Transplacental pharmacokinetics of flecainide in the gravid baboon and fetus

The objective of this study was to characterize the transfer of flecainide across the placenta and determine the fetal: maternal ratio of flecainide in the gravid baboon. Flecainide acetate has been especially successful for the treatment of fetal supraventricular tachycardia associated with hydrops fetalis. However, the degree of transplacental transmission remains unknown. In this study, all animals were placed under general anesthesia. Flecainide 2.5 mg/kg was administered intravenously. Percutaneous umbilical blood sampling was performed simultaneously with maternal sampling. Flecainide levels were measured using high-performance liquid chromatography with ultraviolet detection. A total of six gravid baboons were studied at an average gestational age of 132 days. The mean maternal volume of distribution at steady state was 5.1 +/- 1.8 L/kg. The mean combined elimination constant (k(el)) was 0.79 +/- 0.19 hr(-1) [95% confidence interval (CI), 0.64-0.93]. There was a linear relationship between maternal and fetal concentrations, with a ratio of fetal-to-maternal serum levels of 0.49 +/- 0.05 (95% CI, 0.39-0.59). At steady state, fetal flecainide levels are approximately 50% of maternal flecainide levels. Flecainide is rapidly distributed in the mother and fetus following a single intravenous dose with a maternal volume of distribution similar to that reported in normal healthy human adults. Since fetal levels correlate closely with maternal levels, we propose that it is possible to estimate fetal levels by monitoring maternal levels.

Neonatal repair of Ebstein's anomaly: indications, surgical technique, and medium-term follow-up

BACKGROUND

Ebstein's anomaly in the severely symptomatic neonate is usually fatal. Because the mortality for various surgical interventions has been prohibitively high, the indications for operation in these critically ill neonates are unclear.

METHODS

We reviewed our results with biventricular repair of three consecutive severely symptomatic neonates (2.8 to 3.2 kg) at our institution since 1994. Each had associated complex cardiac pathology, including multiple muscular ventricular septal defects (n = 1), pulmonary stenosis with functional pulmonary atresia (n = 1), and anatomic pulmonary atresia (n = 1). Preoperatively, all infants had severe tricuspid regurgitation, Great Ormond Street Ebstein echocardiogram scores greater than 1.3:1 (grade 3 or 4) and cardiothoracic ratio greater than 0.85. Two patients were severely cyanotic. Hepatic and renal insufficiency with diffuse coagulopathy was present preoperatively in two patients. Surgical repair consisted of (1) reconstruction of a competent monocuspid tricuspid valve, (2) right ventriculorrhaphy, (3) subtotal closure of atrial septal defect (ASD), (4) aggressive reduction atrioplasty, and (5) repair of all associated cardiac defects.

RESULTS

There were no early or late deaths. All patients are currently asymptomatic, without medications, and in sinus rhythm. At 5-year follow-up, trivial tricuspid regurgitation is present in 1 and mild regurgitation in 2 patients. On the basis of these results and review of the current literature, we propose new indications for surgical repair in the neonate with Ebstein's anomaly.

CONCLUSIONS

Biventricular repair of Ebstein's anomaly in the critically ill neonate is feasible and medium-term durability of the repair is excellent. Therefore, conventional management of these patients should be revised and early surgical repair encouraged.

Pulmonary autograft root replacement: mid-term results

BACKGROUND AND AIMS OF THE STUDY

The Ross operation was first performed as a root replacement in 1974, and only limited mid- and long-term results assessing durability and adaptation of the pulmonary root to systemic pressures are available. We reviewed our experience to assess function of the autograft valve and the autograft pulmonary root, and its adaptation to systemic pressures.

METHODS

A total of 244 operative survivors (median age 22 years; range: 1 week to 62 years) were reviewed. Clinical follow up (within one year) was available on 98% of cases, and echocardiographic assessment within one year on 93%. Autograft and homograft valve function, aortic annulus diameter, autograft root sinus diameter and ascending aortic diameter were determined on the most recent echocardiogram.

