| 1. |
- Arvidsson, Per Martin, et al.
(författare)
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Kinetic energy of left ventricular blood flow across heart failure phenotypes and in subclinical diastolic dysfunction
- 2022
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Ingår i: Journal of Applied Physiology. - : American Physiological Society. - 1522-1601 .- 8750-7587. ; 133:3, s. 697-709
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Kinetic energy (KE) of intracardiac blood flow reflects myocardial work spent on accelerating blood and provides a mechanistic window into diastolic filling dynamics. Diastolic dysfunction may represent an early stage in the development of heart failure (HF). Here we evaluated the hemodynamic effects of impaired diastolic function in subjects with and without HF, testing the hypothesis that left ventricular KE differs between controls, subjects with subclinical diastolic dysfunction (SDD), and HF patients.METHODS: We studied 77 subjects (16 controls, 20 subjects with SDD, 16 HFpEF, 9 HFmrEF, and 16 HFrEF patients, age- and sex-matched at the group level). Cardiac magnetic resonance at 1.5T included intracardiac 4D flow and cine imaging. Left ventricular KE was calculated as 0.5*m*v 2. RESULTS: Systolic KE was similar between groups (p>0.4), also after indexing to stroke volume (p=0.25), and was primarily driven by ventricular emptying rate (p<0.0001, R 2=0.52). Diastolic KE was higher in heart failure patients than controls (p<0.05) but similar between SDD and HFpEF (p>0.18), correlating with inflow conditions (E-wave velocity, p<0.0001, R 2=0.24) and end-diastolic volume (p=0.0003, R 2=0.17) but not with average e' (p=0.07). CONCLUSIONS: Diastolic KE differs between controls and heart failure, suggesting more work is spent filling the failing ventricle, while systolic KE does not differentiate between well-matched groups with normal ejection fraction even in the presence of relaxation abnormalities and heart failure. Mechanistically, KE reflects the acceleration imparted on the blood and is driven by variations in ventricular emptying and filling rates, volumes, and heart rate, regardless of underlying pathology.
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| 2. |
- Arvidsson, Per Martin, et al.
(författare)
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Kinetic energy of left ventricular blood flow across heart failure phenotypes and in subclinical diastolic dysfunction.
- 2022
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 1522-1601.
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Tidskriftsartikel (refereegranskat)abstract
- Kinetic energy (KE) of intracardiac blood flow reflects myocardial work spent on accelerating blood and provides a mechanistic window into diastolic filling dynamics. Diastolic dysfunction may represent an early stage in the development of heart failure (HF). Here we evaluated the hemodynamic effects of impaired diastolic function in subjects with and without HF, testing the hypothesis that left ventricular KE differs between controls, subjects with subclinical diastolic dysfunction (SDD), and HF patients.We studied 77 subjects (16 controls, 20 subjects with SDD, 16 HFpEF, 9 HFmrEF, and 16 HFrEF patients, age- and sex-matched at the group level). Cardiac magnetic resonance at 1.5T included intracardiac 4D flow and cine imaging. Left ventricular KE was calculated as 0.5*m*v2.Systolic KE was similar between groups (p>0.4), also after indexing to stroke volume (p=0.25), and was primarily driven by ventricular emptying rate (p<0.0001, R2=0.52). Diastolic KE was higher in heart failure patients than controls (p<0.05) but similar between SDD and HFpEF (p>0.18), correlating with inflow conditions (E-wave velocity, p<0.0001, R2=0.24) and end-diastolic volume (p=0.0003, R2=0.17) but not with average e' (p=0.07).Diastolic KE differs between controls and heart failure, suggesting more work is spent filling the failing ventricle, while systolic KE does not differentiate between well-matched groups with normal ejection fraction even in the presence of relaxation abnormalities and heart failure. Mechanistically, KE reflects the acceleration imparted on the blood and is driven by variations in ventricular emptying and filling rates, volumes, and heart rate, regardless of underlying pathology.
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| 3. |
- Arvidsson, Per M., et al.
