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    Ultrasound assessment of the heart of babies born prematurely using novel techniques


    Dr. Neidin Bussman is a neonatologist in the Department of Neonatology at the Rotunda Hospital. She is funded by the NCRC Research Education Support Grant scheme to undertake a PhD under the supervision of Prof. Afif EL Khuffash, Prof. Naomi McCallion, and Dr. Orla Franklin. She recently published a paper titled “Circumferential and radial deformation assessment in premature infants: Ready for primetime?” in the journal “Echocardiography” (Pubmed). Read Neidin’s plain English summary of the paper below.

    Speckle tracking echocardiography is a non-invasive novel method used to measure how the heart is working. Echocardiography uses high frequency soundwaves (ultrasound) to image and quantify the size and shape of the heart as it pumps blood. It is commonly used to study the left ventricle, the chamber of the heart that is responsible for pumping oxygen rich blood (arriving from the lungs) around the body. Speckle tracking echocardiography assesses the function of the heart muscle by tracking the movement of the “speckles” picked up by echocardiography.

    To pump blood, the left ventricle changes shape in 3 different planes; the longitudinal plane (L, a shortening of the ventricle from top to bottom), the radial plane (R, a thickening of the outer wall), and the circumferential plane (C, a shortening of the circumference). These events lead to a decrease in the size of the chamber and the ejection of blood from the left ventricle.

    When using speckle tracking echocardiography to monitor the left ventricle, clinicians have historically focused on the change in the shape of the heart along the longitudinal plane. Advances in echocardiography now allow us to look at the change in the shape of the ventricle in all 3 planes. In other words, we can look at how the heart changes shape in 3 dimensions.  In our paper, we have shown that it is feasible to use speckle tracking echocardiography to monitor the hearts of babies born prematurely. In order to do this, we performed heart scans on 40 premature babies on the second and eight day of age. We found that the results of the test are very reproducible when performed by different clinicians or the same clinician on separate occasions.

    This suggests that the test could potentially be developed to monitor heart function in the clinical setting.  We were also able to detect differences in the heart function of premature babies with a heart condition called a patent ductus arteriosus (PDA). A PDA is a blood vessel connecting the two major vessels leaving the heart: the aorta and the pulmonary artery. When a baby is in the womb, they get their supply of oxygen from their mother, so blood is not sent to lungs to collect oxygen before being pumped around the body. The PDA works as a lung bypass, sending blood away from the lungs to the rest of the body.

    In babies born at full term (40 weeks gestation), the PDA usually closes in the first few days after delivery. In babies born very prematurely (<29 weeks gestation), the PDA can remain open for a long time. If this occurs, the PDA sends blood towards the lungs and away from the rest of the body (in a way opposite to that in the womb). This can cause the lungs to receive extra fluid and contribute to lung disease. Our results show that babies with a PDA show a difference in how the heart changes shape along the radial plane.  Due to the small size of our study it is difficult to draw conclusions from this in the clinical setting, however it would be interesting to assess this new finding in a larger cohort.


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