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Papers by Ten Harkel

Research paper thumbnail of Assessment of Intraventricular Time Differences in Healthy Children Using Two-Dimensional Speckle-Tracking Echocardiography

Journal of the American Society of Echocardiography, 2013

Background: Parameters describing intraventricular time differences are increasingly assessed in ... more Background: Parameters describing intraventricular time differences are increasingly assessed in both adults and children. However, to appreciate the implications of these parameters in children, knowledge of the applicability of adult techniques in children is essential. Hence, the aim of this study was to assess the applicability of speckle-tracking strain-derived parameters in children, paying special attention to age and heart rate dependency. Methods: One hundred eighty-three healthy subjects (aged 0-19 years) were included. Left ventricular global peak strain, time to global peak strain, and parameters describing intraventricular time differences were assessed using speckle-tracking strain imaging in the apical two-chamber, three-chamber, and four-chamber views (longitudinal strain) and the parasternal short-axis view (radial and circumferential strain). Parameters describing intraventricular time differences included the standard deviation of time to peak strain and differences in time to peak strain between two specified segments. Age and heart rate dependency were evaluated using regression analysis, and intraobserver and interobserver variability were tested. Results: Acquisition and analysis of longitudinal six-segment time-strain curves was successful in 94.8% of subjects and radial and circumferential time-strain curves in 89.5%. No clinically significant linear relation was observed between age or heart rate and parameters describing intraventricular time differences. The coefficient of variation of time to global peak strain parameters was <10, while it was >10 for parameters describing intraventricular time differences. Conclusions: The feasibility of speckle-tracking strain analysis in children is relatively good. Furthermore, no linear relation was observed between age or heart rate and parameters describing intraventricular time differences. However, the limited reproducibility of some parameters describing intraventricular time differences will confine their applicability in clinical practice.

Research paper thumbnail of Disparity in right vs left ventricular recovery during follow-up after ventricular septal defect correction in children

European Journal of Cardio-Thoracic Surgery, 2013

OBJECTIVES: Long-term prognosis after ventricular septal defect (VSD) correction in childhood is ... more OBJECTIVES: Long-term prognosis after ventricular septal defect (VSD) correction in childhood is excellent. Nevertheless, decreased biventricular systolic performance has been described immediately following VSD surgery in children. In an effort to better understand this decrease and its time-course, we characterized biventricular systolic performance following VSD closure in paediatric patients up to 20 months postoperatively.

Research paper thumbnail of Effects of leg muscle pumping and tensing on orthostatic arterial pressure: a study in normal subjects and patients with autonomic failure

Clinical Science, Nov 1, 1994

1. The effects of leg muscle pumping (tiptoeing) and tensing (leg-crossing) on orthostatic blood ... more 1. The effects of leg muscle pumping (tiptoeing) and tensing (leg-crossing) on orthostatic blood pressure were investigated in six healthy adult subjects (aged 28-34 years) and in seven patients with severe hypoadrenergic orthostatic hypotension (aged 20-65 years). 2. Finger arterial pressure was monitored. Relative changes in left ventricular stroke volume were computed by a pulse contour method. 3. Tiptoeing increased mean arterial pressure (7 +/- 5 mmHg) in the healthy subjects, but not in the patients, whereas cardiac output increased in both groups, although by more in the healthy adults than in the patients (35 +/- 10% versus 20 +/- 11%, P < 0.05). Systemic vascular resistance decreased substantially in both groups while tiptoeing. Leg-crossing did not affect arterial pressure in the healthy subjects, although stroke volume had increased. In contrast, in the patients an increase in cardiac output (16 +/- 12%) and mean blood pressure (13 +/- 13 mmHg) was observed. 4. Tiptoeing and leg-crossing have different effects on orthostatic blood pressure in healthy adult subjects and in patients with autonomic failure. In normal humans, tiptoeing increases arterial pressure, whereas leg-crossing has little effect. In the patients, in contrast, tiptoeing has little effect, whereas leg-crossing increases arterial pressure considerably. Patients with autonomic failure should be instructed to apply leg-crossing to combat orthostatic dizziness.

Research paper thumbnail of Measurement of cardiovascular reflexes: effects of body position and duration of supine rest

Journal of the Autonomic Nervous System, 1989

Research paper thumbnail of Longitudinal Strain as Risk Factor for Outcome in Pediatric Dilated Cardiomyopathy

JACC: Cardiovascular Imaging, 2015

Research paper thumbnail of Response profiles of oxygen uptake efficiency during exercise in healthy children

