The wandering pacemaker: intraperitoneal migration of an epicardially placed pacemaker and femoral nerve stimulation.

A premature child with congenital complete heart block had an epicardial single-chamber pacemaker implanted at 2 days of age. At 21 months of age, while sitting or standing, the patient's right anterior thigh muscles contracted at her pulse rate. Surgical exploration revealed a free-floating pacemaker in her peritoneum. A new dual-chamber pacemaker was implanted into the abdominal wall with resolution of the child's symptoms.

Syncope recurrence in children: relation to tilt-test results.

OBJECTIVES: To examine the intermediate-term outcome of children with syncope and its relationship to tilt test. DESIGN: This was a retrospective study of 45 children. In 20, the tilt test was negative. Follow-up with respect to the recurrence of syncope was obtained via chart review, a mailed questionnaire, or telephone interview. RESULTS: Follow-up data were available on 15 children whose tilt test was negative and on all 25 tilt-test positive children. Recurrent syncope was significantly greater in the positive-tilt children (13 of 25) than the negative-tilt children (2 of 15). There was no difference between the syncope-free group and the recurrent syncope group or between the tilt-positive and tilt-negative groups with respect to age at initial syncope, duration of symptoms, age at tilt test, and duration of follow-up. Children with a positive tilt test and those with recurrent syncope had more syncopal episodes before their evaluation than either the group with a negative tilt test or the group with no recurrent syncope, respectively. CONCLUSIONS: Syncope may recur after either a negative or a positive tilt test. The recurrence rate, however, is higher for the tilt-positive children.

Double patch closure of ventricular septal defect with increased pulmonary vascular resistance.

BACKGROUND: Closure of a large ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance is associated with significant morbidity and mortality. Pulmonary hypertensive episodes continue to be a major cause of postoperative morbidity and mortality. We designed a fenestrated flap valve double VSD patch in an effort to decrease the morbidity and mortality associated with the closure of a large VSD with elevated pulmonary vascular resistance. METHODS: Eighteen children (mean age, 5.7 years) with a large VSD and elevated pulmonary vascular resistance (mean, 11.4 Wood units) underwent double patch VSD closure using moderately hypothermic cardiopulmonary bypass and cardioplegic arrest. The routine VSD patch was fenestrated (4 to 6 mm) and on the left ventricular side of the patch, a second, smaller patch was attached to the fenestration along its superior margin before closure of the VSD. RESULTS: All children survived operation and were weaned from inotropic and ventilator support within 48 hours postoperatively. Postoperative pulmonary artery pressures were significantly lower than preoperative values. One child died 9 months postoperatively. CONCLUSIONS: Closure of a large VSD in children with elevated pulmonary vascular resistance can be performed with low morbidity and mortality when a flap valve double VSD patch is used.

Serum electrolytes in children with neurocardiogenic syncope treated with fludrocortisone and salt.

We examined the changes in serum electrolytes of patients with syncope treated with salt and fludrocortisone. The most significant change was an increase in serum bicarbonate concentration, with minimal alteration of sodium, potassium, and chloride concentrations; none was clinically significant.

Contribution of superior vena caval flow to total cardiac output in children. A Doppler echocardiographic study.

BACKGROUND: After a cavopulmonary anastomosis, the superior vena caval flow, by virtue of being the effective pulmonary blood flow, is the most important factor influencing the systemic arterial saturation. Determination of the amount of this blood flow will allow a better understanding of the physiology of the circulation after this anastomosis. The purposes of this study were to determine the volumetric flow in the superior vena cava and to evaluate its contribution to the cardiac output as children grow. METHODS AND RESULTS: Using two-dimensional and Doppler echocardiography, we measured the diameter of and mean flow velocities in the superior venae cavae and the pulmonary arteries of 145 healthy children. We calculated the volumetric flow in each vessel and determined the ratio of superior vena caval flow to total cardiac output. Cardiac output and superior vena caval flow increased with increasing age and body surface area. The superior vena caval flow accounted for 49% of cardiac output in newborn infants. This contribution increased to a maximum of 55% at the age of 2.5 years. Afterward, there was a slow decline in the ratio of superior vena caval-pulmonary arterial flow; it reached the adult value of 35% by 6.6 years of age. CONCLUSIONS: There is a maturational change in the superior vena caval contribution to total cardiac output in children. This is most likely related to somatic growth and changes in body segment proportions. This flow maturation may explain the higher systemic saturation in infants compared with older children after cavopulmonary anastomosis.

