Frank Rademakers | KU Leuven (original) (raw)

Papers by Frank Rademakers

Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall t... more Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall thickness and deformation of the distal myocardium – implications for clinical reperfusion strategies

Circulation, 2019

Introduction: Cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP)... more Introduction: Cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have both been associated with myocardial ischemia, but it remains unclear whether this is directly...

Journal of Cardiovascular Magnetic Resonance, 2007

European Heart Journal, 2015

European Heart Journal - Quality of Care and Clinical Outcomes, 2021

In the European Union (EU) the delivery of health services is a national responsibility but there... more In the European Union (EU) the delivery of health services is a national responsibility but there are concerted actions between member states to protect public health. Approval of pharmaceutical products is the responsibility of the European Medicines Agency, whereas authorizing the placing on the market of medical devices is decentralized to independent ‘conformity assessment’ organizations called notified bodies. The first legal basis for an EU system of evaluating medical devices and approving their market access was the medical device directives, from the 1990s. Uncertainties about clinical evidence requirements, among other reasons, led to the EU Medical Device Regulation (2017/745) that has applied since May 2021. It provides general principles for clinical investigations but few methodological details—which challenges responsible authorities to set appropriate balances between regulation and innovation, pre- and post-market studies, and clinical trials and real-world evidence...

Physiological Measurement, 2017

Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decisi... more Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decision making. The generation of VTCs using echocardiography, however, is time-consuming and prone to inter-operator variability. In this study, we used a new non-invasive, operator-independent technique, the hemodynamic cardiac profiler (HCP), to generate VTCs. The HCP, which uses a low-intensity, patient-safe, high-frequency applied AC current, and 12 standard ECG electrodes attached on the thorax in a predefined pattern, was applied to five young healthy volunteers, five older healthy volunteers, and five patients with severe mitral regurgitation. From the VTCs generated by the HCP, the presence or absence of an isovolumetric contraction phase (ICP) was assessed, as well as the left ventricular ejection time (LVET), time of the pre-ejection period (tPEP), and ratio of the volumes of the early (E) and late (A) diastolic filling (E V /A V ratio), and compared to 2D transthoracic echocardiography (2D TTE) at rest. The reproducibility by two different operators showed good results (RMS = 5.2%). For intrapatient measurement RMS was 2.8%. Both LVET and the E V /A V ratio Institute of Physics and Engineering in Medicine Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

European Journal of Echocardiography, 2005

Regional Em was increased between exam 1 and 2 for the whole group (6,44-1,7cm vs 6,94-1,5cm, p<0... more Regional Em was increased between exam 1 and 2 for the whole group (6,44-1,7cm vs 6,94-1,5cm, p<0,05), but in separating groups only lor group II (6,04-1,5cm vs 6,84-1,7cm, p<0,01), the same as Em/Am ratio (0,94-0,9 vs 1,34-0,9, p<0,05). There were no significant changes in Am, RFT and AFT. IVRT was shorlen for lhe whole group (1034-19ms vs 914-20ms, p<0,05) and for group II (1214-20ms vs 974-91ms, p<0,01). Differences in Em and IVRT were noliced belween two groups in first examination (6,84-1 ,gcm/s vs 6,04-1,5cm/s, p<0,01 and 954-91 ms vs 121-t-gOms, p<0,001, respectively). Alter successlul angioplasly there were no dilferences between assessed paramelers. Conclusions: In patients with coronary artery stenosis afler successlul CA regional diastolic function showed improvement as assessed by TDE. Significant improvement of diastolic function was apparent only lor significant stenosis (> 70%).

