Search

One type of intrinsic response exhibited by the isolated and non-isolated heart is the well-known Frank-Starling mechanism, which endows the ventricles with performance characteristics such that the heart ejects whatever volume is put into it [heterometric autoregulation]. A second type of autoregulation in the isolated and no-isolated heart, one which apparently does not utilize the Frank-Starling mechanism, will be the main subject of this review. It requires at least a few beats to develop fully after an increase in activity. The ventricle then exhibits performance characteristics such that its end-diastolic pressure and fiber length tend to be maintained because of an increase in myocardial contractility. It will, therefore be referred to as homeometric autoregulation or Anrep effect. Assessment of ventricular load-independent parameters, including myocardial contractility, is important to better understand the pathophysiology of acute and right ventricular increased afterload. The role of the Anrep effect, in right ventricular dysfunction in patients with primary or secondary forms of pulmonary artery hypertension with chronic cor pulmonale, is analyzed and presented as an hypothesis to be considered in the pathophysiology in acute and in chronic states of right ventricular afterload. [ABSTRACT FROM AUTHOR]

The purpose of this study is to calculate non invasivelly left ventricular systolic wall stress by echocardiography in patients with primary heart failure, and compare the results with those obtained in parients with overloaded heart failure, diastolic dysfunction by Inapropiatte hypertrophy, with normal ejection fraction and people with normal heart, there stablish the value of the results in clinical settings. We studied 33 patients with heart failure by dilated cardiomyopathy. There was no significant association between the systolic wall stress and the ejection fraction, fractional shortening, dp/dt or left ventricular mass in this group of study. There was a significant association between systolic h/r ratio and the systolic wall stress. This study shows that in primary heart failure the afterload increases and has inverse relationship with ejection fraction (r = 0.86); but, when heart failure obey to an excessive overload exists an exquisite inverse relationship between systolic wall stress and ejection fraction (r = 0.93). The excessive hypertrophy (Inappropriate) reduces the systolic wall stress but causes diastolic dysfunction. The increase of systolic wall stress in Aortic regurgitation with normal ventricular performance is responsible of adequate left ventricular hypertrophy, by other means, in mitral insufficiency the presence of low or normal systolic wall stress does not induce left ventricular hypertrophy, then diameter increases and the hypertrophy is inadequate, despite this, left ventricular function is normal. [ABSTRACT FROM AUTHOR]