PATHOPHYSIOLOGY OF CONGESTIVE HEART FAILURE
Decreased force of contraction
Positive Inotropic Drugs. Low Cardiac Output
Renal blood flow Decreased Carotid Sinus firing Decreased
Activate Renin-Angiotensin Activate sympathetic system Aldosterone system Increase sympathetic discharge. ACEIs ARB Aldosterone AT-II
Salt & Water Vasoconstriction Increased Heart rate Retention. Volume expansion Venous Arterial Vasoconstriction Vasoconstriction
Increased Preload Increased Preload Increased Afterload
Diuretics Venodilators Arterial vasodilators
Classification of C.H.F according to Symtomatology
• Class I: – Symptoms (fatigue and palpitaton) occur with greater than ordinary exercise. • Class II: – Symptoms occur on ordinary exercise. • Class III: – Symptoms occur at minimal activity. • Class IV: – Symptoms occur even at rest.
Management of Ambulatory (non-hospitalized) Heart failure
• Class I: – Diuretics. • Class II: – Angiotensin-converting enzyme inhibitors (ACEIs) or Angiotensin receptor blockers (ARBs). • Class III: – Diuretics + ACEIs or ARBs. • Class IV: – Diuretics + ACEIs or ARBs + Digoxin.
Heart disease refers to any condition affecting the heart. There are many types, some of which are preventable.
According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death in the United States. Around 1 in 4 deathsTrusted Source in the U.S. occur due to heart disease, and the condition affects all genders as well as all racial and ethnic groups.
In this article, learn more about the types, causes, and symptoms of heart disease. This article also covers risk factors and treatment.
Heart disease refers to any condition affecting the cardiovascular system. There are several different types of heart disease, and they affect the heart and blood vessels in different ways.
The sections below look at some different types of heart disease in more detail.
Coronary artery disease
Coronary artery disease, also known as coronary heart disease, is the most common type of heart disease.
It develops when the arteries that supply blood to the heart become clogged with plaque. This causes them to harden and narrow. Plaque contains cholesterol and other substances.
As a result, the blood supply reduces, and the heart receives less oxygen and fewer nutrients. In time, the heart muscle weakens, and there is a risk of heart failure and arrhythmias.
When plaque builds up in the arteries, it is called atherosclerosis. Plaque in the arteries can rupture from blockages and cause blood flow to stop, which can lead to a heart attack.
Congenital heart defects
A person with a congenital heart defect is born with a heart problem. There are many types of congenital heart defects, includingTrusted Source:
- Atypical heart valves: Valves may not open properly, or they may leak blood.
- Septal defects: There is a hole in the wall between either the lower chambers or the upper chambers of the heart.
- Atresia: One of the heart valves is missing.
Congenital heart disease can involve major structural issues, such as the absence of a ventricle or problems with unusual connections between the main arteries that leave the heart.
Many congenital heart defects do not cause any noticeable symptoms and only become apparent during a routine medical check.
According to the American Heart Association (AHA)Trusted Source, heart murmurs often affect children, but only some are due to a defect.
Arrhythmia refers to an irregular heartbeatTrusted Source. It occurs when the electrical impulses that coordinate the heartbeat do not work correctly. As a result, the heart may beat too quickly, too slowly, or erratically.
There are various types of arrhythmias, including:
- Tachycardia: This refers to a rapid heartbeat.
- Bradycardia: This refers to a slow heartbeat.
- Premature contractions: This refers to an early heartbeat.
- Atrial fibrillation: This is a type of irregular heartbeat.
A person may notice a feeling like a fluttering or a racing heart.
In some cases, arrhythmias can be life threatening or have severe complications.
In dilated cardiomyopathy, the heart chambers become dilated, meaning that the heart muscle stretches and becomes thinner. The most common causes of dilated cardiomyopathy are past heart attacks, arrhythmias, and toxins, but genetics can also play a role.
As a result, the heart becomes weaker and cannot pump blood properly. It can result in arrhythmia, blood clots in the heart, and heart failure.
It usually affects people aged 20–60 yearsTrusted Source, according to the AHA.
Also known as heart attack, myocardial infarction involves an interruption of the blood flow to the heart. This can damage or destroy part of the heart muscle.
The most common cause of heart attack is plaque, a blood clot, or both in a coronary artery. It can also occur if an artery suddenly narrows or spasms.
Are there different types of heart attack? Learn more here.
When a person has heart failure, their heart is still workingTrusted Source but not as well as it should be. Congestive heart failure is a type of heart failure that can occur from problems with the pumping or relaxing function.
Heart failure can result from untreated coronary artery disease, high blood pressure, arrhythmias, and other conditions. These conditions can affect the heart’s ability to pump or relax properly.
Heart failure can be life threatening, but seeking early treatment for heart-related conditions can help prevent complications.
This condition usually develops when a genetic problem affects the heart muscle. It tends to be an inherited condition.
The walls of the muscle thicken, and contractions become harder. This affects the heart’s ability to take in and pump out blood. In some cases, an obstruction can occur.
