CONGESTIVE HEART FAILURE
When the heart fail to pump blood to the tissues, in this case the left,
right, or both ventricles fail to do their functions to meet body needs.
There is a good correlation between CHF and both gender and age; the
incidence is twice as high in men as in women, also after the age of fifty
the prevalence doubles in each decade of life.
Etiology:
Heart failure classified as either low cardiac out put or high cardiac out put.
Low cardiac out put is the more common of the two.
*Low out put congestive heart failure:
It is characterized by an inability of the heart to pump all of the blood,
which it is presented. In this form of failure the ejection fraction (EF) is
defined as the percent of left ventricle volume expelled during systole and
less than 40%and may below as 20%, the normal ejection fraction of
60-70%, as a result the ventricle enlarged and lead to the damage of the
heart.
*High out put failure:
In this case the heart is unable to pump enough blood to meet a metabolic
needs of the tissues, this may occur in hyperthyroid patient in which the
metabolic needs in more than normal supply of the heart .
Further classification of low out put failure is divided into two types:
-Systolic dysfunction: low ejection fraction related with a dilated and
hypodynamic left ventricles, decrease in stroke volume, CO.
-Diastolic dysfunction: caused by impaired left ventricular filling during
diastolic and characterized by normal heart size and normal ejection
fraction, also characterized by left ventricular stiffness and inability to relax
during diastole, decrease in cardiac out put.
Drug induced CHF:
This occur by two mechanisms:
first one Inhibition of myocardial contractility(-ve inotropic agents)
these include beta-blockers,calcium antagonists and anti arrhythmia's
second Expansion of plasma volume
include (NSAID,cortesones,androgens,estrogens,drugs high in sodium)
CARDIAC WORK LOAD:
Include:
I-Preload: used to describe the venous side of circulation which affect
myocardial wall tension, in another word Preload is the rate at which blood
return to the heart and this increase the pressure on the left ventricle, the
elevated Preload will aggravated CHF .
II-After load: is the tension developed in the ventricular wall as contraction
occurs, and Itis regulated by the systemic vascular resistance , rate of
blood in the artery ejected after contraction
III-Cardiac contractility:
This term used to describe the force at which heart contracted to pump
blood to the tissues, itis important for systolic.
Forms of heart failure:
1- low and high out put failure
2- Left sided failure :
In this form of failure the blood cannot be adequately pumped from the
left ventricle to the peripheral circulation ;there for it is accumulated in the
left ventricle ,this make the left ventricle unable to accept blood from the
lift atrium and lung and this cause the blood to be accumulated in the
pulmonary alveoli causing pulmonary edema .
3- right ventricular failure:
When blood cannot be pumped from the right ventricle into the lung, it
accumulates with in the right ventricle, and this leads the blood to back up
into the body e.g. liver, legs, bowel producing systemic edema. Because
the cardiac system is closed, the failure in the left ventricle leads to failure
in the right ventricle and vice versa.
There are many response mechanisms:
I-Sympathetic autonomic nervous system:
When heart cannot provide a sufficient amount of blood to the tissues this
leads to response mechanism in which noradrenaline released and causes
positive inotropic chronoropic effect to normalize the defect happened in
the heart. Also these catecholamines cause constriction of the vessels in
the skin, GIT and this increase systemic vascular resistance.
II-Renal function and renin Angiotensin System:
Decrease in cardiac out put leads to decrease in renal blood flow, this in
turn sets of a complex chain of events leading to sodium and water
retention and increase blood volume. Renal vascular resistance is increased
and the glomerular filtration rate is decreased so more sodium is
reabsorbed.
Renin is released by the kidney due to decreased renal perfusion, this
leads to increase angiotensin formation ;angiotensin formation has two
important functions :The first one is: it acts as a direct vasoconstrictor
and the second one: it stimulates aldosteron release and this leads to an
increase of sodium and water retention which increases total peripheral
resistance .
Signs and symptoms of:
1-Left ventricular heart failure: dyspnea, dry wheezing cough. Exertional
fatigue, weakness, and pulmonary edema.
2-right ventricular heart failure: tightness and swelling (e.g. my ring is two
tight, my skin feels two tight ),nausea, vomiting ,edema, abdominal pain,
venous pressure elevation, Jugular vein distention ,edema (bilateral leg
edema is the first sign of right heart failure
Therapeutic goals:
A-To remove the underlying cause by using drugs
B-To relieve the symptoms and improve pump function by:
1-Reducing metabolic demands by rest and relaxation.
2-Reducing fluid volume excess by dietary and pharmacological deuresis .
3-administration of digitalis and other inotropic substances .
4-Promoting patient compliance.
