Blood Tests

Full Blood Count (FBC)

This is a measure of the haemoglobin in your blood, as well as your white cells (fights infection) and platelets (needed for blood clotting). Haemoglobin is the pigment in your blood that contains iron and binds to carry oxygen. If your levels are low, this can indicate anaemia, which results in lower capacity to carry oxygen to your tissues which may cause fatigue in muscles or damage to other tissues if severe enough. If your heart is already struggling to meet its own oxygen demands (it is a specialised muscle that is continuously beating) because of narrowing in the tiny arteries that supply it (coronary arteries); if you then reduce how much oxygen is available in the blood supply you run into trouble quickly. Once the heart rate rises slightly with exercise or stress the imbalance between oxygen demand and supply can become critical leading to cramping of the heart muscle, which we call angina. A significant lack of oxygen to the heart cells can also trigger arrhythmias, which can be life threatening.

For these reasons it is important to address any causes of anaemia and to correct them where possible with diet, supplements and/or medication. It is also important to discuss simple factors that might increase heart rate unnecessarily e.g. caffeine, dehydration, vigorous exercise, altitude exposure.

Iron Studies

By checking your iron studies we can identify low ferritin levels that may detect an anaemia before it is apparent in the full blood count as a low haemoglobin. Paradoxically, high ferritin levels are also important as they may indicate other disease processes but are often raised due to obesity and alcohol consumption.

Folate (5-MTHF)

Folic acid (vitamin B9) is vital for protein synthesis and DNA synthesis and stability and therefore every cell in your body. Low folate is quite common and can be low due to diet or poor absorption in your gut. Certain conditions can also increase your folate consumption but this is less common. There are some important drugs that reduce your folate such as alcohol, anticonvulsants and anti-rheumatoid drugs. Low levels of folate can cause anaemia, brain fog, is linked with certain cancers, and is also an important regulator in the metabolic process of homocysteine, which is a risk factor for atherothrombotic events such as a heart attack or stroke. We test the active metabolite 5-MTHF because a proportion of us cannot metabolise folic acid into ins active form, and therefore even if you have normal levels of circulating folate; if it is not metabolised it will not be able to do its intended roles and in essence causes a deficiency.

Vitamin B12

Vitamin B12, also known as cobalamin, is crucial in red blood cell formation, nerve health, immunity and energy release from fats. Most importantly, a deficiency can lead to anaemia and nerve damage that may cause neurological symptoms such as pins and needles and altered sensation. It can also cause a multitude of other symptoms including fatigue, headaches, breathlessness and increased risk of cognitive impairment and depression. For patients with a history of cardiac issues it is very important to note you may be at increased risk when a moderate-to-severe deficiency is present because it could also lead to a rapid irregular heartbeat or reduced cardiac function. If vitamin B12 is low in the presence of a good balanced diet we recommend a further test for Intrinsic Factor, which is key to its absorption and can be low especially in individuals with autoimmune issues (where the body attacks parietal cells in the stomach that produce Intrinsic Factor).

Thyroid Function (TSH, T3, T4)

The thyroid hormone must stay within the normal limits for the heart to function properly. The thyroid gland acts much like the motor of the body controlling the rate of our metabolism. It is important to note that this is not a stagnant process: the gland may release more or less hormone in response to your current physiology. For this reason, if there is a single blood level out of the normal range, we will recommend repeating the blood test in 3 months to establish if this is a temporary deviation or one we need to investigate further.

Sometimes the thyroid gland’s function can be malfunctioning: either producing too much or too little thyroxine hormone. Sustained higher levels of released thyroxine hormone (hyperthyroidism) cause the motor to run faster, which leads to increased heart rate, the feeling of heat intolerance and agitation. It has an important impact on your blood pressure as well. Increased contraction from the heart causes a rise in the pressure as the heart ejects blood (systolic blood pressure) but causes relaxation of the arteries in your body leading to a reduction in the systemic pressure (diastolic blood pressure). This means you can be at risk of not having enough blood volume to perfuse (fill) the system leading to reduced oxygen delivery causing damage to cells or feeling light headed when standing up. This reduced perfusion is especially felt by main organs: the heart will experience a stitch or ‘angina’ if oxygen demand is not met and our brain function will reduced causing confusion if brain cells are starved even slightly of oxygen.

