Editorial Commentary Myocardial Wall Stress From Hypertension to Heart Tension

Hypertensionologists have become increasingly interestedin measuring “central ” blood pressure at the aortic root rather than that in the upper limb. This is mainly because central blood pressure is more closely related to “load on the left ventricle ” than peripheral blood pressure. A more precise measure of the consequences of hydraulic afterload on the myocardium is myocardial wall stress, the tension in individ-ual myocardial fibers. Myocardial wall stress is determined not just by pressure in the ventricle, which, during systole (and in the absence of aortic valve disease or left ventricular outflow tract gradient), approximates pressure at the aortic root, but also the dimensions of the left ventricular cavity and walls (Laplace law). Ventricular pressure and volume are interdependent properties as a result of the inverse relation-ship at muscle level between force generation and shortening velocity, as well as the length-dependence of contractile forc