(författare)
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Left and right ventricular hemodynamic forces in healthy volunteers and elite athletes assessed with 4D flow magnetic resonance imaging
- 2017
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Ingår i: American Journal of Physiology - Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 312:2, s. 314-328
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Tidskriftsartikel (refereegranskat)abstract
- Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients’ forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies. New & Noteworthy Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the pulmonary circulation. Force patterns were similar between healthy subjects and athletes, indicating potential utility as a cardiac function biomarker.
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| 4. |
- Asgeirsson, Daniel, et al.
(författare)
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Longitudinal shortening remains the principal component of left ventricular pumping in patients with chronic myocardial infarction even when the absolute atrioventricular plane displacement is decreased
- 2017
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Ingår i: BMC Cardiovascular Disorders. - : Springer Science and Business Media LLC. - 1471-2261. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The majority (60%) of left ventricular (LV) stroke volume (SV) is generated by longitudinal shortening causing apical atrioventricular plane displacement (AVPD) in systole. The remaining SV is caused by radial inward motion of the epicardium both in the septal and the lateral wall. We aimed to determine if these longitudinal, septal and lateral contributions to LVSV are changed in patients with chronic myocardial infarction (MI). Methods: Patients with a chronic (>3 months) ST-elevation MI in the left anterior descending (LAD, n = 20) or right coronary artery (RCA, n = 16) and healthy controls (n = 20) were examined with cardiovascular magnetic resonance (CMR). AVPD was quantified in long axis cine CMR images and LV volumes and dimensions in short axis cine images. Results: AVPD was decreased both in patients with LAD-MI (11 ± 1 mm, p < 0.001) and RCA-MI (13 ± 1 mm, p < 0.05) compared to controls (15 ± 0 mm). However, the longitudinal contribution to SV was unchanged for both LAD-MI (58 ± 3%, p = 0.08) and RCA-MI (59 ± 3%, p = 0.09) compared to controls (64 ± 2%). The preserved longitudinal contribution despite decreased absolute AVPD was a results of increased epicardial dimensions (p < 0.01 for LAD-MI and p = 0.06 for RCA-MI). In LAD-MI the septal contribution to LVSV was decreased (5 ± 1%) compared to both controls (10 ± 1%, p < 0.01) and patients with RCA-MIs (10 ± 1%, p < 0.01). The lateral contribution was increased in LAD-MI patients (44 ± 3%) compared to both RCA-MI (35 ± 2%, p < 0.05) and controls (29 ± 2%, p < 0.001). Conclusion: Longitudinal shortening remains the principal component of left ventricular pumping in patients with chronic MI even when the absolute AVPD is decreased.
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| 5. |
- Bidhult, Sebastian, et al.
(författare)
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A new vessel segmentation algorithm for robust blood flow quantification from two-dimensional phase-contrast magnetic resonance images
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 39:5, s. 327-338
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Tidskriftsartikel (refereegranskat)abstract
- Blood flow measurements in the ascending aorta and pulmonary artery from phase-contrast magnetic resonance images require accurate time-resolved vessel segmentation over the cardiac cycle. Current semi-automatic segmentation methods often involve time consuming manual correction, relying on user experience for accurate results. The purpose of this study was to develop a semi-automatic vessel segmentation algorithm with shape constraints based on manual vessel delineations for robust segmentation of the ascending aorta and pulmonary artery, to evaluate the proposed method in healthy volunteers and patients with heart failure and congenital heart disease, to validate the method in a pulsatile flow phantom experiment, and to make the method freely available for research purposes. Algorithm shape constraints were extracted from manual reference delineations of the ascending aorta (n=20) and pulmonary artery (n=20) and were included into a semi-automatic segmentation method only requiring manual delineation in one image. Bias and variability (bias±SD) for flow volume of the proposed algorithm versus manual reference delineations were 0·0±1·9ml in the ascending aorta (n=151; 7 healthy volunteers; 144 heart failure patients) and -1·7±2·9 ml in the pulmonary artery (n=40; 25 healthy volunteers; 15 patients with atrial septal defect). Inter-observer bias and variability were lower (p=0·008) for the proposed semi-automatic method (-0·1±0·9ml) compared to manual reference delineations (1·5±5·1ml). Phantom validation showed good agreement between the proposed method and timer-and-beaker flow volumes (0·4±2·7ml). In conclusion, the proposed semi-automatic vessel segmentation algorithm can be used for efficient analysis of flow and shunt volumes in the aorta and pulmonary artery. This article is protected by copyright. All rights reserved.