If insufficient thyroid hormone is produced (hypothyroidism) if has the opposite effect: we feel tried, depression, cold and fatigued. The effect on the circulatory system is also the reverse: it causes arteries to constrict causing high blood pressure and slows the heart rate down. In both hyper and hypothyroidism it increases your risk of developing heart failure, which can cause significant illness and premature death.
Thankfully we are good at treating hypo and hyperthyroidism on the whole and by ensuring thyroid function is normal we can help reduce unnecessary physiological stress on the heart.

Kidney Function (U&E)

You might find it strange to hear the physiology linking the kidneys and the heart are incredibly intertwined. In school we are told the kidneys filter the blood but they do so much more than that. Along with the little glands called the adrenals that sit on top of our kidneys, they are key in detecting blood pressure and producing both neural and chemical signals to help regulate blood pressure. They also regulate how much salt and other electrolytes (e.g. potassium, bicarbonate) we get rid of in our urine and how much water we either retain or urinate out. Our kidneys are very sensitive to blood flow because they rely on receiving up to 20-25% of our circulating blood volume but also because the physiology is complex. Illnesses and the drugs we use in cardiac health can have a big impact on our kidneys and that is why we monitor blood levels regularly. That is also why your GP may tell you to withhold certain medications when you are poorly (especially if losing large volumes e.g. vomiting / diarrhoea bugs).

When the kidneys are not functioning well they can cause high blood pressure, and in turn this can cause damage to the delicate filtering system in the kidneys leading to more damage: thereby causing a negative spiral and hence why it is so important to avoid.
The kidney regulates electrolyte balance and if they are damaged that can lead to imbalances in potassium and calcium, which can lead to arrhythmia formation (the heart goes into abnormal rhythms which can lead to cardiac arrest) and poor contractility (reduced force of your heart’s pump).
The kidneys also produce erythropoietin (EPO) , the hormone responsible for stimulating your bone marrow to produce red blood cells. In the presence of long term (chronic) kidney disease the kidneys produce less EPO and thereby stimulate your marrow to produce less red cells leading to anaemia.

Liver Function Test (LFT)

Non Alcoholic Fatty Liver Disease (NAFLD) is thought to affect 1 in 5 adults in the UK. It occurs when fat builds up in the liver and often causes no harm but can be associated with malignancy and increased risk of cardiovascular disease. An increasing number of studies have shown increased atherosclerotic build ups and reduced coronary flow associated with NAFLD. Furthermore, cardiac rhythm disturbances are also linked to NAFLD, such as atrial fibrillation, QT prolongation, and ventricular arrhythmias, which can put these patients at righter risk of sudden cardiac death. It is therefore important to monitor liver function, and where possible to address lifestyle changes to promote reversibility. In early stage NAFLD this is usually reversible but once there is scarring (fibrosis of tissue which can lead to cirrhosis) the aim is more to slow further progression.

Chronic liver disease (CLD) also carries a 2-fold increased risk of cardiovascular disease and is especially dangerous in younger patients. If the liver has significant scarring (cirrhosis) this can cause the right ventricle of the heart leading to deteriorating pump function and thereby reducing the ability of the heart to perfuse our other organs.

High Sensitivity C-Reactive Protein) hsCRP

You may have heard of CRP before if you have ever been unwell or had a relative unwell in the hospital. It is a protein released by the liver in response to inflammation or infection. High sensitivity CRP can detect smaller increases in CRP than the standard test. We know that cardiac disease occurs in response to systemic inflammation so picking up on small increases in CRP (in the absence of acute illness) can help indicate whether you have some background inflammation. By correlating with any other risk factors we can generate a risk profile, which may mean lifestyle changes are more radical and swift. We can measure repeated levels over time to demonstrate whether lifestyle changes are helping.

Uric acid

Uric acid is mainly associated with gout: an inflammatory form of arthritis that tends to affect men and typically is related to alcohol, red meat and shellfish. Uric acid also has a role in cardiovascular health, albeit this is not fully understood yet. We do know that elevated uric acid levels are consistently associated with high blood pressure and is observed in 25-60% of patients with untreated essential (primary) hypertension and in nearly 90% of adolescents with essential hypertension of recent onset. For now, we treat raised uric acid as an independent risk factor for cardiovascular disease and aim to help reduce this by means of diet.

