Heart Failure

Heart failure doesn’t suggest that the heart has completely stopped or is in the process of stopping but indicates the inefficiency of the cardiovascular system to function properly. This means that, for some reason, the pumping action of the heart is limited in such a way that sufficient blood is not being pumped or any part of the heart (heart chamber) does not fill with an adequate amount of blood to be pumped elsewhere and as a result fluid congestion manifests. Fluid congestion, simply, refers to the excess fluid that develops due to the compensatory response of the body. This fluid collects as it fails to flow to where it is needed. This fluid congestion may result from the actions of the kidney, in response to reduced blood flow, by fluid retention, which causes an increase in blood volume. Consequently, excess fluid enters the lungs and other parts of the body and swelling occurs. It is important to note that heart failure is not the only reason swelling can occur in certain parts of the body.

Heart failure is a progressive disorder in which the body tries to overcome any serious change in the circulatory system (the cycle that transports blood from the heart to bodily tissues and back to the heart) that prevents the heart from functioning as it should. As the condition worsens, the heart’s capability to do its job lessens and many circulatory problems may surface. With treatment, this condition can be controlled and cured. However, if heart failure is not diagnosed and continues to progress, years of survival are reduced with time. The incidence of heart failure increases as you get older.

Heart Failure Classifications/Terms
Depending on the location of the insult affecting the heart or the way in which the heart functions as a result of heart failure, heart failure can be classified in the following terminology:

§ Right Heart Failure – the inability of the right side of the heart, which receives deoxygenated (low oxygen content) blood from the veins of the body, to adequately pump the venous blood towards the lungs, which plays a role in the pulmonary circulatory system.

§ Left Heart Failure – the inability of the left side of the heart to pump oxygenated blood received from the pulmonary circulation (lungs) to the other parts of the body (systemic circulation).

As a result of left and right heart failures, these heart failures can be further classified into:
§ Backward Heart Failure – the heart is able to pump blood efficiently ONLY when filling pressure of the heart is abnormally high (in other words, only when a chamber of the heart is filled with a greater amount of blood than usual).

§ Congestive Heart Failure – fluid collects in the lungs or body due to inadequate pumping from the heart and high heart filling and venous pressures.

§ Forward Heart Failure – the inability of the heart to pump blood sufficiently to meet the oxygen demands of the body at exercise or at rest.

Signs & Symptoms
With respect to the effect of heart failure on the body, certain signs and symptoms may be acquired. The most common signs and symptoms of heart failure are shortness of breath or difficulty breathing (dyspnea), fatigue (tiredness), and swelling in the ankles, feet, legs, abdomen and sometimes the veins in the neck. Fluid congestion can cause shortness of breath and oedema (swelling as a result of pooling of fluid into certain parts of the body). Reduced blood flow to the bodily tissues can cause difficulty exercising, fatigue and dizziness (due to low blood pressure). Other signs and symptoms are angina, loss of appetite, weight gain or loss.

Causes and Risk Factors
Conditions which damage the heart muscle (myocardium) or make it work too hard to pump sufficient blood to where it is needed can cause heart failure. The heart then weakens with the continued stress it endures. Certain proteins and other substances may be released into the blood.

The major causes of heart failure are coronary artery disease (CAD), diabetes, high blood pressure (hypertension). Some other causes of heart failure include, but are not limited to: arrhythmias (irregular heart beats), heart defects present at birth (congenital heart defects), heart muscle diseases (e.g. cardiomyopathy), heart valve disorders (e.g. valvular heart disease). Alcohol abuse, cocaine and other illegal drug use, HIV/AIDS, intake of too much vitamin E, thyroid disorders, and treatments for cancer such as radiation and chemotherapy may damage the heart muscle and lead to heart failure. Conditions such as lung impairment, anemia, kidney impairment and pericardial disease (very rare) can surface heart failure symptoms.

Some risk factors for heart failure are having a family history of heart failure, being obese, having a large salt intake in diet, consuming large amounts of alcohol or abusing drugs and having sustained rapid heart rhythms.

Diagnosis
Based on medical and family histories, a physical examination, and tests, a heart failure diagnosis can be made. The symptoms of heart failure are also common in other conditions and so the doctor will seek to: (i) discover any damage to the heart and determine how well the heart pumps blood, (ii) find out whether there is an underlying disease causing heart failure symptoms, (iii) rule out any other causes of heart failure symptoms.

In the physical exam, the doctor will look for swelling in your ankles, feet, legs, abdomen, and the veins in the neck, and listen to the lungs for sounds that aren’t normal and for sounds of excess fluid build-up.

For testing, initially the doctor may order for an electrocardiogram (ECG or EKG), a chest xray and a BNP blood test to be done. If you are referred to a cardiologist, other tests may be ordered such as a Doppler test, which measures the speed and direction of blood flow, a nuclear heart scan to give an indication of how well blood is passing through the heart and how much blood is reaching the heart muscle, a cardiac magnetic resonance imaging (MRI), which shows the structures and beating of the heart and can help the doctor determine if the heart has been damaged, and thyroid function tests.

Treatment
Treatment for heart failure depends on the type of heart failure presented and how severe it is (stage of heart failure). Generally, treatment seeks to:
o Deal with the underlying cause of the type of heart failure, such as coronary artery disease (CAD), high blood pressure or diabetes.
o Reduce symptoms.
o Stop heart failure from worsening.
o Increase survival years (lifespan) and improve quality of life.

Treatment will also include lifestyle changes, medicines and ongoing care. If you or your loved one have/has a severe heart failure, surgery may be necessary and other medical procedures.

In depth, heart failure therapy pays particular attention to three things: (1) the reduction of the loading condition on the heart as the heart muscle relaxes to be filled with blood (preload), (2) the reduction of the load against which the ventricle of the heart must contract when it ejects blood into the arteries (afterload), and the inhibition of the renin-angiotensin-aldosterone system (RAAS) and vasoconstrictor factors produced by the sympathetic nervous system in patients with heart failure. The RAAS involves actions of the kidney and a few other bodily tissues which work together to increase blood volume in an attempt to maintain an adequate amount of blood flow to bodily tissues. Vasoconstrictor factors refer to those hormones which cause constriction of blood vessels. The sympathetic nervous system is a part of the nervous system which responds to ‘life or death’ or ‘flight or fright’ situations. This system is responsible for the ‘adrenaline rush’.

A number of medications can be used to accomplish heart failure therapy, for example nitroglycerine (for preload reduction), loop diuretics such as furosemide, vasodilators which reduce both preload and afterload, digoxin which can aid the heart in contractility, sympathomimetic agents like dopamine and adrenaline, beta-adrenergic blocking agents such as metoprolol and carvedilol.