Transcript (preload, contractility and afterload) and heart failure

Heart Failure
What is Heart Failure?
The heart is not pumping properly.
 Usually, the heart has been weakened by
an underlying condition
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Blocked arteries
Heart attack
High blood pressure
Infections
Heart valve abnormalities
 Heart failure can involve the left or right
side of the heart or both.
 Usually the left side is affected first.
 Heart failure occurs when either side of the
heart cannot keep up with the flow of
blood.
 What is Left Heart Failure?
 Involves the left ventricle (lower chamber) of
the heart.
 Systolic failure: The heart looses it’s ability to contract or pump
blood into the circulation.
 Diastolic failure: The heart looses it’s ability to relax because it
becomes stiff.
 Heart cannot fill properly between each beat.
 What is Left Heart Failure?
 Systolic and diastolic heart failure are
treated with different types of medications.
 In both types, blood may “back up” in the
lungs causing fluid to leak into the lungs
(pulmonary edema)
 Fluid may also build up in tissues
throughout the body (edema)
 What is Right Heart Failure?

Usually occurs as a result of left heart
failure.
 Occasionally isolated right heart failure can
occur due to lung disease or blood clots to the
lung (pulmonary embolism).
 Leads to generalized edema → e.g. ankle
edema and hepatomegaly.
Atrial Natriuretic Peptide (ANP)
 Major site of synthesis of ANP is the cardiac atria.
 It stimulates natriuresis (Loss of sodium) and
diuresis (water loss).
 Inhibits the release of renin, aldosterone and
vasopressin (ADH).
 Causes relaxation of blood vessels.
Right heart failure →↑Right atrial pressure → ANP
which will lead to :-
1- ↑ heart rate.
2- ↓Anti diuretic hormone (ADH),Aldosterone, and renin
→ ↑ urine output.
3- ↑ Atrial natriuretic peptide (ANP) → ↑ execretion of
salt and water in urine.
4- ↑ Urine output.
Stimulation
Inhibition
Kidney
Cardiac
atria
Renin
GFR
Urine
Adrenal Gland
Aldosterone
Vsaoconstrictive
action of
Angiotensin II
Natriuresis
ANP
Brain
ADH
 How fast does heart failure
develop?
 Usually a chronic disease
 The heart tries to compensate for the loss
in pumping function by:
1- Developing more muscle mass.
2- Enlarging.
3- Pumping faster.
 What Causes Heart Failure?
 Health conditions that either damage the
heart or make it work too hard.
1- Coronary artery disease
2- Heart attack
3- High blood pressure
4- Abnormal heart valves
5- Heart muscle diseases (cardiomyopathy)
6- Heart inflammation (myocarditis)
 What Causes Heart Failure cont.?
7- Congenital heart defects
8- Severe lung disease
9- Diabetes
10- Severe anemia
11- Overactive thyroid gland (hyperthyroidism)
12- Abnormal heart rhythms
Coronary artery disease:Cholesterol and fat deposits build
up in the heart’s arteries.
↓
Less blood and oxygen reach the
heart muscle.
↓
This causes the heart to work harder
and occasionally damages the heart
Muscle.
Heart attack :An artery supplying blood to the
heart becomes blocked.
↓
Loss of oxygen and nutrients
damages heart muscle tissue
causing it to die (myocardial
infarction).
↓
Remaining healthy heart muscle
must pump harder to keep up.
High blood pressure :Uncontrolled high blood pressure doubles a
persons risk of developing heart failure.
↓
Heart must pump harder to keep blood
Circulating.
↓
Over time, chamber first thickens, then gets
larger and weaker.
Severe anemia:Not enough red blood cells to carry oxygen.
↓
Heart beats faster and can become
exhausted with the effort.
Hyperthyroidism:Body metabolism is increased and
overworks the heart.
Abnormal Heart Rhythm:If the heart beats too fast, too slow or
irregular it may not be able to pump enough
blood to the body.
Signs and Symptoms of Left Heart Failure:Shortness of Breath (dyspnea) due to → Blood
“backs up” in the pulmonary veins because the
left ventricle can not pump blood properly to
the systemic circulation → fluid leaks into the
lungs → pulmonary edema.
SYMPTOMS:Dyspnea on exertion or at rest.
Difficulty in breathing when lying flat.
Waking up with short of breath.
 Signs and Symptoms of Right Heart
Failure:Edema:Decreased blood flow out of the weak heart.
↓
Blood returning to the heart from the veins “backs up”
causing fluid to build up in tissues.
SYMPTOMS:Swelling in feet, ankles, legs or abdomen
Weight gain.
Signs and Symptoms of Heart Failure:Tiredness, fatigue
Heart can’t pump enough blood to meet needs of
bodies tissues.
Body diverts blood away from less vital organs
(muscles in limbs) and sends it to the heart and
brain.
SYMPTOMS:Constant tired feeling.
Difficulty with everyday activities.