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 ◽  
...  

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.

1994 ◽  
Vol 57 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Ryousuke Matsuwaka ◽  
Hikaru Matsuda ◽  
Ryota Shirakura ◽  
Mitsunori Kaneko ◽  
Norihide Fukushima ◽  
...  

1978 ◽  
Vol 42 (3) ◽  
pp. 433-441 ◽  
Author(s):  
S A Glantz ◽  
G A Misbach ◽  
W Y Moores ◽  
D G Mathey ◽  
J Lekven ◽  
...  

Heart ◽  
2009 ◽  
Vol 96 (3) ◽  
pp. 213-219 ◽  
Author(s):  
E. A. ten Brinke ◽  
D. Burkhoff ◽  
R. J. Klautz ◽  
C. Tschope ◽  
M. J. Schalij ◽  
...  

1989 ◽  
Vol 256 (1) ◽  
pp. H56-H65 ◽  
Author(s):  
E. C. Lascano ◽  
J. A. Negroni ◽  
J. G. Barra ◽  
A. J. Crottogini ◽  
R. H. Pichel

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.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jaya Batra ◽  
iacopo olivotto ◽  
Mathew S Maurer

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.


Circulation ◽  
1977 ◽  
Vol 55 (5) ◽  
pp. 761-766 ◽  
Author(s):  
T Mann ◽  
B R Brodie ◽  
W Grossman ◽  
L P McLaurin

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ana Cristina Estrada ◽  
Kyoko Yoshida ◽  
Samantha A. Clarke ◽  
Jeffrey W. Holmes

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.


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