Fluid accumulation in the staged Fontan procedure: the impact of colloid osmotic pressures

OBJECTIVES

Despite Fontan surgery showing improved results, fluid accumulation and oedema formation with pleural effusion are major challenges. Transcapillary fluid balance is dependent on hydrostatic and colloid osmotic pressure (COP) gradients; however, the COP values are not known for Fontan patients. The aim of this study was to evaluate the COP of plasma (COPp) and interstitial fluid (COPi) in children undergoing bidirectional cavopulmonary connection and total cavopulmonary connection.

METHODS

This study was designed as a prospective, observational study. Thirty-nine children (age 3 months-4.9 years) undergoing either bidirectional cavopulmonary connection or total cavopulmonary connection procedures were included. Blood samples and interstitial fluid were obtained prior to, during and after the preoperative cardiac catheterization and surgery with the use of cardiopulmonary bypass (CPB). Interstitial fluid was harvested using the wick method when the patient was under general anaesthesia. Plasma and interstitial fluid were measured by a colloid osmometer. Baseline values were compared with data from healthy controls.

RESULTS

Baseline COPp was 20.6 ± 2.8 and 22.0 ± 3.2 mmHg and COPi was 11.3 ± 2.6 and 12.5 ± 3.5 mmHg in the bidirectional cavopulmonary connection group and the total cavopulmonary connection group, respectively. These values were significantly lower than in healthy controls. The COPp was slightly reduced throughout both procedures and normalized after surgery. The COPi increased slightly during the use of CPB and significantly decreased after surgery, resulting in an increased COP gradient and was correlated to pleural effusion.

CONCLUSIONS

Fluid accumulation seen after Fontan surgery is associated with changes in COPs, determinants for fluid filtration and lymphatic flow.

CLINICALTRIALS.GOV IDENTIFIER

NCT 02306057: https://clinicaltrials.gov/ct2/results?cond=&term=NCT+02306057.

Fluid accumulation after closure of atrial septal defects: the role of colloid osmotic pressure

OBJECTIVES

Following paediatric cardiac surgery with cardiopulmonary bypass (CPB), there is a tendency for fluid accumulation. The colloid osmotic pressure of plasma (COPp) and interstitial fluid (COPi) are determinants of transcapillary fluid exchange but only COPp has been measured in sick children. The aim of this study was to assess the net colloid osmotic pressure gradient in children undergoing atrial septal defect closure.

METHODS

Twenty-three patients had interventional and 18 had surgical atrial septal defect closures. Interstitial fluid was harvested using a wick method before and after surgery with CPB with concomitant blood samples. COP was measured using a colloid osmometer for small fluid samples. Baseline COP was compared with data from healthy children.

RESULTS

COPp at baseline was 21.9 ± 2.8 and 21.4 ± 2.2 mmHg in the interventional and surgical groups, respectively, and was significantly lower than in healthy children (25.5 ± 3.1 mmHg) (P < 0.001). In the surgical group, the use of CPB significantly reduced COPp to 16.9 ± 2.9 mmHg (P < 0.001) and the colloid osmotic gradient [ΔCOP (COPp - COPi)] to 2.9 ± 3.8 mmHg (P < 0.001) compared with interventional procedure. One hour after the procedure, COPi was 15.6 ± 3.8 mmHg and 9.9 ± 2.1 mmHg (P < 0.001) and the ΔCOP was 5.4 ± 3.0 mmHg and 9.1 ± 3.1 mmHg (P < 0.003) in the interventional and surgical groups, respectively.

CONCLUSIONS

Baseline COPp and COPi were lower in atrial septal defect patients compared with healthy children. The significantly lower COP gradient during CPB may explain the tendency for more fluid accumulation with pericardial effusion in the surgical group. The increased COP gradient after CPB may represent an oedema-preventive mechanism.

Right ventricular volumes assessed by echocardiographic three-dimensional knowledge-based reconstruction compared with magnetic resonance imaging in a clinical setting

OBJECTIVES

A technique that uses two-dimensional images to create a knowledge-based, three-dimensional model was tested and compared to magnetic resonance imaging.

BACKGROUND

Measurement of right ventricular volumes and function is important in the follow-up of patients after pulmonary valve replacement. Magnetic resonance imaging is the gold standard for volumetric assessment. Echocardiographic methods have been validated and are attractive alternatives.

METHODS

Thirty patients with tetralogy of Fallot (25 ± 14 years) after pulmonary valve replacement were examined. Magnetic resonance imaging volumetric measurements and echocardiography-based three-dimensional reconstruction were performed. End-diastolic volume, end-systolic volume, and ejection fraction were measured, and the results were compared.

