Brief Review of the Recently Described Short QT Syndrome and Other Cardiac Channelopathies

There are many diseases related to ion‐channel disorders, so‐called “channelopathies.” Hereditary short QT syndrome is a clinical‐electrocardiographic entity with autosomal‐dominant mode of transmission and it is the most recently described channelopathy. The syndrome may affect infants, children, or young adults with strong positive family background of sudden cardiac death. Short QT syndrome is characterized by short QT and heart‐rate‐corrected QTc intervals. It is frequently associated with tall‐, peaked‐, and narrow‐based T waves that are reminiscent of the typical “desert tent” T waves of hyperkalemia. There is a high tendency for paroxysmal atrial fibrillation due to the heterogeneous abbreviation of action potential duration and refractoriness of atrial myocytes. The arrhythmia can also be induced by programmed electrical stimulation. The safest treatment suggested is an implantable cardioverter defibrillator, though the possibilities of inappropriate shocks have caused some concern, especially in teenagers. The ability of quinidine to prolong the QT interval has the potential to be an effective therapy for patients with short QT syndrome. This is particularly important in developing countries, where the implantable cardioverter‐defibrillator therapy is not always available. Since these patients are at risk of sudden cardiac death from birth, and implantable cardioverter‐defibrillator implantation has a lot of limitations in very young children, the utility of quinidine has to be evaluated further. Clinicians need to be aware of this deadly electrocardiographic (ECG) pattern as it portends a high risk of sudden cardiac death in otherwise healthy subjects with structurally normal hearts.     

Implicit strategy affects learning in children with heavy prenatal alcohol exposure

BACKGROUND: Learning and memory deficits are commonly reported in children with heavy prenatal alcohol exposure. Our recent work suggested that children with heavy prenatal alcohol exposure retained information as well as controls on a verbal learning test but not on a test of nonverbal learning and memory. To better understand the cause of this differential pattern of performance, the current study re-analyzed data from our previous study to determine if the presence of an implicit learning strategy may account, at least in part, for the finding of spared retention. METHODS: The current study examined verbal learning and memory abilities in 35 children with Fetal Alcohol Spectrum Disorders (FASD) and 34 nonexposed controls (CON) matched for age (9-16 years), sex, ethnicity, handedness, and socioeconomic status. Groups were compared on two measures of verbal learning, one with an implicit strategy (California Verbal Learning Test-Children's Version; CVLT-C) and one without (Verbal Learning subtest of the Wide Range Assessment of Memory and Learning; VL-WRAML). RESULTS: Children with FASD learned less information overall than children in the CON group. Both groups learned a greater percentage of information and reached a learning plateau earlier on the CVLT-C compared with the VL-WRAML. Groups also showed comparable rates of retention after a delay on the CVLT-C. In contrast, on the VL-WRAML, children with FASD showed poorer retention rates than children in the CON group. Interestingly, children with FASD did not differ from children in the CON group on CVLT-C semantic clustering scores for learning trials 1 through 3, and greater utilization of semantic clustering was correlated with better learning and memory performance in both groups. This overall pattern of results was not related to overall intellectual level. CONCLUSIONS: The finding of spared retention of verbal information on the CVLT-C in our earlier studies may be related to test characteristics of the CVLT-C rather than a finding of spared verbal retention per se, given that spared retention was not found on a separate test of verbal learning and memory without an implicit learning strategy. These results suggest that the use of an implicit strategy positively affected the ability of alcohol-exposed children to learn and retain new verbal information.     

2 338条胎儿心脏cDNA文库的表达序列标签测序分析

目的：寻找在心脏发育过程中具有重要功能的新基因，并研究其表达模式的特点。方法：随意选择8－10周龄胎儿心脏cDNA文库的克隆进行表达序列标签（ESTs)测序，结果与GenBank/EMBL/DDBJ核酸数据库进行同源性比较，其中与已知基因匹配的1550条ESTs用来研究8－10周龄胎儿心脏基因表达特点，并将其与10－12周龄胎儿及成人心脏的基因表达模式相比较，结果：所测2338条ESTs中，69．03％与已知基因匹配，33．18％与其他ESTs或基因组DNA相似，7．57％既不匹配于已知基因，亦不与其他ESTs或基因组DNA相似，发现了心脏发育过程中基因表达的某些特点。结论：大规模随机选择cDNA克隆，并进行ESTs测序是寻找新基因和系统研究不同组织或同一组织不同发育时期基因表达模式的有力工具。     

