In-silico study of accuracy and precision of left-ventricular strain quantification from 3D tagged MRI

Cardiac Magnetic Resonance Imaging (MRI) allows quantifying myocardial tissue deformation and strain based on the tagging principle. In this work, we investigate accuracy and precision of strain quantification from synthetic 3D tagged MRI using equilibrated warping. To this end, synthetic biomechanical left-ventricular tagged MRI data with varying tag distance, spatial resolution and signal-to-noise ratio (SNR) were generated and processed to quantify errors in radial, circumferential and longitudinal strains relative to ground truth. Results reveal that radial strain is more sensitive to image resolution and noise than the other strain components. The study also shows robustness of quantifying circumferential and longitudinal strain in the presence of geometrical inconsistencies of 3D tagged data. In conclusion, our study points to the need for higher-resolution 3D tagged MRI than currently available in practice in order to achieve sufficient accuracy of radial strain quantification.

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Assessment of left ventricular mechanics in right ventricular overload using in silico rat models

European Heart Journal - Digital Health ◽

10.1093/ehjdh/ztab104.3074 ◽

2021 ◽

Vol 2 (4) ◽

Author(s):

H Martinez-Navarro ◽

E K S Espe ◽

O O Odeigah ◽

I Sjaastad ◽

J Sundnes

Keyword(s):

Cardiac Function ◽

Circumferential Strain ◽

Radial Strain ◽

Left Ventricular ◽

Public Institution ◽

Lv Function ◽

Passive Stiffness ◽

Ventricular Mechanics ◽

Longitudinal Strains ◽

Rv Function

Abstract Background To preserve cardiac function in overload conditions, the RV adapts by developing muscular hypertrophy through progressive tissue remodelling. This process may lead to a vicious cycle with detrimental effects on RV diastolic and systolic function, as seen in pulmonary arterial hypertension (PAH) patients [1]. However, how RV overload affects LV function and remodelling remains an open question [2]. Computational models of cardiac physiology offer an opportunity for investigating mechanisms difficult or impossible to analyse otherwise due to the existence of overlapping factors and technical limitations. Aim This study aims to assess the acute effects of RV overload and increased myocardial passive stiffness on the LV mechanical properties in an anatomically-based computational model of healthy rat heart. Methods A computational simulation pipeline of cardiac mechanics based on the Holzapfel-Ogden model has been implemented using MR images from a healthy rat. Whereas LV function was modelled realistically using catheter measurements conducted on the same subject than the MR imaging, RV function was based on representative literature values for healthy and PAH rats with RV overload. The following cases were defined (Fig. 1): CTRL, with normal RV function; PAH1, with 30% increase in RV ESV (end-systolic volume) and 15% increase in RV ESP (end-systolic pressure) in comparison to CTRL; and PAH2, with 60% increase in RV ESV and 30% increase in RV ESP compared to CTRL. The cardiac cycle was simulated for all cases whilst fitting the experimentally measured LV pressure and volume values from a healthy rat, which allowed quantifying the effects of RV overload on LV function. Results The increase of average circumferential strain in the LV correlated with the degree of RV overload simulated (CTRL: −8.7%, PAH1: −8.9%, PAH2: −9.2%), whilst average radial (CTRL: 35.2%, PAH1: 34.8%, PAH2: 30.3%) and longitudinal strains decreased (CTRL: −7.7%, PAH1: −7.4%, PAH2: −6.6%), as seen in Fig.2. However, regional differences in strain were significant: under RV overload conditions, circumferential strain increased in the septum (−3.5% difference in PAH2 vs. CTRL) but lower values were observed in the lateral wall (+1.7% difference in PAH2 vs. CTRL). Cardiac function of case PAH2 was simulated also with increased myocardial passive stiffness (2.67 kPa instead of 1.34 kPa) which presented a mild strain increase in the mid LV ventricle in comparison to PAH2 with normal stiffness (circumferential strain: −0.8%, radial strain: +0.5%, longitudinal strain: −0.2%). Conclusion Our study provides mechanistic evidence on how RV overload and increased passive myocardial stiffness causes a redistribution of strain and fibre stress in the LV, which may play a significant role in LV remodelling and function. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): K.G. Jebsen Center for Cardiac Research Figure 1. Pressure – volume loops Figure 2. Mean mid-LV strains

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P2459Do left atrial strain measurements provide information independent from left ventricular function parameters?

