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Biomedical subjects

B Wandt

Publications and source records attributed to B Wandt.

At least 19 recordsLinked to original sources
PubMed2001

The mode of left ventricular pumping: is there an outer contour change in addition to the atrioventricular plane displacement?

The outer contour of the heart has in some studies been shown to be constant during the heart cycle and the epicardial apex almost stationary whilst the base of the ventricles moves towards apex during systole. The base of the left ventricle has been regarded as a cylinder with constant cross-sectional area with changes in height during the heart cycle, the latter corresponding to the amplitude of mitral annulus motion (MAM). In this echocardiographic study, including 20 healthy adults, the stroke volume calculated by the cylinder model was significantly lower than by a reference method (modified Simpson's rule). MAM explained 82% of the stroke volume and 18% must, therefore, be explained by an inward motion of the outer left ventricular wall. A mean outer diameter shortening of about 3% (about 2 mm) was calculated.

Adolescent↗
PubMed2001

Comparison between circumflex artery motion and mitral annulus motion.

OBJECTIVE: To compare mitral annulus motion (MAM) with circumflex artery motion (CXM) and the motion amplitude at an endocardial site (representing MAM) with an epicardial site (representing CXM) at the most basal lateral part of the atrioventricular plane (AVP). DESIGN: MAM and CXM were obtained in 28 patients examined by echocardiography and coronary angiography. The motion amplitude epicardially and endocardially was recorded by echocardiography in 13 patients with normal ejection fraction (EF) (> or = 0.50) and in 13 patients with decreased EF (<0.50). RESULTS: CXM was higher than MAM in most patients with normal EF but lower than MAM in most patients with decreased EF. The motion amplitude epicardially was significantly higher (p < 0.001) than endocardially in patients with normal EF. while there was no significant difference in patients with decreased EF. CONCLUSION: CXM represents the motion of the epicardial part of the AVP and differs from MAM, which represents the endocardial part of the wall. This must be considered when CXM is used for assessment of left ventricular systolic function.

Adult↗
PubMed2000

The relation between mitral annulus motion and ejection fraction changes with age and heart size.

Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Several echocardiographic studies have shown good agreement between ejection fraction (EF) and MAM x 5, where MAM is the total mitral annulus motion, measured in mm, and EF is expressed as a percentage. This means that if MAM is used for estimation of left ventricular function, the conversion factor 5 is used, if the function is expressed as EF. In these studies, the mean age of the patients was over 60 years. The present study, including 102 patients, shows that in patients aged 20-40 years, the conversion factor is about 4.3, in patients aged 41-60 years it is about 4.6 and in patients aged 61-80 years it is about 5.0. It was also found that the ratio EF/MAM decreases with increasing height and left ventricular diameter, both variables closely connected to heart size. The results suggest that when MAM is used in assessment of left ventricular function, it is unwise to express the function in terms of EF. It is preferable to use MAM as a direct index of ventricular function, using reference values referred to aged and height. If the estimated function is expressed in terms of EF, different converting factors must be used depending on the age of the patients.

Adult↗
PubMed2000

The relation between mitral annulus motion and left ventricular ejection fraction in atrial fibrillation.

Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Previous studies have shown a good agreement between MAM (mm) x 5 and ejection fraction in middle-aged and elderly patients. These studies only included patients with sinus rhythm, while patients with atrial fibrillation were excluded. In the present study, MAM was reduced in patients with atrial fibrillation while ejection fraction (EF) did not differ from age-matched control patients with sinus rhythm. The 'conversion factor' (EF/MAM) was 7.2 in the group with atrial fibrillation and 5. 1 in controls with sinus rhythm. This difference must be taken into account when MAM is used to estimate left ventricular function in patients with atrial fibrillation. Patients with atrial fibrillation had lower stroke volume and higher heart rate than patients with sinus rhythm. A decreased systolic long-axis shortening was found (P<0.005) compared to patients with sinus rhythm, but no difference in short-axis diameter shortening.

