Some comments on ventricular afterload

Abstract

In this issue of Basic Research in Cardiology a paper by Timisjärvi et al. is presented in which the problem of afterload, generated by the resistance against which the left ventricle is ejecting, is discussed. These authors have performed experiments in which they examine the role and validity of the so-called mean outflow resistance (MOR) of the left ventricle. In this editorial, the opportunity is taken to present some thoughts on the different possibilities of expressing the interrelation between the heart and the arterial system. It is intended to show how, from the first ideas about ventricular-arterial interaction bei Ph. Broemser (1935; 1) different concepts about simple descriptions of the functioning of the heart, the arterial system and the matching between both have evolved. In particular, the concept by Sunagawa et al. seems worthy of mention. An examination of this, and several other concepts, prove that the peripheral resistance and, particularly, the MOR, are important parameters that determine the influence of the arterial system on the performance of the heart. However, since MOR by definition is closely related to the total peripheral resistance, there is no essential need to introduce this resistance as a new concept of ventricular afterload. Calculations based on this definition of MOR demonstrate an agreement between theory and experimental results.

Statin Use before By-Pass Surgery Decreases the Incidence and Shortens the Duration of Postoperative Atrial Fibrillation

“…Statins have been shown to decrease cathecolamine levels and normalizes autonomic neural control [17], both of which can also be responsible for indirect anti-arrhythmic effects of statins other than their anti-inflammatory effects. In addition to their indirect anti-arrhythmic effects, statins may also exhibit direct anti-arrhythmic effects by modulating the fatty acid composition and physiochemical properties of cell membranes, with resultant alterations in transmembrane ion channel properties [18, 19]. Based on this knowledge, it is wise to expect a lower rate of postoperative AF in patients receiving statin treatment before the surgery, which was shown in the present study.…”

Arterial blood pressure and its measurement

“…If a spherical configuration of the left ventricle is assumed, then the right side of Equation (10) has to be divided by 2. The arterial pressure is generated by the ejection of blood from the left ventricle and, therefore, is the result of an interaction between ventricle and arterial system as discussed in an earlier editorial (11). The load carried by the fibers of the myocardium on the wall stress, i.e.…”