2 components of ventricular contractility and their determination based on a noninvasive method

It is suggested that a force component and a rate component should be distinguished for elaborating the quantitative values of the contractility of the heart ventricle. In experiments the first component is determined as the maximum pressure in the ventricle during isovolumic contraction, and the second component, as the maximum value of the blood flow in the ejection phase at zero afterload. Analysis of the data found in the literature and the results of the authors' experiments provides evidence that the force and rate components differ in their dependence on the hemodynamic conditions. A noninvasive method for determining the contractility components is suggested. Analysis of the clinical data and the literature confirms that the force and rate components change in a different manner in various types of pathological conditions.