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Myocardial wringing and rigid rotation in cardiac amyloidosis

Open AccessPublished:November 14, 2022DOI:https://doi.org/10.1016/j.cjco.2022.11.008

      ABSTRACT

      Background

      The motion of the heart is a result of the helicoidal arrangement of the myofibers in the organ’s wall. We aimed to study the relationship between wringing motion state and the degree of ventricular function in patients with cardiac amyloidosis (CA).

      Methods

      Fifty patients with CA and decreased global longitudinal strain (LS) were evaluated using two-dimensional speckle-tracking echocardiography. We have expressed LS positive values to facilitate understanding. Normal twist, which occurs when basal and apical rotation occur in opposite directions, was coded as positive. When the apex and base rotate in the same direction (rigid rotation) twist was coded as negative.LV wringing [calculated as twist/LS, which takes into account actions that occur simultaneously during LV systole (i.e., longitudinal shortening and twist)] was evaluated according to LVEF.

      Results

      Most of the patients (66%) who participated in the study were diagnosed with transthyretin amyloidosis. A positive relationship was observed between wringing and LVEF (r = 0.75, p < 0.0001). In advanced stages of ventricular dysfunction, rigid rotation appeared in 66.6% of patients with LVEF 40%, in whom negative values of twist and wringing were observed. LV wringing proved to be a good discriminator of LVEF (AUC 0.90, p < 0.001, 95% CI 0.79–0.97); for example, wringing < 1.30º/% detected LVEF < 50% with 85.7% sensibility and 89.7% specificity.

      Conclusions

      Wringing, which integrates twist and simultaneous LV longitudinal shortening, is a conditioning rotational parameter of the degree of ventricular function in patients with CA.

      Graphical abstract

      Keywords

      Abbreviations:

      LVEF (left ventricle ejection fraction), CA (cardiac amyloidosis), LS (longitudinal strain), CS (circumferential strain), DefI (Deformation Index), STE (speckle tracking echocardiography)

      INTRODUCTION

      The motion of the heart is conditioned by the arrangement of myofibers in the heart´s wall. The helical arrangement of myocardial fibers around the left ventricle (LV), with a gradual change in the direction of the fibers from a right-handed helix in the subendocardial layers to a left-handed helix in the epicardial layers, causes simultaneous longitudinal and circumferential contraction to twist the myocardium
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      During systole the base and apex of the LV normally rotate in opposite directions around its longitudinal axis. When the heart is viewed from the apex, it can be seen that this twist motion is the result (net sum, in degrees) of a clockwise basal rotation and a counterclockwise apical rotation
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      Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging.
      ; in this way, the wringing generated as result of this interaction (twist and longitudinal shortening of the LV) causes the myocardium to thicken towards the ventricular centroid and the corresponding systolic volume to be expelled
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      • et al.
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      . The wringing mechanism of the LV plays a pivotal role in bringing the LV ejection fraction (LVEF) up to 60% with only 15% of longitudinal myocardial fiber shortening, thus increasing the heart’s ability to pump blood during systole
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      • Vannan M.A.
      • Jahangir A.
      • et al.
      Left ventricular structure and function: basic science for cardiac imaging.
      . LV wringing, calculated as twist/longitudinal strain, can be measured non-invasively by imaging techniques –MRI tagging or speckle tracking echocardiography (STE)– and previous research with these techniques has shown normal values
      • Mora V.
      • Roldan I.
      • Romero E.
      • Romero D.
      • Bertolin J.
      • Ugalde N.
      • et al.
      Comprehensive assessment of left ventricular myocardial function by two-dimensional speckle-tracking echocardiography.
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      MR imaging of motion with spatial modulation of magnetization.
      • Helle-Valle T.
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      • et al.
      New noninvasive method for assessment of left ventricular rotation: speckle tracking echocardiography.
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      • Lysyansky P.
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      • Shiota T.
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      • Martin- Miklovic M.G.
      • Weaver J.A.
      • Oryszak S.J.
      • Greenberg N.L.
      • White R.D.
      • Thomas J.D.
      Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging.
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      . The twist, and consequently the wringing, disappears when the base and apex of the LV rotate in the same direction, which is known as rigid rotation
      • Setser R.M.
      • Kasper J.M.
      • Lieber M.L.
      • et al.
      Persistent abnormal left ventricular systolic torsion in dilated cardiomyopathy after partial left ventriculectomy.
      .
      Transmural myocardial involvement in cardiac amyloidosis (CA) allows the pathology’s impact on the LVEF to be measured. The deposition of amyloid substances occurs mainly at the subendocardial level
      • Koyama J.
      • Minamisawa M.
      • Sekijima Y.
      • Ikeda S.
      • Kozuka A.
      • Ebisawa S.
      • et al.
      Left ventricular deformation and torsion assessed by speckle-tracking echocardiography in patients with mutated transthyretin-associated cardiac amyloidosis and the effect of diflunisal on myocardial function.
      , and so a decrease in longitudinal strain (LS) is common among CA patients. Circumferential strain (CS) is also affected by CA as transmural deposit of amyloid substances progresses
      • Wang J.
      • Khoury D.S.
      • Yue Y.
      • Torre-Amione G.
      • Nagueh S.F.
      Preserved left ventricular twist and circumferential deformation, but depressed longitudinal and radial deformation in patients with diastolic heart failure.
      . LV twist is an expression of the interaction between the LS and the CS values.
      Given that different diseases damage the heart and weaken its rotational motion, we aimed to study the relationship between wringing state and the degree of ventricular function in patients with CA.

