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Biomedical subjects

Lars-Ake Brodin

Publications and source records attributed to Lars-Ake Brodin.

At least 19 recordsLinked to original sources
PubMed2007

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.

Adult↗
PubMed2006

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.

Blood Flow Velocity↗
PubMed2006

The assessment of acute load and contractility changes by left ventricular pressure measurements.

The aim of this study was to establish whether analysis of the left ventricular pressure waveform provides indicative information about cardiac load and contractility and to develop an algorithm for computer-based assessment of changes in these variables. In eight healthy standard breed anaesthetized open-chest pigs, a high frequency response guide-wire mounted pressure sensor was introduced into the left ventricle. Preload reduction was induced by vena cava occlusion, afterload increase by an i.v. injection of phenylephrine and increased contractility by an i.v. injection of adrenalin. Left ventricular pressure waveform analysis was performed by plotting the slope of the pressure curve during the systolic ejection period versus maximal systolic pressure. The analysis revealed characteristic changes in left ventricular pressure and pressure waveform and identified easily discernible reaction patterns in the slope versus maximal pressure plot, specific for each provocation. Analysis of the left ventricular waveform provides indicative information about loading conditions and contractility. The proposed algorithm can easily be implemented in pressure monitoring systems allowing real-time assessment and discrimination of acute changes in preload, afterload and myocardial performance.

Algorithms↗
PubMed2006

Differing myocardial response to a single session of hemodialysis in end-stage renal disease with and without type 2 diabetes mellitus and coronary artery disease.

BACKGROUND: Though hemodialysis (HD) acutely improves cardiac function, the impact of background diseases like coronary artery disease (CAD) and Type 2 diabetes (DM) in the setting of end-stage renal disease (ESRD) is not known. Tissue velocity echocardiography (TVE) offers a fast choice to follow changes in myocardial function after HD in ESRD with concomitant DM and /or CAD. METHODS: 46 subjects (17 with ESRD, Group 1; 15 with DM, Group 2; 14 with DM+CAD, Group 3) underwent standard and TVE prior to and shortly after HD. Besides standard Doppler variables, regional myocardial systolic and diastolic velocities, as well as systolic strain rate were post processed. RESULTS: Compared with pre-HD, post-HD body weight (kg) significantly decreased in all the three groups (51 +/- 9 vs. 48 +/- 8, 62 +/- 10 vs.59 +/- 10, and 61 +/- 9 vs. 58 +/- 9 respectively; all p < 0.01). Left ventricular end diastolic dimensions (mm) also decreased post- HD (46 +/- 5 vs. 42 +/- 7, 53 +/- 7 vs. 50 +/- 7, 51 +/- 7 vs. 47 +/- 8 respectively; all p < 0.01). Regional longitudinal peak systolic velocity in septum (cm/s) significantly increased post-HD in Group 1(5.7 +/- 1.6 vs. 7.2 +/- 2.3; p < 0.001) while remained unchanged in the other two groups. Similar trends were noted in other left ventricular walls. When the myocardial velocities (cm/s) were computed globally, the improvement was seen only in Group 1 (6.3 +/- 1.5 vs. 7.9 +/- 2.0; p < 0.001). Global early regional diastolic velocity (cm/s) improved in Group 1, remained unchanged in Group 2, while significantly decreased in Group 3(-5.9 +/- 1.3 vs. -4.1 +/- 1.8; p < 0.01). Global systolic strain rate (1/sec) increased in the first 2 Groups but remained unchanged (-0.87 +/- 0.4 vs. -0.94 +/- 0.3; p = ns) in Group 3. CONCLUSION: A single HD session improves LV function only in ESRD without coexistent DM and/or CAD. The present data suggest that not only dialysis-dependent changes in loading conditions but also co-existent background diseases determine the myocardial response to HD.

Adult↗
PubMed2006

Impaired myocardial functional reserve in hypertension and diabetes mellitus without coronary artery disease: Searching for the possible link with congestive heart failure in the myocardial Doppler in diabetes (MYDID) study II.

