Arrhythmias Following the Mustard and Senning Operations for Dextro-Transposition of the Great Arteries: Clinical Aspects and Catheter Ablation.

The atrial switch operations, the Mustard and Senning procedures, performed for dextro-transposition of the great arteries, have largely been supplanted by the arterial switch operation. As such, affected patients will only exist for approximately 30 more years. The main arrhythmias in these patients include sinoatrial node dysfunction, intraatrial reentry tachycardia, and sudden death. Device therapy for these patients is well-established, and catheter ablation for atrial tachycardias is highly efficacious. The application of meticulous procedural planning, customization of catheter courses, and electrophysiologic principles to this patient group may be extended to all postoperative complex congenital heart patients.

Defibrillation Testing Strategies of Pediatric and Adult Congenital Electrophysiologists during ICD Implantation.

BACKGROUND: Recently, there has been an increasing number of internal medicine-trained electrophysiologists who choose not to test for acute defibrillation efficacy during implantable cardioverter defibrillator (ICD) implantation. It is not known whether this same trend is seen in pediatric electrophysiologists, who care primarily for patients with congenital heart disease or primary electrical problems. METHODS: Through a 14-question survey created on Survey Monkey, we asked the members of the Pediatric and Adult Congenital Electrophysiology Society (PACES) for their approach to ICD implantation. In particular, respondents were asked for their individual practice preferences on testing for acute defibrillation efficacy, including methods used for testing. RESULTS: There were 108 survey respondents. Thirty-nine percent test acute defibrillation efficacy at all implants, while 46% test in most patients, barring any clinical concerns. Another 14% routinely test during initial ICD system implants but not during generator changes with existing leads. Less than 1% of respondents do not routinely test acute defibrillation efficacy. CONCLUSIONS: The practice preferences of pediatric electrophysiologists in evaluating for acute defibrillation efficacy during ICD implants are in contrast to the recent trend in their internal medicine-trained counterparts. More studies are needed to determine if practice changes should be considered in the pediatric and adult congenital patient population.

Ventricular Tachycardia Following Surgical Repair of Complex Congenital Heart Disease.

A nine year old boy with complex congenital heart disease requiring right ventricular outflow tract surgery and palpitations had inducible monomorphic ventricular tachycardia at 300 bpm by programmed ventricular stimulation. He was treated with enteral phenytoin. With a therapeutic plasma level, repeat electrophysiological study was negative for inducible ventricular tachycardia using an aggressive pacing protocol. An insertable loop recorder was implanted, and the family was prescribed an automatic external defibrillator. The decision to not place an implantable cardioverter-defibrillator was based upon anticipated need for serial cardiac MRI scans to monitor the effect of progressive outflow tract stenosis and regurgitation.

Development and gene expression profiling of a metastatic variant of the human breast cancer MDA-MB-435 cells.

We have developed a model system of late stage metastatic progression by isolating a highly malignant variant of human breast cancer cells from the parental MDA-MB-435 cell line. These cells, isolated from early lung metastasis, displayed increased anchorage independent growth in vitro and when transplanted ortho-topically into nude mice showed accelerated tumor growth rate and early lung spontaneous metastasis when compared to its parental counterpart. These cells, designated as MDA-MB-435-F-L, also showed intense wide spread early skeletal metastasis in vertebrae, mandible, femur, tibia and skull as detected by fluorescence imaging in an experimental bone metastasis model. Gene expression profiles from cDNA microarray showed up or downregulation of the expression of several significant genes regulating angiogenesis, apoptosis, ECM remodeling and metastasis in the MDA-MB-435-F-L cells in comparison to the parental cells. Among the up or downregulated genes, some have also been implicated in the survival of breast cancer patients. As such, the candidate genes selected in this breast cancer progression model system may serve as biomarkers of metastatic progression and also as potential tumor targets for breast cancer therapy.