what is systolic blood pressure a measure of
Blood pressure Blood pressure (BP) is the pressure of circulating blood on the walls of blood vessels. When used without further specification, "blood pressure" usually refers to the pressure in large arteries of the systemic circulation. Blood pressure is usually expressed in terms of the systolic pressure (maximum during one heart beat) over diastolic pressure (minimum in between two heart beats) and is measured in millimeters of mercury (mmHg), above the surrounding atmospheric pressure (considered to be zero for convenience).
Diastolic heart failure Diastolic failure is characterized by an elevated diastolic pressure in the left ventricle, despite an essentially normal/physiologic end diastolic volume (EDV). Histological evidence supporting diastolic dysfunction demonstrates ventricular hypertrophy, increased interstitial collagen deposition and infiltration of the myocardium. These influences collectively lead to a decrease in distensibility and elasticity (ability to stretch) of the myocardium. As a consequence, cardiac output becomes diminished. When the left ventricular diastolic pressure is elevated, venous pressure in lungs must also become elevated too: left ventricular stiffness makes it more difficult for blood to enter it from the left atrium. As a result, pressure rises in the atrium and is transmitted back to the pulmonary venous system, thereby increasing its hydrostatic pressure and promoting pulmonary edema.[1]