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| 6. |
- Carlsson, Marcus, et al.
(författare)
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Cardiac output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects, elite athletes and patients with congestive heart failure
- 2012
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - 1097-6647. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cardiovascular Magnetic Resonance (CMR) enables non-invasive quantification of cardiac output (CO) and thereby cardiac index (CI, CO indexed to body surface area). The aim of this study was to establish if CI decreases with age and compare the values to CI for athletes and for patients with congestive heart failure (CHF). Methods: CI was measured in 144 healthy volunteers (39 +/- 16 years, range 21-81 years, 68 females), in 60 athletes (29 +/- 6 years, 30 females) and in 157 CHF patients with ejection fraction (EF) below 40% (60 +/- 13 years, 33 females). CI was calculated using aortic flow by velocity-encoded CMR and is presented as mean +/- SD. Flow was validated in vitro using a flow phantom and in 25 subjects with aorta and pulmonary flow measurements. Results: There was a slight decrease of CI with age in healthy subjects (8 ml/min/m(2) per year, r(2) = 0.07, p = 0.001). CI in males (3.2 +/- 0.5 l/min/m(2)) and females (3.1 +/- 0.4 l/min/m(2)) did not differ (p = 0.64). The mean +/- SD of CI in healthy subjects in the age range of 20-29 was 3.3 +/- 0.4 l/min/m(2), in 30-39 years 3.3 +/- 0.5 l/min/m(2), in 40-49 years 3.1 +/- 0.5 l/min/m(2), 50-59 years 3.0 +/- 0.4 l/min/m(2) and >60 years 3.0 +/- 0.4 l/min/m(2). There was no difference in CI between athletes and age-controlled healthy subjects but HR was lower and indexed SV higher in athletes. CI in CHF patients (2.3 +/- 0.6 l/min/m(2)) was lower compared to the healthy population (p < 0.001). There was a weak correlation between CI and EF in CHF patients (r(2) = 0.07, p < 0.001) but CI did not differ between patients with NYHA-classes I-II compared to III-IV (n = 97, p = 0.16) or patients with or without hospitalization in the previous year (n = 100, p = 0.72). In vitro phantom validation showed low bias (-0.8 +/- 19.8 ml/s) and in vivo validation in 25 subjects also showed low bias (0.26 +/- 0.61 l/min, QP/QS 1.04 +/- 0.09) between pulmonary and aortic flow. Conclusions: CI decreases in healthy subjects with age but does not differ between males and females. We found no difference in CI between athletes and healthy subjects at rest but CI was lower in patients with congestive heart failure. The presented values can be used as reference values for flow velocity mapping CMR.
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| 7. |
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| 8. |
- Edlund, Jonathan, et al.
(författare)
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Noninvasive Assessment of Left Ventricular Pressure-Volume Relations : Inter- and Intraobserver Variability and Assessment Across Heart Failure Subtypes
- 2022
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Ingår i: American Journal of Cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149. ; 184, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- A novel method to derive pressure-volume (PV) loops noninvasively from cardiac magnetic resonance images has recently been developed. The aim of this study was to evaluate inter- and intraobserver variability of hemodynamic parameters obtained from noninvasive PV loops in healthy controls, subclinical diastolic dysfunction (SDD), and patients with heart failure with preserved ejection fraction, mildly reduced ejection fraction, and reduced ejection fraction. We included 75 subjects, of whom 15 were healthy controls, 15 subjects with SDD (defined as fulfilling 1 to 2 echocardiographic criteria for diastolic dysfunction), and 15 patients with preserved ejection fraction, 15 with mildly reduced ejection fraction, and 15 with reduced ejection fraction. PV loops were computed using time-resolved left ventricular volumes from cardiac magnetic resonance images and a brachial blood pressure. Inter- and intraobserver variability and intergroup differences of PV loop-derived hemodynamic parameters were assessed. Bias was low and limits of agreement were narrow for all hemodynamic parameters in the inter- and intraobserver comparisons. Interobserver difference for stroke work was 2 ± 9%, potential energy was 4 ± 11%, and maximal ventricular elastance was -4 ± 7%. Intraobserver for stroke work was -1 ± 7%, potential energy was 3 ± 4%, and maximal ventricular elastance was 1 ± 5%. In conclusion, this study presents a fully noninvasive left ventricular PV loop analysis across healthy controls, subjects with SDD, and patients with heart failure with preserved or impaired systolic function. In conclusion, the method for PV loop computation from clinical-standard manual left ventricular segmentation was rapid and robust, bridging the gap between clinical and research settings.