      METHODS

      Study Population

      Patients with heart failure and CA were consecutively enrolled in the study and prospectively examined. Those with valve prostheses, implanted pacemakers, and devices employed for cardiac resynchronization therapy were excluded from the analysis, as well as those having undergone cardiac surgery, and those with atrial fibrillation or a poor acoustic window.
      Two-dimensional STE confirmed interventricular septal thickness > 12 mm and an apical-sparing pattern in the bullseye strain map in all the patients. Amyloidosis due to transthyretin (TTR) was confirmed by sub-cutaneous fat, rectum or skin biopsy (n = 12), diphosphonate single-photon emission computed tomography (n = 23), or cardiac magnetic resonance (n = 23). Light chain amyloidosis (AL) was confirmed when electrophoresis with immunofixation detected a monoclonal protein in the serum or urine, or when a monoclonal population of plasma cells was detected in the bone marrow
      • Garcia-Pavia P.
      • Rapezzi C.
      • Adler Y.
      • Arad M.
      • Basso C.
      • Brucato A.
      • et al.
      Diagnosis and treatment of cardiac amyloidosis: a position statement of the ESC Working Group on Myocardial and Pericardial Diseases.
      .
      The study complied with the ethical guidelines of the 1975 Declaration of Helsinki and was approved by our institution’s research ethics committee. All subjects gave their informed consent.