RESULTS

Actuarial freedom from autograft valve degeneration (non-endocarditis autograft valve reoperation or severe autograft valve insufficiency or valve-related death) was 95 +/- 3% at 5 years and 93 +/-4% at 10 years. Actuarial freedom from all valve-related complications (autograft valve degeneration, autograft valve reoperation, homograft valve reoperation or valve-related death) was 90 +/- 4% at 5 years and 83 +/-6% at 10 years. Actuarial freedom from autograft valve replacement was 98 +/- 2% at 5 years and 96 +/- 4% at 10 years. Actuarial survival rate was 98 +/- 2% at 5 years and 86 +/- 9% at 10 years. Aneurysmal dilation of the autograft root occurred in two patients; this was not associated with autograft valve degeneration, and these patients were followed closely.

CONCLUSIONS

At 10 years, the Ross root replacement has a low risk of valve degeneration, valve-related complications and autograft valve replacement, and patient survival is excellent. Autograft valve reoperation and homograft valve reoperation have been the only significant late valve-related complications. Techniques to reduce autograft reoperation have been introduced, and hopefully methods to mediate the immunological response to the homograft valve will reduce the incidence of failure. Significant aneurysmal dilation of the pulmonary autograft root is rare.

Blunt injury rupture of tricuspid valve and right coronary artery

Successful surgical repair of an unusual case of blunt trauma to the chest and abdomen is presented. The injury resulted in rupture of the pericardium, avulsion and rupture of the right coronary artery into the right atrium, complete disruption of the tricuspid valve, and acute right heart failure with complete heart block.

Molecular analysis of polyreactive monoclonal antibodies from rheumatic carditis: human anti-N-acetylglucosamine/anti-myosin antibody V region genes

Anti-myosin Abs are associated with inflammatory heart diseases such as rheumatic carditis and myocarditis. In this study, human cross-reactive anti-streptococcal/anti-myosin mAbs 1.C8, 1.H9, 5.G3, and 3.B6, produced from peripheral blood lymphocytes of patients with rheumatic carditis, and mAb 10.2.5, produced from a tonsil, were characterized, and the nucleotide sequences of their V(H) and V(H)L genes were analyzed. Human mAbs 1.C8, 1.H9, 10.2.5, and 3.B6 reacted with human cardiac myosin while mAb 5.G3 did not. The mAbs were strongly reactive with N-acetyl-beta-D-glucosamine, the dominant epitope of the group A streptococcal carbohydrate. mAb 1.H9 was moderately cytotoxic to rat heart cells in vitro in the presence of complement. The anti-myosin mAbs from rheumatic carditis were found to react with specific peptides from the light meromyosin region of the human cardiac myosin molecule. Anti-streptococcal/anti-myosin mAbs from normal individuals reacted with distinctly different light meromyosin peptides. The mAbs were encoded by V(H)3 gene segments V3-8, V3-23, and V3-30 and by the V(H)4 gene segment V4-59. The variable region genes encoding the anti-streptococcal/anti-myosin repertoire were heterogeneous and exhibited little evidence of Ag-driven somatic mutation.

A 26-year experience with surgical management of tetralogy of Fallot: risk analysis for mortality or late reintervention

BACKGROUND

Over the past decade repair of tetralogy of Fallot (TOF) in infancy has gained favor. It is still uncertain what effect early complete repair will have on survival or late reoperation on the right ventricular outflow tract.

METHODS

To assess these outcomes, we reviewed our experience (1971-1997) with 294 patients undergoing operation at one institution. Median follow-up was 10.6 years (range, 0.1 to 26 years), and was complete for 90.2% patients.