RESULTS

Magnetic resonance imaging measurements gave coefficient of variation in the intraobserver study of 3.5, 4.6, and 5.3 and in the interobserver study of 3.6, 5.9, and 6.7 for end-diastolic volume, end-systolic volume, and ejection fraction, respectively. Echocardiographic three-dimensional reconstruction was highly feasible (97%). In the intraobserver study, the corresponding values were 6.0, 7.0, and 8.9 and in the interobserver study 7.4, 10.8, and 13.4. In comparison of the methods, correlations with magnetic resonance imaging were r = 0.91, 0.91, and 0.38, and the corresponding coefficient of variations were 9.4, 10.8, and 14.7. Echocardiography derived volumes (mL/m(2)) were significantly higher than magnetic resonance imaging volumes in end-diastolic volume 13.7 ± 25.6 and in end-systolic volume 9.1 ± 17.0 (both P < .05).

CONCLUSIONS

The knowledge-based three-dimensional right ventricular volume method was highly feasible. Intra and interobserver variabilities were satisfactory. Agreement with magnetic resonance imaging measurements for volumes was reasonable but unsatisfactory for ejection fraction. Knowledge-based reconstruction may replace magnetic resonance imaging measurements for serial follow-up, whereas magnetic resonance imaging should be used for surgical decision making.

Interstitial fluid colloid osmotic pressure in healthy children

Objective

The colloid osmotic pressure (COP) of plasma and interstitial fluid play important roles in transvascular fluid exchange. COP values for monitoring fluid balance in healthy and sick children have not been established. This study set out to determine reference values of COP in healthy children.

Materials and Methods

COP in plasma and interstitial fluid harvested from nylon wicks was measured in 99 healthy children from 2 to 10 years of age. Nylon wicks were implanted subcutaneously in arm and leg while patients were sedated and intubated during a minor surgical procedure. COP was analyzed in a colloid osmometer designed for small fluid samples.

Results

The mean plasma COP in all children was 25.6 ± 3.3 mmHg. Arbitrary division of children in four different age groups, showed no significant difference in plasma or interstitial fluid COP values for patients less than 8 years, whereas patients of 8-10 years had significant higher COP both in plasma and interstitial fluid. There were no gender difference or correlation between COP in interstitial fluid sampled from arm and leg and no significant effect on interstitial COP of gravity. Prolonged implantation time did not affect interstitial COP.

Conclusion

Plasma and interstitial COP in healthy children are comparable to adults and COP seems to increase with age in children. Knowledge of the interaction between colloid osmotic forces can be helpful in diseases associated with fluid imbalance and may be crucial in deciding different fluid treatment options.

Trial Registration

ClinicalTrials.gov NCT01044641

Pulmonary Valve Replacement With a Bovine Pericardial Valve

Objectives:

From a population of 90 patients after pulmonary valve replacement with a biological valve (Carpentier-Edwards Perimount valve), 56 of 80 available patients were examined five years after surgery.

Background:

Pulmonary valve replacement is needed in many patients with congenital heart disease. Homografts have limited availability and predictable degeneration, and mechanical valves require anticoagulation. No superiority of one kind of pulmonary valve replacement has been shown. Biological valves that are readily available are being used and evaluated in increasing numbers.

Methods:

In this cross-sectional study, five years following surgery, data were gathered from hospital charts, echocardiography, stress echocardiography, magnetic resonance imaging, and exercise testing.

Results:

In 90 patients, there were three new valve replacements, one early cardiac death, and four late noncardiac deaths. Echocardiographic assessment of the study group showed pulmonary Doppler velocities (m/s) before, after operation, and at five-year follow-up of 2.8 ± 1.1, 1.6 ± 0.4, and 2.3 ± 0.7, respectively. The assessed insufficiencies (0-3) at the same times were 2.3 ± 1.0, 0.3 ± 0.4, and 1.1 ± 0.8. Maximal oxygen uptake increased from 65.6% ± 10.1% to 77.1% ± 18.2% of predicted and QRS width increased by 7 ± 23ms. Valve degeneration could be associated with young age but not with diagnosis or valve size.

Conclusion:

In our study, the biological valve in the pulmonary position showed excellent mid-term results with few reoperations, low gradients, and mild to moderate insufficiency. Oversizing, in contrast to young age, was not a risk factor for valve degeneration. In younger patients, this allows later percutaneous replacement, reducing the need for further surgery. However, longer follow-up is needed.

Left ventricular function in children and adults after renal transplantation in childhood

BACKGROUND

Renal transplantation improves left ventricular (LV) function, but cardiovascular mortality remains elevated. The aim of this cross-sectional study was to determine whether subclinical abnormalities of LV longitudinal function also persist in patients who underwent renal transplant in childhood.

