Gerd Hausdorf

Coronary Artery Stenosis After Radiofrequency Catheter Ablation of Accessory Atrioventricular Pathways in Children With Ebstein’s Malformation

Background —Complications concerning the coronary arteries that are directly related to radiofrequency catheter ablation procedures have not been reported in children. Coronary artery lesions, however, have been demonstrated after the endocardial application of radiofrequency current in young animals. Methods and Results —Two boys with Ebstein’s anomaly of the tricuspid valve developed clinically asymptomatic coronary artery stenosis after radiofrequency catheter ablation of right-sided accessory atrioventricular pathways with standard catheter technology. Conclusions —The complication of coronary artery stenosis demonstrates a substantial risk after right atrial free wall radiofrequency current application in children. The risk of late coronary alterations should be considered when the use of catheter ablation procedures to young patients is proposed.

Effects of Intracardiac Radiofrequency Current Application on Coronary Artery Vessels in Young Pigs

Radiofrequency Current Lesions in Young Pigs. Introduction: Radiofrequency current is widely used in children to ablate accessory AV pathways. Previous data in a pig model demonstrated coronary artery obstruction adjacent to radiofrequency current lesions 48 hours and 6 months after energy delivery. In the present study, the long‐term effects (>6 months) of radiofrequency current application on coronary artery vessels in young pigs are assessed.

Supraventricular tachycardia in infants, children and adolescents: diagnosis, and pharmacological and interventional therapy.

Supraventricular tachycardia is the most frequent form of symptomatic tachydysrhythmia in children. Neonates and infants with paroxysmal supraventricular tachycardias generally present with signs of acute congestive heart failure. In school-aged children and adolescents, palpitations are the leading symptom. Chronic-permanent tachycardia results in a secondary form of dilated cardiomyopathy.Therapy for episodes of tachycardia depends on the individual situation. In severe haemodynamic compromise, or if ventricular tachycardia is suspected, tachycardia should immediately be terminated by external cardioversion during deep sedation. Vagal manoeuvres are effective in patients with atrioventricular reentrant tachycardias. Adenosine is the drug of first choice in any age group for tachycardias involving the atrioventricular node; its advantages include short half-life and minimal or absent negative inotropic effects. Adenosine may also be used in patients with wide QRS complex tachycardia. Intravenous verapamil is contraindicated in neonates and infants because of the high risk of electromechanical dissociation. In older children (<5 years) and adolescents, verapamil may be administered with the same restrictions as in adult patients (wide QRS complex tachycardia, significant haemodynamic compromise).Spontaneous cessation of tachycardia can be expected in most neonates and infants during the first year of life. Prophylactic pharmacological treatment in this age group is advisable because recognition of tachycardia is often delayed until the occurrence of symptoms. Withdrawal of drug treatment should be attempted around the end of the first year. However, in older children, spontaneous cessation of tachycardia is rare.Prophylactic drug therapy is performed on an empirical basis. Digoxin may be administered in all forms of supraventricular tachycardia in which the atrioventricular node is involved, except in patients with pre-excitation syndrome aged <1 year. In patients with atrioventricular reentrant tachycardia, class 1C drugs such as flecainide and propafenone are effective. Sotalol is also effective in atrioventricular reentrant tachycardia, as well as in primary atrial tachycardia. Although amiodarone has the highest antiarrhythmic potential, it should be used with caution because of its high rate of adverse effects.In school-aged children and adolescents, radiofrequency catheter ablation of the anatomical substrate is an attractive alternative to drug therapy, with a rate of permanent cessation of the tachycardia of up to 90%. Despite the clear advantages of this procedure, it should be performed only with unquestionable indication; the long term morphological and electrophysiological sequelae on the growing atrial and ventricular myocardium are still unknown.

