Mention sound waves and your favorite song or someone’s voice may come to mind. But to a cardiologist, sound waves mean echocardiograms.
Echocardiograms are heart images created from sound waves. They give doctors an inside view of a beating heart, which makes it possible for interventional cardiologists to repair life-threatening heart problems without open-heart surgery.
Doctors specializing in this field, such as Catalin Loghin, MD, assistant professor of cardiovascular medicine at McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), are known as interventional imaging cardiologists. First, they establish a complete diagnosis and contribute to planning complex procedures. Ultimately, they guide the interventional cardiologists during delicate interventions such as heart valve repairs.
In observance of February’s American Heart Month, we asked Loghin for an update on the latest developments in the field of interventional imaging.
Could you please expand on how echocardiography works?
We use high frequency sound waves to make pictures of your heart. We start by placing a transducer on your chest. It generates sound waves that echo back off your heart. We then can convert these sound waves into images and project them onto a television monitor. This is a harmless procedure, which provides complex information about your heart. For example, it shows your heart’s pumping strength, whether the valves are narrowing or leaking, whether there are internal blood clots and measures the pressures at various levels inside the heart.
If further information is needed, a sound wave transducer can be inserted through the mouth, close to the heart, similar to other endoscopic procedures. This way we can generate 3-D pictures of the beating heart in real time and full color, at a much higher resolution than regular echocardiograms. We call this procedure a 3-D transesophageal echocardiogram (3-D TEE).
How are echocardiograms typically used?
If your doctor suspects you have a heart problem, a routine echocardiogram will be ordered. It’s a starting point. If something turns up, the patient may be referred to a dedicated diagnostic imaging cardiologist for an advanced cardiovascular study. The net result is a complete diagnostic, irrespective of the case complexity. This information is then analyzed by a team of physicians including surgeons, interventional and imaging cardiologists to generate a plan of treatment, individualized for each case.
How have echocardiograms contributed to the field of interventional cardiology?
The big news in recent years has been addressing structural heart disease. Certain procedures, which would have warranted open-heart surgery in the past, can now be performed without opening the chest. Doctors instead insert a catheter in one of the patient’s groin arteries and thread it through the artery until it reaches the heart. There, with the aid of real-time echocardiographic images, doctors repair the damaged heart with tiny devices.
In complex cases, interventional imaging cardiologists are in the operating room. They will guide and monitor the procedure, representing the “eyes” of the interventional cardiologist. It is teamwork. Such procedures include repairs of a leaky or narrowing valve, congenital defects and addressing complications of previous surgeries.
What are the other imaging options?
When it comes to a truly complete diagnosis of structural heart disease, we also use computed tomography (CT, or CAT, scans). This involves the use of X-rays to make images of the heart, as opposed to sound waves used for echocardiograms. The current generation CT scan machines are so fast, that a complete heart picture can be taken in less time than it takes for the patient to blink. There is no need for prolonged breath holding, and pictures are of very high quality, almost irrespective of heart rate and rhythm. CT scans are complementary to echocardiograms, as the two exams do not provide the same type of information. Using both techniques is frequently the best way to identify complex problems.
Occasionally, we rely on cardiac magnetic resonance imaging (cMRI). This technique basically transforms the body into a radio transmitter by placing it in a high intensity magnetic field. cMRI indications are the realm of specialized imaging cardiologists.
What type of equipment is required?
I practice at the Memorial Hermann Heart & Vascular Institute -Texas Medical Center and we are fortunate to work with excellent equipment. Our newest ultrafast CT scan machine will take a picture of the whole heart during a single heartbeat, with an exceptionally low radiation dose. Our echo machines have the latest 3-D imaging capabilities. We are at the forefront of imaging technology development, just as we are leaders in structural heart interventional devices.
What exciting research is in the pipeline?
Interventional imaging currently drives the need for innovation in the field. Future directions include fusion imaging, where echocardiographic images are superimposed over CT scans, or straight onto the fluoroscopic screen of the interventional cardiologist. Advanced, 4-D CT scans are now possible, and they will provide not only information on heart structures, but also on their behavior in real time. Lastly, we can now create 3-D prints of any heart, using information generated by both echocardiograms and CT scans, a first in structural heart imaging.
Catalin Loghin, MD, is an assistant professor of cardiovascular medicine at McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth), a practicing physician at the Memorial Hermann Heart & Vascular Institute-Texas Medical Center and a member of UT Physicians, the clinical practice of McGovern Medical School. A valedictorian of the centennial class of the University of Medicine and Pharmacy in Iasi, Romania, and an alumnus of UTHealth, Loghin is a clinician with more than 30 years of experience and a member of the teaching faculty of the school with expertise in all aspects of heart imaging: echocardiography, heart CT scans and cMRI. Loghin pioneered the use of imaging in the field of structural heart disease, and his research appears in major medical journals, including The New England Journal of Medicine, JAMA and Journal of the American College of Cardiology.