BACKGROUND: Although the impact of type 2 diabetes mellitus (DM) and hypertension (HTN) on myocardial function has recently been studied using tissue Doppler echocardiography (TDE), the independent role of both conditions, and the influence of other risk factors on myocardial function has not been completely defined, particularly in absence of coronary artery disease (CAD). The aim of this study was to assess the myocardial functional reserve in patients with DM or HTN with apparently normal left ventricular (LV) systolic function. METHODS: Standard and dobutamine stress echocardiography using TDE was performed in 128 subjects: 59 had DM, 20 had HTN, 27 had both DM and HTN (HTN + DM), and 22 subjects were controls (C). Subjects with known CAD and depressed LV function were excluded. In addition, standard two-dimensional and Doppler measurements, LV regional peak systolic (PSV), early (E') and late (A') diastolic velocities, strain (S%) and strain rate (SR), were assessed at rest and peak stress. RESULTS: The LV mass did not differ, although relative wall thickness was significantly higher in subjects with HTN + DM and HTN. The PSV did not differ at rest but was lowest in subjects with HTN + DM at peak stress. The E' wave velocity was significantly lower in subjects with HTN + DM both at rest and during peak stress, as were S% and SR. CONCLUSIONS: The addition of DM to HTN has a negative effect on LV systolic and diastolic functions. A depressed myocardial functional reserve might be postulated as one of the pathophysiologic mechanisms for the excessive occurrence of congestive heart failure in patients with DM or HTN.

Coronary Artery Disease↗
PubMed2006

Effects of ultrasound contrast agents on Doppler tissue velocity estimation.

The combination of Doppler tissue imaging and myocardial contrast echocardiography has the potential to provide information about motion and perfusion of the myocardium in a single examination. The purpose of this study was to establish how the presence of ultrasound contrast agent (UCA) affects measurements of Doppler tissue velocities in vivo and in vitro. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of the UCA Optison, using color Doppler tissue imaging to examine the effect of contrast agents in vivo. The myocardial peak systolic velocities and their integrals were analyzed in digitally stored cineloops before and after contrast administration. To distinguish between methodologic and physiologic factors affecting the measurement of tissue velocity in vitro, experiments with a rotating disk and a flow cone phantom were also carried out for the 3 contrast agents: Optison, Sonovue, and Sonazoid. In vivo results show that the values for peak systolic velocity increased by about 10% during contrast infusion, from mean 5.2 +/- 1.8 to 5.7 +/- 2.3 cm/s (P = .02, 95% confidence interval 2%-16%). The increase in myocardial peak systolic velocities was verified in experimental models in which the UCA increased the estimated mean velocity in the order of 5% to 20% for the motion interval of 5 to 7 cm/s, corresponding to the myocardial velocities studied in vivo. The response was similar for all 3 contrast agents and was not affected by moderate variations in concentration of the agent. We have shown that the presence UCA will affect Doppler tissue measurements in vivo and in vitro. The observed bias is presumed to be an effect of harmonic signal contribution from rupturing contrast agent microbubbles and does not indicate biologic or physiologic effects.

Aged↗
PubMed2006

Longitudinal isovolumic displacement of the left ventricular myocardium assessed by tissue velocity echocardiography in healthy individuals.

Rapid myocardial isovolumic motions are reportedly involved in the left ventricular reshaping process and may contribute to total systolic myocardial shortening. In this study, the qualitative and quantitative analysis of longitudinal myocardial isovolumic displacement was performed in 49 healthy individuals (23 men and 26 women) in age groups 21 to 49 and 50 to 76 years using tissue velocity echocardiography. The obtained isovolumic contraction and relaxation displacement curves were biphasic and displayed a significant regional heterogeneity most probably reflecting active presystolic and postsystolic reshaping of left ventricular cavity. Besides some sex difference in younger individuals, there was an age-dependent lengthening of the isovolumic relaxation time and their motion components. Even if being of short duration, the longitudinal myocardial isovolumic displacement may accounted for as much as 14% of the total longitudinal myocardial shortening, a fact which should be taken into consideration when assessing left ventricular systolic function.

Adult↗
PubMed2006

Transesophageal echocardiographic acquisition of mitral annulus motion during monitoring of left ventricular function in anesthetized patients.