European journal of preventive cardiology, Jan 13, 2015

Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (... more Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (VE), differs between healthy children and children with heart disease. This study aimed to investigate the normal response profiles of OUE during a progressive cardiopulmonary exercise test. Cross-sectional. Healthy children between eight and 19 years of age (114 boys and 100 girls, mean ± SD age 12.7 ± 2.8 years) performed a maximal cardiopulmonary exercise test. Peak VO2 (VO2peak), ventilatory threshold and peak VE were determined. OUE was determined by the OUE plateau (OUEP), OUE at the ventilatory threshold (OUE@VT) and OUE slope (OUES). OUEP (42.4 ± 4.6) and OUE@VT (41.9 ± 4.7) were similar and less variable than OUES (2138 ± 703). OUEP correlated strongly with OUE@VT (r = 0.974); however, OUEP was weak-to-moderately correlated with VO2peak (r = 0.646), the ventilatory threshold (r = 0.548) and OUES (r = 0.589). OUES correlated strongly with VO2peak (r = 0.948) and the ventilatory t...

Research paper thumbnail of Het lange-qt-tijdsyndroom bij kinderen

Tijdschrift voor kindergeneeskunde, 2002

Summary We examined 29 pediatric patients with long-qt-syndrome in three academic hospitals. The... more Summary We examined 29 pediatric patients with long-qt-syndrome in three academic hospitals. The mean age was 10 years (3-17). Of these patients 22 used betablocker therapy, in three combined with pacemaker. Genotyping has been performed in 22 children. lqts1 (mutation in the kcnq1 gene) was found in twelve, lqts2 (mutation in the herg gene) in eight and lqts3 (mutation in the scn5a gene) in two. Patients came under attention due to bradycardia postnatally in four, after near-drowning in three and after syncope in another four patients. In most of these eleven children family history was found retrospectively to be positive for sudden cardiac death or recurrent syncope. In eighteen children the diagnosis of lqts was made during family screening. Retrospectively, six of these children were found to have had recurrent syncope. Although lqts is becoming a well-known disease, there still are patients that come under attention after a considerable delay. This may result in sudden cardiac death that might have been prevented. Genotyping is essential in this familial disorder. There is a relation between genotype and fenotype, thus leading to differences in therapy and advice. It is also possible to diagnose asymptomatic carriers, thus enabling secondary prevention. In conclusion, lqts has a high mortality, which can be greatly reduced by therapy. It is therefore necessary to evaluate precisely patients and family members in the case of recurrent syncope, near-drowning or sudden cardiac death. The joint management of (pediatric) cardiologist and clinical geneticist plays an important role in diagnosis and therapy.

Research paper thumbnail of Exercise testing and prescription in patients with congenital heart disease

International journal of pediatrics, 2010

The present paper provides a review of the literature regarding exercise testing, exercise capaci... more The present paper provides a review of the literature regarding exercise testing, exercise capacity, and the role of exercise training in patients with congenital heart disease (CHD). Different measures of exercise capacity are discussed, including both simple and more advanced exercise parameters. Different groups of patients, including shunt lesions, pulmonary valvar stenosis, patients after completion of Fontan circulation, and patients with pulmonary arterial hypertension are discussed separately in more detail. It has been underscored that an active lifestyle, taking exercise limitations and potential risks of exercise into account is of utmost importance. Increased exercise capacity in these patients is furthermore correlated with an improvement of objective and subjective quality of life.

Research paper thumbnail of Alkalinization and the tumor lysis syndrome

Medical and pediatric oncology, 1998

Research paper thumbnail of Cardiovascular response to coughing: its value in the assessment of autonomic nervous control

Clinical science (London, England : 1979), 1989

1. The relationship between blood pressure and heart rate responses to coughing was investigated ... more 1. The relationship between blood pressure and heart rate responses to coughing was investigated in 10 healthy subjects in three body positions and compared with the circulatory responses to commonly used autonomic function tests: forced breathing, standing up and the Valsalva manoeuvre. 2. We observed a concomitant intra-cough increase in supine heart rate and blood pressure and a sustained post-cough elevation of heart rate in the absence of arterial hypotension. These findings indicate that the sustained increase in heart rate in response to coughing is not caused by arterial hypotension and that these heart rate changes are not under arterial baroreflex control. 3. The maximal change in heart rate in response to coughing (28 +/- 8 beats/min) was comparable with the response to forced breathing (29 +/- 9 beats/min, P greater than 0.4), with a reasonable correlation (r = 0.67, P less than 0.05), and smaller than the change in response to standing up (41 +/- 9 beats/min, P less tha...

