Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function.

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.

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study.

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.

Effects of hemodialysis on the cardiovascular system: quantitative analysis using wave intensity wall analysis and tissue velocity imaging.

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). Gray-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 years) with ESRD. The WIWA indexes, W(1) and preload-adjusted W(1), W(2) and preload-adjusted W(2), 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 W(1) (P < 0.05) and preload-adjusted W(1) (P < 0.01) after HD. W(2) was significantly decreased (P < 0.05) after HD, whereas the change in preload-adjusted W(2) was not significant. Systolic velocities, IVCV (P < 0.001) and PSV (P < 0.01), were increased after HD, whereas the AV-plane displacement was 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.

Enhanced systolic myocardial function in elite endurance athletes during combined arm-and-leg exercise.

The aim here was to employ color tissue velocity imaging (TVI), to test the hypothesis that highly trained endurance athletes exhibit enhanced systolic function of the left ventricular (LV) myocardium both at rest and during combined arm-and-leg exercise in comparison with untrained subjects. For each of the ten elite male (EG) and ten matched control participants (CG), LV dimensions and systolic function were assessed at rest using echocardiography. Subsequently, these subjects exercised continuously on a combined arm-and-leg cycle ergometer for 3 min each at 50, 60, 70, 80, 90 and 100% of VO(2max). Oxygen uptake, heart rate, systolic blood pressure (SBP) and peak contraction systolic velocities of the LV myocardium (PSV) were recorded in the end of each level. At rest, the trained and untrained groups differed with respect to LV dimensions, but not systolic function. At 60-100% VO(2max), the EG group demonstrated both higher PSV and SBP. The observation that the EG athletes had higher PSV than CG during exercise at 60-100% VO(2max), but not at rest or at 50% of VO(2max), suggested an enhanced systolic capacity. This improvement is likely to be due to an enhanced inotropic contractility, which only becomes apparent during exercise.

Ultrasonographic strain imaging is superior to conventional non-invasive measures of vascular stiffness in the detection of age-dependent differences in the mechanical properties of the common carotid artery.

AIMS: Elastic properties of large arteries have been shown to deteriorate with age and in the presence of atherosclerotic vascular disease. In this study, the performance of ultrasonographic strain measurements was compared with conventional measures of vascular stiffness in the detection of age-dependent differences in the elastic properties of the common carotid artery (CCA). METHODS AND RESULTS: In 10 younger (25-28 years, four women) and 10 older (50-59 years, four women) healthy individuals, global and regional circumferential, and radial strain variables were measured in the short-axis view of the right CCA using ultrasonographic two-dimensional (2D) strain imaging with recently introduced speckle tracking technique. Conventional elasticity variables, elastic modulus (E(p)), and beta stiffness index, were calculated using M-mode sonography and non-invasive blood pressure measurements. Global and regional circumferential systolic strain and strain rate values were significantly higher (P < 0.01 for regional late systolic strain rate, P < 0.001 otherwise) in the younger individuals, whereas the values of conventional stiffness variables in the same group were lower (P < 0.05). Among all strain and conventional stiffness variables, principal component analysis and its regression extension identified only circumferential systolic strain variables as contributing significantly to the observed discrimination between the younger and older age groups. CONCLUSION: Ultrasonographic 2D-strain imaging is a sensitive method for the assessment of elastic properties in the CCA, being in this respect superior to the conventional measures of vascular stiffness. The method has potential to become a valuable non-invasive tool in the detection of early atherosclerotic vascular changes.

Wave intensity wall analysis: a novel noninvasive method to measure wave intensity.

Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.

Magnitude, reproducibility, and association with baseline cardiac function of cardiac biomarker release in long-distance runners aged > or =55 years.

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.

A single session of haemodialysis improves left ventricular synchronicity in patients with end-stage renal disease: a pilot tissue synchronization imaging study.

BACKGROUND: Mechanical left ventricular (LV) dyssynchrony impairs cardiac function in patients with heart failure and LV hypertrophy (LVH) and may be a factor contributing to the high incidence of cardiac deaths in patients with end-stage renal disease (ESRD). Objectives. To evaluate the possible presence of LV dyssynchrony in ESRD patients, and acute effect of haemodialysis (HD) on LV synchronicity using a tailored echocardiographic modality, tissue synchronization imaging (TSI). METHODS: In 13 clinically stable ESRD patients (7 men; 65 +/- 10 years) with LVH, echocardiography data were acquired before and after a single HD session for subsequent off-line TSI analysis enabling the retrieval of regional intraventricular systolic delay data. Six basal and six midventricular LV segments were evaluated. Dyssynchrony was defined as a regional difference in time to peak systolic velocity >105 ms. RESULTS: Before HD, all patients had at least one dyssynchronous LV segment. The percentage of delayed segments correlated positively to LV end-diastolic diameter (r = 0.68, P < 0.05). HD induced a substantial decrease in the percentage of delayed segments from 36 +/- 25% to 19 +/- 14% (P < 0.01), reduced average maximal mechanical systolic LV delay from 300 +/- 89 to 225 +/- 116 ms (P < 0.05) and completely normalized LV synchronicity in three patients (23%). CONCLUSIONS: LV dyssynchrony appears to be present frequently in ESRD patients with LVH. The severity of LV dyssynchrony correlates with LV end-diastolic diameter and decreases after a single session of HD suggesting a mechanistic relevance of volume overload and possibly other toxins accumulating in HD patients.

