What is Heart Failure?
Heart failure is a common health issue in Canada (especially in the elderly) and is currently increasing in our population. It has been estimated that around 400,000 Canadians currently suffer from heart failure. So what exactly is heart failure and how does it occur?
Heart failure occurs when the heart muscle becomes damaged. There are many different ways that heart muscle can become damaged. Some of the most common reasons are:
- Heart disease
- A heart attack
- Long-term high blood pressure
- Diabetes
- A valve in the heart that is not functioning properly
- A congenital birth defect in the heart
- Lung disease
- Infection
- High alcohol consumption over a long period of time
The above conditions can cause your heart chambers to become weakened and enlarged - called “dilated” heart failure. They can also cause your heart muscle to become thicker - called “hypertrophic” heart failure.
When the heart chambers become enlarged (dilated) due to weakness of the heart muscle, less blood is pumped out with each heartbeat. If the heart muscle becomes thicker (hypertrophic) and stiffer with a smaller heart chamber for blood, less blood may also be pumped with each heart beat.
Blood carries nutrients and oxygen to our body tissues. Therefore, when less blood is pumped out, more congestion occurs in the lungs, less nutrients and oxygen get delivered to our body tissues, which ultimately results in many of the symptoms identified with heart failure.
The following sections will serve to provide a more complete understanding of what heart failure is and its causes and consequences.
How your heart works
To help better understand heart failure, it is important to understand how the heart works.
The heart is a hollow muscle about the size of your fist. It pumps oxygen rich blood with nutrients throughout your body. The heart has four chambers: two at the top, called atria, and two at the bottom, called ventricles. The heart is divided into right and left sides. The right side receives blood from the body and pumps the blood to the lungs where the blood oxygen content is increased. This blood is then pumped out to the rest of the body by the left side of the heart to provide oxygen rich blood to your brain, organs, muscles and skin.
When you have heart failure, your heart is unable to pump enough blood forward to satisfy your body’s requirements. Also, blood that should be pumped out of the heart may back up into other organs or tissues causing congestion in your lungs, stomach, liver, intestines or legs.
Healthy Heart
Heart Failure
Symptoms of Heart Failure
The following is a list of the most common signs and symptoms of heart failure:- Tiredness, Fatigue, Dizziness: Caused by less blood being pumped to your bodily tissues
- Shortness of Breath: Caused by fluid build up in the lungs
- Chronic Cough: Commonly described as a dry, hacking cough, this is the result of fluid build up in the lungs
- Edema (Swelling): Less blood being pumped to your kidneys results in fluid retention throughout the body. Most commonly this accumulates in the ankles, legs and abdomen.
- Increase in Body Weight: This is the result of fluid build up throughout the body
- Loss of Appetite: Swelling in the abdomen, gut and liver may cause a “full” feeling that decreases you appetite
- Mental Confusion or Impaired Thinking: Caused by reduced blood flow to the brain
- Rapid or Irregular Heartbeats: The extra strain caused by the heart’s reduced ability to pump blood may cause it to compensate by speeding up
- Cold Hands and Feet: Caused by reduced blood flow
- Inability to Sleep: Congestion in the lungs may cause worsening shortness of breath when you lie down
- Waking up from sleep: Fluid congestion in the lungs can cause shortness of breath or feeling smothered. If there is a lot of fluid congestion, shortness of breath can occur when you first lie down but, if the fluid accumulation is less severe, you may get to sleep but may be awakened during sleep when the fluid seeps slowly into the lungs.
- Enlargement of the Heart (Dilated or Hypertrophied)
- Abnormal Heart Murmur: Caused by a valve-related disorder
- Rapid Heartbeat (Tachycardia) or extra heart sounds
- Abnormal Heart Rhythm (Arrhythmias)
- Crackling sound of fluid in the lungs: Caused by fluid congestion
- Swelling and Fluid Retention in Liver or Gastrointestinal Tract
- Liver Malfunction
Types of Heart Failure
Having heart failure means that your heart has difficultly pumping blood efficiently throughout your body.
