Paul Oslizlok

Radiofrequency catheter ablation of incessant, medically resistant supraventricular tachycardia in infants and small children

OBJECTIVES This study retrospectively evaluates initial experience with radiofrequency catheter ablation in a group of seven infants and small children with a history of incessant, medically resistant supraventricular tachycardia. METHODS Before attempted catheter ablation, all patients had had unsuccessful conventional medical therapy (with digoxin or propranolol, or both) and, in addition, each continued to have daily episodes of supraventricular tachycardia while taking amiodarone or a class IC antiarrhythmic agent alone or in combination. The average patient age was 10 months (range 1 to 27) and the average patient weight was 6 kg (range 3 to 13). Electrophysiologic diagnosis included reentrant supraventricular tachycardia in six patients and atrial ectopic tachycardia in one patient. RESULTS These seven patients underwent a total of nine catheter ablation procedures. The atrial approach to ablation was employed in eight of the nine procedures. Overall, radiofrequency catheter ablation was totally successful in five of the seven patients, partially successful in one patient and unsuccessful in the remaining patient. The combination of radiofrequency catheter ablation and surgical ablation was successful in controlling tachycardia in all patients; with at least 5 months of follow-up study, no patient has had a recurrence of supraventricular tachycardia or reappearance of a delta wave. CONCLUSIONS Surgical ablation of arrhythmogenic substrates in the pediatric age group, although rarely indicated, has been found in the past to be safe and effective. Our initial experience with radiofrequency catheter ablation in infants and small children demonstrates that this procedure is a promising nonpharmacologic therapeutic alternative to surgical ablation.

Natural history of supravalvular aortic stenosis and pulmonary artery stenosis

Data from 35 patients with supravalvular aortic stenosis or pulmonary artery stenosis, or both, undergoing cardiac catheterization between 1973 and 1989 were analyzed retrospectively. Twenty-seven patients had supravalvular aortic stenosis: 11 required surgery after the first investigation and 8 (80%) of 10 others undergoing serial investigation showed an increase in the left ventricle to aorta pressure gradient. Angiographic measurements showed that the increase in the aortic pressure gradient was related to failure of normal growth of the ascending aorta lumen. Nineteen patients had pulmonary artery stenosis, with a right ventricular pressure greater than 33 mm Hg. At restudy, right ventricular pressure had decreased in 9 (82%) of 11 patients. This decrease in right ventricular pressure was associated with an increase in the systolic distensibility of the proximal pulmonary arteries, although there was no increase in the diastolic diameters. One patient had a rapid early increase in right ventricular pressure and no pulmonary artery growth. In two patients, multiple peripheral pulmonary artery stenoses became evident with time and produced persistent right ventricular hypertension. Supravalvular aortic stenosis is usually a progressive lesion, with an increase in left ventricular outflow tract pressure gradient related to poor growth of the ascending aorta. Pulmonary artery stenosis usually improves and only rarely limits prognosis.

Neurocardiogenic syncope in children with a normal heart

OBJECTIVES The purpose of this study was to review the results of investigation and management of children with syncope and a structurally normal heart. BACKGROUND Syncope is a common clinical problem and has many etiologies. Autonomic testing and, in particular, the tilt/orthostatic test have helped to positively diagnose neurocardiogenic syncope in a high proportion of such patients. METHODS Patient case notes and autonomic test charts were reviewed in 162 children aged 1 to 20 years (mean age 12.8 years) with syncope. The autonomic test consisted of orthostatic maneuver, carotid sinus massage, diving reflex, Valsalva maneuver and dose response to intravenous boluses of isoproterenol and phenylephrine. Serum levels of epinephrine and norepinephrine were drawn during the orthostatic test. After confirmation of neurocardiogenic syncope, treatment was begun with fludrocortisone and salt, and beta-adrenergic blocking agents were used as a second line of therapy when indicated. RESULTS The orthostatic test was positive for neurocardiogenic syncope in 100 patients (62%) and negative in 62 (38%). Patients in the former group were older, were more often female and had a diminished response to carotid sinus massage, a higher Valsalva ratio and a higher supine epinephrine level. Both groups showed an increase in epinephrine and norepinephrine levels at 5 min of standing. In the orthostatic positive group at the time of syncope, norepinephrine levels decreased, whereas epinephrine levels increased. Patients in this group were also more sensitive to the vasodilating effect of isoproterenol but not to its chronotropic effects. Eleven patients had cardioinhibitory syncope (asystole > or = 3 s). Of these, three had pacemaker implantation. Fludrocortisone and salt used in 84 patients in the orthostatic positive group produced resolution of symptoms in 55 patients (65%) and improvement in 14 (17%). Ten patients received beta-blockers, with resolution in four and improvement in four. CONCLUSIONS Patients with orthostatic test-proved neurocardiogenic syncope show evidence of autonomic dysfunction. They also show beta-adrenergic hypersensitivity. Treatment initiated on the basis of the protocol was associated with amelioration of symptoms in the majority of patients.

