory failure, which could be life-threatening, as it is in infants and children (2). However the clinical spectrum of adultonset form is wide, ranging from asymptomatic patients with increased CK to muscle cramps and pain syndrome or rigid-spine syndrome (2, 3). Furthermore clinical severity and disease progression is greatly variable.We report on a family with 3 siblings with an unusual adult-onset Pompe disease clinically characterized by weakness of bulbar, axial and limb-girdle muscles in association with atypical histopathological changes.