| 1. |
- Sahlen, Anders, et al.
(författare)
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Arterial vasodilatory and ventricular diastolic reserves determine the stroke volume response to exercise in elderly female hypertensive patients
- 2011
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Ingår i: American Journal of Physiology. Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 301:6, s. H2433-H2441
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Tidskriftsartikel (refereegranskat)abstract
- Sahlen A, Abdula G, Norman M, Manouras A, Brodin LA, Lund LH, Shahgaldi K, Winter R. Arterial vasodilatory and ventricular diastolic reserves determine the stroke volume response to exercise in elderly female hypertensive patients. Am J Physiol Heart Circ Physiol 301: H2433-H2441, 2011. First published September 16, 2011; doi:10.1152/ajpheart.00555.2011.-Elderly female hypertensives with arterial stiffening constitute a majority of patients with heart failure with preserved ejection fraction (HFpEF), a condition characterized by inability to increase cardiac stroke volume (SV) with physical exercise. As SV is determined by the interaction between the left ventricle (LV) and its load, we wished to study the role of arterial hemodynamics for exertional SV reserve in patients at high risk of HFpEF. Twenty-one elderly (67 +/- 9 yr) female hypertensive patients were studied at rest and during supine bicycle stress using echocardiography including pulsed-wave Doppler to record flow in the LV outflow tract and arterial tonometry for central arterial pressure waveforms. Arterial compliance was estimated based on an exponential relationship between pressure and volume. The ratio of aortic pressure-to-flow in early systole was used to derive characteristic impedance, which was subsequently subtracted from total resistance (mean arterial pressure/cardiac output) to yield systemic vascular resistance (SVR). It was found that patients with depressed SV reserve (NoRes; reserve <15%; n = 10) showed decreased arterial compliance during exercise, while patients with SV reserve >= 15% (Res; n = 11) showed increased compliance. Exercise produced parallel increases in LV end-diastolic volume and arterial volume in Res patients while NoRes patients exhibited a lesser decrease in SVR and a drop in effective arterial volume. Poor SV reserve in elderly female hypertensives is due to simultaneous failure of LV preload and arterial vasodilatory reserves. Abnormal arterial function contributes to a high risk of HFpEF in these patients.
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| 2. |
- Bjällmark, Anna, et al.
(författare)
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Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults
- 2009
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 29:3, s. 216-223
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Tidskriftsartikel (refereegranskat)abstract
- Tissue Velocity Imaging (TVI) is a method for quantitative analysis of longitudinal myocardial velocities, which can be used during exercise and pharmacological stress echocardiography. It is of interest to evaluate cardiac response to different types of stress tests and the differences between upright and supine bicycle exercise tests have not been fully investigated. Therefore, the aim of this study was to compare cardiac response during supine and upright exercise stress tests. Twenty young healthy individuals underwent supine and upright stress test. The initial workload was set to 30 W and was increased every minute by a further 30 W until physical exhaustion. Tissue Doppler data from the left ventricle were acquired at the end of every workload level using a GE Vivid7 Dimension system (> 200 frames s(-1)). In the off-line processing, isovolumic contraction velocity (IVCV), peak systolic velocity (PSV), isovolumic relaxation velocity (IVRV), peak early diastolic velocity (E') and peak late diastolic velocity (A') were identified at every workload level. No significant difference between the tests was found in PSV. On the contrary, E' was shown to be significantly higher (P < 0.001) during supine exercise than during upright exercise and IVRV was significantly lower (P < 0.001) during supine exercise compared to upright exercise. Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.
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| 5. |
- Larsson, Matilda, 1981-, et al.
(författare)
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State diagrams of the heart - a new approach to describing cardiac mechanics
- 2009
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Ingår i: Cardiovascular Ultrasound. - : BMC. - 1476-7120. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cardiac time intervals have been described as a measure of cardiac performance, where prolongation, shortening and delay of the different time intervals have been evaluated as markers of cardiac dysfunction. A relatively recently developed method with improved ability to measure cardiac events is Tissue Doppler Imaging (TDI), allowing accurate measurement of myocardial movements. Methods: We propose the state diagram of the heart as a new visualization tool for cardiac time intervals, presenting comparative, normalized data of systolic and diastolic performance, providing a more complete overview of cardiac function. This study aimed to test the feasibility of the state diagram method by presenting examples demonstrating its potential use in the clinical setting and by performing a clinical study, which included a comparison of the state diagram method with established echocardiography methods (E/E' ratio, LVEF and WMSI). The population in the clinical study consisted of seven patients with non ST-elevation myocardial infarction (NSTEMI) and seven control subjects, individually matched according to age and gender. The state diagram of the heart was generated from TDI curves from seven positions in the myocardium, visualizing the inter-and intraventricular function of the heart by displaying the cardiac phases. Results: The clinical examples demonstrated that the state diagram allows for an intuitive visualization of pathological patterns as ischemia and dyssynchrony. Further, significant differences in percentage duration between the control group and the NSTEMI group were found in eight of the totally twenty phases (10 phases for each ventricle), e.g. in the transition phases (Pre-Ejection and Post-Ejection). These phases were significantly longer (> 2.18%) for the NSTEMI group than for the control group (p < 0.05). No significant differences between the groups were found for the established echocardiography methods. Conclusion: The test results clearly indicate that the state diagram has potential to be an efficient tool for visualization of cardiac dysfunction and for detection of NSTEMI.
