Robert H. Pass

Endovascular stent implantation in the pulmonary arteries of infants and children without the use of a long vascular sheath.

Endovascular stent implantation for pulmonary artery stenosis requires the use of a long, large‐bore vascular sheath to insure precise implantation without embolization or malposition. A long vascular sheath may be difficult to position and usage may be associated with vascular compromise and/or hemodynamic embarrassment, especially in infants and small children. We report a new technique for pulmonary artery endovascular stent implantation without the use of a long sheath. From December 2000 to May 2001, 10 patients underwent implantation of 13 Palmaz Corinthian premounted biliary transhepatic stents for pulmonary artery stenosis. Median age was 0.8 years (range, 0.5–18.5) and median weight was 11.8 kg (range, 4.6–65). Patient diagnoses were tetralogy of Fallot (five), double outlet right ventricle (three), branch peripheral pulmonary artery stenosis (two), single ventricle s/p cavopulmonary shunt (one), and truncus arteriosus (one). All Palmaz Corinthian stents were delivered uncovered on Cordis Opta LP balloon catheters via short sheaths (6–7 Fr); super‐stiff guidewires were not always necessary. These stents, with a maximal expanded diameter of 12 mm, were placed for peripheral pulmonary artery stenosis as a definitive procedure or at the pulmonary artery bifurcation in patients who were expected to undergo future open heart surgery. The stents were initially implanted on 4, 6, or 8 mm balloon catheters and further expanded if needed. Stents were placed in the right pulmonary artery alone in three patients, left pulmonary artery alone in four patients, and side‐by‐side stents were implanted simultaneously in three patients. All thirteen stents were implanted successfully in the desired location without stent malposition or embolization. Mean angiographic diameter increased from 2.5 ± 1.5 to 5.7 ± 1.4 mm (P < 0.01) and peak systolic ejection gradients decreased from 44 ± 22 to 14 ± 11.6 mm Hg (P < 0.01). The uncovered delivery of the premounted Palmaz Corinthian stent allowed for precise and safe endovascular stent implantation without the hemodynamic and technical problems associated with long vascular sheath usage. This technique is useful for the palliation of proximal pulmonary artery stenosis and is effective definitive treatment for peripheral pulmonary artery stenosis in small infants and children. Cathet Cardiovasc Intervent 2002;55:505–509.

Endovascular stent placement for venous obstruction after cardiac transplantation in children and young adults.

Survival following cardiac transplantation in children and adults, including the group with complex congenital heart disease, has improved over the last decade secondary to medical and surgical advances in management. There have been rare reports of superior vena cava obstruction at anastomotic sites following transplantation. In patients following heart transplantation, venous stenosis can limit the ability to perform endomyocardial biopsies. We reviewed our experience in three patients who underwent cardiac transplantation and developed significant venous stenosis requiring intervention. All three were successfully treated by transcatheter implantation of endovascular stents. Endovascular stent implantation for venous obstruction in patients following cardiac transplantation was safe and effective, allowing improved ease of catheterization for future posttransplantation monitoring and surveillance. Cathet Cardiovasc Intervent 2002;56:383–386.

Catheter intervention for critical aortic stenosis in the neonate

Neonates with symptomatic valvar aortic stenosis require immediate intervention in the first days of life. Originally, surgery was the preferred and sole option for the management of this patient population. Surgical results (either closed or open) were initially quite variable and often poor, with mortality rates as high as 71% [1–5]. In partial response to these initial results and concurrent with the report of Kan et al. [6] demonstrating the successful use of static balloon valvuloplasty for the treatment of pulmonary valve stenosis, the techniques of static balloon valvuloplasty were applied to the treatment of aortic valve stenosis. First described in 1983 in children and then in 1985 in infants, percutaneous balloon valvuloplasty has emerged as the treatment of choice for the initial palliation of infants with critical aortic valve stenosis [7,8]. Over the past 18 years marked changes in technique have evolved, improving the safety, ease, and results of this intervention. An additional, perhaps equally important, advance during this period has been an improved understanding of predictive echocardiographic features, which may allow for more appropriate initial management strategy decisions, specifically choosing between singleversus two-ventricle repair in this complex patient population [9]. Unfortunately, prospective studies reviewing such potentially predictive features have not thus far been performed. Thus, appropriate patient selection for balloon dilation, though markedly improved in recent years, is still complex and unclear. The goal of this review is to present present-day techniques and the results of catheter intervention for this difficult group of patients.

