Novel Ultrasound Technology To Screen For Heart Conditions

Researchers separeted the total 2D-velocity field of intra-
ventricular flow (left) into a vortex field (center) and an
 irrotational field (right). (Credit: Jacobs School of
Engineering/UC San Diego)
Engineers have determined for the first time the impact of a ring-shaped vortex on transporting blood flow in normal and abnormal ventricles within the human heart. In order to make the study possible, researchers have developed a novel ultrasound technology that makes screening cheaper and much easier, making it possible to reach a large number of people and even infants. Intra-ventricular flow imaging is currently done with MRI scans, which is expensive and not suitable for patients with implanted devices such as pacemakers. 

The findings could have an impact on the tests and measurements that physicians rely on to diagnose and treat two heart conditions: hypertrophic cardiomyopathy, in which the heart muscle becomes abnormally thick, and non-ischemic dilated cardiomyopathy, in which the heart's ability to pump blood decreases as the organ's main pumping chamber, the left ventricle, is enlarged and its muscle thinned. Nearly one million Americans suffer from either one of these conditions.

So far, physicians only take into consideration the geometry of the left ventricle and the thickness and contractility of its walls when they assess how the heart fills itself with blood. But the way the blood flows into the heart's chambers is important too, researchers argue. They reported their findings in the Oct. 21 issue of the Journal of the American College of Cardiology

People suffering from hypertrophic and dilated cardiomyopathies often don't show symptoms of the condition until it's too late, making early screening of paramount importance. When patients are not diagnosed early, these conditions have unfavorable prognosis, worse than a number of cancers, with most of the patients dying within five years.

For this study, the team of cardiologists recruited 60 subjects, including 20 patients with non-ischemic dilated cardiomyopathy; 20 patients with hypertrophic cardiomyopathy; and 20 healthy subjects as a control group.

All subjects underwent comprehensive 2D echocardiographic exams. Then, engineers processed the images with methods typically used to create flow simulations for the aeronautical and naval industries, capturing the blood flow inside each subject's hearts. Researchers found that the ring-shaped vortex helps to allocate about 15 percent of the blood flow within the left ventricle in healthy patients; roughly 20 percent in patients with non-ischemic dilated cardiomyopathy; but only about 5 percent for patients with hypertrophic cardiomyopathy.

Treatment for cardiomyopathies often includes device implantation, such as pacemakers, to regulate blood flow within the heart. The data from these new imaging modalities could be instrumental, helping physicians to properly set up the devices, optimizing blood flow.