European Heart Journal ◽

10.1093/eurheartj/ehz748.0791 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Cited By ~ 1

Author(s):

G G Malaescu ◽

A Petrescu ◽

J Duchenne ◽

R Capota ◽

J U Voigt

Keyword(s):

Cardiac Cycle ◽

Volume Ratio ◽

Lateral Wall ◽

Left Ventricular ◽

Valvular Regurgitation ◽

Additional Information ◽

Tissue Velocity ◽

Strain Components ◽

Lv Volume ◽

Longitudinal Strains

Abstract Introduction LA strain has been proposed to be a reliable and independent prognostic marker, as well as a useful surrogate of LA function. Purpose To assess if LA deformation measurements add independent information to standard echocardiographic measurements. Methods We included 66 normals and patients with a wide range of pathology and diastolic dysfunction grade from the echo data base of our hospital if image quality was sufficient for both LA and LV strain analysis. Patients with a mobile interatrial septum, arrhythmias and more than mild valvular regurgitation were not considered. Standard echocardiographic measurements including LA and LV volumes were performed according to current guidelines. LA and LV longitudinal strains were assessed by 2D speckle tracking in the same cardiac cycle in apical 4 and 2 chambers views using peak R as time reference. Peak LA and LV strain as well as LA and LV strain at onset of LA contraction were measured to calculate the strain components of all three phases of the cardiac cycle (systolic, early diastolic and late diastolic). Results In our cohort, the ratio of LA and LV systolic strain was directly and strongly related to the volume ratio of the two chambers (R2=0,894, slope=-1.001, p<0.0001, see Figure 1). This was confirmed by a multivariate regression analysis, where systolic LA strain proved to be strongly dependent on systolic LV strain, LA volume and LV volume (R2=0.872, p<0.0001 for the final model). For early diastolic strain, confounders were LV early diastolic strain, LA volume, LV volume and lateral wall E' tissue velocity (R2=0.784, p<0.0001); while LA late diastolic strain was dependent on LV late diastolic strain, LA volume, LV volume and lateral wall A' tissue velocity (R2=0.823, p<0.0001). Strain ratio vs volume ratio Conclusions Our data suggest that systolic LA strain (reservoir strain) is strictly dependent on systolic LV strain and the volume ratio of both chambers and, therefore, its measurement cannot provide additional information beyond classical measurements. Diastolic LA strain components show a less strict dependence on LV function and may therefore provide additional information.

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A Study of Clustering for the Enhancement of Image Resolution in Dynamic Photon Emission

ISTFA 2019: Conference Proceedings from the 45th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2019p0068 ◽

2019 ◽

Author(s):

S. Chef ◽

C. T. Chua ◽

C. L. Gan

Keyword(s):

Signal To Noise Ratio ◽

Photon Emission ◽

Optical Signal ◽

Image Resolution ◽

Time Dimension ◽

Processing Scheme ◽

3D Space ◽

Initial Acquisition ◽

Resolution Limits ◽

Emission Microscopy

Abstract Limited spatial resolution and low signal to noise ratio are some of the main challenges in optical signal observation, especially for photon emission microscopy. As dynamic emission signals are generated in a 3D space, the use of the time dimension in addition to space enables a better localization of switching events. It can actually be used to infer information with a precision above the resolution limits of the acquired signals. Taking advantage of this property, we report on a post-acquisition processing scheme to generate emission images with a better image resolution than the initial acquisition.

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Myocardial deformation in patients with a single left ventricle using 2D cardiovascular magnetic resonance feature tracking: a case–control study

The International Journal of Cardiovascular Imaging ◽

10.1007/s10554-021-02230-2 ◽

2021 ◽

Author(s):

Fabian Strodka ◽

Jana Logoteta ◽

Roman Schuwerk ◽

Mona Salehi Ravesh ◽

Dominik Daniel Gabbert ◽

...

Keyword(s):

