scholarly journals Longitudinal Reinforcement of Acute Myocardial Infarcts Improves Function by Transmurally Redistributing Stretch and Stress

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ana Cristina Estrada ◽  
Kyoko Yoshida ◽  
Samantha A. Clarke ◽  
Jeffrey W. Holmes
Keyword(s):  
Diastolic Pressure ◽  
Heart Function ◽  
Systolic Function ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Published Data ◽  
Longitudinal Reinforcement ◽  
Wide Range ◽  
Volume Relationship ◽  
Pressure Volume Relationship

Abstract A wide range of emerging therapies, from surgical restraint to biomaterial injection to tissue engineering, aim to improve heart function and limit adverse remodeling following myocardial infarction (MI). We previously showed that longitudinal surgical reinforcement of large anterior infarcts in dogs could significantly enhance systolic function without restricting diastolic function, but the underlying mechanisms for this improvement are poorly understood. The goal of this study was to construct a finite element model that could match our previously published data on changes in regional strains and left ventricular function following longitudinal surgical reinforcement, then use the model to explore potential mechanisms for the improvement in systolic function we observed. The model presented here, implemented in febio, matches all the key features of our experiments, including diastolic remodeling strains in the ischemic region, small shifts in the end-diastolic pressure–volume relationship (EDPVR), and large changes in the end-systolic pressure–volume relationship (ESPVR) in response to ischemia and to patch application. Detailed examination of model strains and stresses suggests that longitudinal reinforcement reduces peak diastolic fiber stretch and systolic fiber stress in the remote myocardium and shifts those peaks away from the endocardial surface by reshaping the left ventricle (LV). These findings could help to guide the development of novel therapies to improve post-MI function by providing specific design objectives.

scholarly journals Linear end-systolic pressure-volume relationship during pulsatile left ventricular bypass represents native heart function

1995 ◽  
Vol 109 (4) ◽  
pp. 780-786 ◽  
Author(s):  
Osamu Kawaguchi ◽  
John S. Sapirstein ◽  
William B. Daily ◽  
Walter E. Pae ◽  
William S. Pierce
Keyword(s):  
Heart Function ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Volume Relationship ◽  
Pressure Volume Relationship

Single-beat evaluation of left ventricular inotropic state in conscious dogs

1989 ◽  
Vol 256 (1) ◽  
pp. H56-H65 ◽  
Author(s):  
E. C. Lascano ◽  
J. A. Negroni ◽  
J. G. Barra ◽  
A. J. Crottogini ◽  
R. H. Pichel
Keyword(s):  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Time Data ◽  
Inotropic State ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Experimental Findings ◽  
Parameter Values

Two competing left ventricular elastic-resistive (ER) models were used to predict parameter values from pressure, volume, and time data of a single ejective beat in conscious dogs during control, enhanced (dobutamine), and decreased (propranolol) inotropic states. The animals were instrumented with three pairs of microcrystals and a transducer to measure intraventricular volume and pressure. Results showed that with the ER nonlinear model (ERNL), parameter values in all animals lay within the physiological range. These were the slope (Emax) and the intercept (V0) of the isovolumic end-systolic pressure-volume relationship (ESPVR), the slope of the end-diastolic pressure-volume relationship (Ed), the time to Emax (Tmax), the normalized time to end of activation (A), and the resistive constant (K). In the two models, the normalized SE of the estimate of data fitting was below 0.2 Emax, as estimated from a single beat, responded to changes in contractility in a significantly more consistent fashion than the slope of ESPVRs (Ees) generated by preload maneuvers in conscious dogs. Single-beat estimated Tmax and K with the ERNL model did also respond consistently to contractility changes, whereas with the elastic resistive linear (ERL) model, K did not reproduce the experimental findings with decreased inotropic state. We conclude that 1) the ERNL model can be employed to assess contractility changes in conscious dogs from data of a single ejective beat, and 2) these changes are better indicated by single-beat estimated Emax than by Ees calculated from conventional ESPVRs.

