Rohinton K. Balsara

Pacemaker contact sensitivity: clinical recognition and management.

We report a patient in whom vesicular lesions of the skin developed overlying the pacemaker at intervals of 3 to 8 months after each of three consecutive insertions. Patch skin tests were positive for titanium and polyurethane sensitization. Although pacemaker contact sensitivity is rare, its recognition is of vital importance to the pacemaker-dependent patient.

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.

Vasovagal syncope in children requiring pacemaker implantation

Four children presented with episodic loss of consciousness. Two of the children were siblings. Neurologic causes were initially suspected in all but extensive evaluations and EEGs excluded seizures. ECGs in one patient demonstrated first- and second-degree AV block and first-degree AV block in another. The QT and QTc intervals were normal in all. Eyeball pressure in all patients produced profound bradycardia. All patients became asymptomatic after the implantation of pacemakers, although one died 15 months afterward from another cause.

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.

Pulmonary resection for complications of cystic fibrosis

Pulmonary sequelae account for a large proportion of the morbidity and mortality of cystic fibrosis. Bronchiectasis, hemoptysis, and abscess formation are often not responsive to conservative medical therapy. Pulmonary resection in selected cystic fibrosis patients is safe and therapeutically rewarding. Eleven pulmonary resections in ten patients with cystic fibrosis were performed. Patients ranged from 2.5 to 19 years of age. Indications for resection were: (1) abscess and bronchiectasis (nine patients), (2) atelectasis and mass (one patient), and (3) life-threatening hemorrhage (one patient). Surgical resection was employed only for medically refractory lesions which were life-threatening or contaminated otherwise functional lungs. Resection was limited to the most severely diseased areas, sparing functional lung parenchyma when possible. In this series, 9 lobectomies, 1 pneumonectomy, and 1 segmentectomy were performed. Preoperative management included aggressive chest physiotherapy and postural drainage, rigid bronchoscopic lavage, and broad-spectrum parenteral antibiotics. All patients were extubated in the operating room immediately postoperatively. Tracheostomy was not employed. There were no perioperative complications. All patients experienced subjective improvement. Objectively, improvement following surgical resection included: decreased cough and sputum production, and decreased incidence of exacerbations of pulmonary infections. Limited pulmonary resection when combined with intensive preoperative pulmonary toilet is a safe adjunct in the treatment of bronchiectasis and hemoptysis secondary to cystic fibrosis. Pulmonary resection should be limited to only severely destroyed lung parenchyma which is refractory to medical management. In contradistinction to other authors we have not found tracheostomy a necessary adjunct in surgical management.

Staged repair of pentalogy of Cantrell with tetralogy of Fallot

We report a successful two-stage repair of tetralogy of Fallot associated with pentalogy of Cantrell. The first stage, performed in the neonatal period, consisted of repairing the omphalocele, separating the peritoneal from the pericardial cavities, and covering the heart. The second stage, performed at 6 years of age, consisted of complete intracardiac repair and placing the heart in the chest. The patient is alive and well 18 months after the operation.

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.

Alterations in sheep fetal right ventricular tissue with induced hemodynamic pressure overload.

Abstract We report on the cellular and molecular effects of acute and chronic hemodynamic overload on the fetal sheep heart. In one fetus of a twin gestation, the pulmonary artery was banded to create a condition of hemodynamic pressure overload in the right ventricle. The effects of this overload on the right ventricle (RV), left ventricle (LV), and intra-ventricular septum (IVS) of the heart were studied and compared to that in a control, unbanded twin fetus.At the cellular level, the histological data showed that both the size of the nuclei and the overall cell size of cardiac myocytes were increased after five days of banding; although, with one hour of banding no effects were detected at the cellular level. Based on prior studies on connexins which showed their involvement in differentiation, remodeling, and response to load we looked at their expression in control and experimental hearts. At the molecular level, changes in expression of connexin isoforms, the main gap junction protein in the heart, were observed after both one hour and five days of banding. Changes were observed in expression of connexins 40, 43, and 45. For connexin 43 there was a significant reduction confined to the right ventricle, in the chronically treated fetus, whereas, connexins 40 and 45 expression decreased after acute overload. These early molecular changes are significant because the “functional syncytium” of the myocardium is established through the gap junction connections. Alterations in connexin isoform expression affect the development, mechanical, and electrophysiological properties of the heart muscle. These changes may contribute to the ultimate result of continued hemodynamic stress on the right ventricle: heart failure.

Diagnostic dilemma: left aortic arch with right descending aorta--a rare vascular ring.

An infant had a rare type of vascular ring comprising a left aortic arch, a retroesophageal transverse aorta, a right descending aorta, and a right ligamentum arteriosum. Noninvasive studies including echocardiography with Doppler color flow mapping and magnetic resonance imaging were diagnostic of a vascular ring. However, only angiography prospectively established the exact type of ring. This report discusses the pitfalls of noninvasive studies used to diagnose unusual arch anomalies.

The safety of continuous pleural lignocaine after thoracotomy in children and adolescents

Several studies have proven pleural bupivacaine effectively provides postthoracotomy analgesia for both children and adults. When 0.25% bupivacaine is administered as a continuous infusion or repeated bolus, serum bupivacaine levels frequently approach the toxic range. The hazards of bupivacaine toxicity are more difficult to monitor, especially in children who may not report symptoms of local anaesthetic toxicity. Because of this concern, we initiated the use of pleural lignocaine to provide postthoracotomy analgesia for paediatric patients. The records of all patients receiving pleural lignocaine from January 1991 to December 1992 were reviewed. A total of 98 pleural catheters were inserted in 96 patients ranging in age from five months to 20 years. Seven patients had lignocaine levels that exceeded 5 μg·ml‐1 and no patient manifested symptoms of systemic toxicity. This study shows that the administration of pleural lignocaine is a safe method of providing postthoracotomy analgesia. Lignocaine infusions in the dosage range of 20 to 40 μg·kg‐1·min‐1 rarely produce toxic levels, and monitoring of lignocaine levels every 12 h is an effective method of screening for toxicity.