OBJECTIVE: We investigated the feasibility and reproducibility of transesophageal (TE) recordings of displacements and velocities of 4 sites of the mitral annulus in anesthetized patients. Correlations to transthoracic measures and influence of the respiratory cycle were also investigated. METHODS: A total of 24 patients without heart disease were included. Another 10 patients were enrolled for the reproducibility study. Systolic and diastolic velocities and amplitude of motion were extracted from color-coded Doppler tissue recordings. RESULTS: The reproducibility was not acceptable for the anterior site or for late diastolic velocities. Transthoracic values were higher than TE values. A somewhat higher displacement during inspiration in spontaneous respiration and during expiration in positive pressure ventilation was seen. CONCLUSIONS: The anterior site should be omitted when TE recordings of the mitral annulus are used. TE values are about 15% lower than transthoracic values. There is no need to take the respiratory cycle into account.

Anesthesia↗
PubMed2006

Analysis of mitral annulus motion measurements derived from M-mode, anatomic M-mode, tissue Doppler displacement, and 2-dimensional strain imaging.

BACKGROUND: Left ventricular longitudinal shortening plays an important role in cardiac contraction and can be measured by the mitral annulus motion (MAM) toward the cardiac apex. MAM can be evaluated by conventional M-mode, anatomic M-mode (AM-mode), tissue Doppler displacement (TDD), and 2-dimensional strain imaging (2DSI). OBJECTIVE: The aim of the study was to compare these 4 different methods for measuring MAM. METHODS: MAM was evaluated in 25 patients by M-mode, AM-mode, TDD, and 2DSI. Two walls (septal and lateral) in apical 4-chamber view were analyzed. RESULTS: The angle correction between M-mode and AM-mode was significantly higher in the lateral wall (septum 2.2 +/- 1.6 vs lateral 4.1 +/- 1.6 degrees, P < 0.01). However, with angle correction up to 8 degrees, the measurements obtained were not significantly different from those obtained by M-mode. No significant differences were found among 2DSI, M-mode, and AM-mode either, although all of them were significantly higher in comparison with TDD measurements in both septal (M-mode [11.0 +/- 2.4 mm], AM-mode [11.8 +/- 2.4 mm], 2DSI [11.0 +/- 3.4 mm] vs TDD [9.2 +/- 3.3 mm], P < .01) and lateral (M-mode [11.9 +/- 2.3 mm], AM-mode [12.4 +/- 2.8 mm], 2DSI [10.4 +/- 3.9 mm] vs TDD [8.9 +/- 3.0 mm], P < .05) walls. The +/- 2SD variation from the mean difference in septal and lateral walls were, respectively, between: M-mode and TDD, -2.4 to 5.9 and -2.2 to 8.2 mm; M-mode and 2DSI, -5.7 to 5.7 and -5.8 to 8.7; AM-mode and TDD, -2.5 to 5.6 and -2.7 to 9.6; AM-mode and 2DSI, -5.7 to 5.87 and -5.9 to 9.8 and TDD and 2DSI, -3.2 to 6.6 and -5.3 to 8.4. CONCLUSIONS: AM-mode and M-mode measurements did not differ significantly. Despite the good correlation among all methods they were not interchangeable. TDD measurements were significantly lower than M-mode, AM-mode, and 2DSI measurements. M-mode and AM-mode are angle dependent and can, therefore, underestimate or overestimate MAM. The new method of 2DSI is promising because it tracks natural acoustic markers and is not angle dependent and, therefore, measures the true local tissue motion.

Adult↗
PubMed2006

Acute administration of a single dose of valsartan improves left ventricular functions: a pilot study to assess the role of tissue velocity echocardiography in patients with systemic arterial hypertension in the TVE-valsartan study I.