RESULTS

Primary complete repair was done in 199 patients (68%), and a staged repair in 62 patients (21%). Thirty-three patients had only a palliative procedure. Sixty-eight patients (23.1%) had complex pathologic processes, including pulmonary atresia in 53. Hospital mortality for primary repair was 11.1% (22/199), for staged repair was 17.7% (11/62), and for palliative procedures was 15.5% (16/103 procedures). Since 1990 mortality has been 2.1%, 11.8%, and 0% respectively (p < 0.001), despite younger age at repair (0.6+/-0.1 versus 2.1+/-0.2 years; p < 0.001). Multivariate analysis identified longer period of hypothermic circulatory arrest, pulmonary artery patch angioplasty, earlier year of operation, and closure of the foramen ovale as risk factors for hospital death. For hospital survivors 20-year survival was 98%+/-3% for TOF with pulmonary stenosis and 88%+/-9% for TOF with pulmonary atresia (p=0.09). Reintervention on the right ventricular outflow tract was needed in 14.1% (37/261) patients. Freedom from reintervention on the right ventricular outflow tract at 20 years was 86%+/-4% for TOF with pulmonary stenosis and 43%+/-16% for TOF with pulmonary atresia (p=0.001). For the subgroup TOF with pulmonary stenosis, this was 85%+/-5% after primary repair and 91%+/-8% after staged repair (not significant). At 15-year follow-up, this was 78%+/-10% for patients not older than 1 year at operation compared with 88%+/-4% for older patients (not significant).

CONCLUSIONS

Early mortality after primary repair of TOF has significantly improved and late survival is excellent. Primary repair in infancy does not increase risk for reintervention on the right ventricular outflow tract.

Dapsone-induced methemoglobinemia

OBJECTIVE

To report a case of methemoglobinemia in a patient receiving dapsone for prophylaxis of Pneumocystis carinii pneumonia (PCP).

CASE SUMMARY

A 69-year-old white woman was hospitalized to rule out sepsis. Two years prior to this admission, the patient received an orthotopic liver transplant after which she required hemodialysis three times weekly. Because of intolerance to trimethoprim/ sulfamethoxazole and aerosolized pentamidine, she was prescribed dapsone therapy on hospital day 13, that was continued for 11 days. On hospital day 45 the patient received a cadaveric kidney transplant, and dialysis treatments were scheduled only as needed. One week after the transplant, dapsone therapy was resumed. Nine days into this course of dapsone, the patient developed dyspnea and oxygen desaturation of unknown etiology. The patient was evaluated for and diagnosed with methemoglobinemia. She received two doses of intravenous methylene blue and one dose of oral activated charcoal due to fluctuating methemoglobin concentrations.

DISCUSSION

The elimination of dapsone is not completely understood. Several case reports of dapsone-induced methemoglobinemia are present in the literature. Most have occurred in patients who have accidentally or deliberately overdosed. Cases of methemoglobinemia in patients receiving therapeutic doses of dapsone are discussed.

CONCLUSIONS

The growing numbers of immunosuppressed patients due to transplantation of HIV may result in increased dapsone use for the prevention of PCP. Clinicians should be aware of the adverse effects associated with dapsone therapy, and patients with dyspnea and hypoxemia of unclear etiology should be evaluated for methemoglobinemia.

The Ross operation in children: 10-year experience

BACKGROUND

The Ross operation, first performed in children in 1968, may be the ideal aortic valve replacement. Technical demands of the operation and two valves at risk have delayed acceptance. A review of our experience to assess midterm and long-term results with the Ross operation is presented.

METHODS

The records of 150 consecutive patients, aged 7 days to 21 years (median age, 12 years, 75% less than 15 years) were reviewed. Follow-up was complete within the last 12 months (median, 2.8 years; range, 1 month to 10 years). Echocardiographic assessment was available on 116 (71%) within 1 year of closure and in 136 (91%) within 2 years.

RESULTS

Survival was 97.3% at 8 years. Late autograft valve dysfunction required replacement in 2 and reoperation with restitution of autograft function in 6. Freedom from reoperation for autograft dysfunction is 90% +/- 4% at 8 years. Freedom from reoperation for homograft obstruction is 94% +/- 3% at 8 years. Pulmonary homograft dysfunction (gradient > 40 mm Hg) was present in 4 additional patients. Freedom from reoperation on the homograft or a gradient of 40 mm Hg is 89% +/- 4% at 8 years. All patients have a normal, active lifestyle, without anticoagulants for their aortic valve replacement.

CONCLUSIONS

The Ross operation is the preferred operative replacement in children requiring aortic valve replacement.

