Left Ventricular Twist and Torsion

Abstract

A 52-year-old white man visited his physician because he started experiencing shortness of breath on walking short distances at ground level. He had smoked half a packet of cigarettes daily for 40 years. Physical examination revealed a blood pressure of 147/95 mm Hg. Chest examination and chest x-ray were unremarkable, and ECG showed left atrial abnormality. The patient had normal serum electrolytes, blood sugar, and kidney function tests. A stress echocardiogram was ordered to exclude potential coronary artery disease. His resting echocardiography showed an ejection fraction (EF) of 60%, normal septal and posterior wall thickness, and mild diastolic dysfunction (septal early diastolic mitral annular velocity [e′] of 7 cm/s, early diastolic [E wave] to late diastolic [A wave] transmitral Doppler flow velocity ratio [E/A] of 1.4, E-wave deceleration time of 210 ms, E/e′ ratio of 9, and left atrial volume index of 44 mL/m 2 ; Figure 1A). There were no resting segmental wall motion abnormalities suggestive of ischemia. The patient exercised on a treadmill using Bruce protocol for 4 minutes and 43 s, and achieved 6.6 metabolic equivalent of task and maximum heart rate of 148 bpm (88% of his maximum age predicted heart rate). At peak exercise, the patient developed severe dyspnea and his blood pressure was 213/90 mm Hg. Post exercise echocardiography was acquired within 1 minute of exercise termination and showed EF of 69% and no segmental wall motion abnormalities, with Doppler recordings obtained at recovering heart rate of 125 bpm; showing a septal e′ velocity of 7.3 cm/s, E/A of 1.9, E-wave deceleration time of 110 ms, and E/e′ of 13.7, left atrial volume index of 35 mL/m 2 ( Figure 1B). Ten minutes into the recovery period, the blood pressure returned to basal level (145/80 mm Hg). Compared with resting levels, the increased E/A ratio, shortened E-wave deceleration time and relatively increased E/e′ ratio suggested post exercise worsening of diastolic function with elevation of left ventricular (LV) filling pressures. To investigate the mechanistic basis of diastolic dysfunction in this patient, LV deformation was assessed offline using speckletracking echocardiography (STE). Besides characterizing the longitudinal and circumferential shortening, and radial thickening, the LV rotational deformation, that resembles the wringing of a towel, was also measured (Figures 2 and 3). This wringing deformation, also referred to as LV twist (LVT) and the subsequent recoil that occurs in diastole, referred to as untwist, were abnormal in this patient (Figure 4). At rest, the patient had mild diastolic dysfunction, which was associated with a higher than normal LVT and untwist values, compared with the published age-related normal values, 1,2 and low global longitudinal strain. At peak exercise, there was a significant worsening of the patient's diastolic parameters, which was associated with worsening untwist values and further reduction of global longitudinal strain, whereas LVT remained same in magnitude. The following ...

Alterations in Cardiac Deformation, Timing of Contraction and Relaxation, and Early Myocardial Fibrosis Accompany the Apparent Recovery of Acute Stress-Induced (Takotsubo) Cardiomyopathy: An End to the Concept of Transience

“…Torsion was defined as the twist normalized to the base-to-apex LV length measured at end-diastole (/cm) 13,14 . Twist rate was calculated as the peak velocity of twist (/second) 15 . Early systolic "propping" twist (EST) was measured as the difference between the initial apical and basal rotation 13 .…”

Advances in Echocardiographic Imaging in Heart Failure With Reduced and Preserved Ejection Fraction

“…These speckles are stable acoustic markers in the gray-scale cardiac ultrasound images that can be tracked both in 2D and 3D images to generate myocardial deformation curves in different directions. [28][29][30] Despite the great advantages that STE offers over tissue Doppler imaging, it too has several limitations (Table 4). 2D-STE is dependent on imaging quality; suffers inaccuracies because of through plane motion; tracking quality is usually inferior in distal compared with proximal speckles; and too high or too low frame rates are associated with poorer tracking.…”

“…In such patients, exercise can help unmask significant dysfunction of LV myocardial mechanics. 30 LV untwist is markedly compromised, and longitudinal strain is also reduced immediately after exercise. Importantly, these abnormalities of myocardial mechanics are invariably accompanied by evidence of markedly increased LV filling pressure (LVFP) at exercise, providing explanation for the patient's symptoms.…”

Torsion Mechanics as an Indicator of More Advanced Left Ventricular Systolic Dysfunction in Secondary Mitral Regurgitation in Patients with Dilated Cardiomyopathy: A 2D Speckle-Tracking Analysis

“…Twist serves as a compensatory mechanism in the case of systolic dysfunction, and its degree of reduction may reflect a more advanced stage of disease. In the dilated left ventricle, the fiber muscles in both layers are stretched and oriented more circumferentially, which leads to additional reduction in chamber contractility and torsion [2, 3]. In addition to LV dilation, chronic MR would reduce LV twist even more, because of the decrease in lever arm force of the epicardial fibers [4].…”