Cardiopulmonary Capacity in Children During Exercise Testing: The Differences Between Treadmill and Upright and Supine Cycle Ergometry.

Background/Hypothesis: Cardiopulmonary exercise testing (CPET) is used in the assessment of function and prognosis of cardiopulmonary health in children with cardiac and pulmonary diseases. Techniques, such as cardiac MRi, and PET-scan, can be performed simultaneously with exercise testing. Thus, it is desirable to have a broader knowledge about children's normal cardiopulmonary function in different body postures and exercise modalities. The aim of this study was to investigate the effect of different body positions on cardiopulmonary function in healthy subjects performing CPETs. Materials and Methods: Thirty-one healthy children aged 9, 12, and 15 years did four CPETs: one treadmill test with a modified Bruce protocol and three different bicycle tests with different body postures, sitting, tilted 45°, and lying flat (0°). For the bicycle tests, a 20-watt ramp protocol with a pedal frequency of 60 ± 5 rotations per minute was used. Continous ECG and breath-by-breath V . O 2 measurements was done throughout the tests. Cardiac structure and function including aortic diameter were evaluated by transthoracic echocardiography prior to the tests. Doppler measurements of the blood velocity in the ascending aorta were measured prior to and during the test. Prior to every test, the participants performed pulmonary function tests with maximum voluntary ventilation test. Results: There is a significantly (p < 0.05) lower peak V . O 2 in all bicycle tests compared with the treadmill test. There is lower corrected peak V . O 2 (ml kg-0.67 min-1), but not relative peak V . O 2 (ml kg-1 min-1), in the supine compared with the upright bicycle test. There are no differences in peak stroke volume or cardiac output between the bicycle modalities when calculated from aortic blood flow. Peak heart rate decreases from both treadmill to upright bicycle and from upright bicycle to the supine test (0°). Conclusion: There are no differences in peak cardiac output between the upright bicycle test and supine bicycle tests. Heart rate and corrected peak V . O 2 are lower in the supine test (0°) than the upright bicycle test. In the treadmill test, it is a higher absolute and relative peak V . O 2 . Despite the latter differences, we are convinced that both upright and supine bicycle tests are apt in the clinical setting when needed.

Use of incentives for participants in medical and health research in Norway. / Bruk av insentiver til deltagere i medisinsk og helsefaglig forskning i Norge.

BACKGROUND: A fall in recruitment of participants for research has been observed in recent years. In order to ensure a sufficient number of research participants, incentives such as remuneration and gift cards have been used. The number of Norwegian research groups that apply to use payment has not been previously studied. We have investigated the extent to which payment and other incentives are used in medical and health research in Norway. MATERIAL AND METHOD: Four of the seven Regional Committees for Medical and Health Research Ethics (REC) in Norway were selected to participate in the study. All applications for approval of research projects submitted to these committees in 2014 were analysed. Following a review of the application form, research protocol and information and consent form associated with the project applications, a total of 515 of 955 project applications were included in the study. RESULTS: Of 515 project applications that were included, a total of 12 % applied to use incentives. Altogether 4 % applied to use remuneration and 7 % applied to use incentives such as gift cards, gifts and lottery tickets. Of the project applications involving remuneration, 82 % were for amounts of NOK 500 or less. INTERPRETATION: A minority of the research groups applied to use incentives. The amounts that were planned to be used as incentives were low and appear to be acceptable. It is unlikely that the size of the incentives constitutes an undue influence on research participants in Norway.

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.

Transcapillary fluid flux and inflammatory response during neonatal therapeutic hypothermia: an open, longitudinal, observational study.

