Nandini Madan

Fontan’s operation: is aspirin enough? Is coumadin too much?

BACKGROUND Thromboembolism after Fontans operation is attributed to low flow states, stasis in venous pathways, right to left shunts, blind cul-de-sacs, prosthetic materials, atrial arrhythmias, and hypercoagulable states. We assessed the efficacy of a strategy to reduce thromboembolic events including aspirin anticoagulation. METHODS From January 1996 through December 2000, 72 patients underwent Fontan procedures. Management included (1) avoidance of direct caval cannulation and central venous lines, (2) inotropic support for 48 to 72 hours to optimize cardiac output, (3) aortopulmonary anastomosis or suture closure of patent pulmonary valves, and (4) administration of aspirin (81 mg per day) beginning on postoperative day one. No other anticoagulation strategies were used. Surveillance included intraoperative and postoperative transesophageal echo, transthoracic echo at discharge, at first reevaluation, and at 6 month intervals, and catheterization 1 year after surgery. RESULTS There were no early or late deaths. Follow-up was completed with 2,882 patient-months and a mean of 40 months. There were no documented thromboembolic events; however, all suspicious occurrences were investigated by echo and brain imaging. There were no hemorrhagic events or aspirin-related complications. CONCLUSIONS Low dose aspirin can be used safely in young patients with Fontan connections. At intermediate follow-up, the strategies described appear effective in preventing thromboembolic complications. Routine use of more aggressive anticoagulation regimens seems unwarranted.

Congenital unilateral pulmonary venous atresia: definitive diagnosis and treatment.

Three cases of unilateral right-sided pulmonary venous atresia were evaluated over an 18-year period. These bring the total number of cases to 25 in the literature. The clinical presentation of all these patients was similar and consisted of recurrent pulmonary infections, asthma-like symptoms, and exercise intolerance. The patients presented in 1982 (patient 1, a 12-year-old boy), 1994 (patient 2, a 9-year-old girl), and 1999 (patient 3, a 13-year-old boy). All patients were evaluated with a chest roentgenogram, and patients 1 and 2 had a ventilation and perfusion scan. Patients 1 and 3 also had cardiac catheterization and pulmonary angiography. Patient 2 had a magnetic resonance imaging study of the chest. Only patient 3 had wedge pulmonary angiography. Although a rare congenital defect, this diagnosis should be strongly suspected based on the typical clinical presentation and the preliminary studies, such as the chest roentgenogram and ventilation and perfusion scan. However, for definitive diagnosis, cardiac catheterization with wedge pulmonary angiography is necessary. Anastomosis of the atretic pulmonary veins to the left atrium is a theoretical consideration. However, this may not be feasible due to pulmonary venous anatomy or significant pulmonary dysfunction with pulmonary vascular changes. In these circumstances, we recommend performing pneumonectomy to remove the nidus for repeated bouts of pulmonary infections, to eliminate the left-to-right shunt, and to eliminate the dead space contributing to exercise intolerance.

Protocols associated with no mortality in 100 consecutive Fontan procedures

OBJECTIVES Results of Fontans procedure have improved considerably, but perioperative mortality still occurs, attributed to ventricular dysfunction, stroke, arrhythmia, thromboembolism, and multi-organ dysfunction. Our protocols of operative and intensive care unit management address these potential issues, and have been associated with zero mortality, even with many high-risk candidates. METHODS From 1996 to 2006, all Fontan patients were managed as follows: operative strategy based on aortic and single atrial cannulation, cooling on full-flow bypass, and hypothermic circulatory arrest to create the Fontan pathway. No direct caval cannulation. Use of central venous lines was completely avoided. Fresh whole blood was used for pump prime and for volume restoration. Inotropic and vasodilator therapy was continued for at least 48 h. Aspirin was used exclusively as anti-thrombotic therapy. Postoperative pleural drainage was accomplished with small pigtail catheters. The usual Fontan pathway was by lateral atrial tunnel (84), with extra-cardiac conduit when dictated by anatomy (16). RESULTS One hundred Fontan operations were performed with no mortality. All patients were extubated by postoperative day 1. Hospital stay was 10+/-5 days. Complications were: bleeding (1), reintubation (1), emergent fenestration closure (1), pericardial effusion (4), and seizures (1). Risk factors included Fontan connection to one lung (3), diminutive pulmonary arteries (PAs) and unifocalized major aortopulmonary collateral arteries (MAPCAs) (1), discontinuous PAs (3), right ventricle dependent coronaries (3), neonatal pulmonary venous obstruction (3), Trisomy 21 (1), preoperative pacemaker dependence (2), and heterotaxy (10). No candidate was excluded. CONCLUSIONS While many surgeons try to avoid bypass or aortic clamping when performing Fontan operations, the strategies we have employed facilitate safe accomplishment of Fontans operation in diverse anatomic groups with multiple risk factors, with avoidance of operative mortality in 100 consecutive cases.

