Diastole ; physiology ; Exercise ; physiology ; Fractional Flow Reserve, Myocardial ; Heart Rate ; Humans ; Systole ; physiology ; Young Adult

OBJECTIVETo study the differences of cardiovascular system between men and women in response to exercise stress.

METHODSForty healthy youth were tested according to Bruce protocol of exercise stress. They were detected by ultrasonography during the rest, peak exercise, and recovery stages, respectively. The left ventricular diastolic elastance (Ed), effective arterial elastance (Ea), left ventricular end-systolic elatance (Ees), ventricular-vascular coupling index (VVI), and total stiffness index (TSI) were measured and calculated according to the formulas. The results of all stages were compared according to genders.

RESULTSAll stages, the Ed, TSI, and VVI of women were higher than those of men, but the Ees was lower than that of men (all P<0.05); there was no significant difference in Ea between men and women. The Ed, Ees, Ea, and TSI were closely related with left ventricular oxygen consumption and heart function, and women showed more closely. Before and after exercise, the changes were different in Ed, Ees, Ea, TSI, and VVI (all P<0.05), and VVI changed least.

CONCLUSIONSBefore and after exercise, the ventricular stiffness matched well with arterial stiffness and maintained within a narrow range. For women, the tolerance of exercise was lower than that of men.

Adult ; Diastole ; physiology ; Exercise ; physiology ; Female ; Humans ; Male ; Sex Characteristics ; Vascular Resistance ; physiology ; Vascular Stiffness ; physiology ; Ventricular Function, Left ; physiology

To study the blood flow parameters for 2 anatomical segments of posterior cerebral artery (PCA) in normal singleton fetal.
 Methods: The blood flow velocity parameters peak systolic velocity (PSV), end diastolic velocity (EDV), time-average maximum velocity (TAMAXV), velocity time integral (VTI) and resistance parameters systolic peak velocity and end diastolic velocity ratio (S/D), pulsatility index (PI), resistance index (RI) for 2 anatomical segments in PCA were recorded. The first segment of the PCA (PCAS1) was recorded between the origin of PCA and the proximal part of the posterior communicating artery. The second segment of the PCA (PCAS2) was recorded at the distal part of the posterior communicating artery. The blood parameters in both PCAS1 and PCAS2 were analyzed by using Pearson correlation and multiple curves fitting with gestational age (GA). Paired student's t test was performed to compare the difference in blood parameter between PCAS1 and PCAS2.
 Results: The blood flow velocity parameters in both PCAS1 and PCAS2 were increased with the GA (P<0.0001), with the best fitted curves of Quadratic curve (P<0.0001). There were no correlations between resistance parameters in PCA and GA (P>0.05). Resistance parameters in PCAS1 were higher than those in PCAS2 (P<0.05).
 Conclusion: The blood flow velocity parameters in both PCAS1 and PCAS2 are increased with GA. The resistance parameters in both PCAS1 and PCAS2 do not change with GA. Study on the velocities and resistance in these 3 arterial branches provides a more comprehensive evaluation on the process of brain circulation.
Blood Flow Velocity ; physiology ; Diastole ; physiology ; Female ; Gestational Age ; Hemodynamics ; physiology ; Humans ; Posterior Cerebral Artery ; physiology ; Pregnancy ; Systole ; physiology

There have been insufficient numerical methods for particular description and quantitative evaluation of left ventricular diastolic function in the studies in this area. We therefore have summarized the computational models of the affecting factors for diastolic function from five aspects, i. e. the geometry shape of left ventricular, myocardial stiffness, myocardial viscosity, myocardial relaxation and ventricular interaction respectively. Controlling the sensitive parameters and having a mathematical description on left ventricular diastolic dysfunction can provide numerical methods for clinical diagnosis and quantitative evaluation of the disease.
Computer Simulation ; Diastole ; physiology ; Humans ; Models, Theoretical ; Numerical Analysis, Computer-Assisted ; Ventricular Function, Left ; physiology

OBJECTIVETo exacted analysis each time interval in isovolumic relaxation time (IVRT) of normal subjects through observin the changes of cardiac structure and hemodynamics during the IVRT. Then to provide the evidence of cardiac resynchronization therapy.

METHODSQuantitative analysis was performed for 60 subjects. The dual-channel echocardiography(DCE), pulse wave doppler (PW) and tissue wave dapper (TDI) examination of all the subjects were recorded, and IVRT was divided into two intervals, isovolumic relaxation time of early intervals (IVRTe) and isovolumic relaxation time of late interval (IVRT1). Then measured the time of each interval. Indicators were used including: (1) IVRT; (2) IVRTe; (3) IVRTI; (4) IVRTI/IVRT; calculating the data after heart rate corrected; (5) cIVRT; (6) clVRTe; (7) clVRTI; (8) clVRTI/clVRT; (9) measuring the time difference in mitral blood and tissue (TE-é) of DCE group.