Blood sugars HbA1c

Diabetes increases your risk of heart disease twofold and also carries a 1.5 to 2 times risk of having a stroke. It is therefore so important to avoid developing diabetes , and almost entirely possible for everyone! For most people, developing type 2 diabetes will be a slow process because your body is very good at regulating our sugar stores by the use of hormones (predominantly insulin and glucagon) but after a long time of being exposed to high sugars our bodies become desensitised to insulin and at that point our sugars rise. Unfortunately high blood sugar damages our nerves, small blood vessels, eyes and kidneys. Damage to our nerves affects our hands and feet but also the nerves supplying our blood vessels which can lead to reduced ability to control our blood pressure. As described above, damage to our kidneys can lead to high blood pressure. The good news is that in the last ten years two new drugs have emerged that have changes out ability to reverse type 2 diabetes and we can help advise you on this.

Calcium and Red blood cell magnesium

These are two vital electrolytes needed in the correct concentrations to ensure the heart contracts well and stays in a normal rhythm. It is estimated that up to 40% of the population may have normal serum magnesium levels but a low intracellular magnesium and therefore might benefit from supplements. It is helpful to think of magnesium as a ‘universal relaxer’ as it also helps regulate and lower blood pressure, reduces muscle cramps, improves migraines, improves nerve conduction, improves sleep quality, can help reduce inflammation and improve digestion. If you have very low blood pressure I would suggest avoid taking magnesium unless advised by your doctor as it may make you prone to dizziness.

Lipids

Lipids include cholesterol and triglycerides. The levels of these in our blood largely reflect our lifestyle but unfortunately for many of us; it can also be dictated by our genetics. Some families are prone to having very high cholesterol and this is an important risk factor for cardiovascular disease.
Cholesterol is an important molecule in our blood that is a precursor (vital building block) for many important other molecules; most importantly steroids, bile acid and vitamin D. When cholesterol is in excess in our bodies (particularly it seems in the presence of inflamed blood vessels) it predisposes us to having plaque formation in our blood vessels. Many people can manage higher levels by changing their lifestyles but others may need drugs such as statins, fibrates or ezetimibe to achieve this.

Triglycerides are the free fatty acids in your blood. They are derived from food, especially fats, oils, and butter, as well as extra calories that the body doesn’t immediately need. The body stores triglycerides in fat cells and releases them for energy when needed. Like cholesterol you do need triglycerides but not in excess. A triglyceride level over 200 mg/dL raises your risk for a heart attack or stroke. You should try to keep your triglycerides below 150 mg/dL. The good news is that you can reduce your levels with lifestyle alone within just a few months. Dietary and lifestyle changes will help you achieve this.

Additional testing:

NtPro-BNP (B-type natriuretic peptide) , this is used both in the diagnosis of heart failure as well as the monitoring. It is released by heart cells when they are under stress of being overloaded with pressure: usually when the heart cannot pump out enough blood from its chambers leading to a progressive retention of fluid in the body (most often in the lungs and ankles).

Microbiome Testing

We offer microbiome testing which reveals with content of your individual gut bacteria. Did you know that 99% of the DNA in our bodies is actually from bacteria, archaea and viruses?! This is why the medical community is becoming progressively more interested in studying the impact of different compositions of microbiota on our health and on specific illnesses. This is still a relatively new area of medicine so new research is emerging all the time and the impact of changing our compositions is still not well understood. What we can infer from the results of your stool test is whether you have populations of helpful bacteria or whether we feel trialling probiotics may aid in promoting a healthier gut to improve absorption of nutrients and reduction in methane-producing species that may increase symptoms such of IBS and bloating. We currently promote Symprove as our partner for this due to their unique ability to deliver a greater number of colony forming units (CFUs) of bacteria to the gut to help promote their propagation. in particular their research has shown benefit in irritable bowel symptoms, inflammatory bowel conditions and in neurodegenerative disorders (e.g Alzheimer’s and Parkinson’s).

There is no data yet to contribute towards cardiovascular health but results are promising in modulating inflammation. They have shown both a reduction in pro-inflammatory molecules (MCP-1, CXCL 10 and IL-8) and also an increase in production of anti-inflammatory molecules (IL-6 and IL-10). They have also demonstrated an increase in short-chain fatty acid production (e.g.butyrate) from improved bacterial diversity. We are looking forward to learning more about this and sharing this exciting science with you!