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Left Ventricle ◽

Feature Tracking ◽

Systolic Function ◽

Radial Strain ◽

Left Ventricular ◽

Lv Function ◽

Significant Difference ◽

Lv Volumes

AbstractVentricular dysfunction is a well-known complication in single ventricle patients in Fontan circulation. As studies exclusively examining patients with a single left ventricle (SLV) are sparse, we assessed left ventricular (LV) function in SLV patients by using 2D-cardiovascular magnetic resonance (CMR) feature tracking (2D-CMR-FT) and 2D-speckle tracking echocardiography (2D-STE). 54 SLV patients (11.4, 3.1–38.1 years) and 35 age-matched controls (12.3, 6.3–25.8 years) were included. LV global longitudinal, circumferential and radial strain (GLS, GCS, GRS) and strain rate (GLSR, GCSR, GRSR) were measured using 2D-CMR-FT. LV volumes, ejection fraction (LVEF) and mass were determined from short axis images. 2D-STE was applied in patients to measure peak systolic GLS and GLSR. In a subgroup analysis, we compared double inlet left ventricle (DILV) with tricuspid atresia (TA) patients. The population consisted of 19 DILV patients, 24 TA patients and 11 patients with diverse diagnoses. 52 patients were in NYHA class I and 2 patients were in class II. Most SLV patients had a normal systolic function but median LVEF in patients was lower compared to controls (55.6% vs. 61.2%, p = 0.0001). 2D-CMR-FT demonstrated reduced GLS, GCS and GCSR values in patients compared to controls. LVEF correlated with GS values in patients (p < 0.05). There was no significant difference between GLS values from 2D-CMR-FT and 2D-STE in the patient group. LVEF, LV volumes, GS and GSR (from 2D-CMR-FT) were not significantly different between DILV and TA patients. Although most SLV patients had a preserved EF derived by CMR, our results suggest that, LV deformation and function may behave differently in SLV patients compared to healthy subjects.

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3D phonon microscopy with sub-micron axial-resolution

Scientific Reports ◽

10.1038/s41598-021-82639-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Richard J. Smith ◽

Fernando Pérez-Cota ◽

Leonel Marques ◽

Matt Clark

Keyword(s):

Signal To Noise Ratio ◽

Single Cells ◽

Optical Resolution ◽

Acquisition Time ◽

Label Free ◽

Axial Resolution ◽

Force Microscopy ◽

Atomic Force ◽

Accuracy And Precision ◽

Good Agreement

AbstractBrillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.

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Left ventricular and left atrial deformation imaging early after pPCI: does diabetes mellitus make any difference?

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jeaa356.046 ◽

2021 ◽

Vol 22 (Supplement_1) ◽

Author(s):

D Trifunovic Zamaklar ◽

G Krljanac ◽

M Asanin ◽

L Savic-Spasic ◽

J Vratonjic ◽

...

Keyword(s):

Heart Failure ◽

Strain Rate ◽

Myocardial Function ◽

Radial Strain ◽

Left Ventricular ◽

Deformation Analysis ◽

Syntax Score ◽

Deformation Imaging ◽

Early Diastole

Abstract Funding Acknowledgements Type of funding sources: None. onbehalf PREDICT-VT More extensive coronary atherosclerosis in diabetes mellitu (DM) induces poorer clinical outcomes after STEMI, but there are data suggesting that impaired myocardial function in DM, even independently from epicardial coronary lesions severity, might have detrimental effect, predominately on heart failure development in DM. Aim the current study is a sub-study of PREDICT-VT study (NCT03263949), aimed to analyse LV and LA function using myocardial deformation imaging based on speckle tracking echocardiography after pPCI in STEMI patients with and without DM. Methods in 307 consecutive pts enrolled in PREDICT-VT study early echocardiography (5 ± 2 days after pPCI) was done including LA and multilayer LV deformation analysis with longitudinal (L), radial (R) and circumferential (C) strain (S; %) and strain rate (SR, 1/sec), LV index of post systolic shortening for longitudinal (PSS LS) and circumferential (PSS CS) strains and analysis of LV rotation mechanic. Results from 242 patients who completed 1 year follow up, 48 (20%) had DM. Pts with DM were older (60 ± 1,01 vs 57 ± 10; p = 0.067) and had insignificantly higher SYNTAX score (18.5 ± 9.2 vs 15.8 ± 9.8, p = 0.118) . However, diabetics had more severely impaired EF (44.2 ± 8.6 vs 49.2 ± 9.8, p = 0.001), E/A ratio (0.78 ± 0.33 vs 0.90 ± 0.34; p = 0.036) and MAPSE (1.18 ± 0.32 vs 1.32 ± 0.33; p = 0.001). Global LV LS on all layers (endo: -13.6 ± 4.0 vs-16.2 ± 4.7; mid: -11.9 ± 3.5 vs -14.1 ± 4.1; epi: -10.4 ± 3.1 vs -12.3 ± 3.6; p < 0.005 for all) was impaired in DM patients, as well as longitudinal systolic SR (-0.71 ± 0.23 vs -0.84 ± 0.24; p = 0.001) and SR during early diastole (0.65 ± 0.26 vs 0.83 ± 0.33, p < 0.001). Patients with DM had more pronounced longitudinal posts-systolic shortening throughout LV wall (endo: 21.4 ± 16.1 vs 13.7 ± 13.3, p = 0.005; mid: 21.9 ± 16.1 vs 14.3 ± 13.1, p = 0.006; epi: 22.4 ± 16.5 vs 15.3 ± 13.7, p = 0.010) and higher LV mechanical dispersion (MDI: 71.3 ± 38.3 vs 59.0 ± 18.9, p = 0.037). LA strain was significantly impaired in DM patients (18.9 ± 7.7 vs 22.6 ± 10.0, p = 0.011) and even more profoundly LA strain rate during early diastole (-0.73 ± 0.48 vs -1.00 ±0.58, p = 0.002). Patients with DM also had more impaired LV global (15.7 ± 9.1 vs 19.8 ± 10.4, p = 0.013) radial strain, global LV circumferencial strain, especially at the mid-wall level (-13.9 ± 4.2 vs -16.0 ± 4.3, p = 0.005) and impaired circumferential SR E (1.25± 0.44 vs 1.49 ± 0.46, p = 0.003). End-systolic rotation of the LV apex was more impaired in DM (4.7 ± 5.1 vs 6.8 ± 5.5, p= 0.022). During 1 year follow-up heart failure and all-cause mortality tend to be higher among DM pts (46.7% vs 35.2%, p = 0.153). Conclusion STEMI patients with DM have more severely impaired LV systolic and diastolic function estimated both by traditional parameter and advanced echo techniques. These results might, at least partially, explain why outcomes after STEMI in DM might be poorer, even in the absence of more complex angiographic findings, pointing to the significance of impaired myocardial function DM itself.