Research paper thumbnail of Assessment of cardiovascular reflexes: influence of posture and period of preceding rest

The aim of the present study was to investigate the effects of a pretest redistribution of blood ... more The aim of the present study was to investigate the effects of a pretest redistribution of blood volume and of a change in the neurohumoral condition on the blood pressure (BP) and heart rate (HR) responses to three commonly used cardiovascular reflex tests: standing up, forced breathing, and the Valsalva maneuver in 10 healthy male subjects. Base-line conditions were altered by changing posture and the duration of rest preceding the test stimulus. A continuous recording of finger BP was obtained noninvasively by a Finapres. The main observations from this study are with respect to standing up: lengthening the period of preceding rest from 1 to 20 min enlarges the initial BP (systolic/diastolic) decrease (from 8 +/- 10/9 +/- 4 to 27 +/- 8/19 +/- 4 mmHg, P less than 0.01) and the subsequent BP overshoot (from 17 +/- 10/12 +/- 7 to 31 +/- 10/18 +/- 7 mmHg, P less than 0.05); to forced breathing: inspiratory-expiratory changes in BP but not in HR are larger in the upright posture (P less than 0.05); and to the Valsalva maneuver: change in posture from supine to standing increases the phase II BP decrease (from 18 +/- 12/8 +/- 6 to 45 +/- 16/21 +/- 9 mmHg), phase IV systolic BP overshoot (from 26 +/- 16 to 71 +/- 17 mmHg), delta HRmax (from 30 +/- 10 to 47 +/- 12 beats/min), and the Valsalva ratio (HRmax/HRmin), from 2.0 +/- 0.3 to 2.6 +/- 0.7, all significant at P less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Intraoperative evaluation of micromultiplane transesophageal echocardiographic probe in surgery for congenital heart disease☆☆☆

European Journal of Echocardiography, 2007

Introduction: In the last years, transesophageal transducers for multiplane Doppler echocardiogra... more Introduction: In the last years, transesophageal transducers for multiplane Doppler echocardiography have demonstrated their superior imaging performance in pediatric patients undergoing cardiac surgery. To date, the size of these probes has limited their use in neonates and small children. New technologies allowing performing TEE in smaller patients are therefore promising. Methods: We report our clinical experience with the Oldelft micromultiplane TEE probe (8.2e7 mm diameter tip with a 5.2 mm diameter shaft) specifically meant for use in neonates. Results: Forty-two patients were examined intra-operatively using the micromulti TEE harmonic transducer. Patients examined ranged in age from 4 days to 6 years and ranged in weight from 2.5 to 23.8 kg. In two patients we had to adapt ventilatory settings because of increased airway resistance after probe insertion. In 3 patients surgical re-intervention was performed due to TEE assessment immediately after weaning from bypass. In two patients significant obstruction of the right ventricular outflow tract was still present after Fallot correction, and one patient had an additional muscular ventricular septal defect still present after VSD closure.

Research paper thumbnail of Feasibility of Noninvasive Continuous Finger Arterial Blood Pressure Measurements in Very Young Children, Aged 0–4 Years

Pediatric Research, 2008

Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monito... more Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monitoring in very young children, aged 0 -4 y. To achieve this, we designed a set of smallsized finger cuffs based on the assessment of finger circumference. Finger arterial BP measured by a volume clamp device (Finapres technology) was compared with simultaneously measured intra-arterial BP in 15 very young children (median age, 5 mo; range, 0 -48), admitted to the intensive care unit for vital monitoring. The finger cuff-derived BP waveforms showed good resemblance with the invasive arterial waveforms (mean root-mean-square error, 3 mm Hg). The correlation coefficient between both methods was 0.79 Ϯ 0.19 systolic and 0.74 Ϯ 0.24 diastolic. The correlation coefficient of beat-to-beat changes between both methods was 0.82 Ϯ 0.18 and 0.75 Ϯ 0.21, respectively. Three measurements were related to measurement errors (loose cuff application; wrong set-point). Excluding these erroneous measurements resulted in clinically acceptable measurement bias (Ϫ3.8 mm Hg) and 95% limits of agreement (Ϫ10.4 to ϩ 2.8 mm Hg) of mean BP values. We conclude that continuous finger BP measurement is feasible in very young children. However, cuff application is critical, and the current set-point algorithm needs to be revised in very young children. (Pediatr Res 63: 691-696, 2008) PA, WB, AJDH, SBO and CEB have no financial interest, (sponsor) arrangement, or affiliation with BMEYE, other than participation in the present study.

Research paper thumbnail of Topical topic: Alkalinization and the tumor lysis syndrome

Medical and Pediatric Oncology, 1998

ABSTRACT

Research paper thumbnail of Exercise capacity in children after total cavopulmonary connection: Lateral tunnel versus extracardiac conduit technique

The Journal of Thoracic and Cardiovascular Surgery, 2014

Objectives: In patients with univentricular heart disease, the total cavopulmonary connection (TC... more Objectives: In patients with univentricular heart disease, the total cavopulmonary connection (TCPC) is the preferred treatment. TCPC can be performed using the intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) technique. The purpose of the present study was to evaluate exercise capacity in contemporary TCPC patients and compare the results between the 2 techniques.

Research paper thumbnail of Real Time Transthoracic Three-Dimensional Echocardiography: How Should it be Applied in the Clinical Setting?