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| 9. |
- Edlund, Jonathan, et al.
(författare)
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Noninvasive Assessment of Left Ventricular Pressure-Volume Relations: Inter- and Intraobserver Variability and Assessment Across Heart Failure Subtypes.
- 2022
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Ingår i: The American journal of cardiology. - : Elsevier BV. - 1879-1913 .- 0002-9149.
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Tidskriftsartikel (refereegranskat)abstract
- A novel method to derive pressure-volume (PV) loops noninvasively from cardiac magnetic resonance images has recently been developed. The aim of this study was to evaluate inter- and intraobserver variability of hemodynamic parameters obtained from noninvasive PV loops in healthy controls, subclinical diastolic dysfunction (SDD), and patients with heart failure with preserved ejection fraction, mildly reduced ejection fraction, and reduced ejection fraction. We included 75 subjects, of whom 15 were healthy controls, 15 subjects with SDD (defined as fulfilling 1 to 2 echocardiographic criteria for diastolic dysfunction), and 15 patients with preserved ejection fraction, 15 with mildly reduced ejection fraction, and 15 with reduced ejection fraction. PV loops were computed using time-resolved left ventricular volumes from cardiac magnetic resonance images and a brachial blood pressure. Inter- and intraobserver variability and intergroup differences of PV loop-derived hemodynamic parameters were assessed. Bias was low and limits of agreement were narrow for all hemodynamic parameters in the inter- and intraobserver comparisons. Interobserver difference for stroke work was 2 ± 9%, potential energy was 4 ± 11%, and maximal ventricular elastance was -4 ± 7%. Intraobserver for stroke work was -1 ± 7%, potential energy was 3 ± 4%, and maximal ventricular elastance was 1 ± 5%. In conclusion, this study presents a fully noninvasive left ventricular PV loop analysis across healthy controls, subjects with SDD, and patients with heart failure with preserved or impaired systolic function. In conclusion, the method for PV loop computation from clinical-standard manual left ventricular segmentation was rapid and robust, bridging the gap between clinical and research settings.
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| 10. |
- Edlund, Jonathan, et al.
(författare)
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Validation and quantification of left ventricular function during exercise and free breathing from real-time cardiac magnetic resonance images
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Exercise cardiovascular magnetic resonance (CMR) can unmask cardiac pathology not evident at rest. Real-time CMR in free breathing can be used, but respiratory motion may compromise quantification of left ventricular (LV) function. We aimed to develop and validate a post-processing algorithm that semi-automatically sorts real-time CMR images according to breathing to facilitate quantification of LV function in free breathing exercise. A semi-automatic algorithm utilizing manifold learning (Laplacian Eigenmaps) was developed for respiratory sorting. Feasibility was tested in eight healthy volunteers and eight patients who underwent ECG-gated and real-time CMR at rest. Additionally, volunteers performed exercise CMR at 60% of maximum heart rate. The algorithm was validated for exercise by comparing LV mass during exercise to rest. Respiratory sorting to end expiration and end inspiration (processing time 20 to 40 min) succeeded in all research participants. Bias ± SD for LV mass was 0 ± 5 g when comparing real-time CMR at rest, and 0 ± 7 g when comparing real-time CMR during exercise to ECG-gated at rest. This study presents a semi-automatic algorithm to retrospectively perform respiratory sorting in free breathing real-time CMR. This can facilitate implementation of exercise CMR with non-ECG-gated free breathing real-time imaging, without any additional physiological input.
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