Windkessel effect
Encyclopedia
Windkessel effect is a term used in medicine
to account for the shape of the arterial pressure waveform in terms of the interaction between the stroke volume
and the compliance of the aorta and large elastic arteries (Windkessel vessels). Windkessel
in German
literally means 'air chamber', but is generally taken to imply an elastic reservoir. The walls of large elastic arteries (eg. aorta
, common carotid, subclavian
, and pulmonary arteries and their larger branches) contain elastic fibers, formed of elastin
. These arteries distend when the blood pressure
rises during systole
and recoil when the blood pressure falls during diastole
. Since the rate of blood entering these elastic arteries exceeds that leaving them due to the peripheral resistance there is a net storage of blood during systole which discharges during diastole. The Windkessel effect helps in damping
the fluctuation in blood pressure
(pulse pressure
) over the cardiac cycle
and assists in the maintenance of organ perfusion during diastole when cardiac ejection ceases.
The Windkessel effect becomes diminished with age as the elastic arteries become less compliant, termed hardening of the arteries or arteriosclerosis
, probably secondary to fragmentation and loss of elastin
. The reduction in the Windkessel effect results in increased pulse pressure
and systolic pressure for a given stroke volume
. Elevated systolic pressure predicts myocardial infarction
, stroke
, cardiac enlargement, heart failure and a variety of other cardiovascular diseases.
Although the Windkessel is a simple and convenient concept, it is widely seen as in conflict with, and superseded by, modern approaches that interpret arterial pressure and flow waveforms in terms of wave propagation and reflection. .
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
to account for the shape of the arterial pressure waveform in terms of the interaction between the stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
and the compliance of the aorta and large elastic arteries (Windkessel vessels). Windkessel
Windkessel
Windkessel literally means air chamber and is a German translation of a concept described previousy by Stephen Hales, who likened the effect of the elastic arteries in dampening the arterial pulse to that of an air chamber in some 18th century fire engines...
in German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
literally means 'air chamber', but is generally taken to imply an elastic reservoir. The walls of large elastic arteries (eg. aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
, common carotid, subclavian
Subclavian
In general, Subclavian means beneath the clavicle, and it can refer to:* Subclavian vein* Subclavian artery* Subclavian nerve...
, and pulmonary arteries and their larger branches) contain elastic fibers, formed of elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...
. These arteries distend when the blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
rises during systole
Systole (medicine)
Systole is the contraction of the heart. Used alone, it usually means the contraction of the left ventricle.In all mammals, the heart has 4 chambers. The left and right ventricles pump together. The atria and ventricles pump in sequence...
and recoil when the blood pressure falls during diastole
Diastole
Diastole is the period of time when the heart fills with blood after systole . Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are relaxing...
. Since the rate of blood entering these elastic arteries exceeds that leaving them due to the peripheral resistance there is a net storage of blood during systole which discharges during diastole. The Windkessel effect helps in damping
Damping
In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...
the fluctuation in blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
(pulse pressure
Pulse pressure
Pulse Pressure is most easily defined as being the amount of pressure required to create the feeling of a pulse. Measured in millimeters of mercury , the pressure difference between the systolic and diastolic pressures give you the amount of pressure change to create the pulse, which is the pulse...
) over the cardiac cycle
Cardiac cycle
The cardiac cycle is a term referring to all or any of the events related to the flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next. The frequency of the cardiac cycle is described by the heart rate. Each beat of the heart involves five major stages...
and assists in the maintenance of organ perfusion during diastole when cardiac ejection ceases.
The Windkessel effect becomes diminished with age as the elastic arteries become less compliant, termed hardening of the arteries or arteriosclerosis
Arteriosclerosis
Arteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries It should not be confused with "arteriolosclerosis" or "atherosclerosis".Also known by the name "myoconditis" which is...
, probably secondary to fragmentation and loss of elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...
. The reduction in the Windkessel effect results in increased pulse pressure
Pulse pressure
Pulse Pressure is most easily defined as being the amount of pressure required to create the feeling of a pulse. Measured in millimeters of mercury , the pressure difference between the systolic and diastolic pressures give you the amount of pressure change to create the pulse, which is the pulse...
and systolic pressure for a given stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
. Elevated systolic pressure predicts myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, cardiac enlargement, heart failure and a variety of other cardiovascular diseases.
Although the Windkessel is a simple and convenient concept, it is widely seen as in conflict with, and superseded by, modern approaches that interpret arterial pressure and flow waveforms in terms of wave propagation and reflection. .