      Echocardiography

      We employed two ultrasound systems (Vivid E9 and Vivid E95; GE Healthcare, Little Chalfont, United Kingdom) equipped with a 2.5-MHz transducer. Echocardiographic images from the parasternal short axis views at the basal, mid, and apical levels and from the 3 standard LV apical views (4-, 2-, and 3-chambers) were used to generate speckle tracking-derived LS, CS and rotational parameters. All images were obtained at a frame rate of 50-80 frames/sec and were transferred to a workstation for computer analysis (EchoPAC version 112.0.0; GE Healthcare, Little Chalfont, United Kingdom).
      The endocardial border of the LV just inside the myocardium was traced manually to calculate myocardial strain. Next, with the help of the software, a second larger concentric circle was automatically generated close to the epicardium to mark the full thickness of the myocardial wall. The program automatically divided each projection into six equal segments and performed frame-by-frame speckle-tracking, thus providing automated tracking confirmation (verified by the operator) and generating strain values, expressed as percentages.
      LS and CS are negative values, as myocardial fibers are smaller during systolic contraction than during diastole, but we have expressed them herein as positive values to facilitate understanding. Thus, more positive values represent a greater level of deformation.
      Rotation is an angular displacement of a myocardial segment in a transversal projection around the longitudinal axis of the LV. Under normal conditions, apical systolic rotation occurs in a counter-clockwise direction and is expressed in positive values. Conversely, basal rotation is produced in a clockwise direction and is expressed in negative values. Systolic twist was classified as either: a) Normal twist, when basal and apical rotation occur in opposite directions (figure 1A). The twisting that occurs as a consequence is the net sum, in degrees, of apical and basal rotation, which we coded as positive; and b) Rigid rotation, when the apex and base rotated in the same direction. The resulting twist is the subtraction of one from the other (or absence of twist), which was coded as negative (figures 1B and 1C).
      Figure thumbnail gr1
      Figure 1A. Normal twist, which occurs as a consequence the net sum (in degrees) of apical and basal rotation in opposite directions. The twist curve is coded as positive value (white) in echocardiography device (continuous withe line). B. Rigid rotation, in which the apex and base rotate in the same direction (counter-clockwise). The twist curve is coded as positive (white) in echocardiography device (continuous withe line). However, since it is the result of the subtraction (in degrees) of one from the other (or absence of twist), should be represented as negative value (dashed yellow line), and coded as negative value (yellow number). C. Rigid rotation, in which the apex and base rotate in the same direction (clockwise). The twist curve is coded as positive (white) in echocardiography device (continuous withe line). However, since it is the result of the subtraction (in degrees) of one from the other (or absence of twist), should be represented as negative value (dashed yellow line), and coded as negative value (yellow number).
      The deformation index (DefI) is a parameter of LV wringing calculated as twist/LS, and integrates both twist and longitudinal shortening
      • Mora V.
      • Roldan I.
      • Romero E.
      • Romero D.
      • Bertolin J.
      • Ugalde N.
      • et al.
      Comprehensive assessment of left ventricular myocardial function by two-dimensional speckle-tracking echocardiography.
      ,
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      , actions that are simultaneously produced during contraction of the LV. Twist in isolation signals rotational changes, while wringing indicates rotational changes provoked by each unit of longitudinal shortening.
      The value of DefI, as in the case of twist, is positive when basal and apical rotation occur in opposite directions (as in normal function), and is negative in the case of rigid rotation. More positive DefI values represent a greater level of wringing.
      LVEF was calculated by the modified Simpson’s biplane rule. The echocardiographic results were reviewed by two observers.

      Intraobserver and interobserver reproducibility

      The intraclass correlation coefficient was calculated in a random sample of 10 patients, in whom masking and measurements were performed at different times to evaluate intra- and interobserver reproducibility of the results. The Bland-Altman method was used for graphic representation of the findings, and the 95% limits of agreement was calculated to obtain the mean. A normal data distribution was confirmed by means of the Shapiro-Wilk test.

      Statistical Analysis

      Continuous variables with normal distribution are shown with the mean and standard deviation (SD), data with non-symmetric distribution are represented by the median and interquartile range (IQR:25-75) and the proportions as percentages. For the comparisons between groups, we used the Student's t test, the Mann-Whitney U test, and the analysis of variance (ANOVA), with the Tukey HSD test to discern post hoc differences between pairs of means, as appropriate. Normal distribution was tested with the Shapiro-Wilk test and was rejected for age and DefI. The relationship between LVEF (dependent variable) and DefI (independent variable) was estimated using linear regression. The power of DefI to discriminate patients with LVEF < 50% was evaluated by means of the ROC procedure. The threshold value for each of the variables was that which maximized the percentage of correct classifications. Discrimination performance was estimated by calculating the AUC (Area Under the Curve) and was based on the sensitivity and specificity of the 95% CI. P values <0.05 were considered to indicate statistical significance in all the analyses. Statistical analyses and graphics were performed using IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp. and MedCalc® Statistical Software version 20.014 (MedCalc Software Ltd, Ostend, Belgium; 2021).