Severe Sinus Bradycardia in a Patient with Rett Syndrome: A New Cause for a Pause?

Rett syndrome is a progressive disorder seen primarily in young females. It is characterized by autonomic dysfunction affecting many organ systems. Although sudden death is common in these patients, little is known about the cardiovascular manifestations of this dysautonomia. Earlier reports focused on the role of sympathetic overactivity manifest as reduced heart rate variability and prolonged QT intervals indicating a propensity for lethal ventricular arrhythmias. Bradyarrhthmias and sinus node dysfunction, however, have not previously been reported. We describe a 2-year-old with Rett syndrome and severe sinus bradycardia requiring a pacemaker implant. This case represents the first description of a new cardiovascular manifestation of Rett syndrome and may provide an explanation for sudden and unexpected death in some of these patients.

Single-finger subcutaneous defibrillation lead and “active can”: a novel minimally invasive defibrillation configuration for implantable cardioverter-defibrillator implantation in a young child

Implantable cardioverter defibrillators (ICDs) provide a safe and effective treatment for life-threatening ventricular arrhythmias. Several investigators have demonstrated that ICD use in pediatric patients is feasible, effective, and associated with a low risk of sudden death in follow-up. However, ICD placement in young children can usually be accomplished only by a thoracotomy approach involving multiple incisions and placement of epicardial defibrillation electrodes. We describe a less invasive yet efficacious lead configuration likely to be associated with a lower complication rate.

Subcutaneous Array with Active Can Implantable Cardioverter Defibrillator Configuration: A Follow‐up Study

BACKGROUND Novel nontransvenous implantable cardioverter defibrillator (ICD) configurations are sometimes required for small children and children with complex congenital heart disease at risk for sudden death. Mid- to long-term follow-up of these nontraditional implant techniques is not well known. We assessed the mid-term performance of a subcutaneous lead technique used in our practice. METHODS Between July 2002 and November 2003, 4 patients (age 2.1-8.5 years, weight 13-33.3 kg, height 90-126.7 cm) received an ICD with a single-finger (n = 3) or 2-finger (n = 1) subcutaneous array with an active abdominal can and epicardial pace/sense lead. The subcutaneous tunnel was created via a subxiphoid incision using a tunneling tool within a sheath along the seventh intercostal space and extended posterior to the spine. Diagnoses included long QT syndrome (n = 2), idiopathic ventricular fibrillation (n = 1), and idiopathic dilated cardiomyopathy (n = 1). Implantable cardioverter defibrillator indications included syncope (n = 2) and cardiac arrest (n = 2). RESULTS Mean follow-up was 22.3 +/- 13.9 months. During follow-up, 1 patient underwent heart transplantation and the other 3 patients underwent generator replacement secondary to a manufacturers advisory. There was 1 appropriate and successful shock for ventricular fibrillation. This patient experienced a second episode of ventricular fibrillation that the ICD discharge failed to terminate. The arrhythmia spontaneously resolved. There were no inappropriate shocks. There was 1 instance of false detection of ventricular fibrillation because of intermittent T wave oversensing but therapy was not administered. There were no infections, lead fractures, or other complications during follow-up. CONCLUSION This novel nontransvenous ICD configuration can be used safely in a select group of pediatric patients and allows for the applicability of this life-saving technology to small children at high risk for sudden cardiac death.

Right aortic arch, isolated left subclavian artery and ductus arteriosus with normal intracardiac anatomy: rare manifestation of chromosome 22q11 deletion.

