374 Ventricular filling mechanisms: study of regional pressure gradients and myocardial segmental lengths along the cardiac cycle

2006 ◽  
Vol 5 (1) ◽  
pp. 83-83
Author(s):  
M GUERRA ◽  
M AMORIM ◽  
C BRASSILVA ◽  
A LEITEMOREIRA
Keyword(s):  
Cardiac Cycle ◽  
Pressure Gradients ◽  
Ventricular Filling

Catheter Obstruction Effect on Pulsatile Flow Rate-Pressure Drop During Coronary Angioplasty

1999 ◽  
Vol 121 (3) ◽  
pp. 281-289 ◽  
Author(s):  
R. K. Banerjee ◽  
L. H. Back ◽  
M. R. Back ◽  
Y. I. Cho
Keyword(s):  
Cardiac Cycle ◽  
Pressure Sensors ◽  
Reynolds Numbers ◽  
Phase Lag ◽  
Pressure Gradients ◽  
Catheter Obstruction ◽  
Mean Pressure ◽  
Coronary Stenoses ◽  
Basal Flow ◽  
Flow Cross

The coupling of computational hemodynamics to measured translesional mean pressure gradients with an angioplasty catheter in human coronary stenoses was evaluated. A narrowed flow cross section with the catheter present effectively introduced a tighter stenosis than the enlarged residual stenoses after balloon angioplasty; thus elevating the pressure gradient and reducing blood flow during the measurements. For resting conditions with the catheter present, flow was believed to be about 40 percent of normal basal flow in the absence of the catheter, and for hyperemia, about 20 percent of elevated flow in the patient group. The computations indicated that the velocity field was viscous dominated and quasi-steady with negligible phase lag in the Δp(t) – u¯(t) relation during the cardiac cycle at the lower hydraulic Reynolds numbers and frequency parameter. Hemodynamic interactions with smaller catheter-based pressure sensors evolving in clinical use require subsequent study since artifactually elevated translesional pressure gradients can occur during measurements with current angioplasty catheters.

scholarly journals The Wright table of the cardiac cycle: a stand-alone supplement to the Wiggers diagram

2020 ◽  
Vol 44 (4) ◽  
pp. 554-563
Author(s):  
Bruce E. Wright ◽  
Gretchen LeFever Watson ◽  
Nancy J. Selfridge
Keyword(s):  
Aortic Stenosis ◽  
Clinical Training ◽  
Teaching And Learning ◽  
Cardiac Cycle ◽  
Student Survey ◽  
Bundle Branch Block ◽  
Training And Research ◽  
Health And Disease ◽  
Subsequent Phase ◽  
Ventricular Filling

The Wright table is introduced as a novel tool for teaching and learning the cardiac cycle. It supplements the nearly 100-yr-old Wiggers diagram, which is information rich but difficult for many students to learn. The Wright table offers a compact presentation of information, viewable both in terms of how 1) each compartment’s pressures and flows change over time; and 2) the heart works as a pump, first filling and then emptying the ventricles, thereby moving blood from low-pressure venous to high-pressure arterial compartments. This new four-by-four display of interrelated aspects of cardiac cycle events offers a more integrated view of the phases of ventricular filling and emptying than can be easily observed in the Wiggers diagram. It also shows how ECG-related waves of depolarization and repolarization drive the events of each subsequent phase. The Wright table is a stand-alone teaching aid; however, it is designed such that weaknesses of the Wiggers diagram are complemented by strengths of the Wright table, and vice versa. Results of an anonymous student survey support the utility of the Wright table in medical education. Three modifications of the Wright table, each modeling specific cardiac conditions (i.e., paradoxical split S2 in left bundle branch block, mild aortic stenosis, and moderate aortic stenosis), are included to illustrate how the Wright table might be used in clinical training and research. In summary, the Wright table of the cardiac cycle provides new perspectives for visualization of the cardiac cycle in health and disease.