      RESULTS

      Patient Characteristics and 2D Echocardiography

      Fifty patients met all the inclusion criteria and no exclusion criteria, and were divided into groups according to LVEF: 29 with LVEF 50% (group 1); 9 with LVEF 49-41% (group 2); and 12 with LVEF 40% (group 3). Most of the patients (66%) participating in the study had been diagnosed with transthyretin amyloidosis, while 34% had been diagnosed with light-chain amyloidosis. The types of amyloidosis were homogeneous between the groups.
      The results of the analysis of variance are summarized in Table 1. No significant differences in sex, age or heart rate were detected among the groups. Blood pressure values dropped progressively as ventricular function decreased (p < 0.0001). LV end-systolic volume was higher among patients with LVEF 40%.
      Table 1Patient characteristics and 2D-echocardiography.
      Group 1 LVEF 50% (n =29)Group 2 LVEF 49-41% (n =9)Group 3 LVEF 40% (n =12)p
      Age, years75.1 (19)80.5 (18.5)81.5 (12)0.26
      Gender, male (%)22 (75.9)8 (88.9)10 (83.3)0.65
      BSA, m21.8 ± 0.21.7 ± 0.11.8 ± 0.10.76
      HR beats/min73.5 ± 13.473.3 ± 8.570.5 ± 8.70.76
      Systolic BP (mmHg)134 ± 17.1119.9 ± 8104.7 ± 12.30.000
      LV mass, gr270 ± 65250 ± 84367 ± 183bb0.03
      LVEDD, mm44.3 ± 6.442.1 ± 6.450.7 ± 8.8bb,cc0.01
      B-A distance, cm8.2 ± 0.97.6 ± 0.38.5 ± 1.20.11
      LVEDV, ml74.4 ± 20.866.2 ± 19.797.4 ± 49.20.04
      LVESV, ml29.9 ± 0.936.5 ± 10.768.9 ± 35.9b,c0.000
      LVEF, %60.4 ± 7.644.7 ± 2.0a29.9 ± 6.5b,c0.000
      LVEF: Left ventricular ejection fraction. BSA: Body surface area. HR: Heart rate. BP: Blood pressure. LVEDD: Left ventricular end-diastolic diameter. B-A: Base-apex. LVEDV: Left ventricular end-diastolic volume. LVESV: Left ventricular end-systolic volume. a: p <0.01 between groups 1-2; b: p <0.01 between groups 1-3; c: p <0.01 between groups 2-3. bb: p <0.05 between groups 1-3; cc: p <0.05 between groups 2-3.