Early restenosis following biodegradable stent implantation in an aortopulmonary collateral of a patient with pulmonary atresia and hypoplastic pulmonary arteries

Traditionally, the implantation of stents in young children with small blood vessels has been avoided as the presence of a metallic or fixed stent structure limits the ability to further dilate the stent with vessel growth. Pulmonary atresia with ventricular septal defect and hypoplastic pulmonary arteries represents one such cohort where the placement of fixed nondegradable stents has been difficult. We report a 2‐month‐old girl with pulmonary atresia, VSD, and multiple aorto‐pulmonary collaterals with severely hypoplastic pulmonary arteries who underwent placement of a biodegradeable magnesium stent within a stenotic aorto‐pulmonary collateral. Although there was an initial significant increase in vessel diameter, significant restenosis occurred 4 months after stent placement. This to our knowledge represents the first case of the use of biodegradable stents in a child with severely hypoplastic pulmonary arteries. Although further refinements in stent technology are required, this development will hopefully usher in a new era of potential intervention in children previously deemed unsuitable for stent placement.

Comparison of the results of transcatheter closure of patent ductus arteriosus with newer Amplatzer devices.

To compare the success and complication rates for the different devices and patent ductus arteriosus (PDA) types.Objectives To compare the success and complication rates for the different devices and patent ductus arteriosus (PDA) types. Background There are numerous devices available for transcatheter closure of PDA but data comparing the success and complication rates of the newer devices are lacking. Methods A retrospective review was undertaken of all cases of transcatheter PDA closure at a tertiary referral center. Results Transcatheter PDA closure was achieved in 176 of 177 cases. Mean age, weight, and minimum ductal diameter were 3.3 years, 15.0 kg, and 2.5 mm, respectively. Devices used were Amplatzer Duct Occluder I (ADO I, 50.3%), Amplatzer Duct Occluder II (ADO II, 28.2%), Amplatzer Duct Occluder II Additional Sizes (ADO II AS, 5.1%), flipper coils (14.1%), and “other” devices (2.3%). Regarding Amplatzer devices, arterial delivery had a significantly shorter fluoroscopy time as compared to venous delivery (3.7 vs. 5.0 min, P = 0.0068), with no significant difference in outcomes. Immediate residual shunt rates were 7.9% (7/89) for ADO I, 4.1% (2/49) for ADO II, 11.1% (1/9) for ADO II AS, and 0% (0/25) for flipper coils. Aortic protrusion rates were 9% (8/89) for ADO I, 14.3% (7/49) for ADO II, and O% for both ADO II AS (0/9) and flipper coils (0/25). Conclusions All devices achieved excellent occlusion rates with low complication rates, regardless of PDA type. Device delivery via arterial access was associated with a shorter fluoroscopy time as compared to venous delivery, with no significant difference in outcomes. ADO II AS may be preferable to ADO II in the younger infant.

Early clinical experience with a modified amplatzer ductal occluder for transcatheter arterial duct occlusion in infants and small children

To describe early clinical experience with the amplatzer ductal occluder II additional sizes (ADO II AS) for percutaneous arterial duct occlusion in infants and small children.

