Transcript Cardiac Failure

Cardiac Failure
BS 4th Semester
Arsalan Yousuf
Heart Failure or Congestive Heart Failure
Failure of the heart to pump enough blood to satisfy
the needs of the body.
CAUSES
• Decreased contractility of the myocardium resulting from diminished coronary
blood flow.
• Damaged heart valves,
• External pressure around the heart,
• Vitamin B deficiency,
• Primary cardiac muscle disease etc.
Congestive heart failure is a syndrome that can be
caused by multiple underlying diseases such as:
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Congenital heart disease
Atherosclerosis
Rheumatic fever
Cardiomyopathy
Valve disorders
Ventricular failure
Left or right-sided failure
Hypertension
Prolonged alcohol or drug addiction
Previous heart attack
Diabetes
Chronic rapid heartbeats
Common Terminologies
Cardiac Arrest (cardiopulmonary arrest) is
the cessation of normal circulation of the
blood due to failure of the heart to
contract effectively.
Heart Attack (myocardial infarction)
results from the interruption of blood
supply to a part of the heart, causing
heart cells to die.
Cardiomyopathy (heart muscle disease) is
the measurable deterioration of the
function of the cardiomyocyte and
myocardium for any reason.
Acute Effects of Cardiac
Failure
As a result of any damaged
condition two main effects occur:
•Reduced cardiac output
•Damming of blood in the veins, resulting
in increased venous pressure.
Compensation for Acute Cardiac Failure
by
Sympathetic and Parasympathetic Nervous System
Parasympathetic Nerves
Releases acetylcholine
Decreases heart rhythm
and excitability.
Excitatory signals are no
longer transmitted into
the ventricles.
Increased permeability
of the fiber membranes
to potassium ions
Sympathetic Nerves
Releases
norepinephrine at
sympathetic endings.
Increases the rate of
sinus nodal discharge.
Increases the overall
heart activity.
Increases the
permeability of Na+
and Ca2+ ions.
Fluid Retention Helps to Compensate Cardiac
Output
After few minutes of an acute heart attack, a prolonged semi-chronic
state begins, characterized mainly by two events:
(1) retention of fluid by the kidneys.
(2) varying degrees of recovery of the heart itself.
Helps to increases the pressure
gradient for causing venous flow of
blood toward the heart.
Decompensated Heart Failure
Main cause of decompensated heart failure is failure of the heart to
pump sufficient blood to make the kidneys excrete daily the necessary
amounts of fluid.
Heart condition continues to worsen.
EDEMA
Abnormal accumulation of fluid
beneath the skin or in one or more
cavities of the body that produces
swelling.
Treatment of Decompensation.
• Strengthening the heart by administration of a cardiotonic drug, such
as digitalis
• Administering diuretic drugs to increase kidney excretion while at the
same time reducing water and salt intake.
Unilateral Left Heart Failure
In patients with early acute failure, leftsided failure predominates over rightsided failure
• Blood continues to be pumped into the
lungs with usual right heart vigor.
• Not pumped adequately out of the lungs by
the left heart into the systemic circulation.
• The mean pulmonary filling pressure rises
because of shift of large volumes of blood
from the systemic circulation into the
pulmonary circulation.
• Fluid begins to filter out of the capillaries
into the lung interstitial spaces and alveoli,
resulting in PULMONARY EDEMA.
Peripheral Edema
Left or right heart failure is very
slow to cause peripheral edema.
When a healthy heart acutely fails
as a pump, the aortic pressure
falls and the right atrial pressure
rises.
Severe acute cardiac failure often
causes a fall in peripheral capillary
pressure rather than a rise.
Fluid Retention by the Kidneys –
As a result of Peripheral Edema
Peripheral edema begin to occur because of fluid retention by
the kidneys.
• This elevates the right atrial pressure to a still higher value
and returns the arterial pressure back toward normal.
• The capillary pressure now also rises markedly, thus causing
loss of fluid into the tissues and development of severe
edema.
• Decreased glomerular filtration
• Activation of the renin-angiotensin system
• Increased aldosterone secretion.
Cardiogenic Shock
Circulatory shock syndrome caused by inadequate cardiac pumping
is called cardiogenic shock or simply cardiac shock.
• The survival rate is often less than 15 percent.
• Vicious circle of cardiac deterioration.
• Immediate administration of digitalis is often used for strengthening the
heart.
Cardiac Reserve
The maximum percentage that the cardiac output can increase
above normal is called the cardiac reserve.