European Journal of Echocardiography, 2005

Background: Since the left atrial (LA) size has been recognized as a critical determinant in a va... more Background: Since the left atrial (LA) size has been recognized as a critical determinant in a variety of cardiac diseases that show the ventricular diastolic dysfunction, more accurate measurement of LA volume is required in the clinical settings. In this study we tested feasibility and reliability of a new, real-time triplane 3DE to measure LA volume and compared the measures to those from 2DE, which present the current standard. Methods: To test the volumetric reliability of 3DE (Vivid7 Dimension, G E Yokogawa Medical) in vitro, 11 water-filled (36 to 320ml) latex balloon phantoms with various shapes were used. For in vivo study, we studied 52 patients by 2DE and real-time triplane 3DE. LA volume by 3DE was calculated from the geometric method, using simultaneously collected equally spaced 3 tomograms (by increments of 60 degrees) from the apical window. LA volume by 2DE was calculated by the modified single-plane (4-chamber and 2-chamber) and bi-plane Simpson's rule. In addition, LA antero-posterior dimension (LAD) was measured by 2DE. Results: In vitro study, there was a high correlation and good agreement (y=1.0x-3.3(ml), r=0.99, p<0.0001) between the true volume and the estimated volume by 3DE. In patients, LA volume by 3DE ranged from 36 to 199 mL (79±35 mL). These 3DE measures were tightly correlated to any types of LA measures by 2DE. However there were consistent underestimations by 2DE-derived data (biplane: y=0.72x + 13.0, r=0.88, bias=-13.7 mL, single-4 chamber: y=0.68x + 14.1, r=0.81, bias=-16.3 mL, single-2 chamber: y=0.77x + 13.2, r=0.85, bias=-14.3 mL). Besides, while LAD had a statistically significant correlation with 3DE-derived volume, the correlation was not satisfactory (y=0.016x+2.5, r=0.79). Conclusions: The 3DE-derived LA measures provide more accurate data of the actual LA volume. The current standard, LAD, is quite unreliable. In addition, LA volume by 2DE underestimates the volume by 23-32%. 348 The transplantation of bone marrow-derived stem cells in patients with large acute myocardial infarction improves regional myocardial systolic function measured with myocardial velocity imaging

European Heart Journal, 1994

ABSTRACT

Journal of Cardiovascular Magnetic Resonance, 2015

First-pass perfusion cardiac magnetic resonance (CMR) allows the quantitative assessment of myoca... more First-pass perfusion cardiac magnetic resonance (CMR) allows the quantitative assessment of myocardial blood flow (MBF). Currently, clinical translation is lacking, mainly due to considerable disparity in quantification methodology. The aim of this study was to compare shared (SP) and non-shared (NSP) prepulse perfusion MR sequences for MBF quantification.

Acta cardiologica, 1998

Hypertrophic cardiomyopathy is an important cause of sudden death in young and asymptomatic patie... more Hypertrophic cardiomyopathy is an important cause of sudden death in young and asymptomatic patients. Young athletes and patients with unexplained sudden death, including their relatives, should be screened for its presence. Risk stratification identifies a high-risk group, in which preventive measures should be taken to reduce the risk for sudden death: moderate to heavy physical activity has to be avoided and arrhythmias with haemodynamic impact should be rigorously prevented.

Critical Care, 2011

Introduction: Recently, a non-invasive, continuous ventricular stroke volume monitoring system us... more Introduction: Recently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output. Methods: In six Dalland pigs, cardiac output was simultaneously measured with the HCP (CO-HCP), and an invasive ultrasonic flow-probe around the ascending aorta (CO-FP). Variations in CO were achieved by change in ventricular loading conditions, cardiac pacing, and dobutamine administration. Data were analysed according to Bland-Altman analysis and Pearson's correlation. Results: Pearson's correlation between the CO-HCP and the CO-FP was r = 0.978. Bland-Altman analysis showed a bias of-0.114 L/minute, and a variability of the bias (2 standard deviations, 2SD) of 0.55 L/minute. Conclusions: The results of the present study demonstrate that CO-HCP is comparable to CO-FP in an animal model of cardiac output measurements during a wide variation of CO. Therefore, the HCP has the potential to become a clinical applicable cardiac output monitor.

Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall t... more Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall thickness and deformation of the distal myocardium – implications for clinical reperfusion strategies

Circulation, 2019

Introduction: Cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP)... more Introduction: Cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) have both been associated with myocardial ischemia, but it remains unclear whether this is directly...

Journal of Cardiovascular Magnetic Resonance, 2007

European Heart Journal, 2015

European Heart Journal - Quality of Care and Clinical Outcomes, 2021

In the European Union (EU) the delivery of health services is a national responsibility but there... more In the European Union (EU) the delivery of health services is a national responsibility but there are concerted actions between member states to protect public health. Approval of pharmaceutical products is the responsibility of the European Medicines Agency, whereas authorizing the placing on the market of medical devices is decentralized to independent ‘conformity assessment’ organizations called notified bodies. The first legal basis for an EU system of evaluating medical devices and approving their market access was the medical device directives, from the 1990s. Uncertainties about clinical evidence requirements, among other reasons, led to the EU Medical Device Regulation (2017/745) that has applied since May 2021. It provides general principles for clinical investigations but few methodological details—which challenges responsible authorities to set appropriate balances between regulation and innovation, pre- and post-market studies, and clinical trials and real-world evidence...

Physiological Measurement, 2017

Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decisi... more Left ventricular volume-time curves (VTCs) provide hemodynamic data, and may help clinical decision making. The generation of VTCs using echocardiography, however, is time-consuming and prone to inter-operator variability. In this study, we used a new non-invasive, operator-independent technique, the hemodynamic cardiac profiler (HCP), to generate VTCs. The HCP, which uses a low-intensity, patient-safe, high-frequency applied AC current, and 12 standard ECG electrodes attached on the thorax in a predefined pattern, was applied to five young healthy volunteers, five older healthy volunteers, and five patients with severe mitral regurgitation. From the VTCs generated by the HCP, the presence or absence of an isovolumetric contraction phase (ICP) was assessed, as well as the left ventricular ejection time (LVET), time of the pre-ejection period (tPEP), and ratio of the volumes of the early (E) and late (A) diastolic filling (E V /A V ratio), and compared to 2D transthoracic echocardiography (2D TTE) at rest. The reproducibility by two different operators showed good results (RMS = 5.2%). For intrapatient measurement RMS was 2.8%. Both LVET and the E V /A V ratio Institute of Physics and Engineering in Medicine Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

European Journal of Echocardiography, 2005

Regional Em was increased between exam 1 and 2 for the whole group (6,44-1,7cm vs 6,94-1,5cm, p<0... more Regional Em was increased between exam 1 and 2 for the whole group (6,44-1,7cm vs 6,94-1,5cm, p<0,05), but in separating groups only lor group II (6,04-1,5cm vs 6,84-1,7cm, p<0,01), the same as Em/Am ratio (0,94-0,9 vs 1,34-0,9, p<0,05). There were no significant changes in Am, RFT and AFT. IVRT was shorlen for lhe whole group (1034-19ms vs 914-20ms, p<0,05) and for group II (1214-20ms vs 974-91ms, p<0,01). Differences in Em and IVRT were noliced belween two groups in first examination (6,84-1 ,gcm/s vs 6,04-1,5cm/s, p<0,01 and 954-91 ms vs 121-t-gOms, p<0,001, respectively). Alter successlul angioplasly there were no dilferences between assessed paramelers. Conclusions: In patients with coronary artery stenosis afler successlul CA regional diastolic function showed improvement as assessed by TDE. Significant improvement of diastolic function was apparent only lor significant stenosis (> 70%).