There are many different types of heart failure and some of the more common ones are outlined below.
Chronic vs. Acute
Heart failure is commonly a chronic illness that arises as a result of damage to the heart caused by other conditions such as a heart attack, hypertension, diabetes, valve disease (see above). Chronic heart failure develops slowly over time and may not be recognized initially but gradually worsens in most cases and requires long-term therapy.
Although less common than chronic heart failure, many patients can experience acute heart failure. Acute heart failure develops rapidly and symptoms may be temporary due to an event such as a heart attack. Acute heart failure may be reversible in some cases but many progress to chronic heart failure.
Left-sided vs. Right-sided
Heart failure may be defined based on what side of the heart is not functioning adequately.
Left-sided heart failure occurs when the left ventricle is not pumping adequately. This results in a deficiency of oxygen-rich blood that is pumped from the heart to the rest of the body. The main symptoms include shortness of breath, fatigue, coughing and lung congestion (with both blood and fluid).
Right-sided heart failure occurs when the right ventricle is not pumping adequately. This tends to cause fluid build-up in the veins and swelling in the legs and ankles. Right-sided heart failure usually occurs as a direct result of left-sided heart failure but can also be caused by severe lung disease or right heart valve disease.
Systolic vs. Diastolic
Heart failure can also be defined in terms of the cardiac cycle.
Systolic heart failure means that the heart is unable to pump adequate amounts of blood throughout the body during its contraction. Some of the causes for systolic heart failure include coronary artery disease, high blood pressure and heart valve disease. Symptoms from this include lung congestion and swelling (edema) of the lower extremities.
Diastolic heart failure means the heart muscle is unable to relax fully between contractions and allow enough blood to enter the ventricles. This results in fluid buildup and congestion in the lungs. Some of the causes for diastolic heart failure include coronary artery disease, high blood pressure and cardiomyopathy. Diastolic heart failure also occurs to some extent in systolic heart failure. Consequently, symptoms between these two types of heart failure are very similar.
Classification of Heart Failure
Heart failure can be classified by how much physical activity you can do before you start feeling symptoms. The table below is the New York Heart Association Classification which separates heart failure into five categories.
Diagnosing Heart Failure
Determining if you have heart failure is very critical for your health. The sooner your doctor determines you have it, the earlier you can begin treatment and start feeling better.
Starting with a physical examination, your doctor may suspect you have heart failure and begin treatments right away. Then again, depending on your symptoms and medical history, your doctor may perform several tests to determine if you have heart failure .
Examples of common tests used to diagnose and determine the cause of heart failure:
Blood Tests
There are a few blood tests that need to be done to diagnose heart failure and to track how a person with heart failure is doing.
What it Shows:
- One of the blood tests is called BNP. When a high amount of BNP is found in the blood, it usually means that the heart is not working properly. People with heart failure normally have high levels of BNP.
- As excess fluid is excreted through the kidneys. it is important to do blood tests to see how the kidneys are working, and also the liver, and whether you have the right balance of other important hormones in your body.
- Another of the blood tests is referred to as Thyroid Function Tests. These tests will reveal whether the thyroid is overactive or underactive and whether this is responsible for heart failure.
- Other specialized blood tests may be performed based on the characteristics of your heart failure.
Chest X-Ray
Your doctor can use an x-ray to look at your heart, lungs, and blood vessels.
What it shows:
Electrocardiogram or “ECG”
This test measures the electrical activity of the heart. Electrical wires with adhesive ends are placed on the skin of your chest, arms, and legs. The electrical activity of the heart is then recorded on a piece of paper.
What it shows: The ECG can identify a previous heart attack, a change in your heart rhythm, evidence of a thickened heart muscle as well as some other conditions.