METHODS

Conventional and speckle tracking echocardiography was performed in 68 renal transplant recipients (34 children and 34 adults, median 9.8 years (range 2.0-28.4 years) after first transplantation and 68 age- and sex-matched healthy controls.

RESULTS

Mean age at first transplantation was 8.8 ± 4.8 years. Forty-three percent had a pre-emptive transplant. Of the remaining, 70% received haemodialysis and 30% peritoneal dialysis on average for 6.9 months. Thirty-one percent of paediatric and 35% of adult patients had hypertension. LV mass index was increased in adult patients (92 ± 24 vs 75 ± 11 g/m(2), P< 0.01). LV diastolic function and exercise capacity were impaired in both paediatric and adult patients. LV longitudinal peak systolic strain and strain rate were comparable in patients and controls. In multivariate analysis, systolic blood pressure and LV diastolic relaxation were the main covariates of LV peak systolic strain and strain rate (all P < 0.01).

CONCLUSIONS

Patients who underwent renal transplantation in childhood have abnormal LV diastolic function and impaired exercise capacity, despite preserved LV longitudinal systolic deformation.

De novo HRAS and KRAS mutations in two siblings with short stature and neuro-cardio-facio-cutaneous features

Mutations in genes involved in Ras signalling cause Noonan syndrome and other disorders characterised by growth disturbances and variable neuro-cardio-facio-cutaneous features. We describe two sisters, who presented with dysmorphic features, hypotonia, retarded growth and psychomotor retardation. The patients were initially diagnosed with Costello syndrome, an autosomal recessive inheritance was assumed. Remarkably, however, we identified a germline HRAS mutation (G12A) in one sister and a germline KRAS mutation (F156L) in her sibling. Both mutations had arisen de novo. The F156L mutant K-Ras protein accumulated in the active, guanosine triphosphate-bound conformation and affected downstream signalling. The patient harbouring this mutation was followed for three decades, and her cardiac hypertrophy gradually normalised. However, she developed severe epilepsy with hippocampal sclerosis and atrophy. The occurrence of distinct de novo mutations adds to variable expressivity and gonadal mosaicism as possible explanations of how an autosomal dominant disease may manifest as an apparently recessive condition.

De novo HRAS and KRAS mutations in two siblings with short stature and neuro-cardio-facio-cutaneous features

Mutations in genes involved in Ras signalling cause Noonan syndrome and other disorders characterised by growth disturbances and variable neuro-cardio-facio-cutaneous features. We describe two sisters, 46 and 31 years old, who presented with dysmorphic features, hypotonia, feeding difficulties, retarded growth and psychomotor retardation early in life. The patients were initially diagnosed with Costello syndrome, and autosomal recessive inheritance was assumed. Remarkably, however, we identified a germline HRAS mutation (G12A) in one sister and a germline KRAS mutation (F156L) in her sibling. Both mutations had arisen de novo. The F156L mutant K-Ras protein accumulated in the active, guanosine triphosphate-bound conformation and affected downstream signalling. The patient harbouring this mutation was followed for three decades, and her cardiac hypertrophy gradually normalised. However, she developed severe epilepsy with hippocampal sclerosis and atrophy. The occurrence of distinct de novo mutations adds to variable expressivity and gonadal mosaicism as possible explanations of how an autosomal dominant disease may manifest as an apparently recessive condition.

[A 9-week-old boy with fever and diarrhoea]

A 9-week-year-old boy was admitted to the pediatric clinic after 12 hours of fever and diarrhoea. On admission he had a fever of 40 degrees C, rhinitis and moderate diarrhoea. Blood tests were normal, except for elevated CRP (89 mg/L). The tentative diagnosis was viral gastroenteritis, and peroral rehydration with a hypertone glucose-salt-mixture was started. CRP reached a maximum of 199 mg/L, and the boy stayed febrile throughout the next days. Stool examination revealed Enterovirus. After several clinical examinations, findings included a reactive cervical glandular node and mild conjunctivitis. When the child had been febrile for five days, he was admitted to an echocardiography, which showed dilated coronary arteries with abnormal caliber variations and a small amount of pericardial fluid. Since he fulfilled only three of the five criteria of classical Kawasaki disease, he was diagnosed as having neonatal, incomplete Kawasaki disease. Kawasaki disease is an immunologic vasculitis that appears mainly in children between three months and 12 years of age. Only 2% of patients with Kawasaki disease are less than three months old. Neonates with Kawasaki disease often have an atypical presentation of symptoms and have a particular risk of developing coronary artery aneurysms with potentially fatal outcome. With this case-report we will stress the importance of considering Kawasaki disease in neonates with fever of unknown origin.