BACKGROUND: Therapeutic hypothermia is neuroprotective in asphyxiated neonates by counteracting mechanisms contributing to brain injury. Although an initial increased permeability is part of an inflammatory reaction and thereby a natural healing process, an excessive endothelial permeability with edema formation may result in impaired hemodynamics. Reduced permeability may, however, benefit healing. Although plasma and interstitial colloid osmotic pressure are accessible and essential parameters for understanding fluid imbalance, the mechanisms of fluid exchange remain poorly understood. The potential influence of therapeutic hypothermia on plasma and interstitial colloid osmotic pressure, and the relationship between inflammatory markers and colloid osmotic pressure in asphyxiated neonates, was investigated. METHODS: Seventeen neonates with moderate to severe hypoxic ischemic encephalopathy, born after 35 weeks gestation, received servo-controlled whole body cooling before 6 h of age, followed by gradual rewarming after 72 h. All infants were treated according to a national hypothermia protocol. Interstitial fluid in the skin was collected at 7, 13, 25, 49, and 73 h after birth by subcutaneous implantation of multifilamentous nylon wicks with 60 min of implantation time. Biomarkers of inflammation and colloid osmotic pressure were measured in serum and interstitial fluid. RESULTS: A modest decrease in serum and interstitial colloid osmotic pressure was measured, leaving an unaltered difference in colloid osmotic pressure gradient. A decline in mean arterial pressure was observed between 7 and 13 h of life, with a concomitant decrease in positive fluid balance within the same time frame. White blood cell count and leukocyte subclasses dropped significantly throughout treatment, with elevated interstitial interleukin (IL)-1α and decreased serum IL-1RA, IL-6, and IL-10 during treatment time points. CONCLUSIONS: Colloid osmotic pressures measured in serum and interstitial fluid during asphyxia is lower than previously reported, with small alteration of pressure differences across capillaries, reducing vascular filtration. An inherent local and systemic regulation of inflammation together with changes in colloid osmotic pressure may indicate a possible preventive mechanism of edema generation during neonatal asphyxia and therapeutic hypothermia. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01044940 . Date of registration: January 8, 2010.

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.

Parental anxiety related to referral of childhood heart murmur; an observational/interventional study.

BACKGROUND: Detection of a heart murmur in healthy children is common, but may generate anxiety among parents. Many parents believe a heart murmur is a sign of heart disease, although the majority of heart murmurs are innocent. The purpose of this study was to assess anxiety and concerns in parents of children referred for evaluation of a heart murmur and to evaluate the effect of receiving a fact sheet about heart murmurs before the cardiologic consultation. METHODS: Parents of children referred for evaluation of a heart murmur responded to questionnaires assessing family and patient characteristics, parental concerns and anxiety. Anxiety was measured using the State Trait Anxiety Index (STAI) before and two weeks after the consultation. One third of the parents received a fact sheet before the consultation. RESULTS: Two hundred fifty-eight parents of 178 children participated. About 60 % of the parents had an increased level of anxiety before the consultation. The majority of the parents (71 %) had at least one major concern about heart murmurs in children, and having a concern was related to higher anxiety levels (p = 0.02). Anxious personality and lower education predicted an increased anxiety level. Before the consultation, parents who received a fact sheet presented a lower mean STAI state anxiety level (33.2) than those who did not (35.3), but the difference was not significant (p = 0.09). Fewer parents in the intervention group believed their child would have increased risk of heart disease later in life (p = 0.04) or that heart murmurs in children represents valvular-or congenital heart disease (p = 0.02). After the consultation, parental anxiety decreased from a mean STAI state of 34.9 to 30.6 (p < 0.01), and the mean STAI state scores were similar for the control and intervention group. CONCLUSION: Parents with a child referred for a heart murmur presented a higher mean anxiety level than pre-school parents, and having an anxious personality, a major concern or low education predicted an increased anxiety level. After the consultation, parental anxiety decreased. Receiving a fact sheet about heart murmurs did not significantly reduce parental anxiety levels, but had a modest effect on concerns for the consequences of a heart murmur.

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.

[Cardiovascular risk assessment for the use of ADHD drugs in children]. / Kardiovaskulær risikovurdering ved bruk av AD/HD-medikamenter hos barn.