RESULTSThe i-wave within IVRT in PW images was found in 45 subjects, and the i-wave was about 1/2 of IVRT (49.17 +/- 5.37) ms. IVRT was divided into IVRTe and IVRTI by a turning point at descending branch of i-wave as t-point. The j-wave was observed in 84% TDI images, and the j-wave was about 1/2 of IVRT (43.13 +/- 4.83) ms. IVRT was divided into IVRTe and IVRTI by a turning point of the onset of j-wave as t-point. A significant difference was found between PW and TDI with measurement of IVRT, IVRTe, IVRTI (P < 0.05). There were no significant differences between the common group and DCE group (P > 0.05). After heart rate corrected, the data showed no significant difference using pairwise comparisons among the three groups (P > 0.05). The mean and standard deviation of IVRTI/IVRT, cIVRTI/clVRT were (0.50 +/- 0.12) ms. There were little difference of time intervals and good consistenc using DCE measured IVRT with multiple tests confinmed.

CONCLUSIONThe study found that IVRT might be divided into IVRTe and IVRT1 phases. There were i-wave in IVRTe and j-wave in IVRT1. The t-point was nearly midpoint inisovolumic relaxation time.

Adult ; Diastole ; physiology ; Echocardiography ; Female ; Healthy Volunteers ; Humans ; Male ; Middle Aged ; Ventricular Function, Left ; physiology

BACKGROUND AND OBJECTIVES: Movement of mitral valve during diastole and blood flow velocity through the valve can be accurately measured using M-mode and pulsed wave Doppler technique, respectively. However, the relationship between mechanical excursion and flow phenomenon at the same cardiac cycle has not been seriously investigated. METHOD: The subjects of this study included twenty cases with normal mitral flow pattern in Doppler echocardiography (Group I, mean age:44+/-20.8years, mean ejection fraction (EF):52+/-20.9%), twenty three cases with relaxation abnormality (Group II, mean age:59+/-11.4years, mean EF:43+/-18.2%) and seventeen cases with restrictive physiology (Group III, mean age: 47+/-15.9years, mean EF: 24+/-11.0%). We measured excursion of mitral leaflets at early (DE) and late (DA) diastole, area of mitral valvular opening using two dimensional calibration on M mode images, and transmitral inflow velocity (E (early ventricular filling)-, A (atrial contraction)-velocity), TVI (time velocity integral) on Doppler echocardiography. RESULTS: DE-excursions (mm) in group I, II, III were 16.8+/-4.7, 14.2+/-3.5, 15.3+/-4.1, DA-excursions (mm) were 9.8+/-3.2, 10.7+/-3.0, 8.3+/-2.7, E-areas (cm2) were 2.8+/-1.3, 2.6+/-0.8, 2.5+/-1.0, A-areas (cm2) were 1.7+/-0.8, 1.7+/-0.7, 2.0+/-0.6, respectively. In E-, A-velocity, deceleration time, E-TVI and A-TVI, there were significant differences among three groups. However, in DE-, DA-excursion, E-, A-area, there were no significant differences among three groups. Between DE excursion and E velocity, DA excursion and A velocity, and total opening area and total TVI in total subjects, significant correlations were absent. CONCLUSION: The mitral excursions and mitral opening areas on M mode images did not show any significant correlations with the mitral inflow velocities and TVI by pulsed Doppler, which suggests that the excursion of mitral leaflets is independent of transmitral inflow.
Blood Flow Velocity ; Calibration ; Deceleration ; Diastole ; Echocardiography* ; Echocardiography, Doppler ; Mitral Valve* ; Physiology ; Relaxation

Heart failure with a normal ejection fraction is interchangeably termed diastolic heart failure. This condition is often unrecognized and it does have diagnostic, prognostic and therapeutic implications that are distinct from those conditions with systolic dysfunction. It is clinically important to understand and assess the diastolic function to reliably manage the patients suffering with heart failure. With the results of randomized trials for this distinct clinical syndrome, as well as the probability of better diagnostic testing in the future, physicians will in a better position not only to diagnose diastolic dysfunction or heart failure, but also to manage it more effectively. In this review, the physiology of the diastole and how to evaluate the abnormalities of the diastolic function will be discussed.
Diagnostic Tests, Routine ; Diastole ; Heart Failure ; Heart Failure, Diastolic ; Humans ; Physiology ; Ventricular Dysfunction, Left*

