Probably one of the most common questions I am asked by patients is “do I have any blockages in my heart doctor?”
I usually encounter this question after patients have undergone certain investigations. It is an important question no doubt, as more and more people are now concerned about heart disease.
I thought I would briefly discuss what a ‘heart blockage’ is, and how we detect it through certain tests. I will also discuss the best ways to detect heart blockages as well.
What Is A Heart Blockage?
A heart blockage is a term that is used by patients when they wish to know if they are at risk of having a heart attack. What I have found over the years is that when patients undergo cardiac tests, the one thing they almost always ask me is whether they have blockages in the heart.
I often presume that this means whether the heart arteries are blocked or not.
Narrowing of the heart arteries is usually confused with blocked arteries. When arteries are narrowed, the quantity of blood flowing to the heart muscle in times of need is reduced. Narrowing of the arteries is due to a process called atherosclerosis.
For example, the heart requires more blood during exercise. The extra blood gives it the nourishment it needs to continue functioning efficiently.
However, if there are narrowing of the blood vessels that supply these nutrients, the heart begins to struggle.
A ‘narrowing’ and ‘blockage’ describe different conditions. When doctors describe blockages, we mean the heart artery is 100% blocked. A narrowed artery can only be 80% narrowed, but not blocked.
Detecting these ‘narrowings’ or ‘blockages’ can be achieved through certain investigations. Here, I will discuss a step wise approach cardiologists and physicians follow when detecting ‘heart blockages’ for the first time.
For the purpose of this article and for better understanding, I will use the term heart blockages to describe narrowing of the blood vessels.
How Are Heart Blockages Detected?
The first way to detect whether a heart artery is blocked or not is by symptoms. Patients who have severely narrowed arteries can experience a number of symptoms. I have listed these in the table below.
However, some individuals may not experience any symptoms whatsoever. This is particularly common in people who have diabetes.
That being said, sometimes people tend to ignore some of the symptoms I have mentioned above. Many feel their chest pain is due to ‘gas’.
If you ever have chest pain of any sort and are even the slightest bit concerned about it, make sure you see your doctor.
An electrocardiogram, or an ECG, is a good way of determining if there has been any damage to the heart muscle due to heart blockages. It is sometimes called a heart tracing.
Doctors will look for specific changes in your heart tracing that would indicate the presence of a damaged heart muscle.
However, the ECG can sometimes be normal. This is not uncommon.
When the ECG is normal, it comes down to symptoms and clinical suspicion. If your doctor feels that your symptoms are due to reduced blood flow to your heart, you may have additional investigations arranged.
I have discussed treadmill tests in detail here.
While a treadmill test is a good way of screening patients for heart disease and blockages, it does not give 100% accurate results.
We conduct treadmill tests in our clinic all the time, and on rare occasions the test can be negative despite the patient having heart disease.
This is what a patient walking on a treadmill looks like –
Clinical studies have shown that 1 out of 5 cases of heart disease can be missed with a treadmill test. In other words, 20% of patients will have a normal study even if their arteries are narrowed.
When arranging a treadmill test, there are a number of aspects doctors take into consideration.
Is there a family history of heart disease?
Has anyone died at a young age from a heart attack?
Are the symptoms of chest pain very limiting?
Are there any risk factors for heart disease such as smoking and high cholesterol?
By taking these aspects into consideration, doctors can advise patients as to whether a treadmill test is appropriate.
Our approach in our clinic is to assess the symptoms and the risk factors and then decide whether a treadmill test would help. While most of the patients would fit the criteria, there have been times where we have advised coronary angiography as a first investigation as the results are 100% accurate.
One aspect that we always bear in mind is the cost of the tests. A treadmill test costs between Rs 1250 to Rs 3000 depending on where you get it done.
More advanced investigation such as CT scans or angiograms cost between Rs 10,000 to Rs 25,000, depending on the center.
We still recommend treadmill test for our low to intermediate risk patients.
You can read a detailed account of what an echocardiogram is here.
An echocardiogram can help determine if the heart muscle is abnormal. One aspect of this abnormality is damage to the heart muscle.
If someone has suffered a heart attack that they are aware (or unaware) of, a specific part of the heart muscle does not move as well as it should do. This is because the shortage of blood supply from a narrowed blood vessel makes it weak.
An echocardiogram is an excellent way to find out how strong your heart is and whether the blood supply is intact.
In patients who come to our clinic with chest pain, we often perform echo tests. Clinical research has shown that echocardiogram tests can determine heart muscle damage a lot earlier than the ECG can.
So, if your ECG is normal, your doctor may recommend an echo test to assess the function of the heart.
In some cases, the echo may be completely normal. This does not mean there are no heart blockages though. It only means that the blockages have not caused any trouble yet.
CT Coronary Angiogram
You can read about CT Coronary angiography here.
This is an extremely useful test in individuals who are describing symptoms of heart disease but have a very low risk score.
For example, if a patient has no family history of heart disease, no diabetes, does not smoke but suffers from high blood pressure, then a CT angiogram may be an appropriate test to do.
The CT is usually conducted if the treadmill test shows unclear results and is a ‘weak positive’ test.
We do not normally advise CT angiograms for patients who are high risk. This is because this test can miss around 2 to 4% of cases.
In older patients, the arteries around the heart can become thick due to deposition of calcium. Calcium appears very bright on CT angiogram tests.
Excessive calcium can sometimes make it difficult to assess how much the arteries are blocked sometimes. In other words, the narrowing and blockages could be over- or under-estimated.
If there is any concern regarding this, you doctor will arrange a hospital coronary angiogram.
A CT angiogram costs around Rs 6000 – Rs 10,000 in most centers. Some centers require the patient to undergo an echocardiogram first before the CT is conducted.
A CT angiogram requires the injection of a special dye into the blood stream. Since this dye is filtered through the kidneys, the test may not be performed if the creatinine levels are high.
Also called CAG by doctors, a hospital based coronary angiogram is the best test to find out whether you have blockages in your heart arteries.
I have written an article on coronary angiogram here if you wish to read this.
A coronary angiogram is highly accurate and is simple to perform. Unlike previously where it was performed through the artery in the leg, most cases are now done through the wrist.
Coronary angiography can provide very specific details regarding the state of the heart arteries. To this day, it remains the best way for heart blockages to be diagnosed.
Coronary angiograms can cost up to Rs 16,000 – Rs 25,000, depending on where it is performed. It can be done on an outpatient basis without the need for admission.
The above are the common ways heart blockages are investigated. There are a number of other tests that may be performed depending on the clinical requirement.
These tests are myocardial perfusion study or stress thallium testing and stress echo. I have not discussed these here as it would complicate this article.
However, you could read up about these tests here if you wish to.
Heart blockages or narrowings are what lead to heart attacks. Undergoing the right investigations at the right time can pick these up early.
The sooner the treatment is started, the better.
From HeartSense Team – If you wish to know more about heart health packages, drop us an email at [email protected]