A Holter Monitor is a portable device that allows for a continuous ECG recording of heart rhythm during normal activity. This recording can last anywhere from 24 hours to 2 weeks.
What it shows:
The rhythm and regularity of your heart and whether it is normal or abnormal
Treadmill Test or "Exercise Stress Test"
The test requires you to walk on a treadmill. While walking on the treadmill, the doctor monitors the rate and rhythm of your heart to see if they are normal.What it shows:
Echocardiogram or “Echo”
An echo is a simple test that uses sound waves to image your heart and allows doctors to assess the strength of your heart muscle, the function of the heart valves, and the presence of some other diseases of the heart. You lie on a bed and an ultrasound sensor is moved over the surface of your chest. It is a painless test that takes about half an hour. If the pictures obtained in this way are not clear enough, sometimes the echo is obtained by swallowing a small tube into your food pipe or esophagus and excellent pictures can be obtained. In that case, you will receive a light anesthetic.
What it shows
Nuclear Tests – ‘MUGA’ and ‘MIBI’
A MUGA is a common test used to determine the function of your heart. This test consists of a special scan of your heart using a radio-isotope solution that is injected into a vein.A MIBI also uses a different radio-isotope to take pictures of your heart muscle at rest and during exercise or stress to determine if you have narrow or blocked arteries in your heart that could cause chest pain or weak heart muscle.
What the test shows:
Heart Catheterization
A small tube is inserted into an artery in the groin or arm and guided towards the heart. The tip of the tube is positioned either in or near the heart. Dye is then injected.
What it shows:
The dye is visible by x-ray, providing a picture of the blood vessels that supply the heart.
Angiogram
A small tube is inserted into an artery in the groin or arm and guided towards the heart. The tip of the tube is positioned either in or near the heart. Dye is then injected. The dye is visible by x-ray, providing a picture of the blood vessels that supply the heart.What it shows
Specialized Tests
The following tests may be performed by your physician, however they are not available at all institutions.
Magnetic Resonance Imaging (MRI) is an imaging technique that provides detailed images of the structure and beating of the heart. This allows for the assessment of whether the heart structure is normal or abnormal, is weakened or damaged.
Positron Emission Tomography (PET) Scanning is another imaging technique that produces a three-dimensional image that shows the level of chemical activity in different areas of the heart. This information allows for a physician to determine whether enough blood is flowing to the heart in a way that other scanning methods may not be able to provide.
Consequences of HF
Heart failure is a serious medical disorder that may require medical attention from several physicians including your family doctor, internist, cardiologist and heart failure specialist. It is most commonly a chronic illness that often arises as a result from health problems such as coronary artery disease, high blood pressure, diabetes, or a viral infection as well as many other conditions. It can result in a risk of hospitalization, reduced quality of life and reduced survival. The following historical statistics speak to the seriousness of this condition:
- For patients with heart failure, less than 50% of patients are living five years after their initial diagnosis and less than 25% are alive at 10 years.
- Patients hospitalized for heart failure have an average 1-year mortality rate of 33%
- Canada’s average annual in-hospital mortality rate is: i) 9.5 deaths/100 hospitalized patients >65 years of age ii) 12.5 deaths/100 hospitalized patients >75 years of age
Heart failure can be controlled. In most cases, it cannot be cured.
Preventing Heart Failure
In many cases, heart failure arises outside of an individual’s control and thus cannot be prevented. However, making sure to live a healthy life can significantly improve your chances of preventing heart failure. The following are lifestyle changes to focus on in preventing heart failure:
- Make healthy food choices
- Increase physical activity
- Stop smoking tobacco
- Focus on effectively managing stress
For more detailed information on what you can do to increase your chances of preventing heart failure, refer to our ‘Improving Your Diet’ and ‘Physical Activity’ sections within ‘Living With Heart Failure.’
Also, if you feel that you are at a high risk for developing heart failure, be sure to contact your family doctor or a specialist to determine how you can increase your chances of preventing heart failure.