There may be no symptoms, and many people do not receive a diagnosis. However, hypertrophic cardiomyopathy can worsen over time and lead to various heart problems.
Anyone with a family history of this condition should ask for screening, as receiving treatment can help prevent complications.
Hypertrophic cardiomyopathy is the main cause of cardiac deathTrusted Source among young people and athletes under 35 years old, according to the AHA.
Mitral valve regurgitation
This event occurs whenTrusted Source the mitral valve in the heart does not close tightly enough and allows blood to flow back into the heart.
As a result, blood cannot move through the heart or body efficiently, and it can put pressure on the chambers of the heart. In time, the heart can become enlarged, and heart failure can result.
Learn more about heart valves here.
Mitral valve prolapse
This happens when the valve flaps of the mitral valve do not close properly. Instead, they bulge into the left atrium. This can cause a heart murmur.
Mitral valve prolapse is not usually life threatening, but some people may need to receive treatment for it.
Genetic factors and connective tissue problems can cause this condition, which affects around 2%Trusted Source of the population.
In aortic stenosisTrusted Source, the pulmonary valve is thick or fused and does not open correctly. This makes it hard for the heart to pump blood from the left ventricle into the aortaTrusted Source.
A person may be born with it due to congenital anomalies of the valve, or it may develop over time due to calcium deposits or scarring.
The symptoms of heart disease depend on the specific type a person has. Also, some heart conditions cause no symptoms at all.
That said, the following symptoms may indicate a heart problem:
- angina, or chest pain
- difficulty breathing
- fatigue and lightheadedness
- swelling due to fluid retention, or edema
In children, the symptoms of a congenital heart defect may include cyanosis, or a blue tinge to the skin, and an inability to exercise.
Some signs and symptoms that could indicate heart attack include:
- chest pain
- heart palpitations
- stomach pain
- arm, jaw, back, or leg pain
- a choking sensation
- swollen ankles
- an irregular heartbeat
Heart attack can lead to cardiac arrest, which is when the heart stops and the body can no longer function. A person needs immediate medical attention if they have any symptoms of a heart attack.
If cardiac arrest occurs, the person will needTrusted Source:
- immediate medical help (call 911)
- immediate cardiopulmonary resuscitation
- a shock from an automated external defibrillator, if available
Heart disease develops when there is:
- damage to all or part of the heart
- a problem with the blood vessels leading to or from the heart
- a low supply of oxygen and nutrients to the heart
- a problem with the rhythm of the heart
In some cases, there is a genetic cause. However, some lifestyle factors and medical conditions can also increase the risk. These include:
- high blood pressure
- high cholesterol
- a high intake of alcohol
- overweight and obesity
- a family history of heart disease
- dietary choices
- a history of preeclampsia during pregnancy
- low activity levels
- sleep apnea
- high stress and anxiety level
- leaky heart valves
Drug Interactions of Digoxin
A- Pharmacokinetic interactions: • Drugs which decrease plasma level of Digoxin include: I- Cholestyramine, Neomycin, Antacids; these produce decreased absorption. II- Thyroxin; produces increased renal clearance and increased volume of distribution. • Drugs which increase plasma level of Digoxin: I- Erythromycin, Tetracycline, Omeperazole; these increase absorption. II- Quinidine, Amiodarone, Verapamil, Diltiazem and Captopril; these decrease renal clearance and decrease volume of distribution.
B- Pharmacodynamic interactions: • Potassium loosing diuretics decrease serum K+ resulting in increased automaticity and inhibition of Na+/K+ ATPase leading to toxicity. • Sympathomimetics: – Increases automaticity. • Beta-adrenoceptor blockers and calcium channel blockers: 1- Decrease SA node and AV node conduction leading to bradycardia and heart block. 2- Decrease force of myocardial conduction; thereby antagonize the positive inotropic effect of cardiac glycosides.
Digitalis has a low safety margin. Its cardiac toxicity is potentiated by hypokalemia and hypercalcemia. A- Cardiac toxicity (most frequent side effect): – Digitalis can cause every variety of Arrhythmia: 1- Marked sinus bradycardia. 2- Second and third degree heart block. 3- Atrial tachycardia and Atrial flutter and fibrillation. 4- Ventricular premature beats, ventricular tachycardia and fibrillation. B- Extra-cardiac toxicity: • Psychiatric: – Fatigue, Malaise, Confusion, Dizziness, Abnormal dreams. • Visual: – Blurred or Yellow vision. • GIT: – Anorexia, Nausea, Vomiting, Abdominal pain.
Treatment of Digitalis toxicity: 1- Stop the drug and the Potassium loosing diuretic. 2- Treatment of Digitalis-induced arrhythmias: i) Atropine for: – Bradycardia and Second or Third degree heart block. ii) Lidocaine for ventricular arrhythmia. iii) Potassium administration in tachy-arrhythmia (K+ competes with Digitalis for Na+/K+ ATPase preventing inhibition of the enzyme by Digitalis). iv) K+ administration is contraindicated in AV block