Patent ductus arteriosus ligation: are we doing better?

Limitation on health care resource use is stimulating critical evaluation of previous preoperative standards. We retrospectively reviewed the clinical and hospital financial records of all children admitted for patent ductus arteriosus ligation from July 1984 to April 1994 for age, perioperative length of stay, readmissions for postoperative surgical problem, and hospital charges adjusted to 1994 dollars. Patients with an isolated patent ductus arteriosus, greater than 3 months of age, without preoperative or postoperative complications were included in this study and stratified into two groups based on date of operation. Group I had operation before January 1, 1991, and group II had operation on or after January 1, 1991. Comparison of these two groups revealed a significant difference in perioperative length of stay (group I, 3.9 +/- 1.2 days [mean +/- standard deviation]; group II, 2.7 +/- 0.9 days; p < 0.0001) and in hospital charges (group I, $8,700 +/- $2,100; group II, $6,600 +/- $1,000; p < 0.0001). These data support the premise that children older than 3 months undergoing elective ligation of a patent ductus arteriosus have been treated with improved efficiency and less charge without an increase in postdischarge morbidity. Health care policy decisions have forced us to evaluate the standards of perioperative care more critically.

Pulmonary/systemic flow ratio in children after cavopulmonary anastomosis.

OBJECTIVES: This study attempted to provide a formula for calculation of the pulmonary/systemic flow ratio in children after bidirectional cavopulmonary anastomosis. BACKGROUND: With the bidirectional cavopulmonary anastomosis, only the superior vena cava blood is oxygenated by the lungs. The inferior vena cava flow recirculates into the systemic circulation. The ratio of these flows will determine systemic arterial saturation. METHODS: According to the Fick principle, 1) Systemic cardiac output (liters/min) = Pulmonary venous flow + Inferior vena cava flow; 2) Systemic blood oxygen transport (ml/min) = Pulmonary venous blood oxygen transport + Inferior vena cava blood oxygen transport. By substituting the first equation into the second, Pulmonary/systemic flow ratio = (Systemic saturation - Inferior vena cava saturation)/(Pulmonary venous saturation - Inferior vena cava saturation). RESULTS: We applied the third formula to data obtained from 34 catheterizations in 29 patients after bidirectional cavopulmonary anastomosis. Mean [+/- SD] age at operation was 1.70 +/- 1.43 years, and mean age at catheterization was 2.95 +/- 1.65 years. The pulmonary/systemic flow ratio calculated for all 29 patients was 0.58 +/- 0.09. Of 17 patients with aortography, 10 had systemic to pulmonary collateral vessels. Patients with collateral vessels had a significantly higher pulmonary/systemic flow ratio (0.61 +/- 0.07 vs. 0.53 +/- 0.07, respectively, p < 0.02) and systemic saturation (88 +/- 4% vs. 82 +/- 4%, respectively, p < 0.002) than those without collateral vessels. The pulmonary/systemic flow ratio in those patients with no collateral vessels was similar to the previously reported echocardiographically derived superior vena cava/systemic flow ratio in normal children. CONCLUSIONS: The pulmonary/systemic flow ratio after bidirectional cavopulmonary anastomosis can be calculated. Pulmonary blood flow in these patients determines systemic saturation and accounts for the majority of venous return in young children.

The fate of homograft conduits in children with congenital heart disease: an angiographic study.