Journal of Medical Ultrasound, 2009

Research paper thumbnail of Systematic review of the effects of physical exercise training programmes in children and young adults with congenital heart disease

International Journal of Cardiology, 2013

Most patients with congenital heart disease (ConHD) do not perform regular physical exercise. Con... more Most patients with congenital heart disease (ConHD) do not perform regular physical exercise. Consensus reports have stated that exercise should be encouraged and regularly performed in these patients, but this is not common practise. We reviewed the literature on actual evidence for either negative or positive effects of physical exercise training programmes in children and young adults with ConHD. Using the Medline database, we systematically searched for articles on physical exercise training programmes in ConHD. A total of 31 articles met all inclusion criteria; in total, 621 subjects (age range 4 to 45 years) were included. Most studies used training programmes with a duration of 12 weeks. On average, the number of training sessions was 3 times per week. In 12 studies, training intensity was set at a percentage of peak heart rate. Outcome measures reported were PeakVO2, activity levels and muscle strength. Twenty-three studies (72%) found a significant positive change in the main outcome measure after the physical exercise training period. None of the studies reported negative findings related to physical exercise training in ConHD. Cardiac effects have hardly been studied. In most studies, participation in a physical exercise training programme was safe and improved fitness in children and young adults with ConHD. We recommend that patients with ConHD participate in physical exercise training. Cardiac effects need to be studied more extensively.

Research paper thumbnail of Implantable cardioverter defibrillator implantation in children in The Netherlands

European Journal of Pediatrics, 2005

ABSTRACT

Research paper thumbnail of Normal values for cardiopulmonary exercise testing in children

European Journal of Cardiovascular Prevention & Rehabilitation, 2010

Background: A reference set of data of normal values of newly developed cardiopulmonary parameter... more Background: A reference set of data of normal values of newly developed cardiopulmonary parameters of exercise testing in an 8-18-year-old population is lacking. Patients and methods: Cardiopulmonary exercise testing was performed in 175 healthy school children (8-18 years old). Continuous electrocardiography was performed, and minute ventilation, oxygen uptake (VO 2 ), and carbon dioxide (CO 2 ) production were measured continuously with a respiratory gas analysis system. Results: Peak VO 2 /kg did not change with age, whereas the ventilation to carbon dioxide exhalation slope was lower in the older children. The decline in heart rate during recovery was much faster in the youngest children. Linear regression analysis showed a significant effect of age on: peak work rate (WR peak ) and WR peak /kg, ventilation to carbon dioxide exhalation slope, heart rate recovery, and VO 2peak (boys only) (All P < 0.001). The ÁVO 2 /ÁWR slope remained constant throughout all age groups. Conclusion: This study comprehensively provides a reference set of data for the most important cardiopulmonary variables that can be obtained during exercise testing in children.

Research paper thumbnail of Pediatric Pulmonary Hypertension in the Netherlands: Epidemiology and Characterization During the Period 1991 to 2005

Circulation, 2011

Incidence and prevalence rates for pediatric pulmonary hypertension (PH) and pulmonary arterial h... more Incidence and prevalence rates for pediatric pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are unknown. This study describes the nationwide epidemiological features of pediatric PH in the Netherlands during a 15-year period and the clinical course of pediatric PAH. Two registries were used to retrospectively identify children (0-17 years) with PH. Overall, 3263 pediatric patients were identified with PH due to left heart disease (n=160; 5%), lung disease/hypoxemia (n=253; 8%), thromboembolic disease (n=5; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1%), and transient (n=2691; 82%) and progressive (n=154; 5%) PAH. Transient PAH included persistent PH of the newborn and children with congenital heart defects (CHD) and systemic-to-pulmonary shunt, in whom PAH resolved after successful shunt correction. Progressive PAH mainly included idiopathic PAH (n=36; iPAH) and PAH associated with CHD (n=111; PAH-CHD). Pulmonary arterial hypertension associated with CHD represented highly heterogeneous subgroups. Syndromes were frequently present, especially in progressive PAH (n=60; 39%). Survival for PAH-CHD varied depending on the subgroups, some showing better and others showing worse survival than for iPAH. Survival of children with Eisenmenger syndrome appeared worse than reported in adults. For iPAH and PAH-CHD, annual incidence and point prevalence averaged, respectively, 0.7 and 4.4 (iPAH) and 2.2 and 15.6 (PAH-CHD) cases per million children. Compared to studies in adults, iPAH occurred less whereas PAH-CHD occurred more frequently. Pediatric PH is characterized by various age-specific diagnoses, the majority of which comprise transient forms of PAH. Incidence of pediatric iPAH is lower whereas incidence of pediatric PAH-CHD is higher than reported in adults. Pediatric PAH-CHD represents a heterogeneous group with highly variable clinical courses.