[Do patients with ventricular septal defect need endocarditis prophylaxis?]

BACKGROUND

Patients with ventricle septal defect are considered at higher risk of infectious endocarditis than the population in general. According to guidelines, these patients should receive prophylactic antibiotics prior to invasive procedures. Recently, several studies have been published that challenge this view.

MATERIAL AND METHODS

Based on searches in Medline, we discuss the risk of endocarditis and indication for antibiotic prophylaxis in patients with this defect.

RESULTS

Patients with perimembranous and subvalvular defects have higher risk of endocarditis than the population in general. The proportion of patients developing endocarditis in relation to invasive procedures is low. Prophylactic antibiotics are only partially effective.

INTERPRETATION

The proportion of preventable cases of endocarditis is low, and the prophylaxis does not give sufficient protection. Studies suggest that only patients at the highest risk should receive prophylactics.

[Referral practice and clinical assessment of heart murmurs in children]

BACKGROUND

Heart murmurs in infants and children are common, and in most cases these are physiological murmurs. In a few cases they represent congenital heart disease; it is important to detect those few children by referral to paediatric cardiologists.

MATERIAL

220 consecutive children with heart murmur were investigated prospectively as outpatients in the Children's clinic, Haukeland University Hospital from January through December 2001. Referrals were from general practitioners (n = 157), paediatricians or residents at the Children's clinic (n = 51), and from one community-based paediatrician (n = 12). The purpose was to assess the referrals for completeness and judgment before cardiological assessment. Our second goal was to see if the paediatric cardiologist could differentiate between innocent and pathological murmurs by history and clinical assessment only.

RESULTS

22 (10%) of the referred patients had congenital heart defects. They had been through a complete clinical assessment by 38.9% of the general practitioners and 83.3% by the community-based paediatrician (p = 0.0001). A conclusion regarding diagnosis before hospital evaluation was reached in only 17.8% of the patients by the general practitioners and in 50% by the paediatricians (p < 0.0001). The diagnostic accuracy of the clinical evaluation by the paediatric cardiologists had a sensitivity of 81.5%, specificity of 98.5%, positive and negative predictive values of 88 and 97.5%, respectively. Two patients with significant atrial septum defect would have been missed by clinical assessment only.

INTERPRETATION

Skills in clinical assessment of heart murmurs in infants and children can be improved among general practitioners and paediatricians in training. Paediatric cardiologists can differentiate between physiological and pathologic murmurs by clinical evaluation only.

[Evaluation of cardiac murmurs in children]

BACKGROUND

Many normal children have heart murmurs, but most children do not have heart disease. Differentiation of innocent murmurs from those due to structural heart disease, pathological murmurs, is largely clinical.

MATERIAL AND METHODS

This review is based upon the authors' own studies and PubMed searches.

RESULTS

An appropriate history and a properly conducted physical examination can identify children at risk of significant heart disease.

INTERPRETATION

If a murmur cannot clearly be labelled as innocent based on characteristics like sound quality, intensity, location and response to posture, then referral to a paediatric cardiologist is indicated. Other indications for referral are any sign or symptom of cardiovascular disease such as shortness of breath, cyanosis or decreased exercise tolerance. In addition, children with syndromes should, because of their high risk of congenital heart disease, be referred to a paediatric cardiologist for further evaluation.

Exercise capacity in young adults with hypertension and systolic blood pressure difference between right arm and leg after repair of coarctation of the aorta

Coarctation of the aorta represents 5-7% of congenital heart defects. Symptoms and prognosis depend on the degree of stenosis, age at surgery, surgical method and the presence of other heart defects. Postoperative complications are hypertension, restenosis and an abnormal blood pressure response during exercise. This study includes 41 patients, 15-40 years old, operated in the period 1975-1996. All were exercised on a treadmill until maximal oxygen consumption was achieved. Blood pressure was measured in the right arm and leg before and immediately after exercise, and in the right arm during exercise. Oxygen consumption was monitored and we defined an aerobic phase, an isocapnic buffering phase and a hypocapnic hyperventilation phase. The resting systolic blood pressure correlates with the resting systolic blood pressure difference between right arm and leg. A resting systolic blood pressure difference between the right arm and leg of 0.13 kPa (1 mmHg) to 2.67 kPa (20 mmHg) corresponds with a slight increase in resting systolic blood pressure. This rise in blood pressure increases the aerobic phase of the exercise test, helping the patients to achieve higher maximal oxygen consumption. A resting systolic blood pressure difference of more than 2.67 kPa (20 mmHg) corresponds with severe hypertension and causes reduction in the aerobic phase and maximal oxygen consumption. Resting systolic blood pressure and resting systolic blood pressure difference between the right arm and leg are not indicators for blood pressure response during exercise. Exercise testing is important to reveal exercise-induced hypertension and to monitor changes in transition from aerobic to anaerobic exercise and limitation to exercise capacity.

