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Assessment of systolic and diastolic LV function by MR myocardial tagging
Insights
Heart failure involves altered left ventricular (LV) mechanical function. New imaging techniques reveal changes in systolic "wringing" and diastolic "untwisting" motions, aiding heart failure diagnosis.
Area of Science:
- Cardiology
- Biomedical Imaging
- Physiology
Background:
- Heart failure is classified by left ventricular (LV) dysfunction, impacting cardiac output.
- Systolic dysfunction involves depressed LV pump function, while diastolic dysfunction has normal LV pump function.
- Understanding LV mechanical function is crucial for diagnosing and managing heart failure.
Purpose of the Study:
- To investigate alterations in left ventricular (LV) systolic and diastolic motion in heart failure.
- To explore the utility of advanced imaging techniques in characterizing cardiac mechanical function.
- To correlate observed mechanical changes with different forms of heart failure.
Main Methods:
- Utilized magnetic resonance imaging (MRI) with myocardial "tagging" to visualize LV 3D motion.
- Analyzed deformation of tagged myocardial regions to derive rotational and translational heart motion.
- Quantified systolic "wringing" and diastolic "untwisting" motions during cardiac cycles.
Main Results:
- Described characteristic systolic "wringing" (clockwise base, counterclockwise apex rotation) and diastolic "untwisting" motions.
- Observed prolonged diastolic "untwisting" in hypertrophied (aortic stenosis) and hibernating myocardium.
- Demonstrated that heart failure is associated with significant changes in LV mechanical function.
Conclusions:
- Heart failure is characterized by profound alterations in the heart's mechanical function.
- Changes in systolic "wringing" and diastolic "untwisting" are key indicators of heart failure.
- Advanced MRI techniques provide valuable insights into cardiac mechanics for heart failure assessment.
Abstract:
Heart failure has been divided into several different forms depending on etiology, clinical course and pathophysiology of left ventricular (LV) dysfunction. Systolic and diastolic dysfunction are characterized by a reduced cardiac output with normal (= diastolic dysfunction) or depressed (= systolic dysfunction) LV pump function. New diagnostic techniques such as magnetic resonance imaging (MRI) allow to determine noninvasively LV 3D motion by labelling specific myocardial regions (= myocardial "tagging") with a rectangular or radial grid. From the deformation of this grid rotational and translational motion of the heart can be derived. A "wringing" motion of the left ventricle has been described during systole which includes a clockwise rotation at the base and a counterclockwise rotation at the apex. During diastole, an "untwisting" motion has been demonstrated. In the normal heart, diastolic "untwisting" occurs primarily during isovolumic relaxation, analogous to the systolic "wringing" which takes place mainly during isovolumic contraction. A prolongation of the "untwisting" motion was found in the hypertrophied (aortic stenosis) and hibernating myocardium. Thus, heart failure is associated with profound alterations in the mechanical function of the heart which are manifested by changes in systolic "wringing" and diastolic "untwisting" motion.