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Objectives: Myocardial function can be evaluated using color-coded tissue velocity imaging (TVI) to analyze the longitudinal myocardial velocity profile, and by expressing the motion of the atrioventricular plane during a cardiac cycle as coordinated events in the cardiac state diagram (CSD). The objective of this study was to establish gestational age specific reference values for fetal TVI measurements and to introduce the CSD as a potential aid in fetal myocardial evaluation. Methods: TVI recordings from 125 healthy fetuses, at 18 to 42 weeks of gestation, were performed with the transducer perpendicular to the apex to provide a four-chamber view. The myocardial velocity data was extracted from the basal segment of septum as well as the left and right ventricular free wall for subsequent offline analysis. Results: During a cardiac cycle the longitudinal peak velocities of septum increased with gestational age, as did the peak velocities of the left and right ventricular free wall, except for the peak velocity of post ejection. The duration of rapid filling and atrial contraction increased during pregnancy while the duration of post ejection decreased. The duration of pre ejection and ventricular ejection did not change significantly with gestational age. Conclusion: Evaluating fetal systolic and diastolic performance using TVI together with CSD could contribute to increase the knowledge and understanding of fetal myocardial function and dysfunction. The pre and post ejection phases are the variables most likely to indicate fetuses with abnormal myocardial function., QC 20130912. Updated from submitted to published.

QC 20140320

QC 20140218

Objective: The introduction of color-coded tissue velocity imaging (TVI) in fetal medicine is quite recent, and as this method is presently evaluated and developed in regard to diagnostic precision it is of outmost importance to evaluate the reproducibility for adequate clinical use. In this study, reproducibility and intra- and inter-observer variability was assessed for offline analysis as well as echocardiography investigations. Also, we evaluated the importance of exact placement of the region of interest (ROI). Methods: TVI recordings from 21 fetuses, at a gestational age of 27 to 41 weeks, were acquired at 208-239 frames/s for subsequent offline analysis. All recordings were performed with the transducer positioned to provide an apical four-chamber view and the myocardial velocity data was obtained from basal inferoseptum. The data set was analyzed according to Bland-Altman and reproducibility was expressed as the standard error of a single determination, estimated from duplicate determinations in percentage of the total. Results: The variation of reproducibility for the echocardiography investigation ranged from 2.0% to 9.8%. The duration of left ventricular ejection, and the peak velocities of early diastolic filling and atrial contraction being the most robust events measured. The variation of inter-observer variability for the echocardiography investigation ranged from 1.5% to 8.4%, and the variation of intra- and inter-observer variability for the offline analysis ranged from 1.2% to 10.4%. Least robust were the events of shortest duration, including isovolumetric contraction and relaxation. Conclusion: We believe that TVI measurements of the fetal myocardium could be performed in the clinical routine with acceptable reproducibility., QC 20130419

Background: Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI). Methods: TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201-273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis. Results: Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E'/A' ratio also increased with gestational age, while a longitudinal shortening was demonstrated. Conclusions: Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal-and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate., QC 20120824

QC 20150429

QC 20120424

QC 20120703

Objectives The high velocity and short duration of myocardial motion requires a high sampling rate to obtain adequate temporal resolution; this issue becomes even more important when taking into consideration the high fetal heart rate. In this study we have established optimal sampling requirements for assessing the duration of various cardiac cycle events and myocardial velocities of the fetal heart using color-coded tissue velocity imaging (TVI). Methods Recordings from 30 fetuses were acquired at an initial frame rate of 180-273 frames/s. All TVI recordings were performed from an apical four-chamber view and stored as cineloops of five to 10 consecutive cardiac cycles for subsequent offline analysis using software enabling a reduction in frame rate. Different components of the myocardial velocity curve, obtained from the basal part of the ventricular septum, were measured at the initial frame rate and compared with their equivalents at gradually decreased frame rates. Results As acquisition frame rate was reduced, there was a marked increase in deviation from the initial values, resulting in an underestimation of all systolic and diastolic velocities. For the measured durations, there was a clear tendency to underestimate isovolumetric contraction and relaxation, and a clear tendency to overestimate ventricular ejection and diastolic E-wave and A-wave. An acceptable <= 5% deviation from the value obtained at the highest frame rate corresponded to measurements obtained at above 150-200 frames/s. Conclusions A high sampling rate of at least 200 frames/s is necessary for adequate reconstruction of TVI data for the fetal heart. Frame rates that are too low result in considerable loss of temporal and velocity information., QC 20111104