Aged↗
PubMed2000

The relation between ejection fraction and mitral annulus motion before and after direct-current electrical cardioversion.

Mitral annulus motion (MAM) and the relation between left ventricular ejection fraction (EF) and MAM has been shown to differ between patients with sinus rhythm and patients with atrial fibrillation. However, it has not been investigated how the relation between EF and MAM changes on direct-current (DC) electrical cardioversion to sinus rhythm. Therefore, 31 consecutive patients on the waiting list for DC electrical cardioversion were examined by echocardiography before DC electrical cardioversion, and those who maintained sinus rhythm (13 patients) were examined again 4-8 weeks after cardioversion. The conversion factor (CF) (ratio EF/MAM) decreased from 8.4 +/- 1.7 before to 5.8 +/- 0.8 SD after cardioversion (P<0.001). The EF increased slightly (P<0.05) but the MAM had a much greater increase (P<0.001), resulting in the decrease in CF. There was no significant difference in CF between patients after cardioversion and age- and gender-matched control patients with sinus rhythm, indicating that CF is normalized or almost normalized 4-8 weeks after cardioversion. This indicates that when MAM is used for investigation of the left ventricular function, and the function is expressed as EF, the same CF as in other patients with sinus rhythm can be used 4-8 weeks after DC electrical cardioversion.

Aged↗
PubMed2000

Influence of body size and age on maximal systolic velocity of mitral annulus motion.

The maximal systolic velocity of the mitral annulus motion (or maximal systolic long-axis contraction velocity of the ventricle, MLACV) has been suggested as a means to assess left ventricular function. However, reference values for a wide range of age and body size are lacking. The maximal systolic velocity was studied with M-mode echocardiography using the apical four- and two-chamber views. Data are reported as the average of the measurements of four sites of the mitral annulus. Fifty-seven healthy subjects aged 6 months to 72 years were studied. In children and adolescents up to age 18, MLACV had a significant positive correlation with age, height, body surface area, weight and mitral annulus motion amplitude and a significant negative correlation with heart rate. In adults, there was a significant positive correlation between MLACV and height, mitral annulus motion amplitude and body surface area and a significant negative correlation with age and heart rate. Multiple stepwise analysis showed that the maximal systolic velocity is highly dependent on height and age in children and adolescents up to age 18, and on height in adults. The maximal long-axis contraction velocity (MLACV) can be described by the following equations: MLACV (mm s-1) = 24.0 + 0.34 x height (cm) (Standard Error of the Estimate (SEE)=10.5) in children and adolescents, and MLACV (mm s-1) = -50.5 + 0.75 x height (cm) (SEE=9.8) in adults over 18. There were significant differences between the four sites, with the highest velocity at the lateral site and the lowest velocity at the septal site. No significant difference was found between inspiratory and expiratory beats.

Adolescent↗
PubMed2000

The relation between mitral annulus motion and ejection fraction: a nonlinear function.

In previous studies of the relation between mitral annulus motion (MAM) and left ventricular ejection fraction (EF), a linear relationship has been suggested. In this meta-analysis of 434 patients, we show that the relation is nonlinear and that a linear regression model overestimates EF in the lower range of MAM. The relation is better described by an S function and is influenced by age and heart size.

Adolescent↗
PubMed2000

How should we assess diastolic function in hypertension?

OBJECTIVE: the aim of our study was to assess the relative merits of three indices of diastolic LV function in a group of patients with hypertension and normal systolic function and a group of healthy controls. DESIGN: In this echocardiographic study, diastolic LV function was assessed by E/A ratio using pulsed Doppler recording and by atrial to total mitral annulus motion (AC) and maximal longitudinal LV relaxation velocity (RVm) by M-mode recordings from apical views. The study took place in the Department of Clinical Physiology in a secondary referral centre. Nineteen consecutive patients with uncomplicated hypertension referred to echocardiographic examination and 20 age- and sex-matched controls were included in the study. RESULTS: All three measures of diastolic function, E/A ratio, AC and RVm indicated impaired diastolic function in the hypertensive group, compared to the healthy controls. However, E/A ratio and AC showed a considerable overlap between the groups, whereas there was a highly significant difference in RVm between the hypertensive group and the controls, with much less of an overlap. CONCLUSION: The results indicate that of these three indices of diastolic function, RVm may be the most appropriate in patients with hypertension and normal systolic LV function.