When the heart fail to pump blood to the tissues, in this case the left,
right, or both ventricles fail to do their functions to meet body needs.
There is a good correlation between CHF and both gender and age; the
incidence is twice as high in men as in women, also after the age of fifty
the prevalence doubles in each decade of life.
Etiology:
Heart failure classified as either low cardiac out put or high cardiac out put.
Low cardiac out put is the more common of the two.
*Low out put congestive heart failure:
It is characterized by an inability of the heart to pump all of the blood,
which it is presented. In this form of failure the ejection fraction (EF) is
defined as the percent of left ventricle volume expelled during systole and
less than 40%and may below as 20%, the normal ejection fraction of
60-70%, as a result the ventricle enlarged and lead to the damage of the
heart.
*High out put failure:
In this case the heart is unable to pump enough blood to meet a metabolic
needs of the tissues, this may occur in hyperthyroid patient in which the
metabolic needs in more than normal supply of the heart .
Further classification of low out put failure is divided into two types:
-Systolic dysfunction: low ejection fraction related with a dilated and
hypodynamic left ventricles, decrease in stroke volume, CO.
-Diastolic dysfunction: caused by impaired left ventricular filling during
diastolic and characterized by normal heart size and normal ejection
fraction, also characterized by left ventricular stiffness and inability to relax
during diastole, decrease in cardiac out put.
Drug induced CHF:
This occur by two mechanisms:
first one Inhibition of myocardial contractility(-ve inotropic agents)
these include beta-blockers,calcium antagonists and anti arrhythmia's
second Expansion of plasma volume
include (NSAID,cortesones,androgens,estrogens,drugs high in sodium)
CARDIAC WORK LOAD:
Include:
I-Preload: used to describe the venous side of circulation which affect
myocardial wall tension, in another word Preload is the rate at which blood
return to the heart and this increase the pressure on the left ventricle, the
elevated Preload will aggravated CHF .
II-After load: is the tension developed in the ventricular wall as contraction
occurs, and Itis regulated by the systemic vascular resistance , rate of
blood in the artery ejected after contraction
III-Cardiac contractility:
This term used to describe the force at which heart contracted to pump
blood to the tissues, itis important for systolic.
Forms of heart failure:
1- low and high out put failure
2- Left sided failure :
In this form of failure the blood cannot be adequately pumped from the
left ventricle to the peripheral circulation ;there for it is accumulated in the
left ventricle ,this make the left ventricle unable to accept blood from the
lift atrium and lung and this cause the blood to be accumulated in the
pulmonary alveoli causing pulmonary edema .
3- right ventricular failure:
When blood cannot be pumped from the right ventricle into the lung, it
accumulates with in the right ventricle, and this leads the blood to back up
into the body e.g. liver, legs, bowel producing systemic edema. Because
the cardiac system is closed, the failure in the left ventricle leads to failure
in the right ventricle and vice versa.
There are many response mechanisms:
I-Sympathetic autonomic nervous system:
When heart cannot provide a sufficient amount of blood to the tissues this
leads to response mechanism in which noradrenaline released and causes
positive inotropic chronoropic effect to normalize the defect happened in
the heart. Also these catecholamines cause constriction of the vessels in
the skin, GIT and this increase systemic vascular resistance.
II-Renal function and renin Angiotensin System:
Decrease in cardiac out put leads to decrease in renal blood flow, this in
turn sets of a complex chain of events leading to sodium and water
retention and increase blood volume. Renal vascular resistance is increased
and the glomerular filtration rate is decreased so more sodium is
reabsorbed.
Renin is released by the kidney due to decreased renal perfusion, this
leads to increase angiotensin formation ;angiotensin formation has two
important functions :The first one is: it acts as a direct vasoconstrictor
and the second one: it stimulates aldosteron release and this leads to an
increase of sodium and water retention which increases total peripheral
resistance .
Signs and symptoms of:
1-Left ventricular heart failure: dyspnea, dry wheezing cough. Exertional
fatigue, weakness, and pulmonary edema.
2-right ventricular heart failure: tightness and swelling (e.g. my ring is two
tight, my skin feels two tight ),nausea, vomiting ,edema, abdominal pain,
venous pressure elevation, Jugular vein distention ,edema (bilateral leg
edema is the first sign of right heart failure
Therapeutic goals:
A-To remove the underlying cause by using drugs
B-To relieve the symptoms and improve pump function by:
1-Reducing metabolic demands by rest and relaxation.
2-Reducing fluid volume excess by dietary and pharmacological deuresis .
3-administration of digitalis and other inotropic substances .
4-Promoting patient compliance.
Cardiovascular Diseases
 |  |
CONGESTIVE HEART FAILURE