Physiology of Adventue Racing

Cardiovascular disease is the leading cause of death in patients with end stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of systolic and diastolic myocardial function using tissue velocity imaging (TVI). Grey-scale cine loops of the left common carotid artery, conventional echocardiography and TVI images of the left ventricle were acquired before and after HD in 45 patients (17 women, mean age 54) with ESRD. The WIWA indexes, W1 preload-adjusted W1, W2 and preload-adjusted W2, and the TVI variables, isovolumic contraction velocity (IVCV), isovolumic contraction time (IVCT), peak systolic velocity (PSV), displacement, isovolumic relaxation velocity (IVRV), isovolumic relaxation time (IVRT), peak early diastolic velocity (E’) and peak late diastolic velocity (A’), were compared before and after HD. The WIWA measurements showed significant increases in W1 (p < 0.05) and preload-adjusted W1 (p < 0.01) after HD. W2 was significantly decreased (p < 0.05) after HD, whereas the change in preload-adjusted W2 was not significant. Systolic velocities, IVCV (p < 0.001) and PSV (p < 0.01), were increased after HD, whereas the AV-plane displacement were decreased (p < 0.01). For the measured diastolic variables, E’ was significantly decreased (p < 0.01) and IVRT was significantly prolonged (p < 0.05), after HD. A few correlations were found between WIWA and TVI variables. The WIWA and TVI measurements indicate that a single session of HD improves systolic function. The load dependency of the diastolic variables seems to be more pronounced than for the systolic variables. Preload-adjusted wave intensity indexes may contribute in the assessment of true LV contractility and relaxation., Uppdaterad från Manuskript till Artikel (2011208) QC 20100705

QC 20110524

Ultrasound-based algorithms are commonly used to assess mechanical properties of arterial walls in studies of arterial stiffness and atherosclerosis. Speckle tracking based techniques used for estimation of myocardial strain can be applied on vessels to estimate strain of the arterial wall. Previous elastography studies in vessels have mainly focused on radial strain measurements, whereas the longitudinal strain has been more or less ignored. However, recently we showed the feasibility of speckle tracking to assess longitudinal strain of the carotid artery in-silico. The aim of this study was to test this methodology in-vivo. Ultrasound images were obtained in seven healthy subjects with no known cardiovascular disease (39 ± 14 years old) and in seven patients with coronary artery disease (CAD), (69 ± 4 years old). Speckle tracking was performed on the envelope detected data using our previous developed algorithm. Radial and longitudinal strains were estimated throughout two cardiac cycles in a region of interest (ROI) positioned in the posterior vessel wall. The mean peak systolic radial and longitudinal strain values from the two heart cycles were compared between the groups using a student's t-test. The mean peak radial strain was -39.1 ± 15.1% for the healthy group and -20.4 ± 7.5% for the diseased group (p = 0.01), whereas the mean peak longitudinal strain was 4.8 ± 1.1% and 3.2 ± 1.6% (p = 0.05) for the healthy and diseased group, respectively. Both peak radial and longitudinal strain values were thus significantly reduced in the CAD patient group. This study shows the feasibility to estimate radial and longitudinal strain in-vivo using speckle tracking and indicates that the method can detect differences between groups of healthy and diseased (CAD) subjects., QC 20111201

Purpose: The aim of this study was to investigate if extreme workload would induce signs of cardiac fatigue similar to that in skeletal muscle, e.g. decreased velocity of contraction. Methods: The subjects were 12 men and 3 women who participated in the Adventure Racing World Championship, a 5-7 days non-stop competition open for mixed gender teams of four. All subjects were healthy, well-trained ultra-endurance athletes with experince from several years of training and competition at international elite level. Measurements of the heart's contraction velocities were conducted using tissue Doppler imaging (VIVID7) in a resting situation at baseline, immediately after the race, and after 24 hours of recovery. Results: Characteristics for the subjects were at baseline (mean ± SD, for men and women): age 30±3 and 27±4; interventricular septal thickness 10.5±0.7 and 8.0±0.0 mm; left ventricular end-diastolic diameter 54.4±3.4 and 45.0±3.0 mm; posterior wall thickness 10.4±0.9 and 8.0±1.0 mm; early to late diastolic filling velocity (E/A) 2.3±0.6 and 2.2±0.2. Exercise duration was approx. 150 hours, and the calculated average work intensity was 40% of respective VO2peak, including time for rest, change of equipment, and food intake. Values of contraction velocities are presented in the table. Conclusions: All athletes had normally sized hearts. Based on contraction velocities we found no evidence of cardiac fatigue after ultra-endurance exercise. A difference compared to studies that found cardiac fatigue in other sports (e.g. marathon, triathlon) is that even though our population exercised for an extreme duration the average intensity was low. This might point towards that exercise intensity, not duration, is the primary source for cardiac fatigue., Physiology of Adventure Racing