Adult↗
PubMed2000

Enhanced left ventricular endocardial border delineation with an intravenous injection of SonoVue, a new echocardiographic contrast agent: A European multicenter study.

The safety and efficacy of SonoVue (also referred to as BR1), a new contrast agent for delineating endocardial border of the left ventricle after intravenous administration, was assessed. Two hundred and eighteen patients with suspected coronary artery disease undergoing fundamental echocardiography for the assessment of left ventricle were enrolled in a prospective multicenter, single blind, cross-over study with random sequence allocation of four different doses of SonoVue. Endocardial border definition in the apical and parasternal views was scored as 0 = not visible, 1 = barely visible, and 2 = well visualized before and after contrast enhancement. Analysis was performed by two pairs of off-site observers. Safety of SonoVue was also assessed. Results of our study indicated that the mean improvements in the endocardial border visualization score were as follows: 3.1 +/- 7.8 (95% CI, 2.5 and 3.7) for 0.5 ml, 3.4 +/- 8.0 (95% CI, 2.8 and 4.0) for 1 ml, 3.4 +/- 7.9 (95% CI, 2.8 and 4.0) for 2 ml, and 3.7 +/- 8.0 (95% CI, 3.1 and 4.3) for 4 ml (P < 0.05 for all doses from baseline). Changes from baseline in endocardial visualization scores were also seen in the apical views (P < 0.05) and they were dose-dependent (P < 0.001). Similar enhancements of endocardial visualization scores were observed in the apical views in patients with suboptimal baseline echocardiographic images. Diagnostic confidence for assigning a score and image quality also were significantly better following contrast enhancement. No significant changes in the laboratory parameters and vital signs were noted following contrast enhancement, and the side effects were minimal. It was concluded that SonoVue is safe and effective in delineating endocardial border, including in patients with suboptimal baseline images.

Aged↗
PubMed1999

Echocardiographic assessment of ejection fraction in left ventricular hypertrophy.

OBJECTIVE: To investigate the value of Simpson's rule, Teichholz's formula, and recording of mitral ring motion in assessing left ventricular ejection fraction (EF) in patients with left ventricular hypertrophy. DESIGN: Left ventricular ejection fraction calculated by Simpson's rule and by Techholz's formula and estimated by mitral ring motion was compared with values obtained by radionuclide angiography. SETTING: Secondary referral centre. PATIENTS: 16 patients with left ventricular hypertrophy and a clinical diagnosis of hypertrophic cardiomyopathy or hypertension. RESULTS: Calculation by Teichholz's formula overestimated left ventricular ejection fraction by 10% (p = 0.002) and estimation based on mitral ring motion-that is, long axis measurements-underestimated ejection fraction by 19% (p = 0.002), without significant correlation between ring motion and ejection fraction. There was no significant difference between mean values of ejection fraction calculated by Simpson's rule and measured by the reference method, but a considerable scatter about the regression line with a standard error of the estimate of 9.3 EF%. CONCLUSIONS: In patients with left ventricular hypertrophy the ejection fraction, calculated by Teichholz's formula or Simpson's rule, is a poor measure of left ventricular function. When mitral ring motion is used for the assessment in these patients the function should be expressed in ways other than by the ejection fraction.

Adult↗
PubMed1998

Left ventricular contraction pattern changes with age in normal adults.