Fontan-type procedures: residual lesions and late interventions

BACKGROUND The purpose of this study was to determine the type and incidence of hemodynamic and electrophysiological abnormalities requiring surgical or catheter-based interventions in a single-center long-term experience. METHODS Eighty-eight patients with a follow-up of at least 5 years (mean follow-up, 9.6 +/- 2.6 years) after Fontan-type procedures were included. All patients had undergone cardiac catheterization either as part of the regular postoperative protocol or because of symptomatic atrial tachycardia or increasing cyanosis. RESULTS Freedom from reoperation for up to 5 years was documented for 82% of patients and decreased to 76% after 8 years. Late reoperations included conversion of an atriopulmonary anastomosis to a total cavopulmonary anastomosis in 2 patients with atrial dysrhythmia and implantation of an extracardiac conduit in 1 patient with left atrial isomerism and intrapulmonary arteriovenous malformations after a Kawashima operation. Decline in sinus node function with symptomatic bradycardia required pacemaker therapy in 10 patients (11%). Transcatheter interventions included fenestration occlusion in 5 of the 11 patients with initial baffle fenestration. In 6 of 17 patients with aortopulmonary collaterals, coil occlusion was indicated to reduce future systemic ventricular volume load. Various systemic venous collaterals were documented in 11 patients and required coil occlusion in 2. One patient with symptomatic protein-losing enteropathy underwent transcatheter fenestration creation without sustained relief of symptoms. Freedom from transcatheter interventions decreased from 94% to 82% after 5 and 10 years, respectively. CONCLUSIONS During long-term follow-up, reoperations are rare and mainly involve Fontan conversion to either a lateral-tunnel or extracardiac-conduit procedure. Detailed angiographic evaluation on a routine basis allows identification of the vascular sites of origin of aortopulmonary collateral vessels and systemic venous collaterals potentially developing during long-term follow-up. Transcatheter interventions including fenestration occlusion and occlusion of venous collaterals and aortopulmonary collaterals were performed to maintain and improve the Fontan circulation in clinically symptomatic and asymptomatic patients. During long-term follow-up after Fontan-type operations, a regular postoperative cardiac catheterization protocol is recommended.

Transcatheter recanalization and subsequent stent implantation for the treatment of early postoperative thrombosis of modified Blalock-Taussig shunts in two children

Two babies with duct-dependent cyanotic congenital heart disease were palliated with modified Blalock-Taussig shunts. One patient was diagnosed to have tetralogy of Fallot, and the other patient, tricuspid atresia type Ia. Early postoperative arterial oxygen saturations dropped significantly due to shunt thrombosis. Both patients were successfully treated with angioplasty and stent implantation.

Transcatheter Occlusion of a Large Pulmonary Arteriovenous Malformation with Use of a Cardioseal Device

Large pulmonary arteriovenous malformations (PAVMs) carry a significant risk of neurologic complications and present technical difficulties in transcatheter treatment with use of coils or detachable balloons. A 26-year-old man with a giant PAVM, who had undergone unsuccessful attempted closure with use of a Gianturco-Grifka occlusion device in the past, underwent successful transcatheter embolization with two Cardioseal double umbrella devices designed for occlusion of intracardiac communications. The procedure was technically easy, had no complications, and provided sustained improvement in arterial saturation and exercise tolerance during follow-up. Transcatheter double umbrella device occlusion of large arteriovenous malformations is feasible and should be considered, especially for very large fistulas.

Transcatheter retrieval and repositioning of an amplatzer device embolized into the left atrium

A transcatheter technique is described for stabilization and retrieval of an embolized Amplatzer device, which was inadvertently deployed in the left atrium of a 2‐year‐old girl with hemodynamically significant atrial septal defect within the fossa ovalis. Since surgery was not available for immediate device retrieval, transcatheter means were chosen to prevent embolization of the device into the mitral valve. After stabilizing the device by creating a guidewire circuit through the wire mesh of the right atrial disk, the Amplatzer device was repositioned through the interatrial defect by snaring the microscrew. No residual shunting and perfect device position was recorded during Doppler echocardiography directly after the procedure as well as 1, 2, and 120 days after the intervention. Cathet. Cardiovasc. Intervent. 51:297–300, 2000.

Experimental ASD closure using autologous cell-seeded interventional closure devices.