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Strain parameters for predicting the prognosis of non‐ischemic dilated cardiomyopathy using cardiovascular magnetic resonance tissue feature tracking

Journal of Cardiovascular Magnetic Resonance ◽

10.1186/s12968-021-00726-3 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Chengjie Gao ◽

Yajie Gao ◽

Jingyu Hang ◽

Meng Wei ◽

Jingbo Li ◽

...

Keyword(s):

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Dilated Cardiomyopathy ◽

Feature Tracking ◽

Systolic Function ◽

Radial Strain ◽

Left Ventricular ◽

Multivariate Logistic Regression Model ◽

Non Ischemic Dilated Cardiomyopathy

Abstract Background A considerable number of non-ischemic dilated cardiomyopathy (NDCM) patients had been found to have normalized left ventricular (LV) size and systolic function with tailored medical treatments. Accordingly, we aimed to evaluate if strain parameters assessed by cardiovascular magnetic resonance (CMR) feature tracking (FT) analysis could predict the NDCM recovery. Methods 79 newly diagnosed NDCM patients who underwent baseline and follow-up CMR scans were enrolled. Recovery was defined as a current normalized LV size and systolic function evaluated by CMR. Results Among 79 patients, 21 (27%) were confirmed recovered at a median follow-up of 36 months. Recovered patients presented with faster heart rates (HR) and larger body surface area (BSA) at baseline (P < 0.05). Compared to unrecovered patients, recovered pateints had a higher LV apical radial strain divided by basal radial strain (RSapi/bas) and a lower standard deviation of time to peak radial strain in 16 segments of the LV (SD16-TTPRS). According to a multivariate logistic regression model, RSapi/bas (P = 0.035) and SD16-TTPRS (P = 0.012) resulted as significant predictors for differentiation of recovered from unrecovered patients. The sensitivity and specificity of RSapi/bas and SD16-TTPRS for predicting recovered conditions were 76%, 67%, and 91%, 59%, with the area under the curve of 0.75 and 0.76, respectively. Further, Kaplan Meier survival analysis showed that patients with RSapi/bas ≥ 0.95% and SD16-FTPRS ≤ 111 ms had the highest recovery rate (65%, P = 0.027). Conclusions RSapi/bas and CMR SD16-TTPRS may be used as non-invasive parameters for predicting LV recovery in NDCM. This finding may be beneficial for subsequent treatments and prognosis of NDCM patients. Registration number: ChiCTR-POC-17012586.

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Regional myocardial work by strain Doppler echocardiography and LV pressure: a new method for quantifying myocardial function

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00946.2004 ◽

2005 ◽

Vol 288 (5) ◽

pp. H2375-H2380 ◽

Cited By ~ 27

Author(s):

Stig Urheim ◽

Stein Inge Rabben ◽

Helge Skulstad ◽

Erik Lyseggen ◽

Halfdan Ihlen ◽

...