[Risk factors in Kawasaki's syndrome]

BACKGROUND

Few patients with Kawasaki's syndrome have been described in Norway. Different aspects of diagnosis and treatment are assessed in this article.

MATERIAL AND METHODS

We retrospectively reviewed 26 cases of Kawasaki's syndrome at Haukeland University Hospital 1985-1999.

RESULTS

85% of the patients fulfilled all criteria for diagnosis and were treated as recommended; yet we found a high frequency of coronary aneurysms (22%). Children with aneurysms had delayed onset of treatment compared to patients without complications. Infants were treated later and had a higher incidence of aneurysms. Laboratory findings differed among infants and older children, and in patients with or without aneurysms.

INTERPRETATION

Kawasaki's syndrome is still a clinical diagnosis. Laboratory tests may, however, help to identify patients with high risk of complications. Infants should be followed carefully in the acute phase of febrile illness and be treated early, even when the presentation is atypical. Early adequate treatment is of vital importance to avoid complications and reduce short and longterm morbidity.

Magnetic resonance imaging of patients with increased blood pressure and altered blood pressure response to exercise after coarctation repair

OBJECTIVE

Patients successfully operated for coarctation of the aorta are frequently subjected to altered blood pressure (BP) at rest and BP response during exercise. The relationship between these variables and blood flow, peak velocity, restenosis and other morphological features of the thoracic aorta as revealed by magnetic resonance imaging (MRI) was evaluated.

DESIGN

Fifty-one patients subjected to coarctectomy of the aorta were examined by MRI. In addition, a control group of 23 healthy volunteers was evaluated. Morphology of the aorta was demonstrated with both ECG-triggered SE imaging and gadolinium-enhanced MR aortography. Flow-weighted MRI was applied for quantitative flow and velocity measurements.

RESULTS

Structural alteration of the aorta was more commonly seen in those patients having increased BP at rest or altered BP response during exercise than those with a normal BP profile. The luminal diameter of the narrowest site of the aorta was decreased in all patient groups. Accordingly, the peak velocity at the corresponding site was significantly (p < 0.01) increased. However, blood flow was significantly (p < 0.01) decreased among those patients with normal BP profile compared with the other patient groups as well as the controls.

CONCLUSION

Other structural changes than restenosis may contribute as well to the altered BP profile of patients subjected to coarctectomy. Reduced blood flow appears to correlate with normal BP profile, whereas the peak velocity measurements that are obtained by MRI are not able to differentiate between the patient groups. The comprehensive and reliable data obtained by non-invasive techniques, i.e. MRI and Doppler, may replace catheterization when deciding the need for intervention.

Haemoptysis as a late complication of a Mustard operation treated by balloon dilation of a superior caval venous obstruction

Haemoptysis was the presenting symptom in a 27-year-old male. He had undergone a Mustard operation for connection of complete transposition at the age of 2 years. For 6 months prior to admission, he had complained of dyspnoea without chestpain, and swelling of the fingers during hard physical work. Chest radiography and computer tomographic scans showed normal features of the pulmonary parenchyma, and no sign of cardiomegaly or vascular stasis. Fiberoptic bronchoscopy demonstrated a blood clot in the upper right bronchus, without any associated abnormalities of the bronchial tree. Doppler echocardiography showed obstruction of the superior caval vein, which was verified by cardiac catheterization. Balloon dilation at the site of obstruction increased the diameter of the vein from 0.5 to 1.7 cm, and the mean pressure in the superior caval vein was reduced significantly from 18 to 10 mmHg. The haemoptysis did not recur, and no complaints of dyspnoea or swelling of fingers during physical activity was reported 2 years later. Transthoracic echocardiography undertaken at this time revealed no obstruction of the superior caval vein. We conclude that hemoptysis is a rare complication of increased venous pressure in the upper body of patients with superior caval venous obstruction, which can be treated by balloon dilation or stenting.

[Long-term follow-up of patients with congenital heart defects]

There are about 500 new cases of congenital heart disease per year in Norway. Modern diagnostic skills, surgical techniques and follow-up programs have contributed to higher survival rates among patients. Based on international experience, 85-90 per cent of these children will survive into adulthood. Half will suffer from conditions which should be followed up by cardiologists. This article is based upon recommendations on long-term follow-up of patients with congenital heart disease.

