Enhanced external counterpulsation
Encyclopedia
Enhanced External counterpulsation therapy (EECP) is a procedure performed on individuals with angina or heart failure or cardiomyopathy
in order to diminish their symptoms ischemia
, improve functional capacity and quality of life. In various studies, EECP has been shown to relieve angina, and decrease the degree of ischemia in a cardiac stress test
.
monitors that monitor their heart rate and rhythm. The most common type in use involves three cuffs placed on each leg (on the calfs, the lower thighs, and the upper thighs (or buttock)). The cuffs are timed to inflate and deflate based on the individual's electrocardiogram
. The cuffs should ideally inflate at the beginning of diastole
and deflate at the beginning of systole
. During the inflation portion of the cycle, the calf cuffs inflate first, then the lower thigh cuffs and finally the upper thigh cuffs. Inflation is controlled by a pressure monitor, and the cuffs are inflated to about 200 mmHg.
When timed correctly, this will decrease the afterload
that the heart has to pump against, and increase the preload that fills the heart, increasing the cardiac output
. In this way, EECP is similar to the intra-aortic balloon pump
(IABP). Since it increases pressure in the aorta while the heart is relaxing (during diastole
) EECP also increases blood flow into the coronary arteries, which also occurs during that phase.
.
Cardiomyopathy
Cardiomyopathy, which literally means "heart muscle disease," is the deterioration of the function of the myocardium for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both. Cardiomyopathy can often go undetected, making it especially dangerous to...
in order to diminish their symptoms ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
, improve functional capacity and quality of life. In various studies, EECP has been shown to relieve angina, and decrease the degree of ischemia in a cardiac stress test
Cardiac stress test
Cardiac stress test is a test used in medicine and cardiology to measure the heart's ability to respond to external stress in a controlled clinical environment....
.
Method
While an individual is undergoing EECP, one has pneumatic cuffs on his legs and are connected to telemetryTelemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
monitors that monitor their heart rate and rhythm. The most common type in use involves three cuffs placed on each leg (on the calfs, the lower thighs, and the upper thighs (or buttock)). The cuffs are timed to inflate and deflate based on the individual's electrocardiogram
Electrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...
. The cuffs should ideally inflate at the beginning of 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...
and deflate at the beginning of 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...
. During the inflation portion of the cycle, the calf cuffs inflate first, then the lower thigh cuffs and finally the upper thigh cuffs. Inflation is controlled by a pressure monitor, and the cuffs are inflated to about 200 mmHg.
When timed correctly, this will decrease the afterload
Afterload
Afterload is the tension or stress developed in the wall of the left ventricle during ejection. Following Laplace's law, the tension upon the muscle fibers in the heart wall is the product of the pressure within the ventricle, multiplied by the volume within the ventricle, divided by the wall...
that the heart has to pump against, and increase the preload that fills the heart, increasing the cardiac output
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
. In this way, EECP is similar to the intra-aortic balloon pump
Intra-aortic balloon pump
The Intra-aortic balloon pump ' is a mechanical device that increases myocardial oxygen perfusion while at the same time increasing cardiac output. Increasing cardiac output increases coronary blood flow and therefore myocardial oxygen delivery...
(IABP). Since it increases pressure in the aorta while the heart is relaxing (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...
) EECP also increases blood flow into the coronary arteries, which also occurs during that phase.
Physiological considerations
One theory is that ECP exposes the coronary circulation to increased shear stress, and that this results in the production of a cascade of growth factors that result in angiogenesisAngiogenesis
Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. Though there has been some debate over terminology, vasculogenesis is the term used for spontaneous blood-vessel formation, and intussusception is the term for the formation of new blood...
.
See also
- CardiomyopathyCardiomyopathyCardiomyopathy, which literally means "heart muscle disease," is the deterioration of the function of the myocardium for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both. Cardiomyopathy can often go undetected, making it especially dangerous to...
- Ischemic cardiomyopathy
- Coronary circulationCoronary circulationCoronary circulation is the circulation of blood in the blood vessels of the heart muscle . The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries...
- Intra-aortic balloon pumpIntra-aortic balloon pumpThe Intra-aortic balloon pump ' is a mechanical device that increases myocardial oxygen perfusion while at the same time increasing cardiac output. Increasing cardiac output increases coronary blood flow and therefore myocardial oxygen delivery...