[Homeometric autoregulation in the heart. The Anrep effect. Its possible role in increased right ventricular...

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.