Resection of ventricular rhabdomyomas in infants presenting with cardiac failure.

Rhabdomyomas are the most common cardiac tumours in children. They sometimes cause significant obstruction of the ventricular out flow tracts. We report a series of 3 neonates diagnosed antenatally with multiple rhabdomyomas, who developed significant obstruction of the ventricular outflow tracts following birth. They underwent surgical resection in the neonatal period with good outcome. Antenatal diagnosis of obstructive cardiac tumours allows for planning for appropriate early intervention.

Extracardiac Fontan Operation Through a Right Thoracotomy.

An extracardiac Fontan operation through a right thoracotomy incision is an alternative approach in children who have an ascending aorta that is in close proximity to the sternum, as in aortic atresia or transposed great vessels, and in those who have had prior mediastinitis.

Repair of Circumflex Aortic Arch in an Adult.

We describe the diagnoses and repair of a symptomatic circumflex aortic arch in an adult.

Documenting junctional ectopic tachycardia following pediatric open heart surgery.

OBJECTIVE: To determine appropriated documentations for diagnosis junctional ectopic tachycardia (JET) before treatment in post-operative open heart surgery and identify risk factors for post-operative cardiac arrhythmias in children. MATERIAL AND METHOD: The authors performed a retrospective chart review in 277 patients who underwent surgical corrections at British Columbia's Children Hospital from January 1st, 2000 to December 31st, 2001. History, clinical symptoms, complication of surgery and post-operative cardiac arrhythmias were reviewed from medical records. The authors investigated whether JET was being diagnosed accurately and whether it was being adequately documented prior to the initiation of therapy. The authors also identified risk factors that were associated with JET. All documentations before treatment were reviewed by Pediatric cardiologists to confirm diagnosis. RESULTS: Although the diagnostic accuracy (84%), sensitivity (87%), and specificity (84%) are high, a significant number of patients with post-operative arrhythmias were treated without adequate documentation of the arrhythmia. The documentation of arrhythmias in the Intensive Care Unit was largely limited to rhythm strips, with very few 12-lead ECGs and wire studies performed to assist with the diagnosis. CONCLUSION: The presented data indicates that, in this critically-ill population, there was an unacceptable number of patients with post-operative arrhythmias who may have been treated inappropriately. It is very important to emphasize the interpretation of wire studies, an investigation normally done in a critical care setting and whose interpretation is very important to the accurate diagnosis of pediatric arrhythmias.

Clipped tube fenestration after extracardiac Fontan allows for simple transcatheter coil occlusion.

BACKGROUND: Expensive devices are increasingly used to close a patent fenestration after a modified Fontan operation. We report our 5-year institutional experience of clipped tube fenestration after extracardiac Fontan operation, which allows for simple transcatheter coil occlusion. METHODS: We retrospectively reviewed 30 children, median age of 4.0 years (range, 2.4 to 8.8 years) who underwent extracardiac Fontan operation between May 1996 and May 2001, and were fenestrated using a 4- to 8-mm diameter clipped tube graft. RESULTS: Ten children had a patent fenestration occluded by transcatheter placement of 15 detachable coils (5- to 8-mm diameter). Aortic oxygen saturations increased on average by 5.5% (2% to 14%) and mean pressures in the Fontan circuit by 2.5 mm Hg (0 to 3 mm Hg). Four had immediate complete occlusion angiographically and 6 had trivial residual shunt, but complete occlusion by echocardiography at follow-up. There have been no immediate complications, late coil embolizations, thromboembolic events, or documented hemolysis within a follow-up after coil implantation of 1.7 years (0.4 to 4.5 years). Spontaneous fenestration closure was documented in 8 patients at cardiac catheterization and 9 patients by echocardiography with consistent improvement in resting transcutaneous oxygen saturation. Two children with a patent fenestration have been considered inappropriate for closure, and there was one early surgical death. There have been no complications related to the tube fenestration modification within a follow-up postoperation of 2.6 years (0.1 to 5.5 years). CONCLUSIONS: Clipped tube fenestration after extracardiac Fontan operation is a useful surgical modification that allows for simple transcatheter coil occlusion.

Na+/H+ exchange inhibition with HOE 642 improves recovery of the injured neonatal rabbit heart.

BACKGROUND: The effects of inhibition of the Na+/H+ exchanger (NHE) on postischemic recovery of the injured neonatal rabbit heart were examined. The NHE may be an important mechanism for reperfusion injury in the neonate heart. The effects of two NHE inhibitors, HOE 642 (HOE) and 5-(N,N-dimethyl)-amiloride (DMA), given during hypothermic cardioplegic arrest, were evaluated. METHODS: Isolated working crystalloid-perfused neonatal rabbit hearts were subjected to 10 min of normothermic ischemia to cause injury before undergoing 4 h of hypothermic (10 degrees C) cardioplegic arrest with a single dose of crystalloid solution (controls, n=21) or with the addition of 0.5 micromol/L HOE (n=24) or 30 micromol/L DMA (n=15). RESULTS: Hearts subjected to HOE had improved recoveries of aortic flow when compared with controls at 15 min and 30 min of reperfusion (35.7+/-1.3 mL/min versus 26.2+/-1.4 mL/min, respectively, at 15 min, P<0.0001; 36.5+/-1.5 mL/min versus 23.6+/-1.6 mL/min, respectively, at 30 min, P<0.0001) and with DMA at 30 min (36.5+/-1.5 mL/min versus 29.9+/-1.9 mL/min, P=0.0214). Cardiac output and systolic pressure were also improved at 30 min in HOE hearts versus controls (P<0.0001). CONCLUSIONS: NHE inhibition with HOE during cardioplegic arrest resulted in improved functional recovery of injured hearts. Further studies in blood-perfused neonatal preparations are warranted.

