Natiuretic Peptides and Heart Failure
Heart failure is a serious and fairly common heart condition in the UK. Approximately 70 000 people are diagnosed with it every year and it is more common in older people. The peak incidence for heart failure is in the over 85s. When a heart is failing, it is not in danger of stopping. It is more that it can no longer work properly to push enough blood around the body with enough force to keep all the tissues and cells supplied with fresh oxygenated blood.
Heart failure can affect either of the ventricles, causing left or right heart failure. Either type can be classified as either diastolic or systolic heart failure. In diastolic heart failure, the ventricles cannot pump with enough force; in systolic heart failure not enough blood enters the ventricle to be pumped out.
Symptoms of Heart FailureIf you have either form of left heart failure, blood cannot get to and from the lungs very efficiently, so the main symptoms experienced are breathlessness, tiredness and dizziness. If the right ventricle is more affected, blood cannot get to and from the body that well, which leads to a build up of tissue fluid in the parts of the body furthest away. Typically, people with right heart failure develop swollen feet, ankles and legs and their liver can also grow abnormally large. Both types make you feel quite unwell, and feeling sick and having no appetite is common.
Heart failure can develop suddenly after a heart attack and be very severe, or it can come on gradually, with only mild symptoms at first.
Diagnosing Heart FailureMany of the symptoms of heart failure, particularly in the milder forms of the disease, can also occur with other health problems. Diagnosis can be tricky but this is getting easier because of various blood markers that have been discovered. Natriuretic peptides, in particular b-type, or brain natriuretic peptide increase in the blood when someone has heart failure and have become a very reliable diagnostic cardiac marker. This molecule is produced when the heart muscle in the ventricles is overstretched, as it is when the heart is failing. The more severe the heart failure, the greater the quantity of brain natriuretic peptide produced.
Benefits of Measuring Brain Natriuretic PeptideMeasuring the level of natriuretic peptides in the blood is more cost effective than carrying out a full electrocardiogram. The blood test can also either completely exclude heart failure as a diagnosis, or confirm that heart failure is the main problem. People with very high levels of this cardiac marker are also at greater risk of developing atrial fibrillation and of having a stroke. This is impossible to tell through a clinical examination and a positive blood test result makes it more likely that prompt treatment will be started to reduce that increased risk.
Interpreting the test results needs to be done by an expert as there are many factors to consider. Natriuretic peptide levels rise naturally with age and women have higher levels than men of the same age. Although very high levels are almost always an indicator of heart failure, slightly raised levels can be due to other causes such as high blood pressure, heart valve disease, lung problems or infection.