scholarly journals Intraventricular pressure gradients throughout the cardiac cycle: effects of ischaemia and modulation by afterload

2012 ◽  
Vol 98 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Miguel Guerra ◽  
Mário Jorge Amorim ◽  
Cármen Brás-Silva ◽  
Adelino F. Leite-Moreira
Keyword(s):  
Cardiac Cycle ◽  
Intraventricular Pressure ◽  
Pressure Gradients ◽  
Intraventricular Pressure Gradients

scholarly journals Intraventricular Pressure Gradients in Heart Failure

2013 ◽  
pp. 479-487 ◽  
Author(s):  
M. GUERRA ◽  
C. BRÁS-SILVA ◽  
M. J. AMORIM ◽  
C. MOURA ◽  
P. BASTOS ◽  
...  
Keyword(s):  
Heart Failure ◽  
Minimal Length ◽  
Saline Control ◽  
Control Group ◽  
Intraventricular Pressure ◽  
Pressure Gradients ◽  
Saline Control Group ◽  
Failure Group ◽  
Intraventricular Pressure Gradients ◽  
Ventricular Filling

The aim of the present study was to characterize intraventricular pressure gradients (IVPGs) in an animal model of chronic heart failure. New Zealand rabbits were treated with doxorubicin (heart failure group, n=5) or saline (control group, n=5) and instrumented with pressure catheters placed in the apex and outflow-tract of left ventricle (LV) and with sonomicrometer crystals placed in the apex and base of the LV free wall. In heart failure animals, ventricular filling was delayed and slower when compared with control animals. Moreover, the physiological nonuniformity observed between apical and basal segments in normal hearts was abolished in failing hearts. Simultaneously, physiological IVPGs observed during normal ventricular filling were entirely lost in heart failure animals. During ventricular emptying physiological nonuniformity between apical and basal segments observed in control animals was also abolished in heart failure animals. In failing hearts minimal length occurred later and almost at same time both in apical and in basal myocardial segments. Simultaneously, the characteristic IVPG pattern observed in healthy hearts during systole, which promotes ventricular emptying, was not observed in failing hearts. The present study showed that diastolic IVPGs, a marker of normal ventricular filling, and systolic IVPGs, a marker of normal ventricular emptying, are abolished in heart failure.

Relationship of simultaneous atrial and ventricular pressures in stage 16-27 chick embryos

1995 ◽  
Vol 269 (4) ◽  
pp. H1359-H1362 ◽  
Author(s):  
N. Hu ◽  
B. B. Keller
Keyword(s):  
Diastolic Pressure ◽  
Dynamic Balance ◽  
Cellular Tissue ◽  
Pressure Gradients ◽  
Endocardial Cushions ◽  
Mean Pressure ◽  
And Function ◽  
A Site ◽  
Relationship Of ◽  
Ventricular Filling

Ventricular filling is determined by a dynamic balance between atrial and ventricular load and function. The embryonic cardiovascular system undergoes simultaneous growth and morphogenesis at the cellular, tissue, and organ levels to match the embryo's geometrically increasing metabolic demands. As part of our long-term investigation of atrial/ventricular coupling during primary cardiac morphogenesis, we defined the relationship between simultaneous atrial and ventricular pressures in the stage 16-27 white Leghorn chick embryo. We measured atrial and ventricular blood pressures with servo-null micropressure systems and sampled analog waveforms digitally at 500 Hz. Peak atrial pressure increased geometrically from 0.38 +/- 0.03 to 1.21 +/- 0.17 mmHg, while ventricular end-diastolic pressure increased linearly from 0.18 +/- 0.03 to 0.55 +/- 0.04 mmHg. The passive and active mean pressure gradients increased from 0.23 +/- 0.04 and 0.20 +/- 0.03 mmHg at stage 16 to 0.52 +/- 0.10 and 0.62 +/- 0.11 mmHg at stage 27, respectively. The atrioventricular pressure gradients were similar for stages 16, 18, and 21, then increased to stage 27. This diastolic pressure gradient identifies the atrioventricular orifice and developing endocardial cushions as a site of flow resistance that may influence both ventricular filling and chamber morphogenesis.

