Myocardial Deformation Imaging in Congenital Heart Disease – a proof of concept Cardiac MRI Study

Introduction

Myocardial Deformation Imaging (MDI) refers to the assessment of regional myocardial motion over the cardiac cycle. This has previously been performed using echocardiography, although recently advances have been made using cardiac MRI (CMR). Little is known about MDI in different forms of congenital heart disease (CHD). We examined MDI in patients with CHD using CMR techniques and compared the results to normal controls.

Methods

Patients who underwent clinical CMR studies between July 2016 and November 2018 were examined. For this proof of concept study, we looked at patients with predominantly left-sided disease, e.g. aortic stenosis (LV, n=20), and atrial shunts, which cause RV dilation (ASD, n=10). We calculated LV peak basal and apical rotation, and LV twist and compared to normal controls (n=13). MDI parameters were measured by a single researcher, using commercially available software.

Results and Discussion

We found no significant difference in peak basal rotation between controls, LV and ASD patients, and no difference between LV patients and controls in any of the 3 parameters. However, ASD patients had significantly higher mean peak apical rotation and twist than both controls and LV patients, p≤0.02 for all comparisons, despite atrial shunts causing a volume load on the right ventricle. This may be a sign of a remodeling phenomenon due to reduced preload in the LV of patients with atrial level left-to-right shunts. It is unclear why this is expressed in apical, but not basal, mechanics, although these regions have been shown to be affected differently by different pathophysiological states.

Conclusion

In this single-center proof of concept study, patients with atrial shunts had higher apical rotation and twist on CMR than controls and patients with LV disease. Further work is needed to elucidate these relationships more fully, as well as to examine these parameters in other forms of CHD.