Abstract 16333: Racial Differences in Pressure-volume Relationships in Val122Ile Associated Cardiac Amyloidosis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jaya Batra ◽  
iacopo olivotto ◽  
Mathew S Maurer
Keyword(s):  
Racial Differences ◽  
Cardiac Amyloidosis ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Disease Phenotype ◽  
Cardiac Chamber ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
White Patients

Background: Transthyretin cardiac amyloidosis (ATTR-CA) is the leading cause of restrictive cardiomyopathy in older adults. The valine-to-isoleucine substitution (Val122Ile) is the most common inherited variant in the U.S., primarily affecting patients of Afro-Caribbean descent. This variant has also been identified in white individuals in Northern Italy who present with a similar disease phenotype. It is unknown whether there are between-race differences in cardiac chamber function at diagnosis of Val122Ile associated ATTR-CA. Methods: In this retrospective study of 70 patients from two amyloid centers with Val122Ile associated ATTR-CA diagnosed over two decades, clinical and echocardiographic features at diagnosis were compared between races. Cardiac chamber performance was compared using noninvasive, single beat pressure-volume analysis. Results: Average age at diagnosis was 72 years. Compared to white patients (n=17), black individuals (n=53) had lower systolic blood pressure (110 vs. 131 mmHg , p<0.001), reduced pulse pressure (41 vs. 58 mmHg, p<0.001), and impaired renal function (eGFR 46 vs. 67 mL/min/1.73m 2 , p<0.001) at the time of diagnosis. End-systolic pressure-volume relationship (2.3 vs. 1.9 mmHg/mL, p = 0.88), and arterial elastance (3.0 vs. 3.0 mmHg/mL, p = 1.0) were similar between groups (Panel A). Black patients had an end-diastolic pressure-volume relationship shifted upward and leftward relative to white patients, indicating reduced left ventricular capacity. Accordingly, pressure-volume area at a left ventricular end-diastolic pressure of 30 mmHg was lower in black compared to white individuals (8,415 vs. 11,538 mmHg*mL, p = 0.012, Panel B). Conclusion: Despite presenting at a similar age to white patients, black individuals with Val122Ile associated ATTR-CA have a greater degree of cardiac remodeling which drives reduced overall chamber function. These findings suggest a more aggressive disease phenotype.

Effect of lidocaine on left ventricular pressure-volume curves during demand ischemia in pigs

1998 ◽  
Vol 274 (6) ◽  
pp. H2100-H2109 ◽  
Author(s):  
Masao Tayama ◽  
Steven B. Solomon ◽  
Stanton A. Glantz
Keyword(s):  
Diastolic Dysfunction ◽  
Diastolic Pressure ◽  
Systolic Function ◽  
Left Ventricular ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Volume Relationship ◽  
Before And After ◽  
Lidocaine Injection ◽  
Pressure Volume Relationship

The diastolic pressure-volume curve shifts upward during demand ischemia, most likely because of changes in Ca2+ dynamics within the sarcomere. It is possible that agents that affect Na+/Ca2+exchange, such as lidocaine, a class 1b-type Na+-channel blocker that decreases intracellular Na+, could affect the diastolic pressure-volume relationship because of indirect effects on intracellular Ca2+. Lidocaine is a drug widely used to treat arrhythmias in patients with myocardial ischemia. We studied the effects of lidocaine on diastolic dysfunction associated with demand ischemia. We compared diastolic (as represented by the shift in the diastolic pressure-volume relationship) and systolic function during demand ischemia before and after lidocaine injection. We created demand ischemia in pigs before and after administering lidocaine (5 mg/kg) in eight open-pericardium anesthetized pigs. Demand ischemia was induced by constricting the left anterior descending coronary artery and then pacing at 1.5–1.8 times the baseline heart rate for 1.5–3 min. Hemodynamics were recorded during baseline, demand ischemia, baseline after lidocaine injection, and demand ischemia after lidocaine. Lidocaine did not affect systolic function or the time constant of isovolumic relaxation, but it increased the upward shift of the diastolic pressure-volume curve during demand ischemia compared with the increase that occurred before lidocaine was administered. This result suggests that lidocaine could aggravate diastolic dysfunction in patients with ischemic heart disease.

