Heart Failure, Types, Stages, Symptoms, Causes And Treatment

Heart failure is defined as the inadequate ability of the heart to pump enough blood to meet the blood flow and metabolic demands of the body. It is a complex clinical syndrome. It can occur as a result of any structural or functional cardiac disorder that impairs the ability of ventricles to maintain the normal blood flow. It is more common in older and obese peoples.

Types

There are two main types of heart failure,

1.       High output heart failure

2.       Low output heart failure

High output heart failure

In this type of heart failure, your heart is pumping normally. But due to increased metabolic demand, it cannot fulfill the body requirements. This demand is increased due to other medical conditions such as anemia and hyperthyroidism.

Low output heart failure

In this type of heart failure, your heart is not functioning normally and cannot fulfill the normal metabolic demands of the body. This type is more common.

It is further divided into two types,

1.       Right sided heart failure

2.       Left sided heart failure

Right sided heart failure

It is caused by primary or secondary pulmonary arterial hypertension. Pulmonary artery pressure is increased in this type. As a result, it disrupts the emptying of the left ventricle and increases workload on the right side of the heart. This type is not common. It is usually coexist with LV dysfunction. The exact cause of primary pulmonary artery pressure is still not known. The causes responsible for secondary pulmonary artery pressure are collagen vascular disorder, fibrosis, exposure to high altitude or drug and chemical exposure and cor pulmonale.

Left sided heart failure

There are two main types of left sided heart failure,

1.       Systolic dysfunction

2.       Diastolic dysfunction

Systolic dysfunction

In this type, the ejection fraction is reduced to less than 40. The normal value of ejection fraction is 60-70%.  The percentage of left ventricular end-diastolic volume expelled during each systolic contraction is called ejection fraction. The heart muscle becomes weak and cannot contract properly in this type of heart failure. As a result, blood retained in the blood vessels and dilation occurs. Hypokinetic left ventricles become enlarged and emptying of blood is not normal.This type of heart failure occurs as a result of coronary artery disease, myocardial infarction, hypertension and other causes.

Diastolic dysfunction

In this type, the ejection fraction is normal (>45%) because the heart is pumping normally. But the volume of blood to eject is less. As a result, this type is known as heart failure with preserved ejection fraction (HFPEF). The ventricle becomes thick and stiff. The myocardial contractility is not impaired in diastolic dysfunction.It is caused by other medical conditions such as hypertension, coronary ischemia, myocardial infarction, sodium and water retention.If the heart failure is caused by damage to heart muscles or valves then it is called as ischemic heart failure otherwise non-ischemic.

Stages

There are four stages of heart failure,

Heart failure stage A: There is no structural and functional damage to the heart and its muscles. But patients are at higher risk of getting heart failure.

Heart failure stage B: The structure of the heart is damaged. There are no signs and symptoms appear until this stage.

Heart failure stage C: The structure of heart is damaged and symptoms appear but manageable with medications.

Heart failure stage D: This stage is critical requiring heart transplant or palliative care.

Causes

There are different causes that can cause heart failure. It is majorly caused by other medical conditions that have the ability to damage the heart muscles such as,

• Coronary artery disease
• Congenital heart disease (Present at the time of birth)
• Diabetes
• Heart attack
• Cardiomyopathy
• Abnormal heart rhythms
• Atrial fibrillation
• Hypertension (High blood pressure)
• Overweight
• Kidney diseases

Symptoms

There are different sign and symptoms in left or right sided heart failure,

In right sided heart failure, the clinical presentation includes,

• Fatigue
• Ascites
• Increased peripheral venous pressure
• Anorexia
• GI diseases
• Weight gain
• Edema
• Enlarged liver and spleen

In left sided heart failure, the clinical presentation includes,

• Dyspnea (shortness of breath)
• Orthopnea (shortness of breath in the recumbent position i.e. lying down)
• Fatigue
• Anxiety
• Rales (different sounds in the lungs during inhalation)
• Cheyne stokes (abnormal breathing)

Treatment

The aim of treatment is to prevent symptoms and slow down the progression of disease. The standard treatment plan includes the following medications,

Diuretics

They are used for the relief of acute symptoms of congestion. They interfere with sodium retention by increasing urinary sodium and water excretion. They play a vital role in the maintenance of normal blood volume in the body. There are two types of diuretics used in heart failure, loop and thiazide diuretics. Loop diuretics are most widely used diuretics. The most commonly used diuretics are furosemide, bumetanide and torsemide. They exert their action on the thick ascending loop of henle. Thiazide diuretics block sodium and chloride reabsorption in the distal convoluted tubule. The most commonly used thiazide diuretics are hydrochlorothiazide, chlorthalidone and metolazone.

ACE inhibitors

They block the conversion of angiotensin I to angiotensin II and decrease angiotensin II & aldosterone. They are very good in preventing the symptoms of heart failure. They slow down the progression of disease and mortality rate. They reduce myocardial fibrosis, myocyte apoptosis, sodium and water retention and cardiac hypertrophy.The most commonly used ACE inhibitors are captopril, lisinopril, fosinopril, enalapril, ramipril, perindopril and trandolapril. 

B-Blockers

They are used in patients with no or minimum overload of fluid. They work by blocking the effects of the hormone epinephrine. As a result, they block the effects of the sympathetic nervous system at the B adrenergic receptors. Epinephrine is also known as adrenaline. The most widely used beta blockers are propranolol, carvedilol, atenolol and bisoprolol.

Angiotensin II receptor blockers

They antagonize the effects of angiotensin II directly at the AT1 receptor. They are effective and recommended for use in patients with stage A, B and C. Losartan, valsartan, candesartan and irbesartan are angiotensin II receptor blockers.

Aldosterone antagonist

They inhibit the mineralocorticoid receptor and antagonize the action of aldosterone at the  mineralocorticoid receptors. The most common aldosterone antagonists are spironolactone and eplerenone.

Digoxin

It has positive inotropic effect due to its binding to sodium and potassium activated adenosine triphosphate pumps. It increases the concentration of intracellular sodium and calcium during systole.

Nitrates and hydralazine

Nitrates reduce preload while hydralazine reduces peripheral vascular resistance and cardiac output. Their combination is effective in patients who are unable to tolerate ACEIs/ARBs.