Left ventricular ejection fraction is known to be unchanged or slightly increased with advancing age. This echocardiographic study, including 40 healthy subjects 18 to 70 years old, shows that this is a net effect of decreased contractions in the long axis and increased in the short axis. From age 18 to 70 years, the longitudinal shortening decreases by 20% (P < .001) and the short-axis diameter shortening increases by 18% (P=.012). Multiple regression analysis showed strong correlation to age for both short- and long-axis contractions and no significant additional explicatory power when the variables systolic blood pressure, left ventricular wall thickness, heart rate, or sex were included. There was no significant correlation between diameter changes during the isovolumic phases and age. The findings have practical implications when calculating ejection fraction from M-mode measurements. Teichholz's formula will overestimate ejection fraction in elderly subjects, and calculation of ejection fraction from mitral ring motion will overestimate it in young subjects.

Adult↗
PubMed1998

Long and short axis dimensions of the left ventricle change in opposite ways during respiration.

Cardiac output and stroke volume are known to vary with respiration. While right ventricular stroke volume increases on inspiration, left ventricular stroke volume decreases. This is an echocardiographic study of the changes in left ventricular dimensions in 20 healthy subjects. Our results show that the decrease in left ventricular stroke volume on inspiration is a net effect of a decrease in short axis shortening due to a decrease in diastolic diameter by 4.8% (P < 0.001) and an increased motion in the long axis direction expressed as an increase in mitral ring motion by 5.5% (P < 0.001). The findings point to the importance of the interventricular septum for the regulation of stroke volume.

Adolescent↗
PubMed1998

Reduced left ventricular relaxation velocity after acute myocardial infarction.

Diastolic left ventricular function is usually described using Doppler recording of the early to atrial (E/A) ratio. However, because of pseudonormalization in patients with moderately impaired diastolic function, the E/A ratio does not allow a meaningful comparison between a group of patients with varying degrees of dysfunction, e.g. after acute myocardial infarction (AMI), and a group of healthy control subjects. In this study, diastolic function was assessed using the E/A ratio, deceleration time of early mitral inflow and maximal longitudinal relaxation velocity. The relaxation velocity was measured using echocardiographic M-mode recording of mitral annulus motion. Mitral annulus motion was recorded in four- and two-chamber views. Relaxation velocities were measured in the septal, lateral, anterior and posterior parts of the mitral annulus and the mean value (RVm) was calculated. Twenty-two consecutive patients were investigated 3-21 days after first transmural AMI. Twenty-two healthy subjects of similar age served as a control group. The group of patients with AMI had an RVm of 40.9 +/- 15.4 mm s-1 compared with 68.5 +/- 12.4 mm s-1 in the control group (P < 0.0001). In contrast, the E/A ratio, deceleration time and heart rate did not differ significantly between the two groups. The results suggest that maximal longitudinal relaxation velocity is a simple and appropriate measure of diastolic function in patients with transmural AMI.

Aged↗
PubMed1997

Influence of body size and age on mitral ring motion.

Left ventricular systolic and diastolic function can be assessed by studying mitral ring motion. Reference values for a wide range of age and body size are lacking however. The motion of the mitral ring was studied with M-mode echocardiography using the apical four- and two-chamber views. Data are reported as the average of measurements of four points on the mitral ring. Data were analysed using the stepwise multiple regression technique, with age, gender, height, weight, body surface area and heart rate as independent variables. A total of 70 healthy subjects were studied. In children and adolescents under age 18, there was strong correlation between mitral ring motion and body size, age and heart rate. The ring motion was best described as mitral ring motion (mm) = 2.2 + 0.078 x height (cm) (SEE = 1.0 mm). In adults, mitral ring motion was correlated with age, height and heart rate but not with weight or body surface area. Ring motion could be described from the following equations: mitral ring motion (mm) = 12.7 - 0.060 x age (years) + 0.031 x height (cm) (SEE = 1.2) or, if only age is taken into account, mitral ring motion = 18.4 - 0.065 x age (SEE = 1.2). In both children and adolescents up to age 18 and in adults, atrial contribution correlated significantly and positively to age and inversely to heart rate but not to height, weight, body surface area or gender. Atrial contribution was best described by the equation: atrial contribution = 0.15 + 0.0039 x age (SEE = 0.027). Thus, age and body size influences mitral ring motion and should be taken into account when interpreting patient data.

Adolescent↗