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| 6. |
- Larsson, Matilda, et al.
(författare)
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Ultrasound speckle tracking for radial, longitudinal and circumferential strain estimation of the carotid artery : An in vitro validation via sonomicrometry using clinical and high-frequency ultrasound
- 2014
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Ingår i: Ultrasonics. - : Elsevier BV. - 0041-624X .- 1874-9968. ; 56, s. 399-408
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound speckle tracking for carotid strain assessment has in the past decade gained interest in studies of arterial stiffness and cardiovascular diseases. The aim of this study was to validate and directly contrast carotid strain assessment by speckle tracking applied on clinical and high-frequency ultrasound images in vitro. Four polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties and connected to a pump generating carotid flow profiles. Gray-scale ultrasound long-and short-axis images of the phantoms were obtained using a standard clinical ultrasound system, Vivid 7 (GE Healthcare, Horten, Norway) and a high-frequency ultrasound system, Vevo 2100 (FUJIFILM, VisualSonics, Toronto, Canada) with linear-array transducers (12L / MS250). Radial, longitudinal and circumferential strains were estimated using an in-house speckle tracking algorithm and compared with reference strain acquired by sonomicrometry. Overall, the estimated strain corresponded well with the reference strain. The correlation between estimated peak strain in clinical ultrasound images and reference strain was 0.91 (p < 0.001) for radial strain, 0.73 (p < 0.001) for longitudinal strain and 0.90 (p < 0.001) for circumferential strain and for high-frequency ultrasound images 0.95 (p < 0.001) for radial strain, 0.93 (p < 0.001) for longitudinal strain and 0.90 (p < 0.001) for circumferential strain. A significant larger bias and root mean square error was found for circumferential strain estimation on clinical ultrasound images compared to high frequency ultrasound images, but no significant difference in bias and root mean square error was found for radial and longitudinal strain when comparing estimation on clinical and high-frequency ultrasound images. The agreement between sonomicrometry and speckle tracking demonstrates that carotid strain assessment by ultrasound speckle tracking is feasible.
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| 7. |
- Peolsson, Anneli, et al.
(författare)
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A tissue velocity ultrasound imaging investigation of the dorsal neck muscles during resisted isometric extension
- 2010
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Ingår i: MANUAL THERAPY. - : Elsevier Science B.V., Amsterdam. - 1356-689X .- 1532-2769. ; 15:6, s. 567-573
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Tidskriftsartikel (refereegranskat)abstract
- Persons with neck pain exhibit altered patterns of muscle patterning, but limited investigations have been carried out on these alterations or muscle patterning in healthy volunteers. This study investigated the tissue motion of the dorsal neck muscles at the C4 segmental level in 15 healthy subjects during manually resisted head extension. Doppler-based tissue velocity ultrasound imaging (TVI) was used to detect regional tissue deformation, providing indirect evidence of inter-muscular movement patterning. The deep muscles, multifidus and semispinalis, had different muscular movement patterning than the superficial muscles, especially the trapezius muscle. The semispinalis cervicis (SSCerv) was the first deformed upon exercise initiation, followed by multifidus and semispinalis capitis (SSCap). The semispinalis muscles, notably capitis, exhibited a high rate of deformation during the exercise. The trapezius muscle exhibited the least and lowest deformation rate. In conclusion, TVI provided detailed information on regional tissue activity and muscle movement patterning among the dorsal neck muscles. In future studies, data from patients with neck disorders will have to be matched to data from healthy volunteers in a variety of situations and activities.
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| 8. |
- Peolsson, Michael, et al.