BACKGROUND: The advent of colour-coded tissue velocity echocardiography (TVE) has now made it possible to quantify left ventricular (LV) functions in patients with systemic arterial hypertension (HTN). Hypothesis In this project, we have studied the cardiac effects of a single dose of orally administered valsartan in patients with known HTN. METHODS: Fifty-five patients with HTN with a mean age of 56 +/- 10 years were given an early morning dose of 80 mg valsartan withholding regular antihypertensive medications on the day of investigation. TVE images, acquired on VIVID systems were digitized for postprocessing of longitudinal and radial peak systolic velocities, strain rate, and systolic and diastolic time intervals before (pre) and 5 h after (post) administration of the drug. RESULTS: Blood pressure (mmHg) pre and post, respectively, were 147 +/- 15 versus 137 +/- 14 systolic and 90 +/- 7 versus 86 +/- 7 diastolic (all P<0.01). LV longitudinal systolic velocities (cm s(-1)) were significantly higher post in LV septum (5.7 +/- 1.1 versus 6.4 +/- 1.6; P<0.001) with similar results obtained in other LV walls. Radial strain rate (1 s(-1)) was significantly higher post compared with pre valsartan (2.1 +/- 0.6 versus 2.3 +/- 0.9; P<0.01). Regional diastolic filling and ejection times (ms) were significantly shorter post (390 +/- 122 versus 370 +/- 120 and 275 +/- 32 versus 163 +/- 36 respectively; all P<0.05). CONCLUSIONS: Within 5 h after oral administration of valsartan, improvement in regional myocardial systolic functions could be registered. Although the changes could well be secondary to afterload reduction, additional effects of the drug, evidenced by improved strain rate that is relatively load-independent, may have contributed in this improvement.

Adult↗
PubMed2005

Left ventricular function in patients with chronic kidney disease evaluated by colour tissue Doppler velocity imaging.

BACKGROUND: Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD) patients. Tissue Doppler velocity imaging (TVI) is a new objective method that accurately quantifies myocardial tissue velocities, deformation, time intervals and left ventricular (LV) filling pressure. In this study, TVI was compared with conventional echocardiography for the assessment of left ventricular (LV) function in pre-dialysis patients with different stages of CKD. The results obtained by TVI were used to analyse possible relationships between LV function and clinical factors such as hyperparathyroidism and hypertension that could influence LV function. METHODS: Conventional echocardiography and TVI images were recorded in 40 patients (36 men and 4 women, mean age 60+/-14 years, range 28-80 years) and in 27 healthy controls (21 men and 6 women, mean age 58+/-17 years, range 28-82 years). Twenty-two patients had mild/moderate CKD (CCr>29 ml/min; Group 1) and 18 patients had severe CKD (CCr<or=29 ml/min; Group 2). Using TVI, the myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVCv), peak systole (PSv), early (E') and late (A') diastolic filling velocities as well as strain rate (SR), mitral annulus displacement, isovolumetric relaxation time (IVRT) and LV filling pressure were estimated using TVI. The average of six LV wall measurements was used to evaluate LV global function. RESULTS: Using TVI, we were able to identify significantly more patients with diastolic dysfunction than using conventional echocardiography (33 vs 26, P<0.05). There was no difference in the prevalence of diastolic dysfunction between Group 1 and 2. However, using TVI, Group 2 CKD patients had lower E' velocities (6.2+/-1.9 vs 8.0+/-2.9 cm/s, P<0.05) and higher IVRT (137.4+/-13 vs 88.2+/-26 ms, P<0.001) in comparison with controls, indicating more accentuated diastolic dysfunction. Systolic blood pressure (SBP) was associated with E' velocities (rho=-0.68, P<0.005) and E'/A' was strongly associated with SBP (rho=-0.60; P<0.01) and PTH (rho=-0.64, P<0.005) in Group 2. Using conventional echocardiography, there was no difference in the prevalence of systolic and diastolic dysfunction between patients with and without LVH. However, using TVI, patients with LVH had significantly lower IVCv (2.8+/-1.3 vs 3.8+/-1.5 and 3.8+/-1.5 cm/s, P<0.05) and PSv (5.5+/-1.0 vs 6.3+/-1.2 and 6.4+/-1.3 cm/s, P<0.05) compared with patients without LVH and controls, and they also had lower E' velocities (7.1+/-2.7 vs 8.0+/-2.9 cm/s, P<0.05) compared with controls, indicating disturbances in systolic and diastolic left ventricular function. CONCLUSIONS: TVI provided additional information on left ventricular function in CKD patients. In patients with advanced renal failure, TVI revealed more accentuated diastolic dysfunction associated with increased systolic blood pressure (SBP) and increased levels of PTH. TVI also demonstrated disturbances in contractility and contraction in patients with LVH, which could not be detected by conventional echocardiography.

Adult↗
PubMed2005

Isolated type 2 diabetes mellitus causes myocardial dysfunction that becomes worse in the presence of cardiovascular diseases: results of the myocardial doppler in diabetes (MYDID) study 1.

