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

BACKGROUND: Constrictive pericarditis is an uncommon condition that could be easily confused with congestive heart failure. In symptomatic patients, septal "wobble" on echocardiography may be an important sign of constrictive physiology. This study was planned to investigate the effects of constriction on septal motion as identified by echocardiography. METHODS: In this retrospective observational study, nine consecutive patients with constriction underwent careful echocardiographic analysis of the interventricular septum (IVS) with slow motion 2-dimensional echocardiography and inspiratory manoeuvres. Six patients who had undergone cardiac magnetic resonance imaging underwent similar analysis. Findings were correlated with haemodynamic data in five patients who had undergone cardiac catheterisation studies. RESULTS: In mild cases of constriction a single wobble of the IVS was seen during normal respiration. In more moderate cases a double motion of the septum (termed "double wobble") was seen where the septum bowed initially into the left ventricle (LV) cavity in diastole then relaxed to the middle only to deviate again into the LV cavity late in diastole after atrial contraction. In severe cases, the septum bowed into the LV cavity for the full duration of diastole (pan-diastolic motion). We describe how inspiration also helped to characterize the severity of constriction especially in mild to moderate cases. CONCLUSION: Echocardiography appears a simple tool to help diagnose constriction and grade its severity. Larger studies are needed to confirm whether the type of wobble motions helps to grade the severity of constrictive pericarditis.
Classification* ; Constriction ; Diastole ; Echocardiography* ; Heart Failure ; Heart Ventricles ; Humans ; Magnetic Resonance Imaging ; Observational Study ; Pericarditis, Constrictive* ; Physiology ; Respiration ; Retrospective Studies

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

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

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

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

BACKGROUNDMechanical asynchrony is an important parameter in predicting the response to cardiac resynchronization therapy, but detailed knowledge about cardiac timing in healthy persons is scarce. Therefore, in the current study, we sought to investigate the physiological status of interventricular synchronicity using pulse wave flow and tissue Doppler imaging in a healthy Chinese population.

METHODSEighty-eight healthy volunteers underwent standard flow and tissue Doppler echocardiographic examinations. Ventricular inflow and outflow pulse wave flow Doppler patterns were recorded together with annulus pulse tissue Doppler imaging. Time intervals from the beginning of the QRS complex to the onset, peak and end of each wave were measured.

RESULTSThe onsets of systole between left and right ventricles were highly synchronized by both imaging modalities. However, the left ventricle reached the peak flow ejection and peak mechanical contraction earlier than the right ventricle, (165.61 ± 26.23) ms vs. (204.3 ± 34.55) ms (P < 0.01) and (133.62 ± 26.19) ms vs. (191.25 ± 38.47) ms (P < 0.01). Time to peak early diastolic relaxation was earlier in the left ventricle than in the right heart, (500.23 ± 56.52) ms vs. (524.94 ± 47.42) ms (P < 0.01).

CONCLUSIONSLeft and right ventricles were well synchronized at the onsets of systole and diastole even though interventricular peak systolic and peak early diastolic dyssynchrony was observed in healthy people by pulse wave Doppler imaging. In addition, diastolic timing events were slightly affected by age and gender.

Adolescent ; Adult ; Aged ; Asian Continental Ancestry Group ; Diastole ; physiology ; Echocardiography, Doppler ; methods ; Female ; Heart Ventricles ; physiopathology ; Humans ; Male ; Middle Aged ; Systole ; physiology ; Ventricular Function, Left ; Ventricular Function, Right ; Young Adult

OBJECTIVETo study value of velocity vector imaging (VVI) in assessment of normal left ventricular diastolic function and the corresponding reference values.

METHODSNinety-seven healthy subjects were selected by combined clinical, ultrasound, and NT-proBNP examinations. Using a Siemens Acuson Sequoia C512 echocardiograph, VVI was adopted to examine the myocardial early diastolic velocity (E) of the septal, lateral, anterior, inferior, anterior septum, and posterior wall of the left ventricle at the level of mitral annulus. The images were analyzed for VVI and the mean diastolic velocity (E(m)) and hence the E/E(m) ratio was calculated based on the offline workstation interface.

