Jeffrey M. Dunn

Ectopic automatic atrial tachycardia in children: Clinical characteristics, management and follow-up

Ectopic automatic atrial tachycardia, an uncommon type of supraventricular tachycardia in children and adults, has been reported to be resistant to medical therapy, and surgical or cryoblation has been recommended. This report describes 10 infants and children (median age 6 months; range birth to 7.5 years) with automatic atrial tachycardia and their management and follow-up. Digoxin alone was unsuccessful in controlling tachycardia in all 10 patients but decreased the tachycardia rate by 5 to 20% in 8. Intravenous (0.1 mg/kg body weight per dose) and oral propranolol successfully suppressed tachycardia in three of five patients and oral propranolol successfully controlled tachycardia in two of five other patients. Class I antiarrhythmic agents--quinidine (three patients), procainamide (four patients) and phenytoin (three patients)--did not control tachycardia in any patients but made the tachycardia rate worse in three patients. Intravenous (5 mg/kg per dose) and oral amiodarone suppressed tachycardia in three of four patients and oral amiodarone suppressed it in another patient. Thus, intravenous propranolol and amiodarone were effective in acutely suppressing automatic ectopic atrial tachycardia and predicted the response to long-term oral therapy. One patient had persistent tachycardia after surgical ablation of the high right atrial ectopic focus, and another patient had unsuccessful catheter ablation of the high right atrial ectopic focus (25 J). During follow-up (10 to 28 months), ectopic atrial tachycardia resolved completely in four patients and was well controlled in four patients.

Porcine Valve Durability in Children

Calcification of porcine heterograft valves may be greater in the pediatric than in the adult population. This multicenter study evaluates the long-term actuarially determined durability of porcine valves in children less than 21 years old. We evaluated 227 late survivors of porcine valve implantation with 47 aortic valves, 67 mitral valves, 14 tricuspid valves, 14 pulmonary valves, 77 pulmonary conduits, and 8 apicoaortic conduits. In this series, 20 porcine valves degenerated, most in the aortic and mitral positions. At 5 years 40% of aortic, 40% of mitral, 100% of tricuspid, 100% of pulmonary, and 89% of pulmonary conduits remained functional. In this series, calcification and dysfunction occurred significantly faster (p less than 0.05) in younger compared with older children and in left-sided or systemic positions (aortic and mitral) compared with right-sided positions (tricuspid, pulmonary, and pulmonary conduit).

Vascular rings and slings: Long-term follow-up of pulmonary function*

Between 1968 and 1983, 54 patients underwent surgery for symptomatic aortic arch and pulmonary artery anomalies at St Christophers Hospital for Children. Presenting symptoms included stridor, wheeze, apnea, recurrent pulmonary infections, or dysphagia. Diagnosis was established with chest roentgenogram, bronchoscopy, barium esophagram, and arteriography. Four types of vascular anomalies were encountered; double aortic arch (24 patients), right aortic arch with left ligamentum arteriosum (17 patients), anomalous innominate artery (10 patients), and pulmonary artery sling (three patients). There were no intraoperative deaths and only one postoperative death. All surviving patients had immediate relief of their severe respiratory or swallowing symptoms. Mild respiratory symptoms persisted postoperatively from 3 months to 4 years and included frequent or severe upper respiratory infections, persistent cough, stridor and pneumonia. Five of the 53 surviving patients were lost to follow up. The remaining 48 patients were followed from 6 months to 14 years and all but one patient noted complete resolution of all respiratory symptoms. Twenty-nine patients at follow up were old enough to undergo pulmonary function testing including vital capacity, functional residual capacity, and inspiratory and expiratory flow volume loops. Seventeen of these 29 asymptomatic patients consented to these studies, and nine of these patients had abnormal flow volume loops indicative of significant central airway obstruction; the other eight studies were normal. We conclude that surgical repair for vascular rings and slings is safe and symptomatically efficacious. However, anatomic tracheal or bronchial distortion persists in a significant number of these patients as evaluated by pulmonary function studies.

Congenital Cardiac Anomalies Associated with the DiGeorge Syndrome: A Neonatal Experience

The DiGeorge syndrome is a rare congenital abnormality of absent of hypoplastic thymus and parathyroid glands. Thirty neonates who had cardiac lesions and the DiGeorge syndrome are reviewed. The early mortality for 10 neonates undergoing palliative procedures was 80%. Seventy-five percent of the deaths were secondary to sepsis. Twenty neonates did not undergo palliative procedures. In this group, early mortality was 60% and late mortality was 65%. Sixty percent of the deaths in this group were associated with sepsis, with cardiac failure responsible for the remaining deaths. Survival in both groups has improved with appropriate treatment of the immunological and metabolic consequences of the DiGeorge syndrome.