APP gene promoter constructs are preferentially expressed in the CNS and testis of transgenic mice

Transgenic animals were used to examine the spatial and temporal regulation of the human beta amyloid precursor protein (APP) gene promoter region in vivo. A 2.9 kb DNA fragment encompassing the APP gene promoter was fused to the chloramphenical acetyltransferase (CAT) reporter gene (pAMY-CAT) or a partial cDNA encoding the potentially amyloidogenic C-terminal 100 amino acid region of APP (pAMY-C100). Expression of these transgenes occurred primarily, but not exclusively, in the central nervous system (CNS) and testis in multiple independent lineages of transgenic mice. Temporal expression of the CAT reporter gene during development paralleled that reported for the endogenous APP gene. These studies suggest that a CNS-responsive cis-acting element(s) may exist in the promoter/5'-flanking region of the APP gene.

Evaluation of cryopreserved homografts in the right ventricular outflow tract after the Ross procedure: intermediate-term follow up

BACKGROUND AND AIMS OF THE STUDY

The Ross procedure involves replacing a transplanted pulmonary valve with a cryopreserved homograft in order to re-establish right ventricle-pulmonary artery continuity. This study reviews mid-term results of such surgery in children and young adults.

METHODS

Since November 1986, 114 patients have undergone the Ross procedure at the Children's Hospital of Oklahoma using cryopreserved pulmonary homografts (n = 113) and aortic homograft (n = 1) to reconstruct the right ventricular outflow tract. Graft size ranged from 16 to 32 mm. Ninety-three patients (mean age at implant 10.4 years (range: 0.8-22 years) have had complete mean follow up of 3.2 years (range: 5 months to 8.4 years) after surgery. Homograft evaluation included clinical reports and comparison of early post-implant and latest echocardiography. Measurements of homograft valve annulus and peak instantaneous Doppler gradient were compared; quality of valve leaflets, location of obstruction, and the degree of pulmonary regurgitation were assessed.

RESULTS

Compared with early postoperative data, mean homograft annulus size decreased by 15% (p < 0.0001); in 88% of patients, the decrease ranged from one to nine millimeter. Peak Doppler gradient increased significantly (from 10 to 17 mmHg, p < 0.0001); 25% of patients developed gradients > 25 mmHg, and four had gradients > 50 mmHg. Significant obstruction developed most often at the supravalvular level or in the homograft conduit itself. This usually occurred within one year of implant, and was associated with calcification and contracture of the homograft wall. Significant pulmonary regurgitation developed in 19 cases (20%), but was more than mild in only three. Leaflet integrity was maintained except in those who developed severe stenosis or regurgitation. Two patients have undergone re-operation for homograft stenosis 2.8 and 5.4 years respectively after the Ross procedure; one has developed recurrent severe stenosis in the homograft four months later.

CONCLUSIONS

After the Ross procedure: (i) Pulmonary homografts undergo significant annular reduction in most patients, though this is usually not associated with the development of significant obstruction. (ii) Peak Doppler gradients across the homograft increase in most patients, though only 4% develop more than mild obstruction. (iii) Mild pulmonary regurgitation is common (20%); moderate or severe regurgitation is rare and usually develops in concert with severe stenosis. (iv) Severe homograft valve degeneration usually occurs within one year of implant, and may reflect an immune-mediated response.

Meta-analysis of brain and cranial size in schizophrenia

Several meta-analyses are presented that address the issue of brain and/or cranial size reductions in schizophrenia. Separate meta-analyses were conducted for brain size (n = 27 studies), intracranial size (n = 18) or extracranial size (n = 8). For each meta-analysis, the weighted composite effect size (d) was tested for statistical significance (the direction of the effect size was negative if patients with schizophrenia had smaller structure size than controls). The influence of several potential modifiers of effect size (age, methods, region, gender) was individually evaluated. The composite effect sizes for studies of brain, intracranial and extracranial measures were d = -0.26, (p < 0.0001), d = -0.18, (p = 0.0012), and d = +0.14, (p = 0.16), respectively. Thus, the review found evidence for a small, but statistically significant reduction in brain and intracranial size in schizophrenia, but no evidence for a reduction in extracranial size. Studies based on axial image slices had significantly larger effects (d = -0.60) than the studies based on sagittal images (d = -0.09) (chi(2) = 14.0, p = 0.0002). In summary, the findings clearly support a small yet highly significant reduction of brain and intracranial size in schizophrenia.

