Cardiac Profile

What are blood tests for heart disease?

In case any part of the heart muscles have been damaged, it can be reflected by the levels of certain components in the blood. This forms the basis of all the blood tests that are done to predict any heart conditions.

Considering that heart diseases are a leading cause of death in both men and women all around the world, these tests play a vital role in taking the right steps to prevent death. In the United States alone, heart diseases are the cause of every one out of four deaths.  

Heart failure is the inability of the heart to pump sufficient blood to the organs in the body and this can be due to heart muscle damage or weakness. In addition, the blockage of the arteries in the heart, caused by the elevations in lipids, especially cholesterol, is also a major cause of heart diseases.

There are certain proteins that can be present in the blood in abnormal amounts in case of heart disease. Some of these proteins are listed below.

– Creatine kinase (CK)
– Creatine kinase-MB (CKMB)
– Myoglobin
– Cardiac troponin I or cardiac troponin T

In many cases, there is a time lag between the onset of heart damage and the appearance of certain proteins in the blood. So the testing can be done serially to prevent any chances of a heart attack.

At the same time, the absence of any of these proteins does not indicate that there is no heart disease but only indicates that there is no heart damage. Almost one-third of the patients suffering heart attacks have normal cholesterol levels and hence there are other factors in play, which are measured by these tests.

In general, the following tests are a part of the complete series of tests.
– Cholesterol test
– High-sensitivity C-reactive protein test
– Lipoprotein test
– Test for Plasma ceramides
– Test for Natriuretic peptides

Why has the doctor asked me to undergo these blood tests?

These tests are generally ordered when there are any symptoms related to heart disease in the patient. Adults with no other risk factors for heart disease should undergo these tests once every four to six years as a precautionary step. Individuals who have higher risk factors when it comes to heart diseases have the following indications.

– Cigarette smoking
– Being overweight or obese
– Unhealthy diet patterns which are high in saturated fat
– Being physically inactive or leading a sedentary lifestyle.
– In case you are a male 45 years or older or a female 50-55 years or older
– Individuals with hypertension
– A family history of premature heart disease
– Pre-existing heart disease or already having had a heart attack
– Affected by diabetes.

The tests help to diagnose the condition of the heart and allow the doctor to take the right steps to prevent any deterioration of the conditions.

What are the symptoms of heart disease?

The term “cardiovascular disease” generally refers to a condition that indicates a problem in the heart resulting from a blocked or narrowed blood vessel.  There can be other problems related to the heart muscles, valves or the rhythm, which can be termed as heart disease. The following can be considered as the symptoms of cardiovascular disease.

– Chest pain, chest tightness, and increased pressure in the chest or upper abdomen resulting in discomfort.

– Shortness of breath

– Sudden nausea or vomiting.

– Pain, numbness or coldness in your legs or arms in case the blood vessels in those parts of your body are narrowed

– Pain in areas like the neck, jaw, throat, upper abdomen or back.

– Extreme fatigue.

– Sudden swelling in the legs, feet, ankles or abdomen.

In case there is a disease related to abnormal heartbeats, the following symptoms may occur.

– Fluttering sensation in your chest

– Racing heartbeat (tachycardia) or slow heartbeat (bradycardia)

– Chest pain or discomfort

– Shortness of breath

– Light-headedness or dizziness

– Fainting or near fainting

Other than these, there can also be congenital heart defects or birth-defects. In case of any of these symptoms, you should contact your doctor at the earliest.

How do I prepare for the blood tests for heart disease?

The blood tests do not require any elaborate preparation. In case there is a requirement to fast before the test, your healthcare professional will provide you with the necessary instructions. It is important to understand the details of the tests from the doctors along with any restrictions that are needed.

You should also inform the doctor about any sort of external medication that you might be consuming as these may interfere with the test results.

How are the tests performed?

The test is performed by collecting a blood sample from the patient through the process of venipuncture. In this process, a needle is inserted into a vein to draw the required volume of blood. The process involves the following steps.

An elastic band is tied in the upper arm to make the veins swell with blood, thus making the collection process easier. The collection site is generally around the elbow region and the healthcare practitioner disinfects the area where the needle will be inserted. In some cases, blood may also be collected from the back of the hand.

A needle is inserted into the vein and the required volume of blood is drawn through it in an attached tube. A stinging sensation is felt when the needle is inserted.

The band is loosened to remove the pressure on the veins and the needle is then withdrawn and pressure is applied on the site through a gauze or a cotton piece to prevent any excessive bleeding. The spot is then covered with a sterile bandage and the sample is sent to the laboratory for testing.

When will I get the test results?

The result of all the tests is generally delivered within 2 to 3 days though it can get delayed under specific circumstances.

What are the different types of cholesterol tests?

The tests, also known as the lipid panel tests, include the following individual tests.

Total cholesterol- This is a sum of the blood’s total cholesterol content and a high level can put you at an increased risk of heart disease.

Low-density lipoprotein (LDL) cholesterol– This is also called the “bad” cholesterol as it deposits excess cholesterol in walls of veins and arteries, contributing to atherosclerosis.

High-density lipoprotein (HDL) cholesterol-This is termed as the “good” cholesterol because it helps carry away LDL cholesterol to the liver for removal. This keeps the arteries open and allows the blood to flow more freely.

Triglycerides– Triglycerides are another type of fat in the blood which are low-density lipoproteins. Higher levels usually indicate unhealthy food habits and lack of physical exercise and increase the risk of heart diseases.

Non-HDL cholesterol- Non-high density lipoprotein cholesterol is the difference between total cholesterol and high-density lipoprotein cholesterol (HDL-C). This element causes the hardening of the arteries (atherosclerosis).

What is the role of C-reactive protein in heart diseases?

The CRP is a specific protein produced by the liver in response to any inflammation or infection. The levels of the protein are an important indicator of atherosclerosis, in which fat deposits block the arteries.

The process of atherosclerosis involves a complex interaction between the components of the vascular wall, inflammatory cells, and lipoproteins. The high levels of the protein are considered as an important marker of a coronary event in healthy patients, patients with medium or high cholesterol levels and patients with acute coronary syndromes.

As the test alone does not indicate heart disease, it is conducted with other blood tests. Due to the variability in CRP levels, the test is often conducted twice, with a gap of two weeks.

What are the reference ranges for the blood tests for heart disease?

The cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. The following are the reference levels.

Total cholesterol: less than 200 mg/dL
LDL cholesterol: Less than 130 mg/dL ( the lower the better)
HDL cholesterol: Over 40 mg/dL for men and over 50 mg/dL for women
CRP Level: Less than 3.0 milligrams per liter.
Plasma ceramides: These results are measured on a 12 point scale.

The readings are classified as:

0–2 (lower risk)
3–6 (moderate risk)
7–9 (intermediate risk)
10–12 (higher risk)

What do the results mean?

The results will determine the overall risk of coronary heart disease for a patient and whether treatment is necessary. A doctor will judge the results along with the other symptoms and also considering factors like age, gender, blood pressure, presence of diabetes and lifestyle habits. In case the levels are above normal and indicate a high risk of a heart ailment, necessary steps will be taken to reduce the risks.

Can pregnant women undergo blood tests for heart disease?

Pregnant women can undergo the test without any restrictions.

Are the tests possible for new-born babies?

The tests can be conducted on new-born babies as advised by the doctor.