Early age at repair prevents restrictive right ventricular (RV) physiology after surgery for tetralogy of Fallot (TOF): diastolic RV function after TOF repair in infancy

OBJECTIVES

To assess diastolic right ventricular (RV) physiology after tetralogy of Fallot repair in infancy.

BACKGROUND

Restrictive RV physiology after tetralogy of Fallot repair is related to type of repair, pulmonary regurgitation, and late arrhythmias.

METHODS

Forty-seven patients were investigated, 27 and 20 patients in Lund and London, respectively. Median age at repair was 0.78 years (0.08-0.99) and median follow-up was 3.0 years (0.08-10.4). Restrictive RV physiology was assessed by Doppler echocardiography.

RESULTS

Thirteen patients (28%) had restrictive RV physiology at follow-up, three of 19 patients (16%) with transatrial repair and 10 of 28 patients (32%) with transventricular repair, respectively (p=0.1). Ten percent of the patients repaired before 6 months of age were restrictive at follow-up, increasing to 38% with repair after 9 months. Transannular patch (TAP) repair was performed in 55% of the patients, including eight of 10 patients (80%) with repair before 6 months of age. Thirty-one percent of the patients with TAP repair were restrictive. These restrictive patients had more severe preoperative pulmonary stenosis (p < 0.05), were older at repair (p < 0.05), and had shorter duration of pulmonary regurgitation (p < 0.001) at follow-up.

CONCLUSIONS

Restrictive RV physiology is inversely related to age at repair and independent of type of outflow tract repair. Since TAP repair is more common in early repair, and restriction seems to be less frequent, long-term follow-up to assess adverse effects of pulmonary regurgitation is mandatory.

Does restrictive right ventricular physiology in the early postoperative period predict subsequent right ventricular restriction after repair of tetralogy of Fallot?

OBJECTIVE

To assess the relation between immediate postoperative right ventricular (RV) diastolic physiology and subsequent diastolic function in patients after repair of tetralogy of Fallot.

DESIGN

Serial prospective echocardiographic study early after surgical repair of tetralogy of Fallot and at mid-term follow up.

SETTING

Tertiary referral centre.

PATIENTS

34 patients who had repair of tetralogy of Fallot between 1992 and 1995 were studied.

MAIN OUTCOME MEASURES

Restrictive RV physiology defined as antegrade flow in the pulmonary artery in late diastole throughout the respiratory cycle.

RESULTS

Sixteen of the 34 patients had early restrictive RV physiology. The need for transannular patch repair was an independent variable predictive of early restriction (odds ratio 4.3 (1.1-47), p < 0.05). Nine of 16 patients with early restriction also had restriction at follow up, while 15 of 16 patients without restrictive RV physiology continued without restriction. Early restriction was the only independent variable predictive of late restriction (odds ratio 6.0 (1.9-273), p = 0.01).

CONCLUSIONS

Early and mid-term restrictive RV physiology after repair of tetralogy of Fallot is related to the repair type. Although evidence for this physiology tends to resolve in the first few days after operation, it is highly predictive of subsequent abnormalities of RV diastolic function. Similarly, normal RV diastolic physiology without restriction in the immediate postoperative period persists in the mid-term and may be associated with the long term problems of progressive RV dilatation.

Biventricular long axis function after repair of tetralogy of Fallot

Right ventricular restrictive physiology is common after repair of tetralogy of Fallot and relates to exercise performance and symptomatic arrhythmias. In this study, we examined biventricular long axis function in an attempt to clarify further the mechanical substrate of this phenomenon. We studied prospectively 95 patients with tetralogy of Fallot (age range 1-44.3 years) at a median of 4.3 years after repair with Doppler and M-mode echocardiography. Pulmonary arterial, tricuspid, and mitral Doppler spectrals and 2-D guided M-mode recordings of ventricular minor and long axes were obtained with simultaneous phonocardiogram and respirometer recordings. Right ventricular restriction was defined by the presence of antegrade pulmonary arterial flow during atrial systole throughout the respiratory cycle. Restrictive right ventricular physiology was demonstrated in 36 (39%) [group 1] of the 92 patients in whom the data were analyzed. Left ventricular function (FS, isovolumic relaxation time and transmitral E wave deceleration time) was not different in the two groups (p < 0.1, p < 0.6, and p < 0.8, respectively). The presence of antegrade diastolic flow shortened the pulmonary regurgitation in the restrictive group (PR duration/square root of RR 10.7 +/- 2.1 vs 12.1 +/- 2.1, p < 0.01). There was delayed onset of shortening (97.4 +/- 24 vs 88.8 +/- 24 ms, p = 0.01), and the amplitude of right atrioventricular ring excursion, corrected for body surface area, was significantly lower during atrial systole in the restrictive group (0.43 +/- 0.15 vs 0.54 +/- 0.2 cm/m2, p < 0.01). There was also a tendency toward a smaller ratio of right to left total atrioventricular ring excursion in the same group (1.14 +/- 0.19 vs 1.22 +/- 0.23, p = 0.1). Impaired long axis function in patients with restrictive right ventricular physiology following repair of tetralogy of Fallot is associated with abnormal diastolic filling and may contribute to the long-term cardioprotective effect of restrictive physiology by limiting the degree of right ventricular dilatation.