Modified hemi-Fontan operation: an alternative definitive palliation for high-risk patients

BACKGROUND

We conceptualized that by adding small amounts of prograde pulmonary blood flow to the hemi-Fontan operation, or bidirectional Glenn procedure, this modified hemi-Fontan operation could be safely done at an early age, with better oxygenation, and with less potential for pulmonary arteriovenous fistulae.

METHODS

Since April 1992 the hemi-Fontan operation was modified by adding some prograde flow through the native pulmonary artery in 10 high-risk infants, either by leaving the critical subpulmonary stenosis untreated (n = 6) or by tightening a previously placed pulmonary artery band (n = 4). All other sources of pulmonary blood flow were interrupted. Patients were 4 to 23 months old (3.8 to 10.3 kg). Diagnoses included isolated dextrocardia with single ventricle (3) and polysplenia syndrome (2). Cardiopulmonary bypass was needed in 5 patients.

RESULTS

There were no hospital deaths. Mean postoperative intensive care unit stay was 2 days, and 9 of 10 patients were discharged within 7 days of operation. One 4-month-old infant with Down's syndrome survived postoperative takedown of the hemi-Fontan repair after pneumonia and caval thrombosis developed. Eight patients are currently asymptomatic receiving minimal modification, and oxygen saturations range from 84% to 93%.

CONCLUSIONS

Adding small volumes of prograde pulmonary blood flow to the hemi-Fontan operation is safe, provides improved oxygenation, may encourage growth of central pulmonary arteries, and represent an alternative definitive palliation for high-risk Fontan candidates.

Transseptal decompression of the left heart during ECMO for severe myocarditis

A 16-month-old boy suffered a cardiac arrest as a result of acute myocarditis, and venoarterial extracorporeal membrane oxygenation was instituted. Twelve hours later, acute left heart distention developed with cessation of left ventricular ejection. Under transesophageal echocardiographic guidance, a long introducer was placed into the left atrium through a transseptal puncture and connected in-line to the venous circuit. Within hours, left ventricular function improved and ejection returned. Left heart decompression was continued for 5 days, and the patient was weaned from extracorporeal membrane oxygenation after 6 days with normal cardiac and neurologic function.

Associated atrial septal defects increase perioperative morbidity after ventricular septal defect repair in infancy

Although closure of ventricular septal defects (VSDs) is currently associated with a relatively low risk, infants with associated atrial septal defects (ASDs) seem to have a higher perioperative morbidity. To clarify this impression, we reviewed our entire experience (since 1977) with closure of simple VSDs in 163 infants (age, < or = 12 months). Of these, 57 had significant ASDs (ASD-VSD subgroup). Hospital mortality was 3.7% (6/163) overall and 1.4% (2/145) since 1980. Actuarial survival at 10 years was 92% +/- 5%. Significant morbidity occurred in 15.5% (16/103) of the VSD subgroup versus 48.1% (26/54) of the ASD-VSD subgroup (p < or = 0.001). Multivariate analysis identified the presence of multiple VSDs and early date of operation as risk factors for hospital death, and younger age, an associated ASD, the size of the VSD, and use of hypothermic circulatory arrest as risk factors for significant perioperative morbidity. Compared with the VSD subgroup, the ASD-VSD subgroup had a higher hospital mortality (5.3% [3/57] versus 2.8% [3/106]), were younger (5.1 +/- 2.9 versus 7.2 +/- 2.9 months; p = 0.001), had a higher preoperative pulmonary artery pressure (70.2 +/- 19.0 versus 62.7 +/- 21.8 mm Hg; p = 0.08), needed more inotropic support (12.3% versus 3.7%; p = 0.07), needed more prolonged ventilation (3.3 versus 1.8 days; p = 0.02), and had longer postoperative hospital stays (11 versus 8 days; p = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary autograft in children: realized growth potential