AIMS: Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension (HTN). SUBJECTS AND METHODS: Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n = 23), patients with HTN (n = 20), CAD (n = 35), uncomplicated DM (n = 59), DM+HTN (n = 27), DM+CAD (n = 16) and DM+CAD+HTN (n = 20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables. RESULTS: Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls. CONCLUSION: The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

Adult↗
PubMed2005

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.

Atrial Function↗
PubMed2005

Functional diagnosis of coronary stenosis using tissue tracking provides best sensitivity and specificity for left circumflex disease: experience from the MYDISE (myocardial Doppler in stress echocardiography) study.

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.

Adrenergic beta-Agonists↗
PubMed2005

Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase.

The temporal distribution of the diagnostic information for the detection of coronary artery disease (CAD) provided by exercise-induced electrocardiographic (ECG) ST-segment amplitude changes in different ECG leads in men and women has not been fully investigated. To shed further light in this area, 1877 electrocardiograms selected from 8322 patients undergoing a routine exercise test on a bicycle ergometer were evaluated. ST-segment amplitude and the difference between heart rate-matched recovery and exercise ST-segment amplitudes (ST/HR difference) were measured. Coronary artery disease was verified angiographically in 669 patients and excluded in 1208 patients by angiography (n = 119), by myocardial scintigraphy (n = 250), or on clinical grounds (n = 839). The diagnostic performance of the 2 ECG methods used was assessed by constructing receiver operating characteristic curves for each sampling point every 12 seconds during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST-amplitude hysteresis assessed by the difference between recovery ST-segment amplitude and exercise ST-segment amplitude at matched heart rate. Both methods performed better in men and the diagnostic information appeared mainly in leads I, -aVR, II, V 4 , V 5 , and V 6 . The best discrimination of CAD is provided by analysis of ST-segment amplitude changes in 6 specific leads early during the recovery phase. This information should be targeted by exercise ECG diagnostic methods.

Coronary Angiography↗
PubMed2004

Improvement of cardiac function after haemodialysis. Quantitative evaluation by colour tissue velocity imaging.

BACKGROUND: Overhydration and accumulation of uraemic toxins may influence the myocardial function in haemodialysis (HD) patients. To evaluate cardiac function and the effects of fluid and solute removal during a single session of HD, colour tissue velocity imaging (TVI) was used. This new technique, which is less load dependent than conventional echocardiography, allows an objective quantitative assessment of myocardial contractility, contraction and relaxation. METHODS: Conventional echocardiographic and TVI images were recorded before and after a single HD session in 13 clinically stable HD patients (62+/-10 years, six males) and in 13 sex- and age-matched healthy controls. Myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVC), peak systole (PS), early (E') and late (A') diastolic filling and strain rate (SR) were measured. RESULTS: Left ventricular hypertrophy (LVH) was present in 12 patients. TVI gave additional information in comparison with conventional echocardiography. Before HD, PS (5.0+/-0.8 vs 6.0+/-1.2 cm/s, P<0.05), E' (5.7+/-1.7 vs 7.3+/-2.0 cm/s, P<0.05) and A' (6.6+/-1.7 vs. 8.3+/-2.9 cm/s, P<0.05) velocities were lower in the patients than in the controls, indicating systolic and diastolic dysfunction. The HD session increased IVCv (4.0+/-1.7 to 5.5+/-1.9 cm/s; P<0.001), PSv (5.0+/-0.8 to 5.7+/-0.8 cm/s; P<0.05) and SR (0.7+/-0.2 to 0.9+/-0.2 1/s; P < 0.05) and decreased E/E' (16.7+/-7.7 to 12.2+/-4.0, P<0.05), indicating improved systolic function and decreased LV filling pressure, respectively. Linear regression analysis demonstrated a dependency of systolic contraction (PSv) and contractility (IVCv) upon plasma levels of phosphate (r(2) = 0.70, P<0.005, r(2) = 0.33, P<0.01). CONCLUSIONS: Using TVI, HD patients demonstrate myocardial dysfunction, which is found less frequently when using conventional echocardiography. The systolic function seems to be impaired by high plasma levels of phosphate and an increased Ca x P product. One single session of HD improved systolic function as indicated by increases in IVCv, PSv and SR. Further studies are needed to clarify if this effect of HD is due to the acute removal of fluid, the removal of solutes or both.

Aged↗
PubMed2004

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.

Adult↗