ECHO 2013 / Quantifying Myocardial Mechanics Strain and Torsion
.pdf
Reduction in Strain Delay Index with CRT
Lim et al. Circulation 2008; 118: 1130-7 |
Strain2012:41 |
Strain Delay Index Predicts Response to CRT
Regression analysis
ROC analysis
Lim et al. Circulation 2008; 118: 1130-7 |
Strain2012:42 |
What About Torsion?
P
S A L
Ell |
Elc |
Elr |
• Torsion is the longitudinal- |
|
|
|
|
||
Ecl |
Ecc |
Ecr |
circumferential shear |
|
component of strain |
||||
|
|
|
||
Erl |
Erc |
Err |
|
Strain2012:43
Torsion-Volume Loop
|
|
|
|
TV |
|
|
|
|
|
AC |
|
|
|
|
100 |
|
|
|
|
|
|
|
|
|
Ejection |
|
|
%max |
75 |
|
|
|
|
|
50 |
|
MO |
|
|
|
|
|
|
|
|
|
||
Torsion, |
|
|
|
|
|
|
25 |
|
|
Pk-E |
|
AO |
|
|
|
|
|
|||
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
MC |
|
0 |
|
|
|
|
|
|
|
|
|
|
|
En-E |
|
-25 |
|
|
|
|
|
|
-25 |
0 |
25 |
50 |
75 |
100 |
LV volume, %SV
Notomi et al. Circ 2006; 113: 2524-2533 |
Strain2012:44 |
LV Untwisting Predicts Diastolic
Suction Gradient
IVPG, mmHg
7.5 |
|
y = -0.44x + 0.87 |
|
||
|
|
r = 0.72 |
5
2.5
0
0 |
-5 |
-10 |
-15 |
Peak LV untwisting, rad/s
Notomi et al. Circ 2006; 113: 2524-2533 |
Strain2012:45 |
What Will Be the Role of Torsion Assessment?
•Clear value as tool to understand pathophysiology
•Clinical tool? What is needed?
–Easier use
–Compelling application
–New information over existing indices
Strain2012:46
Apical Rotation Gives Most of the Information
Full calculation |
Apical component only |
•11 dogs
•Inotropic modulation with dobutamine and esmolol
•Ligation of LAD or LCx artery
Kim W-J et al. Circ Img 2009; 2: 123-131 |
Strain2012:47 |
Emerging Applications
Transmural strain 3D strain
Seo et al. Circ Img 2009; 2: 451-9Strain2012:48
So Why Is Strain/Torsion Rarely Used?
•In 2013 very few echoes report any advanced mechanics
•No interoperability
–Each company has proprietary format
–No DICOM scan line format (can we agree on one?)
–Different results with different equipment
–ASE and EACVI have active taskforce to address this
•Need for standardization phantom
•Changing workflow requirements
–On-line or off-line? Need for separate review software?
•Too many parameters!
–Need for comparative studies
•No reimbursement
–Can we prove the value of this without devaluing the rest of
echo? |
Strain2012:49 |
|
LV Mechanics: Present State of the Art
We now have the echocardiographic tools available to let us assess LV contraction, relaxation, compliance, suction, and filling pressure.
3D Modelling of
LV Torsion
Strain2012:50