Regulation of contractile force during ventricular arrhythmias

1959 ◽  
Vol 197 (5) ◽  
pp. 971-977 ◽  
Author(s):  
Arthur A. Siebens ◽  
Brian F. Hoffman ◽  
Paul F. Cranefield ◽  
Chandler McC. Brooks
Keyword(s):  
Linear Function ◽  
Refractory Period ◽  
Ventricular Arrhythmias ◽  
Cardiac Cycle ◽  
Pressure Fluctuations ◽  
Contractile Force ◽  
Postextrasystolic Potentiation ◽  
Anesthetized Dogs ◽  
Premature Beats ◽  
Ventricular Filling

Causes of fluctuations in ventricular pressure during arrhythmias were studied in anesthetized dogs. Excitability and contractility were measured throughout the cardiac cycle and their relationship to the problem was assessed. The strength of premature contractions was found to vary inversely with prematurity. Weakness of premature beats could not be ascribed to subnormal excitability nor to insufficient ventricular filling. Contractility was virtually zero at the end of the total refractory period, increased progressively thereafter and was fully restored only at the very end of the cardiac cycle. Sensitivity of contractile force to increments in ventricular filling paralleled the return of contractility. The strength of the postcompensatory contraction was always enhanced, this potentiation increasing as a linear function of the extrasystole's prematurity. Postextrasystolic potentiation was attributed to the extrasystole itself rather than to the pause which follows it or to increases in ventricular filling and distention. It was therefore concluded that pressure fluctuations during ventricular arrhythmias are not due to subnormal excitability and would occur independently of variations in ventricular filling.

The changes in right ventricular diastolic indices in babies with pulmonary atresia and intact ventricular septum undergoing corrective surgery: a pulsed Doppler echocardiographic study

1991 ◽  
Vol 1 (2) ◽  
pp. 114-122 ◽  
Author(s):  
Maurice P. Leung ◽  
Peter T. S. Lo ◽  
Roxy N. S. Lo ◽  
Henry Cheung ◽  
Che-Keung Mok
Keyword(s):  
Heart Rate ◽  
Right Ventricular ◽  
Cardiac Cycle ◽  
Pulmonary Atresia ◽  
Diastolic Filling ◽  
Pulsed Doppler ◽  
Intact Ventricular Septum ◽  
Right Ventricular Filling ◽  
Active Wave ◽  
Ventricular Filling

SummaryWe used pulsed Doppler echocardiography to study the right ventricular diastolic function of29 normal babies and 12 neonates with pulmonary atresia and intact ventricular septum. Eleven patients underwent staged operations of closed pulmonaryvalvotomy followed by either rightventricular outflow reconstruction (n=5) or balloon angioplasty of the pulmonary valve (n=3). In normal babies, the Doppler wave form showed dominant early (E) and separate late active (A) waves of activity, when the heart rate was slow (<100/min). The two waves gradually merged with increasing heart rate, to form a monophasic active wave. Prior to any intervention, all except one of our patients had only a monophasic active right ventricular filling wave over the entire range of heart rates recorded. To quantitate these differences in ventricular filling, we derived 4 diastolic indices from the ratio of: the peak velocity of the early versus the late active wave (EIA); the integral with time of these waves (E/Aarea); the time of diastolic filling relative to the cardiac cycle (TIRR); and the peak diastolic filling velocity relative to the mean filling velocity over the cardiac cycle (Velocity Index). Profiles of the indices against heart rate for both normal controls and patients indicated that only the index of the time of diastolic filling (T/RR) and the Velocity Index were appropriate for our serial comparisons. Thus, for neonates with pulmonary atresia, the index of the time (TIRR) was significantly lower (0.29±0.03 vs 0.43±0.04, p<0.01) and the Velocity Index higher (5.98±0.79 vs 3.98 ±0.31, p<0.001) than those of normal. After valvotomy, but with a poor surgical result, babies continued to have a predominantly monophasic right ventricular filling pattern without significant improvement (p>0.05) of the index of time (T/RR=0.29±0.05) or velocity (5.88±1.17). Babies who underwent a second stage procedure and achieved a final good result had predominantly biphasic right ventricular diastolic filling waves with significant progression (p<0.001) in the index of time (T/RR=0.42±0.03) and velocity (4.09±0.49).