BACKGROUND: Drug therapy for ADHD (Attention Deficit Hyperactivity Disorder) has generally been regarded as safe. ECG screening of healthy children and adolescents before initiating this type of treatment appears to be usual in Norway, despite recommendations that ECGs should only be undertaken in individuals who are at risk. The purpose of this article is to clarify relevant guidelines for cardiovascular risk assessment for the use of ADHD drugs in children and adolescents, as well as to propose practical recommendations. METHOD: The article is based on a literature search in PubMed completed on 1 October 2013, and on the author's own clinical experience and discretionary assessments. RESULTS: The use of CNS stimulants and atomoxetine is associated with a slight rise in blood pressure and pulse rate, as well as small changes in QT interval. A small percentage of patients (5-10%) experience a clinically significant rise in blood pressure and pulse rate. Sudden death does not appear to occur more frequently in children and adolescents taking ADHD drugs in therapeutic doses than in children and adolescents who do not use such drugs. There is little knowledge available on the long-term effects of ADHD drugs on the cardiovascular system of otherwise healthy individuals, or on the risk related to the use of ADHD drugs in children and adolescents with cardiac disease. The drugs are thought to increase the risk of sudden cardiac death in some arrhythmia syndromes. INTERPRETATION: Our assessment is that caution should be exercised in the use of ADHD drugs in children with potentially dangerous cardiac arrhythmias. We recommend clinical examination and a thorough medical history review in order to identify individuals at risk before initiating drug therapy, and also suggest that it is not necessary for healthy children to be given an ECG examination before introducing ADHD drugs. In children with known cardiac disease, arrhythmia or risk factors for cardiac disease, ADHD treatment should be undertaken in consultation with a medical specialist with competence in pediatric cardiology.

Preeclampsia in healthy women and endothelial dysfunction 10 years later.

OBJECTIVE: Recent studies have shown that women with a history of preeclampsia have an increased risk of cardiovascular disease. The present study investigated cardiovascular risk factors 10 years after preeclampsia in previously healthy women. STUDY DESIGN: Based on data from the Medical Birth Registry in Norway, we selected 182 women with and 180 women without preeclampsia in their first pregnancy 9-11 years earlier, excluding women with cardiovascular or renal disease before pregnancy. Flow-mediated dilation of the brachial artery (FMD) and intima-media thickness (IMT) of the carotid artery were measured and blood samples were drawn. Blood samples were analyzed for cardiovascular risk markers and for circulating markers of endothelial function. RESULTS: A total of 89 women with previous preeclampsia and 69 women without preeclampsia participated, an overall attendance rate of 44%. FMD and IMT were similar between groups. Women with previous preeclampsia more often had urate and soluble fms-like tyrosine kinase values above the 75th percentile (odds ratio [OR], 2.4; P = .03, and OR, 2.4; P = .04, respectively) and high-density lipoprotein cholesterol values below the 25th percentile (OR, 2.3; P = .04). Women with preeclampsia with low birthweight offspring were associated with asymmetric dimethylarginine, L-arginine, and homoarginine above the 75th percentile, whereas the women with preeclampsia with normal-weight offspring were associated with urate and soluble fms-like tyrosine kinase above the 75th percentile. CONCLUSION: Preeclampsia was not associated with impaired FMD or increased IMT 10 years after pregnancy in previously healthy women, but preeclampsia was associated with changes in circulating markers that might represent early endothelial dysfunction.

Trends in pediatric imaging: ultrasound.

For the last three decades, two-dimensional (2D) echocardiography and Doppler echocardiography have been the primary imaging modalities for the diagnosis and management of heart disease in infants, children, and adolescents. These methods are non-invasive, highly sensitive, and cost-effective, and widely available, making them very useful in clinical work. During this period, the anatomic and hemodynamic abnormalities associated with different congenital and acquired pediatric heart diseases have been well outlined by echocardiography. Recent advances in computer technology, signal processing, and transducer design have allowed the capabilities of pediatric echocardiography to be expanded beyond qualitative 2D imaging and blood flow Doppler analysis. New modalities such as three-dimensional echocardiography, tissue Doppler imaging and speckle tracking echocardiography have been used to evaluate parameters such as ventricular volume, myocardial velocity, regional strain, and strain rate, providing new insight into cardiovascular morphology and ventricular systolic and diastolic function. Accordingly, a comprehensive and sophisticated quantification of ventricular function is now part of most echocardiography protocols. Use of measurements adjusted for body size and age is common practice today. These developments have further strengthened the position of echocardiography in pediatric cardiology.

Assessment of vascular reactivity in the peripheral and coronary arteries by Cine 3T-magnetic resonance imaging in young normotensive adults after surgery for coarctation of the aorta.