(författare)
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A pilot study using Tissue Velocity Ultrasound Imaging (TVI) to assess muscle activity pattern in patients with chronic trapezius myalgia
- 2008
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Ingår i: BMC Musculoskeletal Disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Different research techniques indicate alterations in muscle tissue and in neuromuscular control of aching muscles in patients with chronic localized pain. Ultrasound can be used for analysis of muscle tissue dynamics in clinical practice. Aim: This study introduces a new muscle tissue sensitive ultrasound technique in order to provide a new methodology for providing a description of local muscle changes. This method is applied to investigate trapezius muscle tissue response especially with respect to specific regional deformation and deformation rates - during concentric shoulder elevation in patients with chronic trapezius myalgia and healthy controls before and after pain provocation. Methods: Patients with trapezius myalgia and healthy controls were analyzed using an ultrasound system equipped with tissue velocity imaging (TVI). The patients performed a standardized 3-cm concentric shoulder elevation before and after pain provocation/exercise at a standardized elevation tempo (30 bpm). A standardized region of interest (ROI), an ellipsis with a size that captures the upper and lower fascia of the trapezius muscle (4 cm width) at rest, was placed in the first frame of the loop registration of the elevation. The ROI was re-anchored frame by frame following the same anatomical landmark in the basal fascia during all frames of the concentric phase. In cardiac measurement, tissue velocities are measured in the axial projection towards and against the probe where red colour represents shortening and red lengthening. In the case of measuring the trapezius muscle, tissue deformation measurements are made orthogonally, thus, indirectly. Based on the assumption of muscle volume incompressibility, blue represents tissue contraction and red relaxation. Within the ROI, two variables were calculated as a function of time: deformation and deformation rate. Hereafter, max, mean, and quadratic mean values (RMS) of each variable were calculated and compared before and after pain provocation/exercise. Results: This new methodology seems valuable when looking at local muscle changes and studying the mechanism behind chronic muscle pain. The univariate analyses indicate that patients with chronic trapezius myalgia after pain provocation due to exercise at group level showed decreased strain and unchanged strain rate while healthy controls had unchanged strain and increased strain rate. However, the multivariate analysis indicates that most patients showed lower levels according to both strain and strain rate after exercise compared to most controls. Conclusion: Tissue velocity imaging can help describe musculoskeletal tissue activity and dynamics in patients with chronic pain conditions. An altered muscle tissue dynamic after pain provocation/exercise among the majority of trapezius myalgia patients compared with the healthy controls was found.
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| 9. |
- Peolsson, Michael, et al.
(författare)
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Tissue motion pattern of ventral neck muscles investigated by tissue velocity ultrasonography imaging
- 2010
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 109:5, s. 899-908
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Tidskriftsartikel (refereegranskat)abstract
- We designed this experimental study to investigate tissue motions and thus infer the recruitment pattern of the ventral neck muscles [sternocleidomastoid (SCM), longus capitis (Lca), and longus colli (Lco)] at the C4-C5 level in healthy volunteers during isometric manual resistance of the head in flexion in a seated position. This exercise is used in the physiotherapeutic treatment of neck pain and is assumed to activate the deep ventral muscles, but the assumption has not been clearly evaluated. Neck flexors of 16 healthy volunteers (mean age 24 years, SD 3.7) were measured using ultrasonography with strain and strain rate (SR) tissue velocity imaging (TVI) during isometric contraction of flexor muscles. TVI involves using Doppler imaging to study tissue dynamics. All three muscles showed a deformation compared to rest. Except for the initial contraction phase, Lco exhibited a lower strain than Lca and SCM but was the only muscle with a significant change in SR between the phases. When the beginning of the contraction phase was analysed, Lco was the first to be deformed among most volunteers, followed by Lca and then SCM. The exercise investigated seems to be useful as a "stabilizing" exercise for Lco. Our suggestion is that in further research, Lco and Lca should be investigated as separate muscles. TVI could be used to study tissue motions and thus serve as an indicator of muscle patterning between the neck flexors, with the possibility of separating Lco and Lca.
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| 10. |
- Quintana, Miguel, et al.
(författare)
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Assessment of atrial regional and global electromechanical function by tissue velocity echocardiography : a feasibility study on healthy individuals
- 2005
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 3:18 February 2005
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The appropriate evaluation of atrial electrical function is only possible by means of invasive electrophysiology techniques, which are expensive and therefore not suitable for widespread use. Mechanical atrial function is mainly determined from atrial volumes and volume-derived indices that are load-dependent, time-consuming and difficult to reproduce because they are observer-dependent. AIMS: To assess the feasibility of tissue velocity echocardiography (TVE) to evaluate atrial electromechanical function in young, healthy volunteers. SUBJECTS AND METHODS: We studied 37 healthy individuals: 28 men and nine women with a mean age of 29 years (range 20-47). Standard two-dimensional (2-D) and Doppler echocardiograms with superimposed TVE images were performed. Standard echocardiographic images were digitized during three consecutive cardiac cycles in cine-loop format for off-line analysis. Several indices of regional atrial electrical and mechanical function were derived from both 2-D and TVE modalities. RESULTS: Some TVE-derived variables indirectly reflected the atrial electrical activation that follows the known activation process as revealed by invasive electrophysiology. Regionally, the atrium shows an upward movement of its walls at the region near the atrio-ventricular ring with a reduction of this movement towards the upper levels of the atrial walls. The atrial mechanical function as assessed by several TVE-derived indices was quite similar in all left atrium (LA) walls. However, all such indices were higher in the right (RA) than the LA. There were no correlations between the 2-D- and TVE-derived variables expressing atrial mechanical function. Values of measurement error and repeatability were good for atrial mechanical function, but only acceptable for atrial electrical function. CONCLUSION: TVE may provide a simple, easy to obtain, reproducible, repeatable and potentially clinically useful tool for quantifying atrial electromechanical function.
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