scholarly journals The Physiology of the Alligator Heart: the Cardiac Cycle

1991 ◽  
Vol 158 (1) ◽  
pp. 539-564 ◽  
Author(s):  
G. SHELTON ◽  
D. R. JONES
Keyword(s):  
Right Ventricle ◽  
Cardiac Cycle ◽  
Pulmonary Arteries ◽  
Outflow Tract ◽  
Pressure Gradients ◽  
Aortic Valves ◽  
Systemic Blood ◽  
Second Stage ◽  
Blood Pressures ◽  
The Right

Pressure recordings from the heart and major arteries of the alligator show that a conventional relationship exists between the left ventricle and the right aorta. Pressure gradients from ventricle to aorta during systole are very small. Right aortic blood flow rises rapidly to a single peak and then falls more gradually until aortic valve closure. The right ventricle is connected both to the pulmonary arteries and to the left aorta. Right ventricular pressures show that systole is a two-stage process. Initially, blood leaves to the low-resistance lung circuit, though appreciable pressure gradients exist across the pulmonary outflow tract. Active contraction of the pulmonary outflow tract stops pulmonary ejection and a second-stage pressure rise is seen in the right ventricle. When systemic blood pressures are high, this second-stage pressure does not reach the levels recorded in the left aorta, and the left aortic valves remain closed so that lung and body circuits are functionally separate. An alternation of flow is found in the left aorta under these conditions, with reversed flow during systole and forward flow during diastole. Flow rates are extremely low, compared with those in the right aorta or pulmonary arteries, and the foramen of Panizza has very little significance in the cardiac cycle. If the systemic blood pressures are low, the second stage of systole in the right ventricle gives rise to pressures that are higher than those in the left aorta, the left aortic valves open and blood is ejected to the systemic circulation, giving a right-to-left shunt. This can occur with no changes in pulmonary pressures or flows. Left aortic flow is not dependent on increased constriction of the pulmonary outflow tract, which continues to function as an on-off active valve. Constriction within the lung vasculature may, on some occasions, be significant in establishing left aortic flow, but it is clear from the present work that low systemic blood pressure is a factor of crucial importance.

Abstract 18692: Evolution of Diastolic Parameters and Their Relationship to Heart Rate in the 7-15 Week Human Fetus

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Claudine M Bohun ◽  
Lisa Howley ◽  
Jesus Serrano Lomelin ◽  
Winnie Savard ◽  
Lindsay Mills ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Cycle ◽  
Fetal Heart ◽  
Left Ventricular ◽  
Time Interval ◽  
Ejection Time ◽  
Systolic Time ◽  
Ventricular Filling ◽  
Diastolic Time ◽  
Isovolumic Relaxation