      LV strain and rotational measurements

      Global LS and CS were below normal values in all the patients regardless of LVEF, and diminished progressively as ventricular function decreased (p < 0.0001 both) (table 2). A bull’s eye map during echocardiography revealed a decrease in global LS with apical sparing morphology in all the patients.
      Table 2Strain values and rotational parameters.
      Group 1 LVEF 50% (n = 29)Group 2 LVEF 49-41% (n = 9)Group 3 LVEF 40% (n = 12)p
      GLS, %10.9 ± 2.810.2 ± 3.77.7 ± 2.8b0.01
      GCS, %16.0 ± 3.314.5 ± 3.810.7 ± 2.6b,cc0.000
      Apical rotation, º13.7 ± 5.98.5 ± 4.6aa7.6 ± 4.1b0.002
      Basal rotation, º-6.9 ± 4.2-3.7 ± 3.20.9 ± 3.3b,cc0.000
      Twist, º20.6 ± 7.612.3 ± 5.2aa-1.6 ± 8.4b,c0.000
      DefI (Twist/GLS), º/%1.63 (0.85)1.14 (0.7)a-0.66 (-0.64)b,c0.000
      Apical rotation/GLS, º/%1.2 ± 0.70.8 ± 0.51.1 ± 0.80.37
      Basal rotation/GLS, º/%-0.6 ± 0.3-0.3 ± 0.20.2 ± 0.4b,c0.000
      GLS: Global longitudinal strain. GCS: Global circumferential strain. DefI: Deformation index. a: p <0.01 between groups 1-2; b: p <0.01 between groups 1-3; c: p <0.01 between groups 2-3. aa: p <0.05 between groups 1-2; cc: p <0.05 between groups 2-3.
      Twist values dropped progressively as ventricular function decreased (p < 0.0001) (table 2). Rigid rotation appeared in 66.6% of patients with LVEF 40%, in whom negative values of twist were registered. This rigid rotation occurred in a counter-clockwise direction in seven patients, and in a clockwise direction in one patient.
      A positive relationship was observed between DefI (wringing) and LVEF (r = 0.75, p < 0.001) (Figure 2). In patients with rigid rotation and negative values of twist, negative values of DefI were registered as a consequence. DefI values were higher in patients with preserved LVEF than in those with moderately and severely depressed ventricular function (1.63 (0.85) º/%, 1.14 (0.7) º/% and -0.66 (-0.64) º/%, respectively, p < 0.0001) (Table 2).
      Figure thumbnail gr2
      Figure 2Scatter plot showing the positive linear relationship between DefI and LVEF. It is represented with a 95% CI (curves close to the regression line) and 95% prediction (wider).
      ROC analysis was performed to identify systolic ventricular dysfunction. DefI (AUC 0.90, p <0.0001, 95% CI 0.79–0.97) was found to be an indicator of ventricular dysfunction (Figure 3); DefI < 1.30º/% determined LVEF < 50% with 85.7% sensitivity and 89.7% specificity.
      Figure thumbnail gr3
      Figure 3ROC curves showing the discrimination capacity of DefI for LVEF < 50%.
      The intra- and interobserver variability analyses were acceptable, with intraclass correlation coefficients > 0.75 (Table 3).
      Table 3Intraobserver and interobserver variability
      Intraclass correlation coefficient (95% CI)Mean of difference (95% LOA)
      Intraobserver p
      Global longitudinal strain0.86 (0.53-0,96)<0.001-0.14 (95% LOA: -2.51 to 2.23)
      Twist0.94 (0.65-0.98)<0.001-1.15 (95% LOA: -3.81 to 1.51)
      Deformation Index0.85 (0.52-0.96)<0.0010.05 (95% LOA: -0.16 to 0.26)
      Interobserver
      Global longitudinal strain0.87 (0.58-0.96)<0.0010.50 (95% LOA: -1.77 to 2.77)
      Twist0.85 (0.53-0.96)<0.001-1.13 (95% LOA: -6.69 to 4.43)
      Deformation Index0.77 (0.31-0.94)<0.010.01 (95% LOA: -0.27 to 0.29)
      LOA: Limits of agreement.