[Coil embolization of persistent ductus arteriosus]

From September 1994 to January 1996, 57 patients were admitted to Brompton Hospital for catheter closure of persistent ductus arteriosus. Umbrella closure was attempted in 22 patients and coil closure in 35. The duct was closed by a device in 55 of 57 patients (96.4%). Two patients were referred for surgical closure, one after failure of the umbrella closure and one after coil embolization to a branch of the pulmonary artery. Two additional coils embolized to pulmonary artery branches. Both coils were successfully retrieved by a snare, and the procedure then finished successfully. We recommend the use of coils for closure of small ducts, and for residual leak after previous umbrella closure. This is also a promising method for closure of larger ducts.

Relationship between type of outflow tract repair and postoperative right ventricular diastolic physiology in tetralogy of Fallot. Implications for long-term outcome

BACKGROUND

Restrictive right ventricular (RV) physiology can be present early and late after tetralogy of Fallot repair. It is associated with a complicated early postoperative course but is favorable late after repair because it is associated with less pulmonary regurgitation, better exercise tolerance, and less QRS prolongation and symptomatic ventricular arrhythmias. It is not known, however, whether in the current surgical era, this physiology is present in tetralogy of Fallot patients at mid-term follow-up and whether it is related to the type of RV outflow tract repair. Finally, the impact of this physiology on the early evolution of QRS prolongation has not been examined previously. In this study we attempted to address these issues in a cohort of recently operated patients.

METHODS AND RESULTS

Ninety-five patients were studied 4.3 years after repair by Doppler echocardiography, serial electrocardiograms, and chest radiographs. Restrictive RV physiology defined by the presence of antegrade pulmonary artery flow in late diastole was present in 38% of the patients. It was more common in patients with transannular patch (TAP) repair compared with non-TAP repair (50% versus 21%, P < .05). QRS duration at follow-up was 121.2 +/- 17.6 and 132.6 +/- 11.8 ms in restrictive and nonrestrictive patients with TAP repair, respectively (P < .02).

CONCLUSIONS

Restrictive RV physiology has been identified at mid-term follow-up in a contemporary surgical series. It is associated with less QRS prolongation, regardless of the technique used for outflow tract repair, and may be associated with fewer long-term complications. Nonrestrictive physiology is associated with the most marked QRS prolongation. This subgroup is most at risk from the late deleterious consequences of chronic pulmonary regurgitation.

[Treatment of supraventricular tachycardia in children]

Although young infants may have severe symptoms from supraventricular tachycardia the majority responds to treatment. In 60-90% of the infants the arrhythmias disappear within 6-12 months, whereas in older children the supraventricular tachycardia tends to reoccur. Our recommended acute treatment in infants less than six months of age is to emmerse the face in cold water, but adenosine should be used for pharmacological termination of supraventricular tachycardia in all age groups. If this fails, direct current cardioversion should be applied without delay. Intravenous verapamil should not be used, however, in infants for termination of supraventricular tachycardia. Flecainide can be used for acute and prophylactic treatment.

Right ventricular size and function as assessed by echocardiography and angiography in patients with different volume load

A comparative study of right ventricular (RV) function, assessed by echocardiography and angiography, undertaken in 20 patients, 10 of whom had atrial septal defects (ASDs) and 10 had various other heart diseases. All of the measured echocardiographic variables of RV size, apart from RV length, were larger in the patients with ASD. When assessed by multiple regression analysis, the RV M-mode dimension was an independent variable of RV angiographic end-diastolic volume (EDV) in patients without RV volume load (R = 0.92, R2 = 0.85, p < 0.001). In the patients with ASD, echocardiographic RV end-diastolic area was an independent variable of angiographic RVEDV (R = 0.75, R2 = 0.55, p < 0.05), whereas M-mode dimension had a weaker correlation (r = 0.29). The agreement between RV ejection fraction (RVEF) obtained by echocardiography and angiography was moderate in both patient groups. However, fractional area change and fractional length change could not estimate RVEF better. Thus care should be taken to use single measurements and derivatives as the only parameters of RV size and function.