Pulmonary autograft replacement of the aortic valve has the potential to remain viable and grow in proportion to the somatic growth of the child. Changes in aortic annulus and sinotubular dimensions were compared early and late postoperatively, and related to normal. Eighty-six children, 0.9 to 21 years, were operated on between 1986 and 1993: 42 had a root replacement, 24 an inclusion cylinder, and 20 a scalloped subcoronary implant. Actuarial survival at 7 years was 96.5% +/- 2.0%. Freedom from reoperation for the pulmonary autograft or the homograft reconstruction of the right ventricular outflow tract was 92% +/- 4%. Freedom from reoperation on the autograft in root replacements was 96% +/- 4%, in the inclusion cylinder was 100%, and in the scalloped subcoronary was 90% +/- 7% (not significant). Aortic annulus and sinotubular junction diameters were compared with normal values predicted by body surface area. In 22 intraaortic implants, early and late postoperative annulus diameter mean Z values are in the normal range. In the 23 root replacements, early annulus diameter was within the normal range, but late Z values were larger than normal (p < 0.02). Intraaortic implant annulus diameter increased proportionally to somatic growth, but the sinotubular junction, which was small, remained small but increased toward normal. In the root replacements, the annulus increased in diameter and became dilated. The sinotubular junction, which was small early, increased and was within the normal range late. Lower operative risk and valve durability without failure suggest improved results with inclusion cylinder technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Reversible inactivation of the lateral dorsal thalamus disrupts hippocampal place representation and impairs spatial learning

Place-specific discharge of hippocampal cells was monitored while rats performed daily 15 trials of a spatial memory task. During the intertrial interval between trials 5 and 6, the lateral dorsal nucleus of the thalamus (LDN) was reversibly inactivated. Choice accuracy on the maze became impaired, and many hippocampal place fields became disrupted. These data support the proposition that the LDN passes onto hippocampus important (spatial) information that is used for accurate maze navigation.

Ventricular function after the arterial switch operation for transposition of the great arteries

The theoretical advantages of anatomical repair have resulted in the widespread use of the arterial switch operation for transposition of the great arteries. However, preservation of systemic ventricular performance and late functional results have not been well documented. To evaluate late postoperative ventricular function, we reviewed 53 consecutive patients undergoing arterial switch operation for transposition of the great arteries with or without a ventricular septal defect over the 8-year period from March 1985 to 1993. Forty-two patients had simple transposition of the great arteries and 11 patients had associated ventricular septal defects that were closed at operation. Mean age at operation was 1.8 months (range, 1 day to 36 months), and mean patient weight was 3.8 kg (range, 1.8 to 15.6 kg). All but 8 patients were neonates. There were six operative deaths (11.3%, 6/53) and two late deaths during a median follow-up of 23 months (range, 0.1 to 99.5 months). Actuarial survival at 8 years was 83% +/- 6%. Left ventricular outflow tract obstruction has not been identified, and 9 patients (20%, 9/45) have right ventricular outflow tract gradients exceeding 20 mm Hg, 3 of whom have required reoperation. Eighteen patients have mild neo-aortic valve regurgitation. All survivors are currently in New York Heart Association class I, and are in sinus rhythm. Systolic left ventricular function is well preserved with ejection fractions greater than 0.60 in all survivors followed up for more than 4 months (41 patients). Left ventricular end-diastolic volume index is elevated in only 1 patient, a patient who had pulmonary artery banding as a neonate.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary autograft replacement of the aortic valve in the potential parent