Research paper thumbnail of Assessment of Intraventricular Time Differences in Healthy Children Using Two-Dimensional Speckle-Tracking Echocardiography

Journal of the American Society of Echocardiography, 2013

Background: Parameters describing intraventricular time differences are increasingly assessed in ... more Background: Parameters describing intraventricular time differences are increasingly assessed in both adults and children. However, to appreciate the implications of these parameters in children, knowledge of the applicability of adult techniques in children is essential. Hence, the aim of this study was to assess the applicability of speckle-tracking strain-derived parameters in children, paying special attention to age and heart rate dependency. Methods: One hundred eighty-three healthy subjects (aged 0-19 years) were included. Left ventricular global peak strain, time to global peak strain, and parameters describing intraventricular time differences were assessed using speckle-tracking strain imaging in the apical two-chamber, three-chamber, and four-chamber views (longitudinal strain) and the parasternal short-axis view (radial and circumferential strain). Parameters describing intraventricular time differences included the standard deviation of time to peak strain and differences in time to peak strain between two specified segments. Age and heart rate dependency were evaluated using regression analysis, and intraobserver and interobserver variability were tested. Results: Acquisition and analysis of longitudinal six-segment time-strain curves was successful in 94.8% of subjects and radial and circumferential time-strain curves in 89.5%. No clinically significant linear relation was observed between age or heart rate and parameters describing intraventricular time differences. The coefficient of variation of time to global peak strain parameters was <10, while it was >10 for parameters describing intraventricular time differences. Conclusions: The feasibility of speckle-tracking strain analysis in children is relatively good. Furthermore, no linear relation was observed between age or heart rate and parameters describing intraventricular time differences. However, the limited reproducibility of some parameters describing intraventricular time differences will confine their applicability in clinical practice.

Research paper thumbnail of Disparity in right vs left ventricular recovery during follow-up after ventricular septal defect correction in children

European Journal of Cardio-Thoracic Surgery, 2013

OBJECTIVES: Long-term prognosis after ventricular septal defect (VSD) correction in childhood is ... more OBJECTIVES: Long-term prognosis after ventricular septal defect (VSD) correction in childhood is excellent. Nevertheless, decreased biventricular systolic performance has been described immediately following VSD surgery in children. In an effort to better understand this decrease and its time-course, we characterized biventricular systolic performance following VSD closure in paediatric patients up to 20 months postoperatively.

Research paper thumbnail of Effects of leg muscle pumping and tensing on orthostatic arterial pressure: a study in normal subjects and patients with autonomic failure

Clinical Science, Nov 1, 1994

1. The effects of leg muscle pumping (tiptoeing) and tensing (leg-crossing) on orthostatic blood ... more 1. The effects of leg muscle pumping (tiptoeing) and tensing (leg-crossing) on orthostatic blood pressure were investigated in six healthy adult subjects (aged 28-34 years) and in seven patients with severe hypoadrenergic orthostatic hypotension (aged 20-65 years). 2. Finger arterial pressure was monitored. Relative changes in left ventricular stroke volume were computed by a pulse contour method. 3. Tiptoeing increased mean arterial pressure (7 +/- 5 mmHg) in the healthy subjects, but not in the patients, whereas cardiac output increased in both groups, although by more in the healthy adults than in the patients (35 +/- 10% versus 20 +/- 11%, P < 0.05). Systemic vascular resistance decreased substantially in both groups while tiptoeing. Leg-crossing did not affect arterial pressure in the healthy subjects, although stroke volume had increased. In contrast, in the patients an increase in cardiac output (16 +/- 12%) and mean blood pressure (13 +/- 13 mmHg) was observed. 4. Tiptoeing and leg-crossing have different effects on orthostatic blood pressure in healthy adult subjects and in patients with autonomic failure. In normal humans, tiptoeing increases arterial pressure, whereas leg-crossing has little effect. In the patients, in contrast, tiptoeing has little effect, whereas leg-crossing increases arterial pressure considerably. Patients with autonomic failure should be instructed to apply leg-crossing to combat orthostatic dizziness.

Research paper thumbnail of Measurement of cardiovascular reflexes: effects of body position and duration of supine rest

Journal of the Autonomic Nervous System, 1989

Research paper thumbnail of Longitudinal Strain as Risk Factor for Outcome in Pediatric Dilated Cardiomyopathy

JACC: Cardiovascular Imaging, 2015

Research paper thumbnail of Response profiles of oxygen uptake efficiency during exercise in healthy children

European journal of preventive cardiology, Jan 13, 2015

Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (... more Oxygen uptake efficiency (OUE), the relation between oxygen uptake (VO2) and minute ventilation (VE), differs between healthy children and children with heart disease. This study aimed to investigate the normal response profiles of OUE during a progressive cardiopulmonary exercise test. Cross-sectional. Healthy children between eight and 19 years of age (114 boys and 100 girls, mean ± SD age 12.7 ± 2.8 years) performed a maximal cardiopulmonary exercise test. Peak VO2 (VO2peak), ventilatory threshold and peak VE were determined. OUE was determined by the OUE plateau (OUEP), OUE at the ventilatory threshold (OUE@VT) and OUE slope (OUES). OUEP (42.4 ± 4.6) and OUE@VT (41.9 ± 4.7) were similar and less variable than OUES (2138 ± 703). OUEP correlated strongly with OUE@VT (r = 0.974); however, OUEP was weak-to-moderately correlated with VO2peak (r = 0.646), the ventilatory threshold (r = 0.548) and OUES (r = 0.589). OUES correlated strongly with VO2peak (r = 0.948) and the ventilatory t...