      DISCUSSION

      This study provides several insights into echocardiography-derived measures of myocardial mechanics in a specific patient population of CA. First, our findings show as the primary outcome of interest, that wringing (DefI) generated as a result of the simultaneous action of twist and longitudinal shortening is a parameter closely related to LVEF. Second, a rigid rotation of the LV is associated with a more severely impaired LVEF. Third, global LS and CS are diminished in cardiac amyloidosis regardless of LVEF.
      The impact of the different myocardial layers on the LVEF can be measured in CA. In all the patients in our series, myocardial LS was significantly lower than reference ranges of normal LV published in previous studies that used the same equipment
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      • Perez-Gil M.M.
      • Saad A.
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      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      and in the EACVI NORRE (Normal Reference Ranges for Echocardiography) study
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      . The deposition of amyloid substance occurs mainly at the subendocardial level; thus, a decrease in LS is a common characteristic of patients with heart failure and CA, regardless of whether their EF is preserved or reduced. Circumferential strain is also affected in CA, as there is transmural deposit as the disease progresses
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      . As we observed in our series, significant decreases in both types of strain coexist in patients with preserved or reduced ventricular function (Table 2).
      Koyama et al
      • Koyama J.
      • Minamisawa M.
      • Sekijima Y.
      • Ikeda S.
      • Kozuka A.
      • Ebisawa S.
      • et al.
      Left ventricular deformation and torsion assessed by speckle-tracking echocardiography in patients with mutated transthyretin-associated cardiac amyloidosis and the effect of diflunisal on myocardial function.
      observed that predominant subendocardial deposition of amyloid protein decreases subendocardial LS in the early-to-middle stages of CA. However, once amyloid infiltration had affected the transmural and subepicardial layers (in the advanced stage), circumferential contraction was further impaired, and LV twist - an expression of the interaction between the LS and the CS values - worsened.
      We observed that twist values dropped progressively as ventricular function decreased (table 2); however, twist values in our patients with CA and LVEF 50% were similar to those considered normal (21.7 ± 6.1º) in previous studies
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      . In this way, only 41.3% (12/29) of our patients with LVEF 50% displayed twist values higher than those considered normal. Therefore, although there is obviously a direct relation between twist and LVEF
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      ,
      • Arts T.
      • Reneman R.S.
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      A model of the mechanics of the left ventricle.
      ,
      • Ru¨ssel I.K.
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      , we can affirm that twist in isolation does not determine whether or not ventricular function is maintained in CA. Twist values were progressively lower as ventricular function decreased, and a rigid rotation appeared in 66.6% of patients with LVEF 40%, in whom negative values of twist were registered.
      We observed a strong positive relationship between DefI (wringing) and LVEF (r =0.75, p < 0.0001) (Table 2 and Figure 2). However, unlike twist, DefI values in patients with CA and LVEF 50% were above those considered normal (1.0 ± 0.3º/%)
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      . In this way, 96.5% (28/29) of our CA patients in whom LVEF 50% displayed DefI values higher than those considered normal. This greater capacity of wringing over twist for identifying patients with preserved ventricular function makes it a more suitable parameter to explain the maintenance of ventricular function in CA. A patient with preserved LVEF and decreased LS can present a normal or decreased twist; it is only when the twist is expressed per unit of longitudinal shortening (DefI) that it becomes evident that wringing has increased. Therefore, twist in isolation is a sign of rotational changes, but not of changes in the wringing that occur during ventricular systole as a consequence of the longitudinal shortening generated simultaneously with rotational movements
      • Mora V.
      • Roldan I.
      • Bertolin J.
      • Faga V.
      • Perez-Gil M.M.
      • Saad A.
      • et al.
      Influence of ventricular wringing on the preservation of left ventricular ejection fraction in cardiac amyloidosis.
      .
      Our findings suggest that increased wringing (parameter of myocardial systolic function) is directly involved in the maintenance of ventricular function, and that decreased wringing is involved in the deterioration of ventricular function. In the more advanced stages of ventricular dysfunction, the rotation of the ventricular base and apex can occur in the same direction, so that the twist itself disappears and is replaced by what is referred to as rigid rotation. We observed that most rigid rotation took place in a counter-clockwise direction. This rigid rotation was documented in 66.6% of the patients with LVEF < 40%, and was characterized by negative values of twist and wringing (Figures 1B and 1C). In this context, Setser et al
      • Setser R.M.
      • Kasper J.M.
      • Lieber M.L.
      • et al.
      Persistent abnormal left ventricular systolic torsion in dilated cardiomyopathy after partial left ventriculectomy.
      described how basal and apical rotation sometimes occurred in the same direction in patients undergoing an MRI tagging scan due to dilated cardiomyopathy and end-stage heart failure. In the absence of twist, this pattern was termed ‘rigid rotation’. Previous studies
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      Impaired systolic torsion in dilated cardiomyopathy: reversal of apical rotation at mid-systole characterized with magnetic resonance tagging method.
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      • et al.
      Effects of cardiac resynchronization therapy on left ventricular twist.
      using STE in patients with ischemic and non-ischemic dilated cardiomyopathy have reported a significant relationship between rigid rotation and more severe LV remodeling. Very few clinical studies have evaluated LV rigid rotation mechanics in myocardial hypertrophy in general, and in CA singularly
      • Nemes A.
      • Fo¨ldeák D.
      • Domsik P.
      • Kalapos A.
      • Sepp R.
      • Borbényi Z.
      • Forster T.
      Different patterns of left ventricular rotational mechanics in cardiac amyloidosis - results from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.
      ,

