Pulse pressure

The heart works in two phases, the contraction phase ( ejection phase, systole) and relaxation phase ( filling or resting phase, diastole ). It thus creates pressure only during the contraction phase. The difference between the peak pressure of the systole and the minimum pressure at the end of the diastole is the pulse amplitude as the pulse pressure ( pulse pressure English, abbreviated as PP) and designated as the blood pressure amplitude.

The blood is ejected into the large vessels. These are not rigid tubes, but elastic tubes. Thanks to their elasticity they expand and soften the pressure rise, otherwise the pressure during the ejection phase would rise very high. During diastole, when the heart is relaxed and filling up with blood again, the pressure does not fall to zero accordingly. Again, thanks to the elasticity of the vessels, the pressure drops gradually to the minimum value, the diastolic value of the cardiac cycle, from. This pressure compensation function of the elastic tubes is called Windkessel function - in analogy to the technical systems where a piston pump combined with a surge tank with the exact same purpose of pressure equalization.

The height of the pulse amplitude is determined mainly by the elasticity of the vessels, the volume ejected from the heart, and the duration of diastole. As with the formation of atherosclerosis decreases the elasticity, the systolic pressure may rise isolated: This creates an isolated systolic hypertension.

There is no generally accepted standard or normal values ​​for the pulse pressure, but it will, among others, by many blood pressure equipment manufacturers, classified values ​​around or lower than 50 mmHg as normal. Spread a need for treatment is accepted from about 65 mmHg.