OBJECTIVE Atrial septal defect (ASD) occluders are permanent implants in paediatric cardiology which serve as mechanical shields until complete overgrowth and incorporation of the occluding device by autologous tissue has occurred. Thereafter, the foreign body material making up the device is dispensable and bears potential long-term adverse effects. Rapid, firm and complete incorporation into the atrial septal wall should be a prerequisite for biodegradable devices. In this study, the feasibility of using autologous cell-seeded devices was investigated by (a) testing the influence of a collagen coating on cellular stress resistance in vitro and (b) comparing the short-term effects between cell-seeded, collagen-coated and acellular ASD occluders in vivo. METHODS Native and collagen-coated Dacon fabrics and Starflex-devices were pre-seeded with autologous fibroblasts (skin biopsy) and evaluated using various mechanical stress tests. In a sheep model interventionally created ASDs were closed using either autologous pre-seeded or conventional (acellular) Starflex-devices. RESULTS ASD closure devices were successfully pre-seeded with autologous cells. The incubation period needed, the cellular density achieved and the mechanical stability of the cytolayer after mechanical stressing (implantation) were improved by applying a collagen matrix on the fabric. Compared to the thin layer of ingrown tissue seen on conventional occluders after 30 days in vivo, a thicker layer of organising, newly formed granulation tissue on pre-seeded collagen-coated devices embedded not only the Dacron fabric, but also completely covered the spring arms of the device underneath a layer of neo-endothelium. CONCLUSION Autologous cell pre-seeding of interventional closure devices is feasible since the cells survive the mechanical stress encountered during implantation. Rapid, firm and complete ingrowth of occluder devices into a thicker layer of young fibrous granulation tissue can be achieved, but an increased thrombogenicity currently limits the in vivo application.

Primary repair of tetralogy of Fallot in infancy – the effect on growth of the pulmonary arteries and the risk for late reinterventions

We sought to analyse the long-term follow-up after primary repair of tetralogy of Fallot in infancy in the first year of life, paying particular attention to growth of the pulmonary arteries and the need for reintervention. We performed a combined retro- and prospective echocardiographic study, including measurements of the pulmonary valve and right and left pulmonary arteries, indexed to the square root of body surface area, in 62 patients prior to primary repair, 18 to 24 months after this event, and at the most recent follow-up, with a mean of 80.4+/-24 months. Of these, 38 patients, with an age at operation of 5.0+/-3.4 months, had presented preoperatively with hypoxic spells or increasing cyanosis. The remaining 24 patients had been asymptomatic, with adequate flow of blood to the lungs. Their age at elective operation was 7.4+/-3.0 months. A transannular patch was needed in 37 patients (63%). There were 3 early postoperative deaths (4.8%). Cross-sectional echocardiography revealed a significantly smaller diameter for the pulmonary valve in patients who had been symptomatic preoperatively compared to the asymptomatic patients (1.09 versus 1.3 cm/BSA0.5; p = 0.019). The diameters of the right and left pulmonary arteries did not differ significantly between the groups. Examination of echocardiographic data obtained 18 to 24 months postoperatively in 43 patients revealed a significant increase in the diameter of the pulmonary arteries; 0.83+/-0.17 cm/BSA0.5 versus 1.1+/-0.26 cm/BSA0.5 for the diameter of the right pulmonary artery, 0.85+/-0.2 cm/BSA0.5 versus 1.0+/-0.25 cm/BSA0.5 for the left pulmonary artery. On comparison between individuals, 18.6% and 25.6% of the patients, respectively, did not show any change in the diameters of their right and left pulmonary arteries, whereas the increase in diameter reached or exceeded the measurements in normal controls in 55.8% and 46.5% of the patients, respectively. On recent follow-up, with a range from 56 to 147 months, no further increase in the indexed diameters of the pulmonaries could be documented in 21 of 33 patients. Of these, 9.1% and 18.2%, respectively, presented with small right and left pulmonary arteries compared with measurements obtained in normal controls. Moderate pulmonary incompetence was found on colour flow mapping in one-third. Of 56 longterm survivors, 8 (14%) had required reinterventions, which were surgical in 6 and achieved by transcatheter techniques in the other 2 patients. Thus, primary correction of tetralogy of Fallot in infancy, with restoration of normal pressures and flows, resulted in sustained increase in the diameters of the right and left pulmonary arteries. It allowed for early normal development of the proximal pulmonary arterial system in most patients regardless of their age and symptomatic status at operation. Patients with persistent subnormal diameter of the pulmonary arteries did not present with significantly elevated right ventricular pressure. Early one-stage repair of tetralogy of Fallot in infancy was associated with a low rate of reinterventions.

Endovascular stenting as an emergency treatment for neonatal coarctation

We describe a neonate with critical coarctation of the aorta. Since treatment with Prostaglandin E1 had failed to reopen the arterial duct, and surgery was deemed to be associated with an unacceptably high risk in this unstable neonate, it was decided to perform balloon dilation of the coarctation as a palliative procedure to stabilize the patient. Balloon angioplasty failed to reduce the pressure gradient across the coarctation, so a stent was implanted retrogradely as an emergency procedure. Subsequently, the stented segment was resected surgically and end-to-end anastomosis created without complications at seven months of age.