This study aimed to investigate whether coarctation of the aorta in infancy indicates an altered vascular reactivity in the peripheral and coronary arteries apart from the secondary effect of hypertension or other complications of the disease. Patients with repaired coarctation of the aorta have a high prevalence of premature cardiovascular complications. The etiology still is not fully understood, and the cause is most likely multifactorial. Endothelial function was assessed by peripheral flow mediated dilation (FMD) and coronary flow reserve (CFR) in a study of 10 control subjects and 10 patients with a successfully repaired coarctation of the aorta (mean age, 20.9 years; 20.5 years after repair). No one had re- or rest-coarctation of the aorta, hypertension, pathologic blood pressure response during exercise, or associated cardiac malformations such as bicuspid aortic valve. CFR was achieved by phase-contrast velocity encoding cine magnetic resonance imaging in the coronary sinus before and during infusion with adenosine (0.14 mg/kg/min). FMD was measured in the brachial artery before and after 5 min of arterial occlusion. A normal CFR and FMD was found in both groups. Most studies have been conducted with large, unselected groups. The current study group represented the best outcome of the coarctation spectrum (i.e., patients with no evidence of a residual gradient across the coarctation site or systemic hypertension). The findings reassuringly suggest that significant endothelial dysfunction and atherosclerotic changes were not present in this selected cohort.

[Cardiac arrest in a 10-month-old boy with spinal cord injury]. / Hjertestans hos en ti måneder gammel gutt med ryggmargsskade.

A 10-month-old boy with a previous upper spinal cord injury was admitted to hospital with acute respiratory and circulatory distress. Shortly after admission the boy had severe bradycardia leading to asystolia and pulseless electrical activity. He was successfully resuscitated, and the investigation that followed excluded infection, congenital heart defect, arrhythmia and cerebral haemorrhage. Over the following days the patient had several episodes of isolated bradycardia and combined bradycardia and hypotension. It was concluded that the patient suffered from autonomic dysreflexia, triggered by a distended urinary bladder. He was treated with intermittent catheterization and a permanent pacemaker, and after 12 months there have not been any symptomatic episodes or registered arrhythmias. Autonomic dysreflexia is a common and well known complication of spinal cord injury above Th6, but the literature on paediatric patients is scarce. Our case report presents an infant with an atypical and severe episode of autonomic dysreflexia. Patients with spinal cord injury, their caregivers and health-care personal should be aware of this complication of spinal cord injury, in order to prevent and treat autonomic dysreflexia properly and avoid potentially fatal episodes.

Effect of topical anaesthetics on interstitial colloid osmotic pressure in human subcutaneous tissue sampled by wick technique.

OBJECTIVES: To measure colloid osmotic pressure in interstitial fluid (COP(i)) from human subcutaneous tissue with the modified wick technique in order to determine influence of topical application of anaesthetics, dry vs. wet wick and implantation time on COP(i). MATERIAL AND METHODS: In 50 healthy volunteers interstitial fluid (IF) was collected by subcutaneous implantation of multi-filamentous nylon wicks. Study subjects were allocated to two groups; one for comparing COP(i) obtained from dry and saline soaked wicks, and one for comparing COP(i) from unanaesthetized skin, and skin after application of a eutectic mixture of local anaesthetic (EMLA®, Astra Zeneca) cream. IF was sampled from the skin of the shoulders, and implantation time was 30, 60, 75, 90 and 120 min. Colloid osmotic pressure was measured with a colloid osmometer. Pain assessment during the procedure was compared for EMLA cream and no topical anaesthesia using a visual analogue scale (VAS) in a subgroup of 10 subjects. RESULTS: There were no significant differences between COP(i) obtained from dry compared to wet wicks, except that the values after 75 and 90 min. were somewhat higher for the dry wicks. Topical anaesthesia with EMLA cream did not affect COP(i) values. COP(i) decreased from 30 to 75 min. of implantation (23.2 ± 4.4 mmHg to 19.6 ± 2.9 mmHg, p = 0.008) and subsequently tended to increase until 120 min. EMLA cream resulted in significant lower VAS score for the procedure. CONCLUSION: COP(i) from subcutaneous tissue was easily obtained and fluid harvesting was well tolerated when topical anaesthetic was used. The difference in COP(i) assessed by dry and wet wicks between 75 min. and 90 min. of implantation was in accordance with previous reports. The use of topical analgesia did not influence COP(i) and topical analgesia may make the wick technique more acceptable for subjects who dislike technical procedures, including children. TRIAL REGISTRATION: ClinicalTrials.gov NCT01044979.

Assessment of coronary flow reserve in the coronary sinus by cine 3T-magnetic resonance imaging in young adults after surgery for tetralogy of Fallot.