Acute effects of low and high intravenous doses of furosemide on myocardial function in anuric haemodialysis patients: a tissue Doppler study.

BACKGROUND: In patients with pulmonary oedema and preserved renal function, furosemide has not only a renal, but also a vascular effect, causing a rapid fall in left ventricular filling pressure accompanied by an increase in venous compliance. Previous studies have shown conflicting findings regarding the vascular effects of furosemide in patients with end-stage renal disease (ESRD). The objective of our study was to investigate whether furosemide induces changes in central cardiac haemodynamics in anuric ESRD patients, using conventional echocardiography and colour tissue Doppler velocity imaging (TVI), a new quantitative and sensitive method. METHODS: Repeated low doses (40 mg followed by an additional dose of 40 mg after 30 min) of i.v. furosemide were administered to 12 (61.6 +/- 16 years, 7 men) and a high dose (250 mg) of i.v. furosemide to 6 (64.1 +/- 3.6 years, 5 men) clinically stable anuric haemodialysis (HD) patients. Conventional two-dimensional echocardiography and colour TVI images were recorded immediately before (0 min) the furosemide infusion in both groups, and in the group receiving the repeated low-dose infusion (at 0 and 30 min), 10, 20, 30, 40, 50 and 70 min after the administration of the first infusion. In the group receiving the single high dose of furosemide the ultrasound investigation was repeated 10, 20, 30 and 40 min after the infusion. The myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVC), peak systole (PS), early (E') and late (A') myocardial diastolic filling velocities were measured in the left ventricle (LV) at six sites (infero-septal, antero-lateral, inferior, anterior, infero-lateral and antero-septal walls) at the basal region. IVC time (IVCT), IV relaxation time (IVRT), PS time (PSt), RR interval, mitral annulus motion (MAM), strain rate (SR), left ventricular filling pressure (E/E') and cardiac output were also measured. The average of the different walls was used to evaluate global function. Right ventricle (RV) dynamics was evaluated from measurements of IVC velocity (IVCv), peak systolic velocity (PSv), E' and A' from the RV free wall. RESULTS: No significant changes in cardiac output, IVCv, PSv, SR, MAM, E', A', E'/A', IVRT and LV filling pressure were observed, indicating that neither 40 mg (plus additional 40 mg after 30 min) nor 250 mg of furosemide had any measurable effects on LV filling pressure and LV and RV systolic and diastolic function. CONCLUSIONS: In anuric HD patients, low and high doses of furosemide had no significant effects on central cardiac haemodynamics. Therefore, the use of furosemide infusion in anuric ESRD patients with acute pulmonary oedema is not supported by the results of this study.

Disturbed glucose metabolism is associated with left ventricular dysfunction using tissue Doppler imaging in patients with myocardial infarction.

AIMS: To investigate the association between glucose abnormalities and left ventricular (LV) function assessed by tissue Doppler imaging (TDI) in patients with previous history of myocardial infarction and without known diabetes mellitus. PATIENTS AND METHODS: In a cross-sectional study, 123 patients, aged 31-80 years, with a history of previous myocardial infarction and without known diabetes mellitus were examined with TDI echocardiography. A standard oral glucose test (OGTT) with 75 g of glucose was performed. RESULTS: Two-hour plasma glucose were significantly and negatively associated with TDI parameters such as LV ejection time; early diastolic filling velocity (E'-v); ratio of the early to late diastolic filling velocity (E'/A') and positively associated with regional myocardial performance index (MPI) (P<0.05). Left ventricular ejection time and MPI were significantly higher; E'/A' and E'-v were significantly lower in patients with disturbed glucose metabolism compared with patients with normal glucose tolerance (P<0.01). These differences remain significant also when the patients with DM were excluded. CONCLUSIONS: The present study demonstrates that disturbed glucose metabolism is associated with more pronounced LV dysfunction using TDI in patients with myocardial infarction. These abnormalities in LV function were more common not only in subjects with diabetes, but also in patients with prediabetic condition, impaired glucose intolerance.