Radiofrequency Ablation of an Accessory Pathway in a Surgically Created Atrioventricular Fontan Anastomosis: Case Report and Review of Previous Published Cases

Supraventricular tachyarrhythmias following the Fontan procedure can be life‐threatening. Though most are commonly due to intraatrial reentry, orthodromic reentrant tachycardia may also be present. Atrioventricular accessory pathways may develop across suture lines following right atrial to right ventricular anastomosis in patients with tricuspid atresia. We report a case of a patient who underwent this type of Fontan who developed orthodromic reentrant tachycardia and heart failure. An electrophysiological study revealed the presence of an atrioventricular accessory pathway traversing the Fontan anastomosis suture line. Successful radiofrequency ablation of the accessory pathway led to control of the tachyarrhythmia and improvement of heart failure.

The implantable loop recorder in children: searching for indications

Assessment of the aetiology of syncope in children can be challenging. In the majority of cases, the cause can be determined from a careful personal and family history, and physical examination. Additional testing such as an ECG, stress test, Holter monitoring and echocardiogram are useful in helping to ferret out the aetiology of syncope. Tilt table testing is also occasionally considered in patients with histories that are consistent with possible neurocardiogenic syncope. An invasive electrophysiological study is indicated when an arrhythmia is suspected, particularly in a patient with structural heart disease.1 Despite extensive investigations, there are rare cases in which the mechanism of syncope cannot be easily determined. The implantable loop recorder (ILR) can be used as a diagnostic tool in cases of recurrent syncope in which an aetiological origin cannot be found.2 It is a device placed in the subcutaneous tissue, usually in the pectoral area, which can monitor heart rhythm continuously. In the case of an event, such as syncope, the rhythm can be automatically or manually stored by applying a hand-held activator over the device. Subsequently, the stored rhythm can be reviewed by the doctor. Over the past decade, use of the ILR in adult patients has improved our ability to demonstrate symptom–rhythm correlation during infrequent episodes of unexplained syncope.3–5 In an international study, Brignole et al demonstrated that 74% of patients with recurrent syncope after ILR implant had documentation of the rhythm at the time of symptoms. Furthermore, treatment …

Optimal surface electrocardiogram lead for identification of the mechanism of supraventricular tachycardia in children.

Objective: Although supraventricular tachycardia (SVT) can be identified from any lead of the bedside monitor, the mechanism of tachycardia is not always obvious. We analyzed the 12-lead electrocardiogram (ECG) in SVT of pediatric patients with different mechanisms of SVT to determine if there is a consistent optimal lead for rhythm identification. Methods: Twelve-lead ECGs during SVT were available for retrospective analysis in 54 patients. The tachycardia mechanism was determined either by intracardiac or transesophageal recording, or after cardioversion analysis of atrial flutter or fibrillation. Blinded analysis of each separate lead of the 12-lead ECG was done to determine the best lead to diagnose the mechanism of tachycardia. For statistical analysis, χ2 or Fisher exact test was used. Results: From analysis of the surface ECG, the mechanism of SVT could be identified in 49 (91%) of 54 patients. Lead V1 was the most useful lead to determine the tachycardia mechanism. V1 identified the mechanism in 39 (80%) of 49 patients compared with 29 (59%) of 49 in lead III (P < 0.05), 22 (51%) of 49 in lead II (P < 0.01), and 12 (24%) of 49 in V6 (P < 0.001). Lead V1 identified accessory pathway-mediated tachycardia in 15 (68%) of 22 patients, atrial flutter in 12 (87%) of 14 patients, atrial fibrillation in 7 (70%) of 10, and atrioventricular nodal reentrant tachycardia in 5 (62%) of 8 patients. The mechanism of tachycardia was more readily diagnosed using a combination of V1 and lead III (47/49 patients, 96%) compared with V1 alone (P < 0.05). Conclusions: A right precordial lead (V1) is the best single lead to diagnose the mechanism of SVT. Furthermore, a combination of V1 and lead III increases the number of patients in whom the mechanism could be identified. Therefore, we recommend that V1 should be combined with an inferior limb lead during cardiac monitoring for optimal identification of the mechanism of SVT in children.

Transcatheter closure of a very large patent ductus arteriosus in a pregnant woman at 22 weeks of gestation

Successful transcatheter closure of a large PDA in a pregnant patient is reported using the Amplatzer ductal occluder device. This procedure was safe and uncomplicated, obviating the need for surgery in this high risk patient. Catheter Cardiovasc Interv 2004;61:140–143.

Transcatheter occlusion of antegrade pulmonary flow in children after cavopulmonary anastomosis

To report our experience with transcatheter occlusion of antegrade pulmonary blood flow (APF) for postoperative complications of cavopulmonary anastomosis (BCPA).