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Left Ventricular Systolic Function (leave + ventricular_systolic_function)

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Medical Sciences	87%

Selected Abstracts

Segmental Contribution to Left Ventricular Systolic Function at Rest and Stress: A Quantitative Real Time Three-Dimensional Echocardiographic Study

ECHOCARDIOGRAPHY, Issue 2 2010
F.A.S.E., Smadar Kort M.D.
Objective: To assess the relative contribution of each myocardial segment to global systolic function during stress using real time three-dimensional echocardiography (RT3DE). Background: During stress, global augmentation in contractility results in an increased stroke volume. The relative contribution of each myocardial segment to these volumetric changes is unknown. Methods: Full volume was acquired using RT3DE at rest and following peak exercise in 22 patients who had no ischemia and no systolic dyssynchrony on two-dimensional (2D) stress echocardiography. The following were calculated at rest and peak stress: end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), relative SV, and relative EF. Results: With stress, an increase in global EDV from 90.8 to 101.1 ml (P < 0.001), SV from 59 to 78.4 ml (P = 0.01), and EF from 65.6 to 78.4% (P = 0.001) was observed. ESV decreased from 31.8 to 22.7 ml (P < 0.001). Segmental analysis revealed significantly higher SV, relative SV, and relative EF for the basal anterior, basal anterolateral, and basal inferolateral segments compared with the apical septum and apical inferior segments at both rest and stress (P < 0.001). The SV, relative SV, and relative EF increased significantly from apex to mid to base at both rest and stress (P < 0.001). Conclusions: The relative volumetric contribution of each myocardial segment to global left ventricular systolic function at rest and stress is not uniform. The basal segments contribute more than the mid and apical segments. Specifically, the basal anterior, basal anterolateral, and basal inferolateral segments contribute the most to augmentation of left ventricular systolic function with exercise. (ECHOCARDIOGRAPHY 2010;27:167-173) [source]

Cardiovascular function in the heat-stressed human

ACTA PHYSIOLOGICA, Issue 4 2010
C. G. Crandall
Abstract Heat stress, whether passive (i.e. exposure to elevated environmental temperatures) or via exercise, results in pronounced cardiovascular adjustments that are necessary for adequate temperature regulation as well as perfusion of the exercising muscle, heart and brain. The available data suggest that generally during passive heat stress baroreflex control of heart rate and sympathetic nerve activity are unchanged, while baroreflex control of systemic vascular resistance may be impaired perhaps due to attenuated vasoconstrictor responsiveness of the cutaneous circulation. Heat stress improves left ventricular systolic function, evidenced by increased cardiac contractility, thereby maintaining stroke volume despite large reductions in ventricular filling pressures. Heat stress-induced reductions in cerebral perfusion likely contribute to the recognized effect of this thermal condition in reducing orthostatic tolerance, although the mechanism(s) by which this occurs is not completely understood. The combination of intense whole-body exercise and environmental heat stress or dehydration-induced hyperthermia results in significant cardiovascular strain prior to exhaustion, which is characterized by reductions in cardiac output, stroke volume, arterial pressure and blood flow to the brain, skin and exercising muscle. These alterations in cardiovascular function and regulation late in heat stress/dehydration exercise might involve the interplay of both local and central reflexes, the contribution of which is presently unresolved. [source]

Segmental Contribution to Left Ventricular Systolic Function at Rest and Stress: A Quantitative Real Time Three-Dimensional Echocardiographic Study

Amplitude and Velocity of Mitral Annulus Motion in Rabbits

ECHOCARDIOGRAPHY, Issue 4 2004
Li-ming Gan M.D., Ph.D.
Objective: During recent years, the amplitude and the maximal systolic velocity of the mitral annulus motion (MAM) have been established as indices of the left ventricular systolic function and the maximal diastolic velocity of the annulus motion has been suggested as an index of diastolic function. The main aims of the present study were to investigate the feasibility of these techniques in rabbits and to investigate age-related changes concerning these variables. Methods: Twenty-one New Zealand white rabbits were investigated by echocardiographic M-mode and pulsed tissue Doppler. One subgroup (I) included 11 still-growing, 3.0 ± 0.2 month-old, animals and another group (II) included 10 young grown up rabbits, 12.1 ± 1.5 months old. Results: The amplitude (4.8 ± 0.6 and 3.5 ± 0.3 mm, respectively) and maximal systolic (98 ± 14 and 66 ± 7 mm/s, respectively) and diastolic (111 ± 21 and 80 ± 12 mm/s, respectively) velocities of the MAM were significantly (P < 0.001) higher in group I than in group II, despite a bigger heart in the animals in the latter group. A coefficient of variation of <5% was found for both inter- and intraobserver variability for both amplitude and velocities. Conclusions: The amplitude and velocities of MAM are easily recorded in rabbits with excellent reproducibility and the changes with age seem to be very similar to those in humans. These noninvasive M-mode and tissue Doppler methods are therefore suitable for the investigation of left ventricular function in experimental studies in rabbits. (ECHOCARDIOGRAPHY, Volume 21, May 2004) [source]

