Heart palpitations

Many people will experience heart palpitations at some point in their life, and the vast majority of the time the cause will be harmless. However, in some rare cases, heart palpitations can be a symptom of leukaemia. Find out why, and what to look out for, in our blog.

What are heart palpitations?

Heart palpitations are described as an unpleasant heightened awareness of your own heart beating. Often reported as a “fluttering”, “sudden thump” or a “fast pounding” sensation in the chest, heart palpitations may also be felt in your neck or through your ear when you are lying down.

“I could hear my heartbeat in my ears so loud my head felt like it was throbbing, and it would not go away when I lay down.”

Heart palpitations are very common. In fact, nearly everyone has experienced a palpitation at some point in their life. Although they can be quite frightening, they are nearly always harmless and resolve without any treatment. Common causes include certain stimulants such as alcohol, caffeine, specific medicines, tobacco or psychological factors such as stress or excitement.

However, on rare occasions, heart palpitations can be a sign of a more serious underlying medical condition, such as an underlying heart problem, hormone imbalances, or anaemia (a lack of red blood cells). Because leukaemia can directly lead to anaemia, heart palpitations can sometimes be one of the first symptoms of leukaemia.

Regardless of whether you think leukaemia is a possibility, you should see your GP if you have palpitations that don’t disappear or are getting worse, or if they occur alongside other symptoms such as sudden dizziness or shortness of breath.

Heart palpitations as a symptom of leukaemia

Heart palpitations are a relatively rare symptom of leukaemia. According to our 2018 patient survey, palpitations or heart irregularities occur as a symptom of leukaemia in 6% of all patients before they are diagnosed, making it one of the least reported symptoms in our survey. Because heart palpitations are so common and are rarely related to leukaemia, (primarily because leukaemia is a relatively rare disease in its own right), both the public and healthcare professionals will often put palpitations down to stress or other non-serious causes.

“After a month of experiencing extreme tiredness and rashes, along with an increasingly gaunt complexion and, eventually, heart palpitations, I went to visit my GP. However, having a runny nose (which doctors later realised was as a result of a depleted immune system) I was told I simply had a cold.”

Patients with pre-existing heart conditions who develop leukaemia may also experience chest pains. “I became increasingly breathless and then got central chest pain. I couldn’t walk 10 minutes to the train without stopping for a rest.”

Anaemia, the cause of palpitations in leukaemia

Anaemia is defined as a decrease in the level of functioning red blood cells in the blood. As previously mentioned, when heart palpitations do occur in cases of leukaemia, they are normally caused by the person being anaemic, which is a common complication of the leukaemia itself. Leukaemia directly causes anaemia by preventing the bone marrow from producing blood cells efficiently.

Bone marrow is a spongy tissue found in the centre of some of your bones. It contains stem cells which develop into all the various blood cells. Leukaemia occurs when cancerous blood cells form in the bone marrow and crowd out the healthy blood cells. One type of blood cell that is sometimes crowded is red blood cells, which leads to anaemia.  Red blood cells contain haemoglobin that carries oxygen from the lungs to the body’s cells and tissues. A deficiency of red blood cells, therefore, means there is less oxygen being carried around the body and so the cells and tissues become starved of oxygen. As a consequence of this, the heart begins to pump harder and faster to try and maximise the amount of oxygen that reaches the tissues. This excess pressure exerted on the heart can result in an abnormal heartbeat, as well as an increased awareness of each heartbeat, which is perceived as palpitations.

Other symptoms caused by leukaemia-related-anaemia

Anaemia is responsible for a diverse range of symptoms, many of which are also commonly associated with leukaemia. For this reason, it is extremely rare for heart palpitations to occur as a symptom on their own. One reason for the relative rarity of palpitations presenting as a symptom is that they only occur in very severe anaemia – symptoms such as fatigue, shortness of breath and loss of concentration are likely to proceed this symptom as they develop sooner when anaemia is not as serious.

Weakness and Fatigue – Cells in the body use the oxygen to fuel the combustion of sugar and fat, which produces the body’s energy. Without oxygen, the body cannot function properly, and this leads to the feelings of extreme tiredness, known as cancer-related fatigue.

Breathlessness – Your body will automatically try and compensate for the lack of oxygen by breathing more heavily to replenish oxygen levels from the air.

Pale skin – When oxygen binds to haemoglobin on the red blood cells, it forms a bright red substance known as oxyhaemoglobin, causing the blood to become bright red. Skin that is paler than a person’s usual complexion may occur due to the reduced amount of oxyhaemoglobin in the vessels supplying the skin.

Dizziness and poor concentration – Dizziness and lack of concentration can be caused by the brain’s shortage of oxygen. It can also result from low blood pressure in the vessels supplying the brain due to poor oxygenation of the heart muscles, reducing its ability to efficiently pump blood.

Keeping an eye out for these other symptoms of anaemia and connecting the dots between them may be crucial in spotting leukaemia early. Since anaemia is usually diagnosed using a full blood count, leukaemia can also be picked up at this stage.

Acute myeloid leukaemia (AML)

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