Research paper thumbnail of Het lange-qt-tijdsyndroom bij kinderen

Tijdschrift voor kindergeneeskunde, 2002

Summary We examined 29 pediatric patients with long-qt-syndrome in three academic hospitals. The... more Summary We examined 29 pediatric patients with long-qt-syndrome in three academic hospitals. The mean age was 10 years (3-17). Of these patients 22 used betablocker therapy, in three combined with pacemaker. Genotyping has been performed in 22 children. lqts1 (mutation in the kcnq1 gene) was found in twelve, lqts2 (mutation in the herg gene) in eight and lqts3 (mutation in the scn5a gene) in two. Patients came under attention due to bradycardia postnatally in four, after near-drowning in three and after syncope in another four patients. In most of these eleven children family history was found retrospectively to be positive for sudden cardiac death or recurrent syncope. In eighteen children the diagnosis of lqts was made during family screening. Retrospectively, six of these children were found to have had recurrent syncope. Although lqts is becoming a well-known disease, there still are patients that come under attention after a considerable delay. This may result in sudden cardiac death that might have been prevented. Genotyping is essential in this familial disorder. There is a relation between genotype and fenotype, thus leading to differences in therapy and advice. It is also possible to diagnose asymptomatic carriers, thus enabling secondary prevention. In conclusion, lqts has a high mortality, which can be greatly reduced by therapy. It is therefore necessary to evaluate precisely patients and family members in the case of recurrent syncope, near-drowning or sudden cardiac death. The joint management of (pediatric) cardiologist and clinical geneticist plays an important role in diagnosis and therapy.

Research paper thumbnail of Exercise testing and prescription in patients with congenital heart disease

International journal of pediatrics, 2010

The present paper provides a review of the literature regarding exercise testing, exercise capaci... more The present paper provides a review of the literature regarding exercise testing, exercise capacity, and the role of exercise training in patients with congenital heart disease (CHD). Different measures of exercise capacity are discussed, including both simple and more advanced exercise parameters. Different groups of patients, including shunt lesions, pulmonary valvar stenosis, patients after completion of Fontan circulation, and patients with pulmonary arterial hypertension are discussed separately in more detail. It has been underscored that an active lifestyle, taking exercise limitations and potential risks of exercise into account is of utmost importance. Increased exercise capacity in these patients is furthermore correlated with an improvement of objective and subjective quality of life.

Research paper thumbnail of Alkalinization and the tumor lysis syndrome

Medical and pediatric oncology, 1998

Research paper thumbnail of Cardiovascular response to coughing: its value in the assessment of autonomic nervous control

Clinical science (London, England : 1979), 1989

1. The relationship between blood pressure and heart rate responses to coughing was investigated ... more 1. The relationship between blood pressure and heart rate responses to coughing was investigated in 10 healthy subjects in three body positions and compared with the circulatory responses to commonly used autonomic function tests: forced breathing, standing up and the Valsalva manoeuvre. 2. We observed a concomitant intra-cough increase in supine heart rate and blood pressure and a sustained post-cough elevation of heart rate in the absence of arterial hypotension. These findings indicate that the sustained increase in heart rate in response to coughing is not caused by arterial hypotension and that these heart rate changes are not under arterial baroreflex control. 3. The maximal change in heart rate in response to coughing (28 +/- 8 beats/min) was comparable with the response to forced breathing (29 +/- 9 beats/min, P greater than 0.4), with a reasonable correlation (r = 0.67, P less than 0.05), and smaller than the change in response to standing up (41 +/- 9 beats/min, P less tha...