Outcome after prenatal diagnosis of the hypoplastic left heart syndrome

Objective—To derive accurate survival figures in the current surgical era for counselling in early pregnancy after the diagnosis of fetal hypoplastic left heart syndrome.
Setting—A tertiary referral centre for paediatric cardiology and cardiac surgery.
Design—A retrospective study of the outcome in all cases of hypoplastic left heart syndrome presenting in fetal life between mid-1993 and the end of 1996.
Patients—The diagnosis was made in 30 fetuses. In four of 12 identified before 24 weeks' gestation the mothers chose to terminate the pregnancy. There was an intention to treat in 24 of the remaining fetuses.
Main outcome measure—Survival to six months of postnatal life.
Results—Of the 24 infants, five were not offered Norwood stage 1 because of trisomy 18 (n = 2), unfavourable cardiac anatomy (n = 2), or neurological impairment (n = 1). One further infant did not survive to cardiac surgery after gastrointestinal surgery. Of the remaining 18 patients, eight had features that were considered to increase the risk of surgical repair. Of the 18 patients who underwent Norwood stage 1, there were nine survivors. There was a survival rate of 70% in infants undergoing surgery with no complicating features, a 50% survival of the all surgical candidates, and 37.5% survival from an intention to treat position.
Conclusions—At the initial diagnosis of fetal hypoplastic left heart syndrome, the overall survival appears to be less than 40%. Evaluation must include detailed extracardiac and intracardiac assessment to predict the risks of surgical treatment. Prenatal counselling can be modified as pregnancy advances, depending on the detection or exclusion of complicating factors.

Keywords: fetus;  congenital heart disease;  hypoplastic left heart syndrome     

Congenital transmission of Trypanosoma cruzi: an operational outline for detecting and treating infected infants in north-western Argentina

We designed a set of procedures for first-line local health services to detect and treat the congenital transmission of Trypanosoma cruzi at a province-wide scale, and field-tested the programme in the province of Tucumán, northwestern Argentina, from 1992 to 1994. The programme consists of routine screening of pregnant women for seroreactivity to T. cruzi, serological and parasitological follow-up of the newborn at least twice during the first year of age, treatment of the infected infants, and evaluation of the outcome. 927 (5.5%) of 16 842 pregnant women were seroreactive to T. cruzi by indirect haemagglutination assay and ELISA. Twenty-one (6.7%) of 315 newborns to seroreactive mothers were diagnosed as infected with T. cruzi parasites microhaematocrit concentration before 30 days of age. Five newborns who initially tested negative had a T. cruzi infection detected by microhaematocrit and/or serological techniques at 3 or 6 months of age. Thus, congenital infection was diagnosed in 26 (7.1%) infants born to seroreactive women and residing in houses free of triatomine bugs. Four of 6 infants born to seroreactive mothers died during the first year of age and had some evidence of T. cruzi infection; one of the deaths was attributed to T. cruzi based on clinical evidence. After specific treatment with nifurtimox or benznidazole, 30 of 32 infants remained parasitologically and serologically negative. This study shows the feasibility of controlling the incidence of congenitally acquired T. cruzi infections at a province-wide scale by means of a specific screening programme at first-line health services level.     

Indicator dilution curves in the diagnosis of D-transposition of the great arteries in infancy

Paired right and left atrial indicator dilution curves performed in a series of 17 patients with D-transposition of the great arteries (D-TGA) were reviewed. Taken together, the patterns obtained from patients who had trivial mixing between the pulmonary and systemic circulations were distinctive and easily recognizable. In the presence of substantial degrees of intracardiac mixing, however, the paired curves recorded become virtually identical and cannot be distinguished from curves recorded from patients with other forms of cyanotic congenital heart disease characterized by obligatory admixture. Thus paired atrial dye curves demonstrate a high degree of diagnostic specificity for the infant with D-TGA at greatest risk, normally those with a small intracardiac shunt. Such a procedure should facilitate early balloon atrial septostomy and obviate deterioration in the infant's condition due to prolonged catheter manipulation and/or angiography.     

介入治疗心脏复合畸形疗效及安全性研究

目的评估介入治疗心脏复合畸形的可行性,安全性及疗效。方法心脏复合畸形患者10（男6,女4）例,年龄5～53岁。其中房间隔缺损（ASD）并发肺动脉瓣狭窄（PS）2例、室间隔缺损（VSD）2例和动脉导管未闭（PDA）1例,PDA并发主动脉瓣关闭不全和PS各1例;VSD修补术后遗留ASD2例,ASD修补术后遗留PDA1例和刀刺伤致左室前侧术后遗留VSD1例。ASD或PDA并发PS者,先扩张肺动脉瓣,再行ASD或PDA封堵治疗。ASD并发VSD者,先封堵VSD,再封堵ASD。结果10例患者介入手术均1次成功。5例ASD封堵器的直径为8～38mm,2例膜部对称性VSD封堵器的直径为14mm和6mm,1例用10mm肌部VSD封堵器。2例PDA均用弹簧圈封堵。封堵PDA或VSD后造影无残余分流。封堵ASD后超声心动图示无残余分流。3例并发PS者,肺动脉瓣扩张术后即刻肺动脉跨瓣压差明显下降,由术前50、38、40mmHg分别降低为20、15和21mmHg。有1例PDA封堵弹簧圈脱落至肺动脉远端未能取出。随访1年肺功能正常,无肺不张。全部患者随访3个月～1年,无任何并发症发生。结论经导管介入治疗心脏复合畸形安全可行,近期疗效肯定。     

Echocardiographic diagnosis of congential absence of the pericardium in a patient with VATER association defects

The VATER association denotes a nonrandom pattern of congential malformations which typically include vertebral defects, anal atresia, tracheo-esophageal fistula, and radial and renal dysplasia. Vascular anomalies including ventricular septal defect and single umbilical artery have also been described, although the frequency of cardiovascular anomalies in this congenital association is unknown. In this report, we describe a 26-year-old patient with several VATER association defects who, in addition, was found to have congenital absence of the left pericardium and an aberrant right subclavian artery.     

