Introduction to ArtificiaI Intelligence in Higher Education
Pathophysiology of Heart failure notes
1. HEART FAILURE/ CONGESTIVE CARDIAC FAILURE
Heart failure is defined as the pathophysiologic state in which impaired cardiac function
is unable to maintain an adequate circulation for the metabolic needs of the tissues of the
body.
CHF is the end-result of various forms of serious heart diseases.
TYPES OF HEART FAILURE
Heart failure may be acute or chronic, right-sided or left-sided, and forward or backward failure.
ACUTE AND CHRONIC HEART FAILURE
Depending upon whether the heart failure develops rapidly or slowly, it may be acute or
chronic.
1. Acute heart failure
Sudden and rapid development of heart failure occurs in the following conditions:
o i) Larger myocardial infarction
o ii) Valve rupture
o iii) Cardiac tamponade
o iv) Massive pulmonary embolism
o v) Acute viral myocarditis
o vi) Acute bacterial toxaemia.
In acute heart failure, there is sudden reduction in cardiac output resulting in systemic
hypotension but oedema does not occur. Instead, a state of cardiogenic shock and
cerebral hypoxia develops.
2. Chronic heart failure
More often, heart failure develops slowly as observed in the following states:
o i) Myocardial ischaemia from atherosclerotic coronary artery disease
o ii) Multivalvular heart disease
o iii) Systemic arterial hypertension
o iv) Chronic lung diseases resulting in hypoxia and pulmonary arterial
hypertension
2. o v) Progression of acute into chronic failure.
In chronic heart failure, compensatory mechanisms like tachycardia, cardiac dilatation
and cardiac hyper trophy try to make adjustments so as to maintain adequate cardiac
output. This often results in well-maintained arterial pressure and there is accumulation
of oedema.
LEFT-SIDED AND RIGHT-SIDED HEART FAILURE
Left-sided CHF
It is the most common type of CHF. It occurs when left ventricle doesn’t properly pump
blood out to body.
As the condition progresses, fluid can build up in lungs, which makes breathing
difficult.
There are two kinds of left-sided heart failure:
Systolic heart failure occurs when the left ventricle fails to contract normally. This
reduces the level of force available to push blood into circulation. Without this force, the
heart can’t pump properly.
Diastolic failure, or diastolic dysfunction, happens when the muscle in the left ventricle
becomes stiff. Because it can no longer relax, the heart can’t quite fill with blood between
beats.
Right-sided CHF
It occurs when the right ventricle has difficulty pumping blood to lungs. Blood backs up
in blood vessels, which causes fluid retention in lower extremities, abdomen, and other
vital organs.
It’s possible to have left-sided and right-sided CHF at the same time. Usually, the disease
starts in the left side and then travels to the right when left untreated.
ETIOLOGY
Heart failure is caused by many conditions that damage the heart muscle, including:
Coronary artery disease
Coronary artery disease (CAD), a disease of the arteries that supply blood and oxygen to
the heart, causes decreased blood flow to the heart muscle. If the arteries become blocked
or severely narrowed, the heart becomes starved for oxygen and nutrients.
Heart attack
3. A heart attack occurs when a coronary artery becomes suddenly blocked, stopping the
flow of blood to the heart muscle. A heart attack damages the heart muscle, resulting in a
scarred area that does not function properly.
Cardiomyopathy
Damage to the heart muscle from causes other than artery or blood flow problems, such
as from infections or alcohol or drug abuse.
Conditions that overwork the heart. Conditions including high blood pressure, valve
disease, thyroid disease, kidney disease, diabetes, or heart defects present at birth can all
cause heart failure. In addition, heart failure can occur when several diseases or
conditions are present at once.
PATHOGENESIS
4. COMPLICATIONS OF CHF
Kidney damage or failure. Heart failure can reduce the blood flow to kidneys, which
can eventually cause kidney failure if left untreated. Kidney damage from heart failure
can require dialysis for treatment.
Heart valve problems. The valves of heart, which keep blood flowing in the proper
direction through heart, may not function properly if heart is enlarged or if the pressure
in heart is very high due to heart failure.
Heart rhythm problems. Heart rhythm problems (arrhythmias) can be a potential
complication of heart failure.
Liver damage. Heart failure can lead to a buildup of fluid that puts too much pressure on
the liver. This fluid backup can lead to scarring, which makes it more difficult for liver
to function properly.
RISK FACTORS
Risk factors include:
High blood pressure.
Coronary artery disease.
5. Heart attack.
Diabetes.
Some diabetes medications. The diabetes drugs rosiglitazone (Avandia) and pioglitazone
(Actos) have been found to increase the risk of heart failure in some people
Certain medications. Some medications may lead to heart failure or heart problems.
Medications that may increase the risk of heart problems include nonsteroidal anti-
inflammatory drugs (NSAIDs); certain anesthesia medications; some anti-arrhythmic
medications etc
Sleep apnea. The inability to breathe properly while you sleep at night results in low
blood oxygen levels and increased risk of abnormal heart rhythms. Both of these
problems can weaken the heart.
Congenital heart defects. Some people who develop heart failure were born with
structural heart defects.
Valvular heart disease.
Viruses.
Alcohol use.
Tobacco use.
Obesity..
Irregular heartbeats.
SIGN AND SYMPTOMS
1. Congested lungs.
o Fluid backup in the lungs can cause shortness of breath with exercise or difficulty
breathing at rest or when lying flat in bed. Lung congestion can also cause a dry,
hacking cough or wheezing.
2. Fluid and water retention.
o Less blood to kidneys causes fluid and water retention, resulting in swollen
ankles, legs, abdomen (called edema), and weight gain. Symptoms may cause an
increased need to urinate during the night. Bloating in stomach may cause a loss
of appetite or nausea.
3. Dizziness, fatigue, and weakness.
6. o Less blood to major organs and muscles makes you feel tired and weak. Less
blood to the brain can cause dizziness or confusion.
4. Rapid or irregular heartbeats.
o The heart beats faster to pump enough blood to the body. This can cause a rapid
or irregular heartbeat.
DIAGNOSIS OF CHF
By using Electrocardiogram, Echocardiogram, MRI, Blood tests etc. CHF can be diagnosed
CONGESTIVE HEART FAILURE DRUGS
ACE inhibitors
Angiotensin-converting enzyme inhibitors (ACE inhibitors) open up narrowed blood vessels
to improve blood flow. Eg: Captopril, Enalapril
Vasodilators are another option if you cannot tolerate ACE inhibitors.
Beta blockers. Eg: Atenolol, Bisoprolol
Diuretics reduce body’s fluid content. CHF can cause body to retain more fluid than it
should.