Effect of human urotensin-II infusion on hemodynamics and cardiac function

2003 ◽  
Vol 81 (2) ◽  
pp. 125-128 ◽  
Author(s):  
Ghada S Hassan ◽  
Fazila Chouiali ◽  
Takayuki Saito ◽  
Fu Hu ◽  
Stephen A Douglas ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Diastolic Pressure ◽  
Cardiac Contractility ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Urotensin Ii ◽  
Ventricular Systolic Pressure ◽  
Wide Range ◽  
Dose Dependent Decrease

Recent studies have shown that the vasoactive peptide urotensin-II (U-II) exerts a wide range of action on the cardiovascular system of various species. In the present study, we determined the in vivo effects of U-II on basal hemodynamics and cardiac function in the anesthetized intact rat. Intravenous bolus injection of human U-II resulted in a dose-dependent decrease in mean arterial pressure and left ventricular systolic pressure. Cardiac contractility represented by ±dP/dt was decreased after injection of U-II. However, there was no significant change in heart rate or diastolic pressure. The present study suggests that upregulation of myocardial U-II may contribute to impaired myocardial function in disease conditions such as congestive heart failure.Key words: urotensin-II, rat, infusion, heart.

scholarly journals The pericardium substantially affects the left ventricular diastolic pressure-volume relationship in the dog.

1978 ◽  
Vol 42 (3) ◽  
pp. 433-441 ◽  
Author(s):  
S A Glantz ◽  
G A Misbach ◽  
W Y Moores ◽  
D G Mathey ◽  
J Lekven ◽  
...  
Keyword(s):  
Diastolic Pressure ◽  
Left Ventricular ◽  
Volume Relationship ◽  
Pressure Volume Relationship

Effects of mechanical vibration on left ventricular diastolic properties during global ischemia

1992 ◽  
Vol 263 (1) ◽  
pp. H88-H95
Author(s):  
J. Kikuchi ◽  
Y. Koiwa ◽  
T. Takagi ◽  
H. Honda ◽  
N. Hoshi ◽  
...  
Keyword(s):  
Diastolic Pressure ◽  
Mechanical Vibration ◽  
Pressure Change ◽  
Left Ventricular ◽  
Global Ischemia ◽  
Stiffness Index ◽  
Diastolic Interval ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
Diastolic Properties

To examine the effect of mechanical vibration on ventricular relaxation and diastolic chamber stiffness under global ischemia, we studied eight coronary perfused, isolated, isovolumic canine left ventricles (LV). To produce varying degrees of impaired relaxation, graded coronary flow reduction and paced tachycardia were imposed. A mechanical 50-Hz, 2-mm-amplitude vibration was applied during diastole and was turned off during systole. Without diastolic vibration, the relaxation time constant of LV pressure (tau) increased with the severity of ischemia. The chamber stiffness index (K) from the diastolic pressure-volume relationship showed a slight increase during ischemia; tau decreased with diastolic vibration. The change in tau with vibration increased with ischemia and was dependent on vibration amplitude but not heart rate. The ratio of tau to the diastolic interval (DI, the time from peak negative rate of LV pressure change to end diastole) always decreased with vibration and was linearly correlated with K (r = 0.93; P less than 0.01). K decreased with vibration when tau/DI was greater than 0.3. We conclude that diastolic vibration improves impaired relaxation and chamber stiffness under myocardial ischemia.

Pressure-volume-based single-beat estimations cannot predict left ventricular contractility in vivo

2002 ◽  
Vol 282 (5) ◽  
pp. H1739-H1750 ◽  
Author(s):  
Knut E. Kjørstad ◽  
Christian Korvald ◽  
Truls Myrmel
Keyword(s):  
Systolic Pressure ◽  
Left Ventricular ◽  
Clinical Applications ◽  
Volume Data ◽  
Ventricular Contractility ◽  
Limits Of Agreement ◽  
Volume Relationship ◽  
Pressure Volume Relationship ◽  
State Pressure

The end-systolic pressure-volume relationship is regarded as a useful index for assessing the contractile state of the heart. However, the need for preload alterations has been a serious limitation to its clinical applications, and there have been numerous attempts to develop a method for calculating contractility based on one single pressure-volume loop. We have evaluated four of these methods. Pressure-volume data were obtained by combined pressure and conductance catheters in 37 pigs. All four methods were applied to 88 steady-state pressure-volume files, including eight files sampled during dopamine infusions. Estimates of single-beat contractility (elastance) were compared with preload-varied multiple-beat elastance [ E es(MB)]. All methods had a low average bias (−0.3 to 0.5 mmHg/ml) but limits of agreement (±2 SD) were unacceptably high (±2.6 to ±3.8 mmHg/ml). In the dopamine group, E es(MB) showed an increase of 1.7 ± 0.8 mmHg/ml (mean ± SD) compared with baseline ( P < 0.001). None of the single-beat methods predicted this increase in contractility. It is therefore doubtful whether any of the methods allow for single-beat assessment of contractility.

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