Feasibility of creating estimates of left ventricular flow-volume dynamics using echocardiography.

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.

Assessment of atrial regional and global electromechanical function by tissue velocity echocardiography: a feasibility study on healthy individuals.

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.

Analysis of the effect of temporal filtering in myocardial tissue velocity imaging.

Signal filtering to reduce random noise may compromise the reliability of tissue velocity measurements. This study evaluates the influence of temporal filters on time and velocity variables derived from myocardial tissue velocity images acquired in 15 healthy individuals at a high frame rate (142-184 Hz). Different time and velocity variables from the basal septum were analyzed offline before and after temporal filtering from 20 to 60 milliseconds in 10-millisecond steps using software enabling retrieval of myocardial Doppler velocity and 2-dimensional information from different cardiac locations during the same cardiac cycle. Filtering affected the results by increasing variability of time and by underestimation of velocity variables, the rapid isovolumic events being particularly filter sensitive. In addition, at a certain range of sampling rate, ambiguity of filtering effect was observed. This ought to be considered if an optimal, high-fidelity tissue Doppler velocity signal is to be obtained.

Distribution of left ventricular longitudinal peak systolic strain and impact of low frame rate.

The myocardium has complex 3-D motion that is frequently described using ultrasound (US) Doppler techniques that are limited to recording velocities in one dimension only. Studies using 3-D tagged magnetic resonance show that the myocardium has strain components with varying angles throughout the myocardium. Despite this, there seems to be a belief that the left ventricular longitudinal strain distribution should be homogeneous. When measuring myocardial strain, there are several parameters for the clinician to decide on, one of them being recording frame rate. The current study aims to further investigate the alleged homogeneity of the longitudinal myocardial strain distribution and to discover the impact that the frame rate has on these measurements. Myocardial strain was measured in 43 healthy individuals at different frame rates. Analysis of variance results clearly demonstrate that the strain is not uniformly distributed over the wall; there seems to be an increasing strain from apex toward the base. However, subjects exist with different distributions; thus, it is not possible to conclude that certain strain patterns are normal. Reduced frame rate had a highly significant impact on the measured strain results and it is seen that, at low frame rates, the strain values were reduced.

Myocardial velocities measured during adenosine, dobutamine and supine bicycle exercise: a tissue Doppler study in healthy volunteers.

BACKGROUND: Dobutamine stress echocardiography (DSE) quantified by tissue Doppler (TVI) have improved the diagnostic capacity of the procedure. Quantification of other stress modalities, e.g. adenosine stress echo (ASE) and exercise stress echocardiography (ESE) are necessary for assessing any pathophysiological differences in different forms of stress. METHODS: Ten healthy individuals underwent ASE, DSE, and ESE during a span of 2-5 days. Left ventricular (LV) apical images at rest and peak stress (max) were postprocessed using TVI on a GE System FiVe equipment. ECG-derived QRS duration (QRSD, ms), heart rate (HR, bpm), TVI-estimated basal systolic velocities (S2V, cm s(-1)), ejection time (S2T, ms) and strain (S, %) were computed off-line and compared. Longitudinal displacement imaging, tissue tracking, was also made. RESULTS: Data for ASE, DSE and ESE during peak stress were (HR: 84 +/- 12***, 142 +/- 19, 137 +/- 27; P<0.001) (QRSD: 92 +/- 18**, 74 +/- 13, 79 +/- 9; P<0.05), (S2T: 307 +/- 34***, 175 +/- 53, 192 +/- 25; P<0.001) and (S%: 26.0 +/- 3.0, 21.2 +/- 7.3, 22.1 +/- 5.1; P = n.s.) respectively. Velocity response, registered in the LV septum at max, was lowest during ASE (7.4 +/- 1.4) highest during DSE (13.0 +/- 2.7; P<0.001 versus ASE) and somewhat intermediate during ESE (11.3 +/- 3.5; P<0.001 versus ASE). In contrast, strain and displacement did not differ. CONCLUSION: ASE evokes significantly less LV systolic response compared with both DSE and ESE. Increased velocity (P<0.05 versus rest) and strain (P>0.05) response at a much lower HR indicates that adenosine has minor effects on contraction presumably secondary to vasodilatation. Powerful chronotropic response to DSE and ESE is probably prerequisite for strong velocity response at the expense of strain and displacement. TVI-assisted stress echocardiography thereby shows different LV systolic response in healthy individuals, depending on stress modality.

The cardiac state diagram as a novel approach for the evaluation of pre- and post-ejection phases of the cardiac cycle in asphyxiated fetal lambs.