Left Ventricular Long-Axis Function Is Reduced in Patients with Rheumatic Mitral Stenosis

ECHOCARDIOGRAPHY, Issue 2 2004
Necla Özer M.D.
Left ventricular long-axis function evaluated by M-mode or tissue Doppler echocardiography has been shown to be useful indexes of left ventricular systolic function; however it has not been evaluated in patients with mitral stenosis. We examined the left ventricular long-axis function of the patients with pure mitral stenosis and normal global systolic function as assessed by fractional shortening of the left ventricle (LV). Fifty-two patients with pure mitral stenosis and twenty-two healthy controls were evaluated by echocardiography. Although there was no statistically significant difference in global systolic function, M-mode derived systolic motion of the septal side and (12 ± 3 vs 14.4 ± 1.5 mm, P = 0.016) the lateral side of mitral annulus (13.2 ± 3 vs 16.8 ± 2 mm, P = 0.001) were both significantly lower in the patients with mitral stenosis than control subjects. Similarly tissue Doppler systolic velocity of the septal annulus (7.6 ± 1.1 vs 10.4 ± 3.2 cm/s, P = 0.03) and lateral mitral annulus (7.6 ± 1.1 vs 10.4 ± 3.2 cm/s, P = 0.003) were also significantly lower in patients with mitral stenosis than in controls. There was a statistically significant correlation between septal annular motion and annular velocity (r = 0.643, P = 0.002). Septal annular motion and annular velocity were also correlated with left atrial ejection fraction (r = 0.338, P = 0.005 and r = 0.676, P = 0.001, respectively). Thus, patients with mitral stenosis had significantly impaired long-axis function evaluated by M-mode or tissue Doppler echocardiography despite normal global systolic function. (ECHOCARDIOGRAPHY, Volume 21, February 2004) [source]

Long-Term Mechanical Consequences of Permanent Right Ventricular Pacing: Effect of Pacing Site

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2010
DARRYL P. LEONG M.B.B.S.
Optimal Right Ventricular Pacing,Introduction: Long-term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long-term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. Methods: Fifty-eight patients who were prospectively randomized to long-term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18-segment time-to-peak longitudinal systolic strain and 12-segment time-to-peak systolic tissue velocity. Intra-LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time-to-onset of systolic flow in the RVOT and LV outflow tract. Septal A' was measured using tissue velocity images. Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end-systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT-paced group over the RVA-paced patients. RVA-pacing was associated with greater interventricular mechanical dyssynchrony and intra-LV dyssynchrony than RVOT-pacing. Septal A' was adversely affected by intra-LV dyssynchrony (P < 0.05). Conclusions: Long-term RVOT-pacing was associated with superior indices of LV structure and function compared with RVA-pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120-1126) [source]

Assessment of left ventricular systolic function using tissue Doppler imaging in children after successful repair of aortic coarctation

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2010
Tomasz Florianczyk
Summary Aim:, Assessment of left ventricular systolic function in children after the successful repair of aortic coarctation using tissue Doppler imaging (TDI). Methods:, The study group consisted of 32 patients (mean age 12·0 ± 4·2 years) after the aortic coarctation repair. The TDI parameters and the conventional echocardiographic endocardial and midwall indices of the left ventricular systolic function were analysed and compared with the results obtained from 34 healthy children. Results:, The systolic mitral annulus motion velocity, systolic myocardial velocity of the medial segment of the left ventricular septal wall, left ventricular strain and Strain Rate (SR) in the study group were significantly higher than in the control group, respectively: 6·92 ± 0·75 cm s,1 versus 6·45 ± 0·83 cm s,1; 5·82 ± 1·03 cm s,1 versus 5·08 ± 1·11 cm s,1; ,28·67 ± 6·04% versus ,22·53 ± 6·44% and ,3·20 ± 0·76 s,1 versus ,2·39 ± 0·49 s,1. Except midwall shortening fraction the conventional endocardial and midwall echocardiographic indices in the study group were significantly higher in comparison to the healthy controls. The left ventricular systolic meridional fibre stress and end-systolic circumferential wall stress did not differ between the examined groups. There were no differences of the TDI or conventional parameters between hypertensive and normotensive patients. Conclusions:, Left ventricular systolic performance in children after the surgical repair of aortic coarctation reveals tendency to rise in late follow-up despite a satisfactory result after surgery. Higher systolic strain and SR in children treated due to coarctation of the aorta may suggest the increased preserved left ventricular performance despite normalization of afterload. [source]