Associated inflammation or increased flow-mediated shear stress, but not pressure alone, disrupts endothelial caveolin-1 in infants with pulmonary hypertension.

Endothelial caveolin-1 loss is an important feature of pulmonary hypertension (PH); the rescue of caveolin-1 abrogates experimental PH. Recent studies in human PH suggest that the endothelial caveolin-1 loss is followed by an enhanced expression of caveolin-1 in smooth muscle cells (SMC) with subsequent neointima formation. In order to evaluate caveolin-1 expression in infants with PH, we examined the available clinical histories, hemodynamic data, and the expression of caveolin-1, PECAM-1, vWF, and smooth muscle α-actin in the lung biopsy/autopsy specimens obtained from infants with congenital heart disease (CHD, n = 8) and lung disease (n = 9). In CHD group, PH associated with increased pulmonary blood flow exhibited loss of endothelial caveolin-1 and PECAM-1 in pulmonary arteries; additional vWF loss was associated with enhanced expression of caveolin-1 in SMC. In the absence of PH, increased or decreased pulmonary blood flow did not disrupt endothelial caveolin-1, PECAM-1, or vWF; nor was there any enhanced expression of caveolin-1 in SMC. In Lung Disease + PH group, caveolin-1, PECAM-1, and vWF were well preserved in seven infants, and importantly, SMC in these arteries did not exhibit enhanced caveolin-1 expression. Two infants with associated inflammatory disease exhibited loss of endothelial caveolin-1 and PECAM-1; additional loss of vWF was accompanied by enhanced expression of caveolin-1 in SMC. Thus, associated flow-induced shear stress or inflammation, but not elevated pulmonary artery pressure alone, disrupts endothelial caveolin-1. Subsequent vWF loss, indicative of extensive endothelial damage is associated with enhanced expression of caveolin-1 in SMC, which may worsen the disease.

Does troponin-I measurement predict low cardiac output syndrome following cardiac surgery in children?

OBJECTIVE: To determine whether serum troponin I (TnI), measured 4 hours after surgery for congenital heart disease, is a predictor of myocardial dysfunction and low cardiac output syndrome (LCOS). DESIGN: Prospective, observational study. SETTING: Paediatric intensive care unit in a tertiary care academic children's hospital, 1 June 2003 to 12 May 2004. PATIENTS: 99 consecutive eligible children who underwent a variety of surgical procedures for congenital heart disease, using cardiopulmonary bypass. All patients were cared for by a consistent perioperative care team. INTERVENTIONS: Measurement of TnI preoperatively, and at 0, 4, 8, 12, 24 and 36 hours after ICU admission. RESULTS: Patient demographics and outcome (as median and 25th-75th percentile) were as follows: age, 23.9 (4.6- 65.9) months; cardiopulmonary bypass time, 135 (98-178) minutes; aortic cross-clamp time, 65 (28-85) minutes; preoperative TnI level, 0.02 (0.01-0.03) ng/mL; 4h TnI, 10.6 (3.0-23.4) ng/mL; highest 24 h TnI, 11.7 (3.9-29.5) ng/mL; time to discontinuation of inotropes, 43.9 (18.7-92.9) hours; maximal inotrope score, 10.0 (5.0-16.3); time to extubation, 42.4 (19.8-137.5) hours; and time to ICU discharge 91.8 (45.7-169.7) hours. Twenty-three patients developed LCOS. A 4h TnI level > 13 ng/mL predicted LCOS with a sensitivity of 0.78 (95% CI, 0.56-0.93), and a specificity of 0.72 (95% CI, 0.61-0.82). The area under the receiver operating characteristic curve for TnI as a predictor of LCOS was 0.75 (95% CI, 0.63-0.88). TnI was the only predictive variable associated with LCOS in multivariate logistic regression analysis, with an odds ratio of 1.45 (95% CI, 1.05-2.01) for developing LCOS with each 10 ng/mL increase in 4h TnI. Linear regression analysis showed TnI to be significantly correlated with increased time to discontinuation of inotropes, maximal inotrope administration, time to extubation, and time to ICU discharge. CONCLUSIONS: Measurement of early postoperative levels of TnI may aid in the early identification of children who will develop LCOS.

Congenital right atrial diverticulum, atrial septal defect within the oval fossa, and complex pulmonary valvar obstruction in an infant with chromosome 8(p23.1) deletion.

We describe an unusual right atrial aneurysm, occurring with progressive obstruction of the right ventricular outflow tract and increasing cyanosis, in a nine-month-old boy with chromosome 8(p23.1) deletion. Surgical resection of the diverticulum, and relief of the right ventricular obstruction, was successful, although impairment of right ventricular compliance persists after 19 months follow-up.

Repair in infancy of right aortic arch with aberrant left brachiocephalic artery in the setting of a variant of the hypoplastic left heart syndrome.

A right aortic arch, with a retroesophageal transverse arch and an aberrant left brachiocephalic artery, is a rare anomaly by itself. When combined with severe mitral stenosis and hypoplasia of the left ventricle, it is rarer still. We describe the diagnosis and treatment of this rare anomaly in an infant using a modification of the Norwood operation.

Compression of mediastinal structures treated by extra-anatomic bypass grafting.

Extra-anatomic bypass grafts have been used to treat complex and recurrent forms of coarctation of the aorta. Here we describe the use of an extra-anatomic bypass graft from the ascending to supraceliac aorta to treat an unusual complication of compression of mediastinal structures caused by a bucket handle graft.