Aortic valve replacement in the child and young adult is often delayed, and multiple operations or invasive procedures are performed to avoid valve replacements. Prosthetic valves, bioprosthetic valves, or allograft valves have been associated with significant complications or early failure and have been a disappointing solution for the patient requiring aortic valve replacement. The pulmonary autograft replacement (PAR) of the aortic valve in children has been shown to be safe and effective with a low incidence of late valve dysfunction. The absence of thromboembolism, the avoidance of anticoagulants, and its viability with the potential for growth and repair strongly support its use for the potential parent, patients of age 35 or less. The experience with 112 patients, 32 females and 80 males, ages 1.5 to 35 years (average 16.1) are reviewed. Twenty-four had aortic insufficiency, 34 had aortic stenosis, and 54 had both aortic stenosis and insufficiency. Actuarial survival was 95.4% +/- 2.0% at 7 years and freedom from reoperation or significant aortic insufficiency of the autograft valve was 92.7% +/- 3.7%. Freedom from all valve related complications of the autograft valve and the homograft replacement of the pulmonary valve was 90.0% +/- 4.0%. Reoperation for the autograft valve was related to limited experience in one, leaflet prolapse and adherence to a VSD patch in one, associated lupus erythematosus in one, and annular and sinotubular dilatation in one. Reoperation of the homograft valve in two patients was secondary to early homograft stenosis, probably due to rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Medium-term follow-up of pulmonary autograft replacement of aortic valves in children

Pulmonary autograft replacement (PAG) of the aortic valve in children has been shown to be safe and effective with a low incidence of late valve dysfunction. Relief of all types of left ventricular outflow tract obstruction using the pulmonary root has been possible. Concern about the durability of the pulmonary root in the aortic position, and the potential for growth of the pulmonary autograft used either as a root replacement or intraaortic implant, has been questioned. Sixty-five consecutive patients, aged 1.8 to 21 years (mean 12 years) operated on between September 1986 and January 1993, 35 with an intra-aortic implant (IA) and 30 with root replacement (RR), were evaluated by clinical and serial echocardiographic studies (ECHO) up to 6.5 years post-operatively. The hospital mortality rate was 3.0% (70% CL 2.1-5.1%). Two patients required reoperation for PAG insufficiency (AI), one for technical malalignment necessitating replacement at 6 months, and one with progressive leaflet prolapse due to adherence of the valve leaflet to a ventricular septal defect (VSD) patch. Freedom from significant aortic regurgitation at 6-year follow-up was 100% for RR and 91 +/- 6% for IA, and freedom from all valve-related complications including reoperation was 92 +/- 5% at 6 years. Significant enlargement of the aortic annulus which parallels somatic growth has been measured by ECHO in 17 IA implants (P < 0.001) and 17 RR patients (P < 0.01) by 1 year, and in 10 IA (P = 0.007) and 6 RR (P < 0.05) by 2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal coarctation repair. Influence of technique on late results

BACKGROUND

Coarctation repair in the neonate (< or = 28 days) is associated with higher mortality and increased incidence of restenosis compared with older infants. It has been suggested that resection of pericoarctation ductal tissue may reduce this risk of restenosis.

METHODS AND RESULTS

To further clarify these issues, we reviewed our experience with 111 consecutive neonates undergoing primary repair between 1973 and 1991. Hospital mortality was 14.4% (16 of 111) and was not significantly different for the type of repair:resection and end-to-end anastomosis (RETE) 10.7% (6 of 56), subclavian flap angioplasty (SFA) 16.7% (6 of 36), and patch angioplasty (PA) 16.7% (3 of 18). Associated complex cardiac pathology was associated with higher operative risk: 25% (10 of 40) versus 8.4% (6 of 71) (P = .02). Median follow-up of 4.2 years (range, 0.1 to 18.5 years) was 99% complete. Late mortality was 13.6% (13 of 95), of which 92% occurred within 1 year of repair. Twenty percent (19 of 95) needed reintervention for restenosis, RETE 16% (8 of 50), SFA 13% (4 of 30), and PA 47% (7 of 15) (P = .02). Of these, 84.2% (16 of 19) required reintervention within 1 year of repair. Freedom from reintervention 1 and 8 years after operation was 80 +/- 4% and 77 +/- 5%, respectively. Actuarial survival 8 years after operation was 73 +/- 4%; for simple coarctation, this was 90 +/- 4%. By multivariate analysis, survival was negatively influenced only by presence of associated cardiac pathology (P = .002) and reintervention only by patch angioplasty technique of repair (P = .007).