      Nemes A, Szántó G, Kalapos A, Domsik P, Forster T. Reversal of left ventricular “rigid body rotation” during dipyridamole-induced stress in a patient with stable angina: a case from the three-dimensional speckle tracking echocardiographic MAGYAR-Stress Study. Quant Imaging Med Surg 2016; 6(3):308-311

      . Wringing is a parameter closely related to ventricular function in CA, and negative values (rigid rotation pattern and negative twist) are registered in more advanced cases. The specific causes of the direction in which rigid rotation occurs remain unclear.
      Representation of the twist should be more graphic in echocardiography devices. Twist is positive as a consequence of the net sum, in degrees, of apical and basal rotation in opposite directions (as occurs in normal function) (Figure 1A). We propose that, in cases of rigid rotation (either clockwise or counter-clockwise), the twist curve should be represented as a negative value (or absence of twist), since it is the result of the subtraction of apical and basal curves (Figures 1B and 1C).
      In summary, LVEF is the end result of all the elements involved in the contraction of the ventricular cavity, of which the most important is the myocardium. In CA, despite the affectation of the longitudinal and circumferential contraction of the myocardium, wringing maintains ventricular function until the advanced stages of the disease. Given the obvious limitations of ejection fraction, it is essential to find alternative parameters on which to base clinical decisions
      • Sto¨hr E.J.
      • Shave R.E.
      • Baggish A.L.
      • Weiner R.B.
      Left ventricular twist mechanics in the context of normal physiology and cardiovascular disease: a review of studies using speckle tracking echocardiography.
      . Although a number of clinical studies have shown global LS to be predictive of outcome
      • Cimino S.
      • Canali E.
      • Petronilli V.
      • Cicogna F.
      • De Luca L.
      • Francone M.
      • et al.
      Global and regional longitudinal strain assessed by two-dimensional speckle tracking echocardiography identifies early myocardial dysfunction and transmural extent of myocardial scar in patients with acute ST elevation myocardial infarction and relatively preserved LV function.
      • Smiseth O.A.
      • Torp H.
      • Opdahl A.
      • Haugaa K.H.
      • Urheim S.
      Myocardial strain imaging: how useful is it in clinical decision making?.
      • Stanton T.
      • Leano R.
      • Marwick T.H.
      Prediction of all-cause mortality from global longitudinal speckle strain: comparison with ejection fraction and wall motion scoring.
      , it does not always provide accurate clinical insight
      • Blomstrand P.
      • Engvall M.
      • Festin K.
      • Lindstro¨m T.
      • La¨nne T.
      • Maret E.
      • et al.
      Left ventricular diastolic function, assessed by echocardiography and tissue Doppler imaging, is a strong predictor of cardiovascular events, superior to global left ventricular longitudinal strain, in patients with type 2 diabetes.
      , and in isolation does not determine whether ventricular function is maintained. The relevance of the present study lies in that it identifies indicators other than LVEF that can be relied upon in a routine evaluation of LV function. Our data have been obtained in a cross-sectional specific patient population of CA, and it remains to be seen whether impaired wringing in the follow-up of individual patients could be an early detector or warning sign of incipient ventricular dysfunction, both in CA and other pathologies.

      CONCLUSION

      Wringing, which integrates the twist and simultaneous longitudinal shortening of the LV, is a rotational parameter directly related to the state of the LVEF in patients with CA, reaching negative values in those with severely reduced LVEF and a rigid rotation pattern.

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