Clinical utility and various types of Cardiac Echocardiography; what a common man needs to know!
“Reading a technically poor echocardiogram is like looking at a polar bear in a snowstorm” Lynn Y. Zoiopoulos, DO
Ultrasound is a technology which uses sound waves higher than the hearing capacity of the human ear and hence called “ULTRAsound”. In technical terms, ultrasound of the heart is called “echocardiography”. It was first devised by two navy engineers who were researching on sonar, the tech to detect submarines in the deep ocean. The most familiar use of echocardiogram is to study the function of the heart. The echo sound waves change their pitch when they recoil from blood cells moving through the heart and blood vessels. Through echocardiography, we make pretty pictures of the heart from sound waves reflected from various structures of the heart.
There are several types of echocardiography. The most common is looking through the chest. We rotate the recording instrument called the “probe” at various angles to look at the heart from different directions. Due to the bulk of the chest, it’s challenging to look at the backside of the heart. The heart has four chambers, the two receiving chamber “atria”, right and left. And two pumping chambers, the “ventricles”, right and left. The right atrium and part of right ventricle lie on the backside and are relatively challenging to see with conventional chest echo.
“it’s not the hole in the doughnut where the action is; it is the doughnut itself”. Steven E Nissen, MD
Scientists have found a smarter way out to see them. The probe is passed through a food pipe called “oesophagus” which lies on the back of the heart. This type of echo is called a “transesophageal echo”. It can define the posterior structures more clearly. Still technically challenging, as we have to pass and move the probe through the mouth into the food pipe.
The science of echocardiography does not stop here. Scientists have found limitation that we cannot look at internal structures with great details through the chest or food pipe. So they devised a technique to use probe during open-heart surgery, called “transcardiac echo”. The transcardiac echo can provide by far one of the possible crisp images. And also can guide valve surgery and stent placement. However, it is used for driving electrical procedures on the heart in good centres routinely.
There are some heart issues, particularly those involving the blood vessels supplying blood to the heart muscle (coronary arteries), occur only during physical exercise. “Stress echocardiogram” is acquired before and immediately after the workout on the treadmill to get information about any blockages in the coronary arteries. In cases unable to perform the exercise, an injection of a medication is injected to make the heart pump just as hard as exercising is used.
Another type of echo worth mentioning is “portable echo” which can be moved in a small box anywhere rather than big machines we usually see in heart centres. The advancement in science has reduced the size of echocardiography equipment. Currently, the vendors offer pocket echocardiography machines worth the size of a small cell phone. Most importantly, the echocardiography experts can report echocardiograms from thousands of miles away through teleradiology. The field of echocardiography is changing dramatically. Still, these are must-have units for a low to the middle-income economy like Pakistan. These are considered essential building blocks of a heart centre in the developed world.
The article has been co-authored by Dr. Maimoona Siddique and Dr. Aitzaz Bin Sultan Rai.
Disclaimer: The views expressed in the article are the author’s own and do not necessarily reflect Dunya News’ editorial stance.