European Journal of Echocardiography, 2005

Background: Since the left atrial (LA) size has been recognized as a critical determinant in a va... more Background: Since the left atrial (LA) size has been recognized as a critical determinant in a variety of cardiac diseases that show the ventricular diastolic dysfunction, more accurate measurement of LA volume is required in the clinical settings. In this study we tested feasibility and reliability of a new, real-time triplane 3DE to measure LA volume and compared the measures to those from 2DE, which present the current standard. Methods: To test the volumetric reliability of 3DE (Vivid7 Dimension, G E Yokogawa Medical) in vitro, 11 water-filled (36 to 320ml) latex balloon phantoms with various shapes were used. For in vivo study, we studied 52 patients by 2DE and real-time triplane 3DE. LA volume by 3DE was calculated from the geometric method, using simultaneously collected equally spaced 3 tomograms (by increments of 60 degrees) from the apical window. LA volume by 2DE was calculated by the modified single-plane (4-chamber and 2-chamber) and bi-plane Simpson's rule. In addition, LA antero-posterior dimension (LAD) was measured by 2DE. Results: In vitro study, there was a high correlation and good agreement (y=1.0x-3.3(ml), r=0.99, p<0.0001) between the true volume and the estimated volume by 3DE. In patients, LA volume by 3DE ranged from 36 to 199 mL (79±35 mL). These 3DE measures were tightly correlated to any types of LA measures by 2DE. However there were consistent underestimations by 2DE-derived data (biplane: y=0.72x + 13.0, r=0.88, bias=-13.7 mL, single-4 chamber: y=0.68x + 14.1, r=0.81, bias=-16.3 mL, single-2 chamber: y=0.77x + 13.2, r=0.85, bias=-14.3 mL). Besides, while LAD had a statistically significant correlation with 3DE-derived volume, the correlation was not satisfactory (y=0.016x+2.5, r=0.79). Conclusions: The 3DE-derived LA measures provide more accurate data of the actual LA volume. The current standard, LAD, is quite unreliable. In addition, LA volume by 2DE underestimates the volume by 23-32%. 348 The transplantation of bone marrow-derived stem cells in patients with large acute myocardial infarction improves regional myocardial systolic function measured with myocardial velocity imaging

European Heart Journal, 1994

ABSTRACT

Journal of Cardiovascular Magnetic Resonance, 2015

First-pass perfusion cardiac magnetic resonance (CMR) allows the quantitative assessment of myoca... more First-pass perfusion cardiac magnetic resonance (CMR) allows the quantitative assessment of myocardial blood flow (MBF). Currently, clinical translation is lacking, mainly due to considerable disparity in quantification methodology. The aim of this study was to compare shared (SP) and non-shared (NSP) prepulse perfusion MR sequences for MBF quantification.

Acta cardiologica, 1998

Hypertrophic cardiomyopathy is an important cause of sudden death in young and asymptomatic patie... more Hypertrophic cardiomyopathy is an important cause of sudden death in young and asymptomatic patients. Young athletes and patients with unexplained sudden death, including their relatives, should be screened for its presence. Risk stratification identifies a high-risk group, in which preventive measures should be taken to reduce the risk for sudden death: moderate to heavy physical activity has to be avoided and arrhythmias with haemodynamic impact should be rigorously prevented.

Critical Care, 2011

Introduction: Recently, a non-invasive, continuous ventricular stroke volume monitoring system us... more Introduction: Recently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output. Methods: In six Dalland pigs, cardiac output was simultaneously measured with the HCP (CO-HCP), and an invasive ultrasonic flow-probe around the ascending aorta (CO-FP). Variations in CO were achieved by change in ventricular loading conditions, cardiac pacing, and dobutamine administration. Data were analysed according to Bland-Altman analysis and Pearson's correlation. Results: Pearson's correlation between the CO-HCP and the CO-FP was r = 0.978. Bland-Altman analysis showed a bias of-0.114 L/minute, and a variability of the bias (2 standard deviations, 2SD) of 0.55 L/minute. Conclusions: The results of the present study demonstrate that CO-HCP is comparable to CO-FP in an animal model of cardiac output measurements during a wide variation of CO. Therefore, the HCP has the potential to become a clinical applicable cardiac output monitor.