What are cardiac tests? What are the differences between them?

by Dec 10, 2020Respiratory0 comments

What are cardiac tests? Which kinds of tests currently exist and what are the differences between them?

In terms of cardiac testing, hospitals now usually use three types of tests: cardiac color doppler ultrasounds, electrocardiogram tests, and coronary angiographies. These three tests are responsible for examining the structure of the heart, understanding the rhythm of the heart, and showing the condition of the blood vessels, respectively.


If one day, you ever feel that your heart is uncomfortable and have to go to the hospital for an examination, the doctor will ask you to lie on the bed, stretch your legs, and untie your shirt. A light blue, sticky, and gelatinous liquid will be applied to your chest, and a thick-headed pillar will be pulled out.

The colloidal liquid is called a “medical ultrasonic couplant,” and the thick-headed column is an ultrasound probe. The human heart can be seen as comprising of four “rooms” (right and left atria and ventricles) separated by walls (myocardium) and doors (valves) that allow blood to pass through the rooms. There is a normal range of door size and wall thickness for all people. And if something goes wrong, it means the heart is “sick”.

For example:

  • Some people have defects in the “walls” of the heart as soon as they are born, which is often referred to as congenital heart disease.
  •  For some people, long term high blood pressure causes the heart muscle to become fat and the “walls” to become thicker, which is called hypertensive heart disease.
  • For some people, due to infections, the “valves” are narrowed or not closed properly, which prevents the “doors” from opening and closing smoothly and affects the blood flow. That is called valvular heart disease.

The cardiac color ultrasound, also known as cardiac color Doppler, is responsible for observing these “door-wall” structures. The cardiac color Doppler ultrasound is one kind of ultrasound examination, but compared with the ordinary B-ultrasound, it is clearer and finer, and it can better avoid the interference of obesity and other conditions.

It clearly identifies structural abnormalities in the heart, such as the size of the chambers, the thickness of the interstitial wall, and the presence of valves that are not closing properly, narrowing, or prolapsing, as well as the heart’s ability to pump blood.

It is precisely because it is a type of ultrasound that cardiac ultrasound is a very safe way to examine the heart.

(Heart color Doppler ultrasound : this is what the doctor sees when you are lying on the bed, and he/she is scanning your chest with the thick-headed pillar.)


If one day you go to the hospital for a checkup and the doctor makes you lie on the bed with your legs stretched out, unbutton your shirt, and then stick a bunch of patches with random wires attached to them on your chest, it might make you feel like an internet or video game addict,  who needs to be sent to an internet addiction treatment facility to receive electric shocks.

The human heart beats, and in addition to the number of beats having a normal range, the rhythm of the beat is also important.

A normal person’s heartbeat is as accurate as clockwork, and if it is occasionally fast or slow, it is an arrhythmia, which may affect the heart’s ability to supply blood. For example, the most common clinical arrhythmia, called atrial fibrillation, brings about a feeling of panic and palpitations, shortness of breath, fatigue, and even dizziness and fainting.

This is where the electrocardiogram (ECG) comes into play. It is made to understand the rhythm of the heart.

A routine electrocardiogram (ECG) is performed by placing electrode pads (which seems like an electrocution) and a hand and foot electrical lead system on the skin for a few minutes, which depicts the electrical activity of the heart on a curve. An experienced doctor can use these curves to know if the heart is beating rhythmically.

In addition to the conventional ECG, there is a “dynamic ECG” that compensates for a routine ECG by detecting the heartbeat 24 hours a day. In clinical practice, the ECG, combined with troponin and cardiac enzymes, is often used to detect myocardial infarction.

By the way, the technology used in lie detectors that we often see in movies is also used in ECGs, and by finding the slightest “unintentional twitch” in your wonderful little heart, your “inconsistencies” will be uncovered.


If one day you go to the hospital for a checkup and the doctor pushes you into a strange kind of big room, makes you lie down on a bed, has you spreading your legs, and you then feel like you are paralyzed, and you see several doctors in lab blouses, masks and hair covers, all wrapped up tightly, slowly pushing some kind of strange looking liquid towards your body,…

A coronary angiography is a relatively low-risk, relatively safe, surgery performed under local anesthesia. It is mainly used to visualize the blood vessels in the heart through X-rays, while the “contrast agent” is pushed towards the body in order to enhance the visualization.

As stated above, the human heart is like a house, and the coronary arteries are the tubes that supply water and oxygen to the house. The coronary arteries are located outside the heart and provide a steady flow of oxygen and nutrients to the heart. Diabetes, high blood pressure, dyslipidemia, smoking, etc., can cause impurities in the blood vessels to increase and the water flow to become less and less smooth.

To understand the condition of these coronary arteries, a “coronary angiogram” is used, through a contrast agent, that allows the physician to clearly visualize the thickness of the coronary arteries under X-rays to determine a subsequent treatment.

Because if these pipes are severely blocked, various clinical symptoms (with chest pain as the main syndrome) may appear, that is, “coronary heart disease”, which is why coronary angiography is the “gold standard” for the diagnosis of coronary heart disease.

Through local anesthesia, the femoral artery is punctured, the arterial sheath is implanted, the angiography catheter is sent into the left and right coronary orifices, the contrast agent is injected at multiple projection angles, and then the condition of the coronary artery is displayed on the monitor screen to determine the degree of coronary artery disease.

But don’t be afraid to look. A coronary angiography is generally used for coronary heart disease, not for ordinary cardiac examinations.

In conclusion, the three most common types of heart tests are cardiac ultrasounds, electrocardiograms (EKG), and coronary angiograms. Doctors will use one or more of these tests to help determine what is wrong with the heart by understanding its structure, rhythm, and blood vessels.

In addition, cardiac tests also include cardiac MRIs (magnetic resonance imaging), etc. As for the choice of which test to do, you should go to the hospital and listen to your doctor’s advice based on your symptoms.


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