Comparison of outcome and complications using different types of devices for percutaneous closure of a secundum atrial septal defect in adults: a single-center experience.

The objective of this study was to find differences in outcome and complications using three different types of devices for percutaneous atrial septal defect (ASD) closure in adults. Percutaneous closure of a secundum-type ASD is increasingly performed in adult patients. All adult patients who underwent a percutaneous closure of a secundum-type ASD in our center between November 1996 and November 2004 were included. Failure was defined as dislocation or embolization of the device, which required surgical intervention. Periprocedural and mid-term complications were registered. Sixty-five patients, mean age 45.7+/-18.1 years (18 men, 47 women), underwent a percutaneous closure of an ASD with an ASDOS in 3, an Amplatzer in 36, and a Cardioseal/Starflex closure device in 26 patients. During an overall median follow-up of 1.2 years (range, 0.1-6.7 years), the failure occurred in four patients, all Cardioseal/Starflex (P=0.04). Within the Cardioseal/Starflex subgroup, the ASD and device diameters were significantly higher in those patients in whom the primary endpoint occurred compared to the others, 18.8+/-3.8 vs. 13.0+/-3.8 mm for ASD diameter (P=0.01) and 40 (range, 40-43) vs. 33 mm (range, 20-40) for device diameter (P=0.008). Overall complications were transient arrhythmias in 15.4%, pericardial effusion in 1.5%, and transient ischemic attack in 1.5%. Complete closure 6 months after the procedure occurred in 79.6%, without difference between the devices. Percutaneous ASD closure seems to be a relatively safe and effective procedure. However, using the larger Cardioseal/Starflex devices for closure seems to be related to a higher rate of device dislocation and embolization.     

Maternal dietary ethanol consumption is associated with hypertriglyceridemia in adult rat offspring

BACKGROUND: The consumption of significant amounts of alcohol (ethanol, EtOH) may markedly increase serum triglyceride levels. This study describes a significant increase in fasting serum triglyceride (TG) levels in adult male rats whose mothers consumed EtOH. The hypertriglyceridemia occurred although the offspring never directly consumed EtOH and had consumed only rat chow for the preceding 14 months. Furthermore, both male and female adult offspring had an additional, significant increase in TG levels if their mothers consumed EtOH and experienced stress (restraint) during the pregnancy. METHODS: Harlan-derived Sprague Dawley female rats were dosed during pregnancy with EtOH via a liquid diet, and their offspring were compared with offspring of mothers who were either fed ad libitum or pair-fed the liquid diet without EtOH. At birth, the offspring of EtOH mothers exhibited no visible abnormalities except reduced weight, and all offspring were surrogate fostered within 48 hr of birth to mothers who had consumed commercial rat chow throughout their pregnancy. After weaning, all offspring consumed only commercial rat chow, and they were examined over the next 14 months for changes in triglyceride homeostasis as a function of maternal alcohol intake. RESULTS: Adult male offspring of mothers that consumed EtOH during their pregnancy had significant increases in fasting serum triglycerides associated with an increase in the very low density lipoprotein serum fraction. Acute administration of insulin to the offspring of all maternal dietary groups resulted in a rapid clearing of the serum triglycerides, and there were no differences in basal or heparin-releasable lipoprotein lipase activity between any of the progeny. Castration of the male offspring of EtOH-treated mothers prevented the development of elevated TG levels. Administration of testosterone to littermate female offspring increased circulating TG levels compared with testosterone-treated offspring of pair-fed mothers. EtOH-consuming mothers who also underwent five periods of restraint-induced stress (approximately 10 min each session) produced offspring whose fasting serum TG levels were higher than those whose mothers consumed EtOH but experienced no restraint or who experienced restraint but no EtOH. Maternal stress significantly reduced lipoprotein lipase activity in some offspring treatment groups, but the changes did not correspond to changes in the serum TG levels of the offspring. That is, maternal restraint-induced stress was associated with a loss of heparin-releasable lipoprotein lipase activity by male progeny from pair-fed and EtOH-fed mothers and the female offspring of ad libitum-fed and EtOH-fed mothers. CONCLUSIONS: Although serum triglycerides increased with age in all offspring, the increase was much more pronounced in the progeny of mothers who consumed EtOH during their pregnancy. The hypertriglyceridemia was significantly more pronounced in the male offspring and in female offspring treated with testosterone. Castration of male offspring inhibited the hypertriglyceridemia development, which suggests that male sex hormones may play a role in the development of this condition. Maternal EtOH consumption coupled with maternal restraint-induced stress significantly increased the level of hypertriglyceridemia in both male and female offspring compared with offspring whose mothers experienced restraint but no EtOH or EtOH with no restraint. If this study models the human condition, the results could represent an unrecognized risk factor in a number of adult disease states hypothesized to be associated with hypertriglyceridemia, such as cardiovascular disease, hypertension, and diabetes.