The use of homograft conduits in the repair of congenital heart disease is widely accepted. We reviewed the catheterization and angiographic data from 20 patients with homograft conduits. All conduits were to the pulmonary arteries. The age at operation was 4.7 +/- 5.6 years (mean +/- standard deviation) and at follow-up catheterization, 7.8 +/- 6.7 years. At implantation, conduit cross-sectional area and Z value were 219 +/- 96 mm2 and 3.5 +/- 1.8, respectively. At subsequent catheterization, the conduit diameters were measured in two projections at the shaft, annulus, valve opening, and insertion into the pulmonary artery. The transconduit gradient was 47 +/- 26 mm Hg. The cross-sectional areas were 149 +/- 56 mm2 at the shaft, 151 +/- 92 mm2 at the annulus, 108 +/- 116 mm2 at the valve opening, and 127 +/- 84 mm2 at the pulmonary artery insertion. The Z values were -0.9 +/- 2.5, -0.9 +/- 2.8, -3.8 +/- 4.0, and -2.0 +/- 3.4, respectively. The cross-sectional areas and the Z values at the levels of measurement were significantly smaller than the corresponding values at implantation. The change in cross-sectional areas and Z values exceeded what would be expected from growth alone. These data indicate that there is a decrease, with time, in the functional lumen of homograft conduits, and this may have implications for follow-up strategy after implantation.

A longitudinal study of cardiac output in normal human pregnancy.

OBJECTIVE: Our purpose was to investigate the maternal hemodynamic and cardiac structural changes that occur during pregnancy. STUDY DESIGN: Eighteen women underwent serial echocardiography beginning at 8 to 11 weeks' gestation, then at monthly intervals throughout pregnancy and at 6 and 12 weeks post partum. Cardiac output was measured by pulsed- and continuous-wave Doppler at the aortic valve. Left ventricular chamber size, wall thickness, and mass were determined by M-mode echocardiography. Ventricular diastolic function was assessed by Doppler recording of mitral inflow. RESULTS: Cardiac output by pulsed Doppler increased from 6.7 +/- 0.6 L/min at 8 to 11 weeks' gestation to 8.7 +/- 1.4 L/min at 36 to 39 weeks' gestation before falling to 5.7 +/- 0.7 L/min 12 weeks post partum. Heart rate increased 29%, and stroke volume increased 18%. Left ventricular mass increased because of an increase in wall thickness. Peak mitral A wave velocity increased in late pregnancy. Cardiac output by pulsed and continuous-wave Doppler was similar. CONCLUSION: Cardiac output continues to increase even in late pregnancy. Left ventricular mass increases because of increased wall thickness. The mitral flow velocity findings suggested decreased ventricular compliance or increased preload.

Anomalous systemic and pulmonary venous pathways diagnosed in utero by ultrasound.

Anomalies of systemic and pulmonary venous return are found as either isolated lesions or as part of a complex cardiac malformation. Specifically, these venous pathway malformations are associated frequently with the cardiac defects in asplenia or polysplenia. This report describes the prenatal ultrasound diagnosis of both anomalous pulmonary and systemic venous drainage in three late gestation fetuses with a splenic syndrome and complex congenital heart disease. In addition, the utility of color-flow Doppler as an aid in making the diagnosis is emphasized.

Significance of the Doppler-derived gradient across a residual aortic coarctation.

Few data exist which address the significance of the Doppler gradient across a residual narrowing in older children who have had a coarctation repaired. Therefore, we evaluated 11 patients with repaired aortic coarctation with and without residual obstruction by Doppler echocardiography. The Doppler-derived transcoarctation pressure gradient correlated poorly with catheter-measured peak-to-peak and catheter maximal instantaneous gradients when only the maximal velocity across the repair was utilized in the simplified Bernoulli equation, [r = 0.73, standard of error of the estimate (SEE) = 5.0 mmHg and r = 0.56, SEE = 7.6 mmHg, respectively]. However, when the precoarctation velocity was included in the simplified Bernoulli equation, the correlation between Doppler-derived and catheter-measured gradients became excellent. The maximal Doppler gradient correlated well with catheter peak-to-peak gradient (r = 0.95, SEE = 2.2 mmHg) and catheter maximal instantaneous gradient (r = 0.94, SEE = 3.2 mmHg). However, the maximal Doppler gradient slightly overestimated the catheter peak-to-peak gradient and underestimated the catheter maximal instantaneous gradient. The Doppler mean gradient showed excellent correlation with the catheter mean gradient (r = 0.97, SEE = 0.85 mmHg). Precoarctation velocities were generally twofold greater than published normals due to a spatial acceleration phenomenon. All subjects had residual hypoplasia of the transverse aorta such that its transverse diameter was 29% less than, and its cross-sectional area was 50% less than, the ascending and descending aorta.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute poststreptococcal glomerulonephritis and acute rheumatic fever: occurrence in the same patient.