Research paper thumbnail of Assessment of cardiovascular reflexes: influence of posture and period of preceding rest

The aim of the present study was to investigate the effects of a pretest redistribution of blood ... more The aim of the present study was to investigate the effects of a pretest redistribution of blood volume and of a change in the neurohumoral condition on the blood pressure (BP) and heart rate (HR) responses to three commonly used cardiovascular reflex tests: standing up, forced breathing, and the Valsalva maneuver in 10 healthy male subjects. Base-line conditions were altered by changing posture and the duration of rest preceding the test stimulus. A continuous recording of finger BP was obtained noninvasively by a Finapres. The main observations from this study are with respect to standing up: lengthening the period of preceding rest from 1 to 20 min enlarges the initial BP (systolic/diastolic) decrease (from 8 +/- 10/9 +/- 4 to 27 +/- 8/19 +/- 4 mmHg, P less than 0.01) and the subsequent BP overshoot (from 17 +/- 10/12 +/- 7 to 31 +/- 10/18 +/- 7 mmHg, P less than 0.05); to forced breathing: inspiratory-expiratory changes in BP but not in HR are larger in the upright posture (P less than 0.05); and to the Valsalva maneuver: change in posture from supine to standing increases the phase II BP decrease (from 18 +/- 12/8 +/- 6 to 45 +/- 16/21 +/- 9 mmHg), phase IV systolic BP overshoot (from 26 +/- 16 to 71 +/- 17 mmHg), delta HRmax (from 30 +/- 10 to 47 +/- 12 beats/min), and the Valsalva ratio (HRmax/HRmin), from 2.0 +/- 0.3 to 2.6 +/- 0.7, all significant at P less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Research paper thumbnail of Intraoperative evaluation of micromultiplane transesophageal echocardiographic probe in surgery for congenital heart disease☆☆☆

European Journal of Echocardiography, 2007

Introduction: In the last years, transesophageal transducers for multiplane Doppler echocardiogra... more Introduction: In the last years, transesophageal transducers for multiplane Doppler echocardiography have demonstrated their superior imaging performance in pediatric patients undergoing cardiac surgery. To date, the size of these probes has limited their use in neonates and small children. New technologies allowing performing TEE in smaller patients are therefore promising. Methods: We report our clinical experience with the Oldelft micromultiplane TEE probe (8.2e7 mm diameter tip with a 5.2 mm diameter shaft) specifically meant for use in neonates. Results: Forty-two patients were examined intra-operatively using the micromulti TEE harmonic transducer. Patients examined ranged in age from 4 days to 6 years and ranged in weight from 2.5 to 23.8 kg. In two patients we had to adapt ventilatory settings because of increased airway resistance after probe insertion. In 3 patients surgical re-intervention was performed due to TEE assessment immediately after weaning from bypass. In two patients significant obstruction of the right ventricular outflow tract was still present after Fallot correction, and one patient had an additional muscular ventricular septal defect still present after VSD closure.

Research paper thumbnail of Feasibility of Noninvasive Continuous Finger Arterial Blood Pressure Measurements in Very Young Children, Aged 0–4 Years

Pediatric Research, 2008

Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monito... more Our goal was to study the feasibility of continuous noninvasive finger blood pressure (BP) monitoring in very young children, aged 0 -4 y. To achieve this, we designed a set of smallsized finger cuffs based on the assessment of finger circumference. Finger arterial BP measured by a volume clamp device (Finapres technology) was compared with simultaneously measured intra-arterial BP in 15 very young children (median age, 5 mo; range, 0 -48), admitted to the intensive care unit for vital monitoring. The finger cuff-derived BP waveforms showed good resemblance with the invasive arterial waveforms (mean root-mean-square error, 3 mm Hg). The correlation coefficient between both methods was 0.79 Ϯ 0.19 systolic and 0.74 Ϯ 0.24 diastolic. The correlation coefficient of beat-to-beat changes between both methods was 0.82 Ϯ 0.18 and 0.75 Ϯ 0.21, respectively. Three measurements were related to measurement errors (loose cuff application; wrong set-point). Excluding these erroneous measurements resulted in clinically acceptable measurement bias (Ϫ3.8 mm Hg) and 95% limits of agreement (Ϫ10.4 to ϩ 2.8 mm Hg) of mean BP values. We conclude that continuous finger BP measurement is feasible in very young children. However, cuff application is critical, and the current set-point algorithm needs to be revised in very young children. (Pediatr Res 63: 691-696, 2008) PA, WB, AJDH, SBO and CEB have no financial interest, (sponsor) arrangement, or affiliation with BMEYE, other than participation in the present study.

Research paper thumbnail of Topical topic: Alkalinization and the tumor lysis syndrome

Medical and Pediatric Oncology, 1998

ABSTRACT

Research paper thumbnail of Exercise capacity in children after total cavopulmonary connection: Lateral tunnel versus extracardiac conduit technique

The Journal of Thoracic and Cardiovascular Surgery, 2014

Objectives: In patients with univentricular heart disease, the total cavopulmonary connection (TC... more Objectives: In patients with univentricular heart disease, the total cavopulmonary connection (TCPC) is the preferred treatment. TCPC can be performed using the intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) technique. The purpose of the present study was to evaluate exercise capacity in contemporary TCPC patients and compare the results between the 2 techniques.

Research paper thumbnail of Real Time Transthoracic Three-Dimensional Echocardiography: How Should it be Applied in the Clinical Setting?