CONCLUSIONS

In the neonate, resection of coarctation (RETE) does not diminish the risk for reintervention compared with SFA. The risk for both late death and recurrent coarctation are highest within the first year after repair, and follow-up should be particularly vigilant during this period.

Hypertrophic cardiomyopathy during corticotropin therapy for infantile spasms. A clinical and echocardiographic study

OBJECTIVE

To evaluate the incidence and clinical features of abnormal cardiac hypertrophy during treatment of infantile spasms with corticotropin.

DESIGN

A prospective, echocardiographic study.

PARTICIPANTS

Eighteen children treated for infantile spasms with high-dose corticotropin at a large tertiary children's hospital.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Abnormal cardiac hypertrophy was seen in 13 (72%) of 18 patients. Five of 18 patients (group 1) developed hypertrophic cardiomyopathy with asymmetric septal hypertrophy; none developed significant left ventricular outflow obstruction. Concentric left ventricular hypertrophy was seen in eight patients (group 2), whereas no changes were observed in five (group 3).

CONCLUSION

Abnormal ventricular hypertrophy occurs in the majority of patients treated with corticotropin for infantile spasms. In our study, many of these patients developed hypertrophic cardiomyopathy with dramatic asymmetric septal hypertrophy; however, none developed significant obstruction to left ventricular outflow. All changes were reversible, and did not require premature discontinuation of therapy.

Pulmonary autograft replacement in children. The ideal solution?

Fifty-one children, aged 1.8 to 21 years (mean, 11.4) with aortic valve replacement using a pulmonary autograft are reviewed. Twenty-nine were intra-aortic implants and 22 were root replacements. There was one operative death, no late deaths, and two have required reoperation. Actuarial freedom from reoperation was 93% +/- 5.5 at 5.6 years. Freedom from progression of aortic insufficiency (AI) was 81% +/- 9 at 5.6 years in the intra-aortic implants and 86% +/- 10 in the root replacement. Enlargement of the pulmonary autograft was seen echocardiographically in both groups. This enlargement was consistent with somatic growth and not associated with progression of AI. Ten of 19 patients with aortic stenosis had an LV mass index suggestive of LV hypertrophy before operation. At 1 year, 18 of 25 had a normal LV mass index. Thirteen of 16 patients with AI had preoperative abnormal LV mass index. All but four returned to normal by 1 year. Low operative risk, excellent function, resolution of abnormal LV hemodynamics, and enlargement consistent with somatic growth suggest that the pulmonary autograft is the ideal replacement for the malfunctioning aortic valve.

Medial septal modulation of entorhinal single unit activity in anesthetized and freely moving rats

Reversible inactivation of the medial septal area results in a spatial memory impairment and selective disruption of hilar/CA3, but not CA1, location-specific discharge. The present study examined the possibility that such septal deafferentation produces effects on hippocampal function by altering physiological properties of the primary input and output structures for hippocampus, the entorhinal cortex and the subiculum, respectively. Single unit activity of hippocampal, entorhinal, and subicular cells was recorded before, during, and after septal injection of lidocaine in anesthetized rats. When compared to hippocampal cells, relatively few subicular and entorhinal cells showed a change in mean firing rate following septal inactivation. Entorhinal unit responses to septal inactivation (via tetracaine injection) were also examined in freely moving rats performing a spatial maze task. About one-third of entorhinal cells showed enhanced or reduced firing rates of 40% or more. Also, the spatial distribution of cells found in the superficial, but not deep, entorhinal layers became less clear following septal inactivation. Together, these data are consistent with the hypothesis that manipulation of the medial septum affects hippocampal function via its septosubicular and septo-entorhinal projections in addition to the more direct septohippocampal pathway. Since entorhinal cortical function was affected by tetracaine injection into the septum, it does not appear that direct entorhinal-CA1 afferents were primarily responsible for the maintenance of CA1 location-specific neural activity in previous septal inactivation experiments. Rather, these data are consistent with the hypothesis that the persistence of CA1 place fields was accomplished by intrahippocampal neural network operations.