Ventricular Torsion and Untwisting: Further Insights into Mechanics and Timing Interdependence: A Viewpoint

Abstract

Ventricular torsion and untwisting are essential for normal ventricular function and their mechanisms are related to the temporal responses of the helical and circular muscle fibers that comprise cardiac architecture. Explanation of the presystolic isovolumic contraction (IVC) period is essential for analysis of these interactions. Structural and imaging studies by magnetic resonance, speckle tracking, velocity vector encoding, and sonomicrometer crystals are described to define why and how different muscular components contract asynchronously. Mechanical and functional relationships are described for pre-systolic IVC, torsion, postejection isovolumic interval, and rapid and slow filling. Circular fibers dominate to cause pre- and posttwisting global counterclockwise and clockwise movement, and helical fibers govern torsion whereby the base rotates clockwise and apex counterclockwise; untwisting cannot begin until torsion is completed. Prolonged torsion extends into the postejection isovolumic interval and delays untwisting, and is caused by prolonged contraction of the right-handed helical arm or descending segment of the helical ventricular myocardial band that narrows the ∼80 ms "timing hiatus" between end of shortening of the descending and the ascending segment or left-handed arm of the helical muscle. Longer torsion duration by this mechanism becomes the common theme for unbalanced torsion and untwisting in diastolic dysfunction, physiological, structural, and electrical disease processes, whose management may be guided by changing the interconnected reasons for these adverse mechanical and timing factors.

Novel Echocardiography Methods in the Functional Assessment of the Newborn Heart

“…5 ). These rotational parameters add important information on myocardial performance [63] . The twisting motion of the LV is aided by the helical arrangement of the subepicardial (left handed) and subendocardial (right handed) fibres [7] .…”

“…Similarly, in the preterm neonatal population, increased afterload appears to negatively impact those measurements [65] . Rotational mechanics can be assessed by STE in a similar fashion to the method described above and demonstrates acceptable agreement with twist measured by magnetic resonance imaging (MRI) [63,66] . Twist as a marker of cardiac function has been validated in adults and children [45,67] .…”

Results of the Modified Left Ventricle Reconstruction With Evaluation of Geometric Parameters in Postinfarction Aneurysm of the Heart

“…Кони-ческая форма верхушки ЛЖ необходима для обеспе-чения нормальной сократительной функции сердца. При ишемическом повреждении геометрия ЛЖ изме-няется в результате переориентации косых волокон верхушки в более горизонтальное положение, что приводит к снижению торсионного движения вер-хушки и впоследствии к ухудшению систолической функции ЛЖ [12,27,28].…”

Tissue Doppler Imaging-Derived Myocardial Acceleration During Isovolumetric Contraction Predicts Pulmonary Capillary Wedge Pressure in Patients With Reduced Ejection Fraction

“…However, myocardial untwist also occurs preejection, and an understanding of IC is said to be essential to explain this systolic-diastolic interaction. 20 Luo et al found that in patients with systolic HF, myocardial untwist during IC is prolonged into the ejection phase and that torsion during ejection is also prolonged into the diastolic phase. 23 Cho et al also reported that the ability of the IVV and IVA to predict the exercise capacity of patients with depressed systolic function might be explained by dynamic changes of IC that affect the force of cardiac contraction during ejection, and the timing of systolic cross-over into diastole.…”