Journal of Medical Ultrasound, 2009

Research paper thumbnail of Systematic review of the effects of physical exercise training programmes in children and young adults with congenital heart disease

International Journal of Cardiology, 2013

Most patients with congenital heart disease (ConHD) do not perform regular physical exercise. Con... more Most patients with congenital heart disease (ConHD) do not perform regular physical exercise. Consensus reports have stated that exercise should be encouraged and regularly performed in these patients, but this is not common practise. We reviewed the literature on actual evidence for either negative or positive effects of physical exercise training programmes in children and young adults with ConHD. Using the Medline database, we systematically searched for articles on physical exercise training programmes in ConHD. A total of 31 articles met all inclusion criteria; in total, 621 subjects (age range 4 to 45 years) were included. Most studies used training programmes with a duration of 12 weeks. On average, the number of training sessions was 3 times per week. In 12 studies, training intensity was set at a percentage of peak heart rate. Outcome measures reported were PeakVO2, activity levels and muscle strength. Twenty-three studies (72%) found a significant positive change in the main outcome measure after the physical exercise training period. None of the studies reported negative findings related to physical exercise training in ConHD. Cardiac effects have hardly been studied. In most studies, participation in a physical exercise training programme was safe and improved fitness in children and young adults with ConHD. We recommend that patients with ConHD participate in physical exercise training. Cardiac effects need to be studied more extensively.

Research paper thumbnail of Implantable cardioverter defibrillator implantation in children in The Netherlands

European Journal of Pediatrics, 2005

ABSTRACT

Research paper thumbnail of Normal values for cardiopulmonary exercise testing in children

European Journal of Cardiovascular Prevention & Rehabilitation, 2010

Background: A reference set of data of normal values of newly developed cardiopulmonary parameter... more Background: A reference set of data of normal values of newly developed cardiopulmonary parameters of exercise testing in an 8-18-year-old population is lacking. Patients and methods: Cardiopulmonary exercise testing was performed in 175 healthy school children (8-18 years old). Continuous electrocardiography was performed, and minute ventilation, oxygen uptake (VO 2 ), and carbon dioxide (CO 2 ) production were measured continuously with a respiratory gas analysis system. Results: Peak VO 2 /kg did not change with age, whereas the ventilation to carbon dioxide exhalation slope was lower in the older children. The decline in heart rate during recovery was much faster in the youngest children. Linear regression analysis showed a significant effect of age on: peak work rate (WR peak ) and WR peak /kg, ventilation to carbon dioxide exhalation slope, heart rate recovery, and VO 2peak (boys only) (All P < 0.001). The ÁVO 2 /ÁWR slope remained constant throughout all age groups. Conclusion: This study comprehensively provides a reference set of data for the most important cardiopulmonary variables that can be obtained during exercise testing in children.

Research paper thumbnail of Pediatric Pulmonary Hypertension in the Netherlands: Epidemiology and Characterization During the Period 1991 to 2005

Circulation, 2011

Incidence and prevalence rates for pediatric pulmonary hypertension (PH) and pulmonary arterial h... more Incidence and prevalence rates for pediatric pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are unknown. This study describes the nationwide epidemiological features of pediatric PH in the Netherlands during a 15-year period and the clinical course of pediatric PAH. Two registries were used to retrospectively identify children (0-17 years) with PH. Overall, 3263 pediatric patients were identified with PH due to left heart disease (n=160; 5%), lung disease/hypoxemia (n=253; 8%), thromboembolic disease (n=5; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1%), and transient (n=2691; 82%) and progressive (n=154; 5%) PAH. Transient PAH included persistent PH of the newborn and children with congenital heart defects (CHD) and systemic-to-pulmonary shunt, in whom PAH resolved after successful shunt correction. Progressive PAH mainly included idiopathic PAH (n=36; iPAH) and PAH associated with CHD (n=111; PAH-CHD). Pulmonary arterial hypertension associated with CHD represented highly heterogeneous subgroups. Syndromes were frequently present, especially in progressive PAH (n=60; 39%). Survival for PAH-CHD varied depending on the subgroups, some showing better and others showing worse survival than for iPAH. Survival of children with Eisenmenger syndrome appeared worse than reported in adults. For iPAH and PAH-CHD, annual incidence and point prevalence averaged, respectively, 0.7 and 4.4 (iPAH) and 2.2 and 15.6 (PAH-CHD) cases per million children. Compared to studies in adults, iPAH occurred less whereas PAH-CHD occurred more frequently. Pediatric PH is characterized by various age-specific diagnoses, the majority of which comprise transient forms of PAH. Incidence of pediatric iPAH is lower whereas incidence of pediatric PAH-CHD is higher than reported in adults. Pediatric PAH-CHD represents a heterogeneous group with highly variable clinical courses.