Group A streptococcus can cause both acute glomerulonephritis and acute rheumatic fever. The occurrence of characteristic acute poststreptococcal glomerulonephritis and acute rheumatic fever in the same patient is rare. We describe a 10-year-old girl with acute rheumatic fever who presented with the typical clinical and biopsy findings of acute poststreptococcal glomerulonephritis.

The hyperdense choroid plexus: a CT finding associated with aortic arch obstruction in the newborn.

We report the first observation of choroid plexus hyperdensity depicted by CT in two newborns with aortic arch obstruction. Neither infant had intracranial hemorrhage or infarction demonstrated by autopsy or cranial ultrasonography. Although not proven, we believe that such hyperdensity in these two cases represents abnormal vascularity within the choroid plexus related to upper extremity hypertension.

Doppler estimation of pressure gradient in pulmonary stenosis: maximal instantaneous vs peak-to-peak, vs mean catheter gradient.

We undertook a study to identify the hemodynamic significance of a Doppler-derived gradient across a stenotic pulmonary valve. Furthermore, we attempted to define the optimal plane for velocity data acquisition. A total of 17 children with valvar pulmonary stenosis were evaluated using Doppler echocardiography. Flow-velocity profiles were obtained from both the parasternal and subxiphoid windows. Ten of 17 patients were studied before and after balloon valvotomy. Therefore, 27 different transvalvar gradients were assessed by Doppler and these data were compared with the catheter-derived maximal instantaneous, peak-to-peak, and mean pressure gradients. The maximal Doppler gradient correlated well with the catheter-derived peak-to-peak pressure gradient (r = 0.95) and catheter maximal instantaneous pressure gradient (r = 0.95). Although these correlation coefficients were similar, the Doppler maximal gradient consistently overestimated the peak-to-peak catheter gradient by as much as 25%-40%. Such an overestimation was not observed when we compared the maximal Doppler gradient with the catheter-derived maximal instantaneous gradient. Moreover, the regression line of the latter comparison closely approximated the line of identity. The correlation coefficient between Doppler mean and catheter mean gradients was only 0.91. Doppler velocities were best derived when multiple transducer positions were employed to interrogate pulmonary artery velocity.

Coarctation repair without cardiac catheterization in infants.

Of 35 infants who underwent an operation for coarctation of the aorta, 15 did not undergo cardiac catheterization before surgery. The diagnoses in all uncatheterized patients were made by clinical examination, chest radiography, ECG, and two-dimensional echocardiography combined with pulsed Doppler echocardiography. Associated anomalies diagnosed by two-dimensional/Doppler echocardiography included a patent ductus arteriosus in all patients, bicuspid aortic valve in six, small ventricular septal defect in four, and complete common atrioventricular canal in one. In no instance was the diagnosis of coarctation in error. In addition, the clinical significance of the ventricular septal defect was judged correctly by two-dimensional echocardiography, and no patient required an early reoperation because of significant left-to-right shunt. Two significant lesions were missed in one patient each: mitral stenosis and aortic stenosis. These diagnoses were missed in patients who were first seen with either profound congestive heart failure or shock. Coarctation of the aorta and associated lesions can be diagnosed accurately by two-dimensional echocardiography. This permits proper patient management without the added risk of cardiac catheterization. Although mitral and aortic lesions may be missed because of low cardiac output, this does not result in management errors.

Diagnosis and treatment of intrapericardial teratoma.

Intrapericardial teratoma is a rare mediastinal tumor that originates from aberrant clusters of multipotential cells from three germinal layers. Previous reports have used the combination of cardiac angiography, CT scan, and echocardiogram to establish the diagnosis prior to surgery. We report a case of intrapericardial teratoma diagnosed noninvasively and removed surgically within the first three days of life. Furthermore, we compare the diagnostic accuracy of echocardiography and computerized tomography (CT), and discuss the superiority of noninvasive evaluation in the management of these critically ill infants.