RESULTSThe reference range of E/E(m) ratio derived from the data of the 97 healthy subjects was (unilateral boundaries with 95% limit) and (1, 22.935), was (1, 22.300) in male subjects and (1, 24.766) in female subjects. The reference E/E(m) range was (0, 22.413) in male subjects under 50 years of age, (1, 24.766) in female subjects under 50 years, (1, 22.300) in male subjects over 50 years, and (1, 24.766) in female subjects over 50 years.

CONCLUSIONVVI is a good method for non-invasive evaluation of the left ventricular diastolic function and provides an accurate and reliable means for clinical assessment of the left ventricular diastolic function.

Adolescent ; Adult ; Aged ; Blood Flow Velocity ; physiology ; Diastole ; physiology ; Echocardiography ; methods ; Female ; Humans ; Male ; Middle Aged ; Reference Values ; Ventricular Function, Left ; physiology ; Young Adult

The methods for evaluating left ventricular diastolic function completely and simply are lacking in our country at present. To solve this problem, we presents in this paper a novel method, which is developed according to certain algorithms and mathematic models and is carried out by a MATLAB program. This method mainly obtains dP/dt loops, and calculates four important indices, including left ventricular end-diastolic pressure (LVEDP), Maximal decrease in velocity of left ventricular pressure (--(dP/dt)max), Time constant of ventricular isovolumic relaxation (tau) and Chamber stiffness (Kd), according to the changes of left ventricular pressure. The results obtained from the experiment of isolated rat hearts during ischemia/reperfusion have demonstrated the usefulness and validity of this method. Therefore, with the use of tau and Kd as indicators, this is a sensitive and effective method for evaluating the left ventricular diastolic function, and it can be applied to early detection of left ventricular diastolic dysfunction.
Algorithms ; Animals ; Blood Pressure ; Diastole ; Humans ; In Vitro Techniques ; Male ; Models, Cardiovascular ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; physiopathology ; Ventricular Dysfunction, Left ; diagnosis ; physiopathology ; Ventricular Function, Left ; physiology

OBJECTIVETo evaluate the relationship between myocardial systolic, diastolic functions and perfusion in coronary artery stenosis using velocity vector imaging (VVI) and myocardial contrast echocardiography (MCE).

METHODSStenoses in the anterior descending branch of the coronary artery were induced in 8 dogs. Before and after coronary artery stenosis, two-dimensional images of the left ventricular mastoid muscle section on the short axis at rest and in the peak dose of dobutamine were obtained for evaluation of VVI and MCE. The myocardial blood flow A.beta values, peak systolic strain rate (SRsys) and peak diastolic strain rate (SRdia) in the direction of the circumference of the short axis were measured.

RESULTSAt rest, only severe coronary stenosis resulted in significantly lowered SRsys, SRdia and A.beta value of the stenotic bed compared to the values before the stenosis (-1.1-/+0.50 vs -1.62-/+0.50, 1.19-/+0.48 vs 1.75-/+0.51, 0.4-/+0.21 vs 0.80-/+0.47, P<0.05). In stress, SRsys, SRdia and A.beta value of the stenotic bed gradually decreased as coronary stenosis worsened (-4.31-/+1.14 vs -3.20-/+0.98 vs -1.18-/+0.64, 4.51-/+1.13 vs 3.39-/+0.98 vs 1.37-/+0.64. 3.54-/+1.95 vs 1.81-/+0.89 vs 0.82-/+0.42, P<0.05). Both at rest and in stress, good correlations were noted between SRsys and SRdia (r(rest)=0.88, r(stress)=0.96, P<0.01), between SRsys and the standard A.beta values (r(rest)0.56, r(stress)=0.71, P<0.01), and between SRdia and A.beta (r(rest)=0.57, r(stress)=0.72, P<0.01) in the direction of the circumference of the short axis.

CONCLUSIONSUsing VVI and MCE, the changes in myocardial perfusion and the systolic and diastolic functions in the direction of the circumference can be observed dynamically. VVI may help assess the condition of myocardial perfusion by evaluating the systolic and diastolic function.

Animals ; Blood Flow Velocity ; physiology ; Coronary Circulation ; Coronary Stenosis ; complications ; diagnostic imaging ; physiopathology ; Diastole ; Dogs ; Echocardiography ; methods ; Female ; Male ; Myocardial Contraction ; Ventricular Dysfunction, Left ; diagnostic imaging ; etiology ; physiopathology ; Ventricular Function, Left ; physiology