Ventricular stiffness

Causes of diastolic dysfunction (restriction in ventricular filling) are increased ventricular stiffness, ventricular hypertrophy, infiltrative myocardial diseases, myocardial ischemia and infarction, mitral or tricuspid valve stenosis, and pericardial disease (e.g., pericarditis, pericardial tamponade). 

Earlier, 3-phenacyl-4,5-dimethylthiazolium chloride (ALT-711) had been shown to reverse diabetes-induced increases in large artery stiffness in streptozotocin-treated rats,604 age-related left ventricular stiffness in aged dogs,605 and age-related deterioration in arterial and ventricular function in aged primates606... 

Systolic dysfunction, or decreased contractility, can be caused by dilated cardiomyopathies, ventricular hypertrophy, or a reduction in muscle mass. Diastolic dysfunction, or restriction in ventricular filling, can be caused by increased ventricular stiffness, mitral or tricuspid valve stenosis, or pericardial disease. Both ventricular hypertrophy and myocardial ischemia can contribute to increased ventricular stiffness. Angiotensin II causes and/or exacerbates heart failure by increasing systemic vascular resistance, promoting sodium retention. 

Relationship between ventricular stiffness, cavity size, wall mass, coronary blood volume and myocardial stiffness... 

Janz et al. (1978) attempted to describe the effects of various types of aneurysms on the local fiber elongation and also obtain a relationship between ventricular stiffness and aneurysm size. 

Relationship between ventricular stiffness, myocardial elasticity, coronary blood volume, cavity size and the volume mass ratio... 

Templeton GH, Wildenthal K, Willerson JT and Mitchell JH (1975) Influence of acute myocardial depression on left ventricular stiffness and its elastic and viscous components. J Clin Invest 56 278-285... 

While Equation 28.7 is useful because of its simplicity, the one-to-one relation between DT and chamber stiffness implied by Equation 28.7 is incomplete. It implies that, with other hemodynamic variables constant, two ventricles having the same DTs should have the same values for left ventricular stiffness (AP/A vg) However, subjects with indistinguishable DTs by Doppler echo having significantly different catheterization-determined chamber stiffness AP/AVavg were often observed [64]. This finding... 

Likewise, heart failure is not always associated with systolic dysfunction and an obvious decline in cardiac pumping ability. In approximately half the cases of symptomatic heart failure, systolic function and cardiac output may appear normal when the patient is at rest.53,63 In this type of heart failure, cardiac function is impaired because the left ventricle is stiff and unable to relax during the filling phase, resulting in increased pressures at the end of diastole.31 This condition is often described as diastolic heart failure, but it is also identified by other names such as heart failure with preserved left ventricular... 

Nagueh, S. F., Shah, G., and Wu, Y. (2004). Altered titin expression, myocardial stiffness, and left ventricular function in patients with dilated cardiomyopathy. Circulation 110, 115-162. 

Unlike other animals, the dog appears sensitive to chlorphenoxy herbicides, such as 2,4-D the dog s oral LD50 to 2,4-D is 100 mg kg body weight. Ventricular fibrillation is the cause of death in severely poisoned dogs. Ingestion of sublethal doses induces stiff extremities, ataxia, myotonia, paralysis, coma, and subnormal temperatures. 

Calcium accumulation and overload secondary to ischemia impair ventricular relaxation as well as contraction. This is apparently a result of impaired calcium uptake after systole from the myofilaments, leading to a less negative decline in the pressure in the ventricle over time. Impaired relaxation is associated with enhanced diastolic stiffness, decreased rate of wall thinning, and slowed pressure decay, producing an upward shift in the ventricular pressure-volume relationship put more simply, MVO2 is likely to be increased secondary to increased wall tension. Impairment of both diastolic and systolic function leads to elevation of the filling pressure of the left ventricle. 

S4 (atrial gallop) Reduced ventricular compliance ("stiff heart") Common very common in patients who have sustained a prior Ml as well as during angina... 

HUMAN HEALTH RISKS Acute Risks irritation of eyes and skin nausea diarrhea dysphagia gastrointestinal distress vomiting ventricular fibrillation Chronic Risks liver and kidney damage convulsions stiffness of extremities ataxia paralysis coma muscular weakness mutagenic and teratogenic effects. 

Mechanical performance of the heart, more specifically the left ventricle, is typically characterized by estimates of ventricular elastance. The heart is an elastic bag that stiffens and relaxes with each heartbeat. Elastance is a measure of stiffness, classically defined as the differential relation between pressure and volume ... 

Poreba, R., P. Gac, M. Poreba, J. Antonowicz-Juchniewicz, and R. Andrzejak. 2011a. Relationship between occupational exposure to lead and local arterial stiffness and left ventricular diastolic function in individuals with arterial hypertension. Toxicol. Appl. Pharmacol. 254(3) 342-348. 

Right ventricular perforation. Because of their stiffness, certain models of bipolar leads, particularly those insulated with polyurethane, were more prone to right ventricular perforation. The stiff distal end of the lead may damage the endomyocardium and in some cases result in ventricular penetration and perforation (6). Such stiff bipolar leads are no longer available and today there is very little difference in the stiffness between unipolar and bipolar leads. 

What is the effect of ventricular shape on the diastolic LV pressure-volume relations and on the quantitation of myocardial stiffness-stress relations ... 

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