This study aimed to evaluate CFR by assessing blood flow in the coronary sinus and systemic endothelial function measured by FMD of the brachial artery in an open prospective study of 10 control subjects and 10 patients (ages, 15-25 years) who have undergone surgical TOF repair. Reduced ventricular function, impaired exercise capacity, and ventricular arrhythmia have been proposed as risk factors for sudden cardiac death after surgical repair of TOF. Some of this may be related to impaired myocardial perfusion. A 3.0T GE Signa Excite scanner was used to achieve phase-contrast, velocity-encoding cine magnetic resonance imaging in the coronary sinus before and during infusion with adenosine (0.14 mg/kg/min). FMD was measured in the brachial artery before arterial occlusion and 5 min afterward. The TOF group demonstrated significantly higher volumetric blood flow in the coronary sinus (282 ± 63 ml/min) than the normal control subjects at rest (184 ± 57 ml/min) (P = 0.006). During adenosine infusion, this difference disappeared. The CFR was 2.00 ± 0.43 in the control group and 1.19 ± 0.34 in the TOF group (P = 0.002). No correlation between FMD and CFR was observed in the study group (r (s) = 0.61, n = 8, P = 0.15). This study showed a reduced CFR due to a higher blood flow of the subject at rest in the TOF group. This reduced CFR may disable a normal adaptation to increased oxygen demand during exercise and increase myocardial vulnerability to reduced blood supply postoperatively for TOF patients with coronary heart disease.

[Should children be treated with ephedrine mixture?]. / Bør barn behandles med efedrin mikstur?

Lower respiratory tract infections are common in small children, and are often associated with obstruction of the respiratory tract and coughing. In Norway, symptomatic treatment with ephedrine is common in children. The clinical effect of such treatment is not sufficiently documented and serious adverse drug reactions have been reported in small children administered sympathomimetic medication. This article presents current knowledge of clinical effects and adverse drug reactions of ephedrine in infants and children, and discusses the practical implications of these findings.

Circulatory effects of inhaled iloprost in the newborn preterm lamb.

Inhaled NO (iNO) has an established role in the treatment of pulmonary hypertension (PH) in the newborn. However, costs and potential toxicity associated with iNO have generated interest in alternative inhaled selective pulmonary vasodilators such as iloprost. In a preterm lamb model of respiratory distress syndrome, we studied effects of increasing doses of iloprost followed by iNO on right ventricular pressure (RVP) and circulation including cerebral oxygenation. Fetal sheep were randomized to three doses (0.2-4 mg/kg) of iloprost (n = 9) or saline (n = 10), administered as 15-min inhalations with 15-min intervals after a 60-min postnatal stabilization. No differences were found in RVP, arterial PO2, or cardiac index according to treatment. The cerebral oxygenation, measured with near-infrared spectroscopy, deteriorated in control lambs, but not in iloprost lambs. Iloprost treatment followed by iNO resulted in a larger decrease (p = 0.007) in RVP than saline treatment followed by iNO. In conclusion, iloprost stabilized cerebral oxygenation and when followed by iNO had a larger effect on RVP than iNO alone. Although species differences may be relevant, these results suggest that iloprost should be studied in newborn infants for the treatment of PH.

Effects of balloon valvuloplasty on coronary blood flow in neonates with critical pulmonary valve stenosis assessed with transthoracic Doppler echocardiography.

BACKGROUND: Treating pulmonary valve stenosis with balloon valvuloplasty (BV) is a good model to study the effect of right ventricular (RV) pressures on coronary flow. METHODS: Transthoracic Doppler echocardiography was used to register coronary flow in 10 age-matched healthy controls and 7 neonates before and 1 day after BV. RESULTS: Left ventricular fractional shortening and cardiac output increased significantly after BV. Right coronary artery diameter decreased from 1.2 +/- 0.2 to 1.1 +/- 0.1 mm (P < .02). Posterior descending coronary artery flow parameters decreased significantly, with blood flow decreasing from 8.4 to 5.7 +/- 1.9 mL/s (P < .003). RV end-diastolic pressure and RV systolic pressure explained almost totally the variation in coronary flow (r(2) = 0.87). CONCLUSIONS: RV end-diastolic pressure and RV systolic pressure determined coronary flow in neonates with critical pulmonary valve stenosis. Cardiac output and left ventricular fractional shortening increased after pulmonary valve BV.