Repair of Supravalvar Aortic Stenosis: Cardiovascular Morphometric and Hemodynamic Results

Supravalvar aortic stenosis is associated with normal systolic pressure in the aorta and its branches with the singular exception of the coronary arteries, which are hypertensive. This uncommon lesion has been treated by patch aortoplasty of several types. We examined hemodynamics and morphometrics in 13 patients who underwent operation for supravalvar aortic stenosis from 1979 through 1988. They ranged in age from 2 to 43 years (mean age, 14.5 +/- 3.8 years [+/- standard error of the mean]). There were no operative deaths. Preoperative and postoperative (1 to 5 years) catheterization or echocardiography or a combination of these was done in all but 3 patients (1 died late suddenly without a postmortem examination; 1 was lost to follow-up; and 1 has not yet been restudied). Pressure gradients across the stenosis in patients treated with a single-sinus patch (n = 4) were 65 +/- 18 mm Hg preoperatively and 5 +/- 3 mm Hg postoperatively (p less than 0.05) and in patients with a bisinus patch (n = 6), 83 +/- 15 mm Hg preoperatively and 6 +/- 2 mm Hg postoperatively (p less than 0.05); the two groups were not significantly different. Measurements of the diameters of the coronary arteries, aortic annulus, and descending aorta were made, and calculation of the ratio of the coronary artery and annulus diameters to the descending aortic diameters both preoperatively and postoperatively was possible in 5 patients. The left coronary artery was larger than normal before and after operation. Preoperatively there was a disproportionate increase in left coronary artery and annulus size during systole. Left ventricular wall thickness decreased significantly postoperatively (p less than 0.05). Repair of supravalvar aortic stenosis (localized and diffuse) by both single sinus and bisinus patch repair is safe and hemodynamic results are good.(ABSTRACT TRUNCATED AT 250 WORDS)

Fetal and neonatal dysrhythmia associated with a ventricular aneurysm

The presentation and etiology of ventricular dysrhythmias in the newborn period are varied. Although the causes of newborn ventricular ectopy are diverse, in most cases they are idiopathic and self-resolving. The association between ventricular dysrhythmia and congenital ventricular aneurysm has been previously reported in older children and adults. We describe an unusual case of a ventricular aneurysm in a newborn who presented with fetal and perinatal dysrhythmia

Percutaneous closure of postoperative ventricular septal defects with the Amplatzer device.

The objective of this study was to look at the procedure, the results, and the follow‐up of patients who underwent percutaneous closure of a residual ventricular septal defect (VSD) following a surgical closure using the Amplatzer VSD device. Four patients had an original diagnosis of tetralogy of Fallot, two patients had a patch leak following a surgical repair of a VSD, and three patients had a VSD not repaired at the time of surgery. All patients fulfilled the currently accepted surgical criterion for reoperation (Qp/Qs > 1.5). The mean Qp/Qs was 1.8 ± 0.3 (1.5–2.3). Four patients underwent VSD closure using an Amplatzer perimembranous VSD device and in five patients an Amplatzer muscular VSD device was implanted. We performed percutaneous closure in nine patients. The size of the residual shunt ranged from 6 to 14 mm and the size of device used ranged from 8 to 16 mm. The arteriovenous loop needed to be recreated in two patients because of failure to advance the delivery sheath. There was complete closure of the defect in six cases, and a small residual shunt remained in three cases. Percutaneous closure of postoperative VSDs appears to be an effective way to resolve a hemodynamically significant residual shunt. There were no difficulties encountered with implantation of the devices. These promising short‐term results need reinforcement with additional long‐term data.

Initial Experience of Pacing with a Lumenless Lead System in Patients with Congenital Heart Disease

Background: Long‐term pacing is frequently necessary in patients with congenital heart disease (CHD). Preservation of ventricular function and avoidance of venous occlusion is important in these patients. Site‐selective pacing with a smaller diameter lead is achievable with the model 3830 lead (SelectSecure®, Medtronic Inc., Minneapolis, MN, USA), which was specifically designed to target these complications. We describe our initial experience with the Model 3830 lead in patients with CHD.