Objectives: Fetal echo offers a unique opportunity to investigate cardiac function in humans from the 1st trimester. We sought to explore the evolution left ventricular (LV) diastolic parameters and their relationship to fetal heart rate (HR) from 7-15 weeks gestational age (GA). Methods: We prospectively performed fetal echo in 137 healthy pregnancies recruited from 7+0 to 15+0 (mean 11.5±2.1) weeks GA. From Doppler studies we measured LV isovolumic relaxation time (IRT), mitral valve (MV) inflow patterns,and duration, diastolic time (IRT+inflow duration), LV ejection time (ET) and systolic time interval (isovolumic contraction time+ET). All variables were compared to GA and HR and were assessed as a proportion of the cardiac cycle length (R-R). Data were analyzed by regression and correlation analyses. Results: Results: From 7+0-15+0 weeks, HR and GA showed a non-linear relationship (R2=0.55, p<0.001) with low HRs at 7-8 weeks, peaking between 8-9 weeks, then falling thereafter. Diastolic time linearly increased with GA (R2=0.65, p<0.001) and inversely correlated with HR (r=0.77, p<0.001). IRT showed a nonlinear inverse relationship with GA (R2= 0.70, p<0.001), but did not correlate with HR, and IRT/RR increased linearly with GA (R2=0.71, p<0.001). Both inflow duration and inflow duration/R-R linearly increased with GA (R2=0.81,p<0.001). Inflow duration inversely correlated with HR (r=-0.70) and with IRT (r=-0.71) and IRT/R-R (r=-0.83, p<0.001 for all 3). A uniphasic MV atrial systolic inflow signal was present in 20/21 fetuses at 7+1-9+0 weeks, whereas, biphasic MV inflow was seen in 45% at 9+1-10+0 , 76% at 10+1-11+0 , 95% at 11+1-13+0 and 100% after 13+1 weeks GA. Inflow duration was significantly longer (146.9±25.4 vs 85.2±12.6ms, p<0.001) and HR was lower (160±9 vs 170±10 bpm, p<0.001) in fetuses with a biphasic flow pattern. ET demonstrated a weak relationship with GA (R2=0.41) and no relationship with HR, IVRT,or IVRT/R-R, and the systolic time showed a nonlinear trend of decreasing with GA (R2=0.46). Conclusions: In the 7-15 week fetus, improvements in relaxation suggested by decreasing IRT, decreasing HR, and, to a lesser extent, decreasing systolic time likely contribute to increasing inflow duration and to early ventricular filling.

scholarly journals Role of Mitral Annulus Diastolic Geometry on Intraventricular Filling Dynamics

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Ikechukwu U. Okafor ◽  
Arvind Santhanakrishnan ◽  
Vrishank S. Raghav ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Valves ◽  
Cardiac Cycle ◽  
Vortical Structure ◽  
Mitral Annulus ◽  
Energy Dissipation Rate ◽  
Prosthetic Heart Valves ◽  
Prosthetic Devices ◽  
Geometric Changes ◽  
Ventricular Filling ◽  
Circular Design

The mitral valve (MV) is a bileaflet valve positioned between the left atrium and ventricle of the heart. The annulus of the MV has been observed to undergo geometric changes during the cardiac cycle, transforming from a saddle D-shape during systole to a flat (and less eccentric) D-shape during diastole. Prosthetic MV devices, including heart valves and annuloplasty rings, are designed based on these two configurations, with the circular design of some prosthetic heart valves (PHVs) being an approximation of the less eccentric, flat D-shape. Characterizing the effects of these geometrical variations on the filling efficiency of the left ventricle (LV) is required to understand why the flat D-shaped annulus is observed in the native MV during diastole in addition to optimizing the design of prosthetic devices. We hypothesize that the D-shaped annulus reduces energy loss during ventricular filling. An experimental left heart simulator (LHS) consisting of a flexible-walled LV physical model was used to characterize the filling efficiency of the two mitral annular geometries. The strength of the dominant vortical structure formed and the energy dissipation rate (EDR) of the measured fields, during the diastolic period of the cardiac cycle, were used as metrics to quantify the filling efficiency. Our results indicated that the O-shaped annulus generates a stronger (25% relative to the D-shaped annulus) vortical structure than that of the D-shaped annulus. It was also found that the O-shaped annulus resulted in higher EDR values throughout the diastolic period of the cardiac cycle. The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design.

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