What is heart failure?

 

Image | DocJana

Heart failure is a term used to describe a broad range of conditions that all share similar symptoms and signs. At the core, these conditions all involve one key principle: the heart’s function cannot match the body’s requirements.

There are many signs and symptoms of heart failure – the most common ones are:

  • Shortness of breath (dyspnoea)
    • when doing physical activity (exertional dyspnoea)
    • when lying down flat (orthopnoea)
    • Causing sudden awakenings at night, gasping for breath (paroxysmal nocturnal dyspnoea)
  • Fatigue
  • Fluid accumulation (oedema)
    • Of the legs, particularly the ankles (peripheral oedema)
    • of the abdomen (ascites)

There are many (over 50!) different causes of heart failure, and the easiest way to understand heart failure is to start by understanding how the heart works and how we measure its function.

In brief, there are four key steps:

  1. The heart is designed to pump blood around the body
  2. With every heart beat the main pumping chamber squeezes blood out (systole), then relaxes to bring blood in ready for the next beat (diastole)
  3. Valves in the heart stop blood from going in the wrong direction
  4. The heart can change its speed or pumping volume depending on how much blood the body asks for

We measure the heart’s pumping and relaxing function using various tests, most commonly an echocardiogram.

With this test, we measure how much blood is pumped out every beat as a proportion of the total volume inside that main pumping chamber (left ventricle) – this is called the ejection fraction. In a normal heart, at least 50% of the blood is pumped out each beat, and the valves stop blood from going backwards.

If any of these parts fail, then people can develop heart failure. A few of the main categories of heart failure include:

  • Heart failure with reduced ejection fraction (HFREF)
    • The heart doesn’t squeeze out blood properly
  • Heart failure with preserved ejection fraction (HFPEF)
    • The heart doesn’t relax normally
  • Heart failure due to valvular disease
    • Blood is allowed to go backwards due to leaking valves (regurgitation), or the valves become narrow and stop blood from going forwards (stenosis)
  • Heart failure due to something else
    • The lining of the heart (pericardium) can sometimes become inflamed and compress the heart
    • Abnormal heart rhythms (arrhythmia)
    • Infiltrative heart disease, where certain substances can build up inside the heart muscle and stop it from working properly

Treatment of heart failure depends very much on the cause, the category and the other conditions a patient may have. Treatments range from lifestyle modifications, to medications, to pacemakers, to mechanical pumps and even cardiac transplantation.

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