Variability of digitized left ventricular M-mode echocardiography: a study in healthy subjects and patients with repaired tetralogy of Fallot

To assess possible factors affecting the variability of digitized left ventricular M-mode echocardiograms, the influence of respiration and the variability due to different beats and observers were analysed in 11 healthy subjects and 11 patients with repaired tetralogy of Fallot. Left ventricular end-diastolic dimension (LVEDD) decreased from end-expiration to end-inspiration in the healthy subjects, but not in the patients. The maximal rate of dimension change decreased in both healthy subjects and patients from end-expiration to end-inspiration. The beat-to-beat variability assessed by the coefficient of variation (CV,%) between measurements of one cardiac cycle was twice the CV for three cycles, whereas the CV for three and five cardiac cycles was not different. The CV for intraobserver variability was less than 5.0% for dimensions and less than 13.0% for the rates of dimension change, whereas the interobserver variability had CV of 17.1% for rates of dimension changes. The influence of respiration and different observers on the variability of LV end-systolic dimension and shortening fraction was larger in the patients than in the healthy subjects. Thus, to obtain optimal technique for analysis of digitized LV M-mode echocardiograms in serial patient studies, the number of observers should be kept at a minimum and at least 3 beats at end-expiration should be used.

Hemodynamic status in repaired tetralogy of Fallot assessed by Doppler echocardiography and cardiac catheterization. Comparisons with healthy subjects and elucidation of factors associated with cardiorespiratory function

Thirty-four patients were studied after corrective surgery for tetralogy of Fallot (mean follow-up 10 years) and compared with healthy matched controls. All underwent Doppler echocardiography, spirometry and treadmill exercise test. Post-operative cardiac catheterization had been performed on 26 (76%) of the patients and showed poor hemodynamic results in four (15%). Significant correlations of pressure gradients obtained from catheterization and estimated by Doppler echocardiography were right ventricular to right atrial (r = 0.77), pulmonary outflow (r = 0.75), pure valvular pulmonary outflow (r = 0.94) and diastolic pulmonary pressure gradients (r = 0.53). Pulmonary outflow gradients and right ventricular to right atrial pressure gradients estimated from tricuspid regurgitation jets were significantly increased in the patients. Diastolic pulmonary artery pressure, vital capacity and ventilatory anaerobic threshold were independent factors of maximal oxygen consumption. It is suggested that Doppler-derived diastolic pulmonary artery pressure, lung function studies and exercise testing with assessment of the ventilatory anaerobic threshold should be included in follow-up after repair of Fallot's tetralogy.

Effects of impaired lung function and pulmonary regurgitation on maximal exercise capacity in patients with repaired tetralogy of Fallot

Long-term haemodynamic results and exercise capacity were studied in 34 patients with tetralogy of Fallot (24 men and 10 women) repaired 10.0 +/- 4.9 (mean +/- SD) years previously and compared to 34 healthy matched controls. All subjects were studied by resting spirometry, echocardiography and a symptom limited treadmill exercise test (modified Bruce protocol). The maximal oxygen consumption was 38.2 +/- 8.0 ml.kg-1.min-1 in patients and 48.1 +/- 8.1 ml.kg-1.min-1 in the control group (P < 0.001). Reduced maximal oxygen consumption was found in patients with low vital capacity (VC) and pulmonary regurgitation (PR). The ventilatory anaerobic threshold (VAT) was 23.8 +/- 0.6 ml.kg-1.min-1 and 29.9 +/- 0.6 ml.kg-1.min-1 in patients and controls, respectively (P < 0.001). VC was 3.4 +/- 1.21 in patients and 4.0 +/- 1.31 in controls (P < 0.02). In the patients, maximal ventilation was reduced and at submaximal exercise, the breathing frequency increased. Heart rates during exercise were similar in patients and controls. Tricuspid regurgitation (TR) was detected in 20 patients (58.8%); however, the exercise capacity was not reduced. Thus, impaired exercise capacity in tetralogy of Fallot is partly due to reduced resting lung function, pulmonary regurgitation and low ventilatory anaerobic threshold.

Effects of respiration on right ventricular size and function: an echocardiographic study

The effects of quiet respiration and body position on right ventricular (RV) size and function were assessed by two-dimensional (2DE) and M-mode echocardiography in 15 healthy children. All end-diastolic echocardiographic dimensions, areas, and volumes increased slightly but significantly with inspiration. At end-systole similar changes were found. RV ejection fractions were significantly higher during inspiration, as were stroke volume indices. RV dimensions also increased from supine to left lateral decubitus position. Thus, our results indicate a need for standardization of 2DE and M-mode measurements not only for body position, but also for respiratory phase when used to assess RV size and function.