Heart Failure - Understanding It

The heart is a very important organ that pumps blood to all parts of the body. The heart is often thought of as a large and powerful muscle. It is divided into four chambers which are separated by “doors” or valves.

For the heart to function efficiently, it needs to have:

  • Healthy heart muscles that relax properly to allow the heart chambers to fill with blood, and contract strongly to push forward the blood to the rest of the body;
  • Valves that work properly to make sure the blood flows in a forward direction;
  • A complex electrical conduction system that coordinates the pumping and relaxing action of the heart;
  • Unblocked coronary (heart) arteries to supply blood to the heart muscles.

There are also complex interactions between the heart and the lungs, kidneys, nervous system, hormones and other organ systems.

A normal heart fills with blood when the heart muscle relaxes and then pumps out at least 50% to 70% of the blood when it contracts in a person who is resting. The amount of blood that the heart supplies to the body generally depends on the body’s metabolic or energy demands.

The heart is able to match the body’s energy demands by contracting harder and faster. This increases blood supply (also called cardiac output) to the body whenever it is needed. However, there is a limit as to how much the heart can pump.

What is Heart Failure?

When the heart is no longer able to match the body’s metabolic demands, a condition called heart failure (HF) may happen. This most commonly occurs because the heart is unable to function efficiently due to disease or injury. Less commonly, HF happens because the body’s metabolic demands are more than what the heart can cope with, even though the heart may be normal.

There are two main ways by which heart function can become abnormal:

  1. More commonly, the heart which is weak is unable to pump enough blood to meet the body’s demands. Any disease condition or injury to the heart muscles, heart valves or electrical conduction system of the heart can damage and weaken the heart causing heart failure.
  2. Another way is a stiff heart that is unable to fill properly with blood even though it may still be able to “pump” well. This situation leads to increased pressures within the heart chambers and eventually in the blood vessels of the lungs, causing heart failure.

Both conditions eventually cause a decrease in cardiac output and inadequate blood supply to the rest of the body. When this occurs, the body will compensate for the lack of blood supply through a number of ways.

For instance, certain hormones and the nervous system (also known as the neurohormonal systems) become active, making the injured heart contract harder and faster. These systems also cause the kidneys to retain salt and fluid in order to increase blood volume, and also make the blood vessels in the body and limbs become narrower to increase blood pressure. While these processes may initially improve the heart function and cardiac output, in the long run, they damage the body and the heart, particularly if the heart remains injured. Altogether, these processes produce the syndrome of heart failure.

Why does my heart function become abnormal?

Any one or a combination of these various conditions can cause the heart to function inefficiently:

  • Heart muscle damage due to heart attack or when the heart arteries become severely narrowed
  • Poorly controlled long-term high blood pressure
  • Faulty heart valves
  • Cardiomyopathy (disease of the heart muscle due to genetic causes, or damage to the heart muscle by external causes like a virus or alcohol)
  • Congenital heart disease (heart defects present since birth)
  • Infection of the heart and/or heart valves
  • Arrhythmia (heart rhythm disorder)
  • Certain toxins (alcohol, cocaine, certain chemotherapy drugs)
  • Other medical conditions (e.g. thyroid disease, autoimmune conditions, tumours affecting the heart, etc)

Related: Heart Failure - Alcohol and Smoking

What happens when my heart becomes weak?

The heart pumps less blood than normal, to which the kidneys respond by retaining fluids. Excess fluids collect in the body, giving rise to these symptoms:

  • Feeling tired or waking up in the night due to breathing difficulties
  • Swelling of feet, ankles, or abdomen
  • Sudden weight gain
  • Fluid in the lungs causing shortness of breath, coughing and wheezing

What Can Worsen the Heart Failure?

With proper treatment, heart failure can be controlled. Even if the heart is not functioning normally, the patient can feel better.

Treatment helps to balance the heart’s cardiac output function with the body’s metabolic demands.

However, certain factors may upset this balance and worsen the HF condition. It is important to realize this because many of these factors can be avoided.

Examples include:

  • Not taking the heart failure medications properly or adequately
  • Infections such as flu, food poisoning, urine infection, etc
  • Certain medications such as non-steroidal anti-inflammatory painkillers
  • Too much alcohol
  • Another heart attack
  • Poorly controlled high blood pressure
  • Sudden heart rhythm abnormalities
  • Smoking

Managing Heart Failure

By taking certain steps, you can relieve your symptoms and prevent your heart from getting weaker. You can also reduce the risks of complications that may lead to hospitalisation.

Tips to Manage Heart Failure

  1. Understand heart failure and be involved in your care.
  2. Treat the cause of the heart failure, such as coronary artery disease to prevent progression of the heart failure.
  3. Follow your doctor’s advice.
  4. Take your medicines as prescribed.
  5. Eat a healthy diet that is low in salt and saturated fat.
  6. Limit the amount of fluids as instructed by your doctor (generally within 1.5 litres/ day).
  7. Do not smoke.
  8. Drink alcohol beverages in moderation, or stop alcohol if instructed by your doctor.
  9. Remain active and increase the amount of activities to what your body can tolerate.
  10. Weigh daily to check for fluid retention.
  11. Monitor your blood pressure and manage stress.
  12. Attend all your medical appointments.
  13. Record your daily weight and condition in a diary. Bring this diary with you when you see your doctor.
  14. Follow the “Heart Failure Action Plan”

Read this next:

Back to Top