Oncocytic cardiomyopathy of infancy with Wolff-Parkinson-White syndrome and ectopic foci causing tachydysrhythmias in children

Two female infants, ages 6 months and 13 months, were first seen in the newborn period with supraventricular tachycardia associated with Wolff-Parkinson-White syndrome. One infant had echocardiographic and angiographic evidence of diffuse cardiomyopathy and died suddenly at home. The other infant was seen initially at 13 months of age with refractory ventricular tachycardia and died following surgical resection of arrhythmogenic foci on the left and right ventricles. Autopsy showed diffuse patchy oncocytic cardiomyopathy in both instances. Serial histologic sections of the cardiac conduction system showed oncocytic involvement of the atrioventricular (AV) node, His bundle, and bundle branches. Both infants had interruption of the anulus fibrosus by oncocytic cells at several sites, resulting in multiple accessory AV and nodoventricular connections. Additionally, patient No. 1 had an accessory AV connection by oncocytic cells in the fatty fibrous tissue of the left AV sulcus. To our knowledge, this is the first report of multiple accessory AV connections of oncocytic cells seen during histologic study. In addition, both infants had oncocytic involvement of the exocrine and endocrine glands. This report discusses the clinicopathologic correlations in these two patients, the literature on oncocytic cardiomyopathy, and the types of dysrhythmias found in these patients and their management.

Early and Late Results of Surgical Correction of Pulmonary Artery Sling

Since 1976, we have operated on 4 children with pulmonary vascular sling. They were 5, 12, 19, and 54 months old. All patients were seen initially with severe stridor. Diagnosis was made by barium swallow in all 4. Each child was operated on through a left thoracotomy; the left pulmonary artery was dissected deep between the trachea and esophagus. Systemic heparinization and microsurgical techniques were used. All patients improved after operation. Radioisotope pulmonary ventilation/perfusion scans were performed 9, 9, 14, and 21 months after operation. Decreased ventilation was noted in the right upper lobe of one scan; the other three ventilation scans were normal. Perfusion scans showed good patency of both pulmonary arteries in all 4 patients. It is concluded that pulmonary vascular slings should be treated surgically as soon as diagnosed. Delayed operation can lead to severe tracheomalacia, as demonstrated in our 54-month-old patient.

Posterior mediastinal teratomas

Eight benign posterior mediastinal teratomas have been found in the worlds literature. Including our case, four teratomas were intimately involved with, and often required, partial resection of the major surrounding structures--aorta, chest wall, and esophagus. Preoperative evaluation of posterior mediastinal teratomas should include consideration of a barium swallow and/or aortography to rule out significant local involvement.

Pleural effusion and fibrosis secondary to Sansert administration.

Abstract Sansert (methysergide), used in the treatment of vascular headaches, has been implicated as an etiological agent in the formation of retroperitoneal and pleural fibrosis as well as coronary vascular disease and cardiac valvular disease. This report presents the case history of a patient with extensive pleural effusion and severe pleural fibrosis probably secondary to long-term methysergide therapy.

Pressure-Volume Relationship of the Fetal Lamb Heart

In contrast to the adult heart, the fetal heart reportedly has little functional reserve. With increased clinical emphasis on fetal cardiac diagnosis, neonatal surgery, and the potential for future fetal cardiac intervention, it is essential that we better understand fetal cardiac function. Therefore, to demonstrate the extent of fetal cardiac preload reserve, we studied 10 fetal lambs using an isolated, isovolumic, blood-perfused heart preparation. We maintained constant afterload, inotropic state, coronary blood flow, heart rate, and perfusate blood gas values. As left ventricular (LV) volume (preload) was incrementally increased, LV end-diastolic pressure and LV peak systolic pressure were recorded. Linear regression analysis demonstrated that increases in LV developed pressures were predicted by the LV volume, demonstrating the presence of the Frank-Starling mechanism in each case. The plateau of the Starling pressure-volume curve occurred at an LV end-diastolic pressure of 12.5 +/- 4.79 mm Hg (95% confidence interval, 9.07 to 15.9 mm Hg), lower than the plateau expected in the adult heart. This implies that, in the management of fetal and immature neonatal hearts, preload reserve plays an important but limited role in cardiac reserve.

Aneurysm of Main Pulmonary Artery in a Neonate with Airway Obstruction and Heart Failure: Long-term Survival after Pulmonary Artery Aneurysmectomy and Patent Ductus Arteriosus Ligation

A neonate was seen with complete atelectasis of the left lung secondary to compression of the left main bronchus by a congenital aneurysmal main pulmonary artery. Operation consisted of pulmonary artery aneurysmectomy and ligation of an associated patent ductus arteriosus. Follow-up (3 years after operation) demonstrated complete resolution of the atelectasis and congestive heart failure.