32-week twin gestation, with a birth weight of 1.5 kg. The neonatal course was characterized by feeding difficulties, however she was discharged at 3 weeks of age feeding orally and gaining weight. The patient was readmitted at 4 weeks of age following an acute lifethreatening event attributed to significant nasopharyngeal aspiration. The patient was discharged after initiation of nasojejunal feeds. During follow-up, fluoroscopy performed during replacement of the nasojejunal tube was suspicious for the presence of a right aortic arch. At the evaluation, the patient weighed 3.1 kg (less than fifth centile) with a length of 51 cm (less than fifth centile). Blood pressure in the right arm was 78/44, left arm was 70/38 mmHg and left leg was 82/47 mmHg. The patient was mildly tachypneic. The cardiac examination was normal. The patient had micrognathia, ear cupping, a preauricular pit, a single palmar crease and a large umbilical hernia. The presence of the right aortic arch was confirmed on echocardiography. In addition, a ductus arteriosus was noted which entered the left pulmonary artery but arose from an atypical location. The origin of the ductus arteriosus could not be well delineated (Fig. 1). The left ventricle and left atrium were enlarged. On catheterization the aortogram demonstrated a right aortic arch, which gave rise to three branches: the first was the left common carotid, followed by the right common carotid artery and the right subclavian artery (Fig. 2). The left upper lobe had dual blood supply from aortopulmonary collateral arising from the descending aorta that was coil embolized (Fig. 2). The left subclavian artery opacified late in the injection and was supplied by collaterals arising from the left vertebral artery. The

Reversal of Fenestration Flow During Ventricular Systole in Fontan Patients in Junctional or Ventricular Paced Rhythm

Sinus node dysfunction is relatively common in patients with Fontan palliation for single ventricle congenital heart disease, and such patients often are in junctional rhythm or may have pacemaker systems for bradycardia. Because the physiologic determinants of left atrial pressure play a major role in determining pulmonary blood flow and therefore cardiac output in Fontan patients, the loss of atrioventricular (AV) synchrony in junctional rhythm or demand ventricular pacing in these patients might be expected to influence cardiac output. We report two cases of Fontan patients with the absence of AV synchrony that resulted in reversal of flow through the Fontan fenestration during ventricular systole. In both cases, restoration of AV synchrony by atrial pacing resulted in the elimination of retrograde fenestration flow, increased cardiac output, and improved clinical status.

Neurological Complications of Cardiac Disease

This article focuses on the complex interactions between the cardiovascular and neurologic systems. Initially, we focus on neurological complications in children with congenital heart disease both secondary to the underlying cardiac disease and complications of interventions. We later discuss diagnosis and management of common syncope syndromes with emphasis on vasovagal syncope. We also review the diagnosis, classification, and management of children and adolescents with postural orthostatic tachycardia syndrome. Lastly, we discuss long QT syndrome and sudden unexpected death in epilepsy (SUDEP), reviewing advances in genetics and current knowledge of pathophysiology of these conditions. This article attempts to provide an overview of these disorders with focus on pathophysiology, advances in molecular genetics, and current medical interventions.

Comparison of Corrected QT Interval as Measured on Electroencephalography Versus 12-Lead Electrocardiography in Children With a History of Syncope

Long QT syndrome can present with neurological manifestations, including syncope and seizure-like activity. These patients often receive an initial neurologic evaluation, including electroencephalography (EEG). Our previous retrospective study suggested an increased prevalence of prolonged corrected QT interval (QTc) measured during the EEG of patients with syncope. The aim of the current study is to assess the accuracy of the EEG QTc reading compared with the nonsimultaneous 12-lead electrocardiography (ECG) in children with syncope. Abnormal QTc was defined as ≥450 ms in boys, ≥460 ms in girls. Forty-two children were included. There was no significant correlation between QTc readings in the EEG and ECG. EEG failed to identify 2 children with prolonged QTc in the ECG and overestimated the QTc in 3 children with normal QTc in the ECG. This study suggests that interpretation of the QTc segment during an EEG is limited. Further studies with simultaneous EEG and 12-lead ECG are warranted.