Synopsis

Myocardial strains are defined as a fractional change in length of a myocardial segment relative to its baseline length. Myocardial strains are more sensitive than ventricular ejection fraction (EF) to identify sub-clinical ventricular dysfunction in diverse heart diseases. Among all the strain parameters, longitudinal strain is more reproducible than radial and circumferential strain and rotation and hence is recommended as routine measurements to detect reduction in ventricular function prior to conventional EF falls. Methods for myocardial strains beyond left ventricle will be presented.

Abstract

Myocardial strains are defined as a fractional change in length of a myocardial segment relative to its baseline length. Myocardial strains are more sensitive than ventricular ejection fraction (EF) to identify sub-clinical ventricular dysfunction in diverse heart diseases. There are 4 principal types of strains: longitudinal strain, circumferential strain, radial strain and torsion during cardiac contraction and relaxation. Among all the strain parameters, longitudinal strain is more reproducible than radial and circumferential strain and rotation and hence is recommended as routine measurements to detect reduction in ventricular function prior to conventional EF falls.
The strain imaging methodology is still undergoing development. Up to date, speckle tracking echocardiography (STE), feature-tracking computed tomography (FT-CT), and FT cardiac magnetic resonance (FT-CMR) are feasible. Echo is largely operator-dependent and due to acoustic window limitations, suffers from poor inter-study reproducibility.(1) CMR provides superior resolution and reproducible results of ventricular volume and EF. FT-CMR is emerging method to quantify myocardial strains.(2) Among all four chambers of the heart: left ventricle, right ventricle, left atrium and right atrium, left ventricular (LV) strains were more studied. In this talk, the methods of FT-CMR (Full FT-CMR, manual FT-CMR and our fast automated FT-CMR) for myocardial strains beyond the LV will be discussed. (3-9) Their applications including left atrial strain heart failure with preserved ejection fraction (HFpEF) (6), right atrial strain in pulmonary artery hypertension (PAH) (7), right ventricular strain in volume-overload and pressure-overload (3,7), will be also discussed.

Acknowledgements

No acknowledgement found.

References

1. Farsalinos et al J Am Soc Echocardiogr. 2015. 2. Leng S, et al. Am J Physiol Heart Circ Physiol 2015. 3. Leng S, et al. Ann Biomed Eng 2016. 4. Leng S, et al. Sci Rep 2018. 5. Leng S, et al Int J Cardiol Heart Vasc. 2018. 6. Leng S, et al. J Cardiovasc Magn Reson 2018. 7. Leng S, et al. Circ Cardiovasc Imaging 2019. 8. Leng S, et al. Eur Radiol 2020. 9. Leng S, et al. Radiology 2020.