The aim of this study was to investigate myocardial wall motion using echocardiography and color-coded tissue velocity imaging and to generate a cardiac state diagram for evaluation of the duration of the pre- and post-ejection phases in asphyxiated fetal lambs. Six near-term lambs were partly exteriorized and brought to cardiac arrest through asphyxia. Echocardiography measurements were recorded simultaneously with arterial blood sampling for lactate and blood gases. All fetal lambs exhibited prolongation of the pre- and post-ejection phases at the time when the most pronounced changes in lactate concentration and pH occurred. The mean change in duration of the pre- and post-ejection phases for all fetal lambs was 36 ± 7 ms (p < 0.002) and 77 ± 17 ms (p < 0.019), respectively, and the percentage change was 50% (p < 0.001) and 38% (p < 0.049), respectively. As asphyxia progressed in fetal lambs, the duration of the pre- and post-ejection phases increased. The cardiac state diagram has the potential to be a comprehensible tool for detecting fetal asphyxia.

Changes in circulating biomarkers during a single hemodialysis session.

The hemodialysis (HD) procedure induces an inflammatory response potentially contributing to cardiovascular disease. Here we investigated the acute impact of HD on circulating biomarkers. Circulating biomarkers (small solutes, middle molecular-sized peptides, and proteins) related to inflammation, oxidative stress, and vascular calcification (VC) were measured before and after a single session of HD in 45 clinically stable patients. Concentrations were corrected for ultrafiltration-induced hemoconcentration. Among vascular calcification-related biomarkers, osteoprotegerin and fetuin-A remained unchanged while fibroblast growth factor-23 (FGF23) decreased by -19%. Changes of FGF23 and changes of phosphate correlated (ρ = 0.61, P < 0.001). While C-reactive protein did not change, interleukin-6 (IL-6) increased by 14% and pentraxin 3 (PTX3) increased by 45%. IL-6 and PTX3 appear to be valid biomarkers of the intradialytic inflammatory response. VC-related markers were in general not affected by the single HD session; however, the observed correlation between acute changes of FGF-23 and phosphate during HD warrants further studies.

Left ventricular mechanical dyssynchrony in patients with different stages of chronic kidney disease and the effects of hemodialysis.

Left ventricular (LV) dyssynchrony is a known cause of mortality in patients with heart failure and may possibly play a similar role in patients with chronic kidney disease (CKD) in whom sudden death is one of the most common and as yet not fully explained cause of death. LV synchronicity and its relationship with increased volume load and various biomarkers was analyzed in 145 patients including 53 patients with CKD stages 3 and 4 and in 92 CKD stage 5 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) using color tissue Doppler imaging and tissue synchronization imaging. The HD patients were evaluated both before and after a single HD session. LV dyssynchrony was defined as a regional difference in time to peak systolic myocardial velocity, between 12 LV segments > 105 milliseconds. LV dyssynchrony was present in 54% of the patients with no difference between CKD 3 and 4 (58%), HD (48%), and PD (51%). LV dyssynchrony was independently associated with LV mass index and increased estimation of LV end-diastolic pressure. A single HD session resulted in significant changes in LV synchronicity variables-with improvement in 50% of the patients-especially in patients with higher myocardial systolic velocities and lower LV mass index. Abnormalities in LV synchronicity are highly prevalent in CKD patients already prior to dialysis treatment and are associated with LV hypertrophy, LV dysfunction and load conditions, underlining the importance of volume status for LV synchronicity in CKD patients.

Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults.

BACKGROUND: 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. METHOD: 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. RESULT: 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. CONCLUSION: Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.

Velocity tracking--a novel method for quantitative analysis of longitudinal myocardial function.

Doppler tissue imaging is a method for quantitative analysis of longitudinal myocardial velocity. Commercially available ultrasound systems can only present velocity information using a color Doppler-based overlapping continuous color scale. The analysis is time-consuming and does not allow for simultaneous analysis in different projections. We have developed a new method, velocity tracking, using a stepwise color coding of the regional longitudinal myocardial velocity. The velocity data from 3 apical projections are presented as static and dynamic bull's-eye plots to give a 3-dimensional understanding of the function of the left ventricle. The static bull's-eye plot can display peak systolic velocity, late diastolic tissue velocity, or the sum of peak systolic velocity and early diastolic tissue velocity. Conversely, the dynamic bull's-eye plot displays how the myocardial velocities change over one heart cycle. Velocity tracking allows for a fast, simple, and intuitive visual analysis of the regional longitudinal contraction pattern of the left ventricle with a great potential to identify characteristic pathologic patterns.