After stenting, complications are common for congenital heart disease. The vast diversity of stenotic sites combined with relatively small patient populations makes these procedures sensitive to complications. Combining operator experience may reduce the risks of stenting in congenital heart disease. The availability of premounted stents for greater vessel diameters will likely reduce incidences of stent migration and embolization.

Background-In long-QT syndrome (LQTS), heterozygosity for a mutation in 1 of the K(+) channel genes leads to prolongation of the cardiac action potential, because the aberrant protein exhibits "loss of function." HERG, which is involved in LQT2, is the gene encoding the rapid component of the delayed rectifier, I(Kr). Methods and Results-In a consanguineous family, a stillbirth was followed by the premature birth of a child in distress due to ventricular arrhythmia in the presence of QT prolongation. LQTS was diagnosed, beta-blocker therapy was begun, and a pacemaker was implanted. She developed well and remained symptom-free for 1.5 years. In the index patient, we identified a duplication of bp 558 to 600 in exon 4 of HERG on both alleles. This will result in a frameshift and a premature stop codon before the S1 domain of the HERG protein. Because it is present on both alleles, no functional I(Kr) is anticipated. The same mutation was found heterozygously in both parents and homozygously in the stillborn brother. Conclusions-It is concluded that absence of I(Kr) gives rise to a severe cardiac phenotype, with no indication of malfunction of any other organ.

SUMMARY Twenty three patients with fragile X syndrome underwent cardiovascular assessment. Echocardiography showed dilatation ofthe aortic root in 12 (52%) and mitral valve prolapse in five (22%), four of whom had an apical mid-systolic click on auscultation.Patients with fragile X syndrome have cardiac defects similar to those seen in other disorders of connective tissue such as Marfan's syndrome and Ehlers-Danlos syndrome. These, and other somatic features, suggest an underlying connective tissue dysplasia.The fragile X syndrome is the commonest inherited cause of mental retardation and it affects approximately one in a 1000 males.'2 It is so called because there is a fragile site on the long arm of the X chromosome in affected patients.' Common somatic manifestations include a long face, large and prominent ears, prognathism, and macroorchidism. Other associated findings such as hyperextensible finger joints, pectus carinatum, a high-arched palate, and flat feet suggest an underlying connective tissue dysplasia.4 Previous reports of mitral valve prolapse and aortic root dilatation in patients with fragile X syndrome support this proposition.56This study was performed to establish the frequency of cardiac abnormalities in a population of patients with fragile X syndrome who underwent voluntary cardiac assessment. Patients and methods PATIENTSWe studied 23 men (aged 18-80, mean 51) with proven fragile X syndrome. Most were moderately or severely mentally handicapped. A few were living in the community while most were resident in a hospital for the mentally handicapped. They were drawn from a group of 28 patients identified by cytogenetic examination in a prospective survey of an inpatient population. Five

All patients with supraventricular tachycardia during the first 12 months of life who presented between 1977 and 1988 were identified by a retrospective survey of records in this hospital and by a questionnaire sent to paediatricians in the Northern region. Twenty two of 29 patients (76%) were in heart failure and seven (24%) had cardiogenic shock. Seven patients (24%) were free of symptoms. All had narrow QRS tachycardia at 215-315