QC 20190218

Cardiac biomarker release after endurance exercise has been described in young athletes. Although older athletes are increasingly active in such sports, they have not previously been studied. Therefore, the aim of this study was to assess the magnitude and reproducibility of biomarker release in athletes aged > or =55 years. Forty-three healthy athletes (mean age 61 +/- 3.6 years) were assessed before and immediately after a 30-km cross-country race and studied with echocardiography at rest. The median N-terminal pro-brain natriuretic peptide (NT-proBNP; normal <194 ng/L) level was 42 ng/L (interquartile range 30 to 95) at baseline and 191 ng/L (interquartile range 114 to 308) after the race. Troponin T (normal <0.03 microg/L) was elevated in 19 subjects (44%) after the race. Twenty-two subjects had also been studied 3 years before at the same race, using an identical test protocol. Between the 2 races, strong correlations were seen for individual runners' postrace biomarker levels (NT-proBNP: r = 0.82, log transformed data; troponin T: Spearman's rho = 0.84; p <0.001 for both). The coefficient of variation for NT-proBNP release was 8.1%. Levels of NT-proBNP after the race were correlated with levels at baseline (r = 0.93, p <0.001) and with left ventricular mass index (r = 0.32, p = 0.03). Moreover, participants with elevated postrace NT-proBNP were significantly older (62.0 vs 59.8 years, p = 0.04). In conclusion, long-distance runners aged > or =55 years released NT-proBNP and troponin T in a reproducible fashion. The magnitude of NT-proBNP release during the race was correlated strongly with NT-proBNP baseline levels and was associated with left ventricular mass and age. These findings may suggest a potential adverse effect of long-distance running on cardiac function in certain participants in this age group., QC 20122013

Background:This study explores the feasibility of non-invasive assessment of left ventricular volume and flow relationship throughout cardiac cycle employing echocardiographic methods. Methods:Nine healthy individuals and 3 patients with severe left-sided valvular abnormalities were subject to resting echocardiography with automated endocardial border detection allowing real-time estimation of left ventricular volume throughout the cardiac cycle. Global and regional (6 different left ventricular segments) estimates of flow-volume loops were subsequently constructed by plotting acquired instantaneous left ventricular 2-D area data (left ventricular volume) vs. their first derivatives (flow). Results:Flow-volume loop estimates were obtainable in 75% of all echocardiographic images and displayed in normal individuals some regional morphological variation with more pronounced isovolumic events in the paraseptal segments and significantly delayed maximal systolic flow paraapically. In patients with aortic stenosis, maximal systolic flow occurred at a lower estimated left ventricular systolic volume whereas in mitral stenosis, maximal diastolic flow was observed at a higher estimated left ventricular diastolic volume. Aortic regurgitation caused a complex alteration of the estimated flow-volume loop shape during diastole. Conclusion:Non-invasive assessment of left ventricular flow-volume relationship with echocardiography is technically feasible and reveals the existence of regional variation in flow-volume loop morphology. Valvular abnormalities cause a clear and specific alteration of the estimates of the normal systolic or diastolic flow-volume pattern, likely reflecting the underlying pathophysiology., QC 20100922

Colour-coded tissue velocity imaging (TVE) with Echocardiography is an established method for evaluation of the global cardiac function and of the regional myocardial movements. The TVE-technique allows measurements of velocity and deformation variables from any discrete point in the myocardial wall during the cardiac cycle with high temporal and longitudinal spatial resolution. Even the rapid kinetic events during the isovolumic phases can be analysed which has been reported to be involved in the process of pre and postsystolic ventricular reshaping. However, the optimal sampling requirements for a proper rendering of the tissue velocity variables and the effect of different temporal smoothing filters incorporated in the WE software have not yet been established. The aims for current thesis were to establish optimal values for temporal resolution and also to study the effect of temporal filtering algorithms on colour-coded tissue derived duration and velocity variables registered at the base of left ventricle in apical views. After ensuring adequate sampling rate and temporal filter width for the myocardial velocity profiles the isovolumic periods were analysed in fortynine healthy subjects to describe normal reference values in the base of four different cardiac walls. The influence of gender and age were also studied for isovolumic time, velocity variables as well their respectively amplitude motion. The reproducibility for the longitudinal and radial myocardial velocity and displacement variables was studied and varied between 5-12% (CV). The temporal resolution should at least 100 frames/s for a proper rendering of the myocardial velocity variables during the entire cardiac cycle. Increased temporal filter width affected the results by decreased myocardial velocities and the effect was most pronounced during the rapid isovolumic events. The longitudinal motions of left ventricular wall showed biphasic patterns during the isovolumic contraction and relaxation pe

AIMS: To evaluate the diagnostic capacity of quantitative analysis of segmental longitudinal myocardial displacement images (tissue tracking, TT) during dobutamine stress echocardiography for the detection of patients with coronary artery disease (CAD). METHODS AND RESULTS: TT-generated colour-coded maps of systolic segmental longitudinal displacement were obtained by post-processing of echocardiographic data from 105 patients with CAD and 90 low risk individuals selected from MYDISE database. Quantitative analysis of the distribution pattern of segmental displacement during dobutamine stress was most successful when a ratio of basal (high amplitude) to apical (low amplitude) colour-coded displacement bands (B/A ratio) was employed. Applied in four different left ventricular sectors, the B/A ratio provided a significant discrimination of patients with CAD (p<0.05 in the anterior and p<0.001 in the inferior wall) as assessed by receiver operating characteristic analysis. The procedure was most sensitive when applied in inferior wall for the detection of left circumflex coronary artery disease, the B/A ratio of 0.8 giving the best combination of sensitivity (77+/-8%) and specificity (77+/-5%) values. CONCLUSION: Quantification of dobutamine stress echocardiography using TT is an efficient diagnostic approach and a valuable additional modality in functional cardiac imaging for the initial identification of patients suspected for CAD., QC 20120221

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., QC 20120221