Heart failure is a term used to describe a heart that cannot keep up with its workload. The body may not get the oxygen it needs.
The term ‘heart failure’ makes it sound like the heart is no longer working at all and there’s nothing that can be done. Actually, heart failure means that the heart isn’t pumping as well as it should be. Congestive heart failure is a type of heart failure which requires seeking medical attention. Although sometimes the two terms are used interchangeably.
Your body depends on the heart’s pumping action to deliver oxygen and nutrient rich blood to the body’s cells. When the cells are nourished properly, the body can function normally.
With heart failure, the weakened heart can’t supply the cells with enough blood. This results in fatigue and shortness of breath and some people have coughing. Everyday activities such as walking, climbing stairs or carrying the groceries can become very difficult.
Heart failure is a serious condition and usually there’s no cure. But many people with heart failure lead a full, enjoyable life when the condition is managed with heart failure medications and healthy lifestyle changes. It is also helpful to have the support of family and friends who understand your condition.
How the Normal Heart Works
The normal healthy heart is a strong, muscular pump a little larger than a fist. It pumps blood continuously through the circulatory system.
The heart has four chambers, two on the right and two on the left. The upper chambers are called the atria. The lower chambers are called the ventricles.
The right atria takes in oxygen depleted blood form the rest of the body and sends it back out to the lungs through the right ventricle where the blood becomes oxygenated.
Oxygen rich blood travels from the lungs to the left atrium then on to the left ventricle, which pumps to the rest of the body.
The heart pumps to the lungs and to all the body’s tissues by a sequence of highly organised contractions of the four chambers. For the heart to function properly, the chambers must beat in an organised way.
What happens during heart failure?
At first, the heart tries to make up for its inability to pump enough blood to meet the body's needs by:
- Enlarging: When your heart chamber enlarges, it stretches more and can contract more strongly, so it pumps more blood. With an enlarged heart, your body starts to retain fluid, your lungs get congested with fluid and your heart begins to beat irregularly.
- Developing more muscle mass: The increase in muscle mass occurs because the contracting cells of the heart get bigger. This lets the heart pump more strongly, at least initially.
- Pumping faster: This helps to increase the hearts output.
The body also tries to compensate in other ways:
- The blood vessels narrow to keep blood pressure up trying to make up for the heart’s loss of power.
- The body diverts blood away from less important tissues and organs (like the kidneys), to the heart and the brain.
These temporary measures mask the problem of heart failure, but they do not solve it. Heart failure continues and worsens until these compensatory processes no longer work.
Eventually the heart and body just cannot keep up and the person experiences fatigue, breathing problems and other symptoms that usually prompt a trip to the doctor.
The body’s compensation mechanisms help explain why some people may not become aware of their condition until years after their heart begins its decline.
Heart failure can involve the hearts left side, rights side or both. However, it usually affects the left side first.
Left-sided Heart Failure
The heart’s pumping action moves oxygen rich blood as it travels from the lungs to the left atrium, then on to the left ventricle, which pumps it to the rest of the body. The left ventricle supplies most of the heart pumping power, so it’s larger than the other chambers and essential for normal heart function. In left-sided or left ventricular (LV) heart failure, the left side of the heart must work harder to pump the same amount of blood.
There are two types of left sided heart failure. Drug treatments are different for the two types:
- Systolic failure: The left ventricle loses its ability to contract normally. The heart can’t pump with enough force to push enough blood into circulation.
- Diastolic failure: (also called diastolic dysfunction): The left ventricle loses its ability to relax normally (because the muscle has become stiff). The heart can’t properly fill with blood during the resting period between each beat.
Right-sided Heart Failure
The heart’s pumping action moves “used” blood that returns to the heart through the veins through the right atrium into the right ventricle. The right ventricle then pumps the blood back out of the heart into the lungs to be replenished with oxygen.
Right-sided or right ventricular (RV) heart failure usually occurs as a result of left-sided failure. When the left ventricle fails, increased fluid pressure is, in effect, transferred back through the lungs, ultimately damaging the hearts right side. When the right side loses pumping power, blood backs up in the body’s veins. This usually causes swelling or congestion in the legs, ankles, and swelling within the abdomen such as the GI tract and liver (causing ascites).
Congestive Heart Failure
Congestive heart failure (CHF) is a type of heart failure which requires seeking timely medical attention, although sometimes the two terms are used interchangeably.
As blood flow out of the heart slows, blood returning to the heart through the veins backs up, causing congestion in the body’s tissues. Often swelling (oedema) results. Most often there’s swelling in the legs and ankles, but it can happen in other parts of the body too.
Sometimes fluid collects in the lungs and interferes with breathing, causing shortness of breath, especially when a person is lying down. This is called pulmonary oedema, and if left untreated can cause respiratory distress.
Heart failure also affects the kidneys’ ability to dispose of sodium and water. This retained water also increases swelling in the body’s tissues (oedema).