BACKGROUND AND OBJECTIVES: Mitral flow Doppler has been used to evaluate left ventricle (LV) diastolic function by mitral E/A flow ratio, isovolumic relaxation time (IVRT) and deceleration time (DT) of E wave. Such variables can be affected by various factors. The increase in left atrium (LA) afterload and preload is accompanied by increased LA size. So, we investigated the relationship of LA volume and LV diastolic dysfunction. MATERIALS AND METHOD: From January 2000 to July 2000, 39 patients were included in this study. They were classified into normal (M:F=5:6, mean age 54.0+/-11.4 years), impaired relaxation (M:F=5:4, mean age 70.0+/-5.5 years), pseudonormal (M:F=5:3, mean age 68.3+/-13.2 years) and restrictive physiology (M:F=10:1, mean age 65.5+/-12.7 years) according to mitral inflow variables. The LA volume of each groups was measured by Simpson method, M-mode method and arealength method. RESULTS: 1) The LA volumes measured by Simpson method, M-mode method and area-length method were correlated (p<0.001, r=0.925 in Simpson compared with arealength method). 2) The LA volume by Simpson method were found 54.4+/-16.4 cm3 in normal, 57.3+/-9.2 cm3 in impaired relaxation, 81.4+/-28.8 cm3 in pseudonormal and 119.8+/-64.5 cm3 in restrictive physiology. 3) The LA volume were significantly increased in pseudonormal group compared with normal (p<0.05). CONCLUSION: The LA volume is a useful and easy diagnostic stool for evaluating of LV diastolic function.
Cardiac Volume ; Deceleration ; Diastole ; Heart Atria ; Heart Ventricles ; Humans ; Physiology ; Relaxation

The volume-time curve change in patients with normal left ventricular (LV) diastolic function and diastolic dysfunction was evaluated by real-time three-dimensional echocardiography (RT3DE). LV diastolic dysfunction was defined by E'0.05). It is concluded that PFR, as a diastolic filling index of RT3DE, can reflect the early diastolic function and serve as a new non-invasive, quick and accurate tool for clinical assessment of LV diastolic function.
Diastole/physiology ; Echocardiography, Three-Dimensional/*methods ; Ventricular Dysfunction, Left/physiopathology ; Ventricular Dysfunction, Left/*ultrasonography ; Ventricular Function, Left/*physiology

We analyzed Doppler echocardiographic data in 120 subjects with normal sinus rhythm; normals (NL, n=60, ages 54.1 15.1) and essential hypertensive patients (HT, n=60, ages 57.3 10.2). The IMP was calculated as follows: IMP=(ICT+IRT)/ET, ICT; isovolumic contraction time, IRT; isovolumic relaxation time, ET; ejection time. There were no significant differences in ejection fraction (EF), stroke volume index (SVI), cardiac index (CI), ET and ICT between NL and HT. There were, however, significant differences in deceleration time (DT), E/A ratio, IRT and the IMP between the two groups (199.5 45.6 msec vs 222.3 54.3 msec, p<0.01; 1.4 0.7 vs 0.9 0.2, p<0.01; 113.6 30.2 msec vs 134.2 29.6 msec, p<0.01; 0.6 0.1 vs 0.8 0.3, p<0.05). In HT, there were no differences in EF, SVI, CI, E/A ratio and DT between the NYHA I (Gp I, n=36) and II (Gp II, n=24) groups. However, ET of Gp II was significantly shorter than that of Gp I (259.4 43.5 msec vs 297.8 33.6 msec, p<0.01). ICT, IRT and the IMP were significantly increased in Gp II, compared to those of Gp I (64.4 23.9 msec vs 89.4 46.2 msec, p<0.05; 120.3 21.0 msec vs 155.2 28.5 msec, p<0.001; 0.6 0.2 vs 1.0 0.4, p<0.001). There were no differences in heart rate and mean blood pressure between Gp I and Gp II (70.9 11.4/min vs 66.3 11.4/min, p>0.05; 138.4 21.2 mmHg vs 131.3 19.9 mmHg, p>0.05). These data suggest that the IMP may be a useful parameter and an early indicator of left ventricular dysfunction in essential hypertensive patients with normal systolic function.
Adult ; Aged ; Diastole/physiology ; Echocardiography, Doppler* ; Female ; Human ; Hypertension/ultrasonography* ; Hypertension/physiopathology* ; Male ; Middle Age ; Systole/physiology ; Ventricular Function, Left/physiology*