Keyword(s):

Doppler Echocardiography ◽

Myocardial Function ◽

Reference Method ◽

Left Ventricular ◽

Positive Sign ◽

Volume Loading ◽

Short Term ◽

Loop Area ◽

Work Index ◽

Longitudinal Strains

There is a need for better methods to quantify regional myocardial function. In the present study, we investigated the feasibility of quantifying regional function in terms of a segmental myocardial work index as derived from strain Doppler echocardiography (SDE) and invasive pressure. In 10 anesthetized dogs, we measured left ventricular (LV) pressure by micromanometer and myocardial longitudinal strains by SDE and sonomicrometry. The regional myocardial work index (RMWI) was calculated as the area of the pressure-strain loop. As a reference method for strain, we used sonomicrometry. By convention, the loop area was assigned a positive sign when the pressure-strain coordinates rotated counterclockwise. Measurements were done at baseline and during volume loading and left anterior descending coronary artery (LAD) occlusion, respectively. There was a good correlation between RMWI calculated from strain by SDE and strain by sonomicrometry ( y = 0.73 x + 0.21, r = 0.82, P < 0.01). Volume loading caused an increase in RMWI from 1.3 ± 0.2 to 2.2 ± 0.1 kJ/m3 ( P < 0.05) by SDE and from 1.5 ± 0.3 to 2.7 ± 0.3 kJ/m3 ( P = 0.066) by sonomicrometry. Short-term ischemia (1 min) caused a decrease in RMWI from 1.3 ± 0.2 to 0.3 ± 0.04 kJ/m3 ( P < 0.05) and from 1.3 ± 0.3 to 0.5 ± 0.2 kJ/m3 ( P < 0.05) by SDE and sonomicrometry, respectively. In the nonischemic ventricle and during short-term ischemia, the pressure-strain loops rotated counterclockwise, consistent with actively contracting segments. Long-term ischemia (3 h), however, caused the pressure-strain loop to rotate clockwise, consistent with entirely passive segments, and the loop areas became negative, −0.2 ± 0.1 and −0.1 ± 0.03 kJ/m3 ( P < 0.05) by SDE and sonomicrometry, respectively. A RMWI can be estimated by SDE in combination with LV pressure. Furthermore, the orientation of the loop can be used to assess whether the segment is active or passive.

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Atrial and Ventricular Structural and Functional Alterations in Obese Children

Medicina ◽

10.3390/medicina57060562 ◽

2021 ◽

Vol 57 (6) ◽

pp. 562

Author(s):

Rima Šileikienė ◽

Karolina Adamonytė ◽

Aristida Ziutelienė ◽

Eglė Ramanauskienė ◽

Jolanta Justina Vaškelytė

Keyword(s):

Speckle Tracking ◽

Longitudinal Strain ◽

Speckle Tracking Echocardiography ◽

Myocardial Dysfunction ◽

Global Longitudinal Strain ◽

Radial Strain ◽

Left Ventricular ◽

Z Score ◽

Obese Children ◽

2D Speckle Tracking

Background and objectives: Childhood obesity has reached epidemic levels in the world. Obesity in children is defined as a body mass index (BMI) equal to or above the 95th percentile for age and sex. The aim of this study was to determine early changes in cardiac structure and function in obese children by comparing them with their nonobese peers, using echocardiography methods. Materials and methods: The study enrolled 35 obese and 37 age-matched nonobese children. Standardized 2-dimensional (2D), pulsed wave tissue Doppler, and 2D speckle tracking echocardiography were performed. The z-score BMI and lipid metabolism were assessed in all children. Results: Obese children (aged 13.51 ± 2.15 years; 20 boys; BMI z-score of 0.88 ± 0.63) were characterized by enlarged ventricular and atrial volumes, a thicker left ventricular posterior wall, and increased left ventricular mass. Decreased LV and RV systolic and diastolic function was found in obese children. Atrial peak negative (contraction) strain (−2.05% ± 2.17% vs. −4.87% ± 2.97%, p < 0.001), LV and RV global longitudinal strain (−13.3% ± 2.88% vs. −16.87% ± 3.39%; −12.51% ± 10.09% vs. −21.51% ± 7.42%, p < 0.001), and LV global circumferential strain (−17.0 ± 2.7% vs. −19.5 ± 2.9%, p < 0.001) were reduced in obese children. LV torsion (17.94° ± 2.07° vs. 12.45° ± 3.94°, p < 0.001) and normalized torsion (2.49 ± 0.4°/cm vs. 1.86 ± 0.61°/cm, p = 0.001) were greater in obese than nonobese children. A significant inverse correlation was found between LV and RV global longitudinal strain and BMI (r = −0.526, p < 0.01; r = −0.434, p < 0.01) and total cholesterol (r = −0.417, p < 0.01). Multivariate analysis revealed that the BMI z-score was independently related to LV and RV global longitudinal strain as well as LV circumferential and radial strain. Conclusion: 2D speckle tracking echocardiography is beneficial in the early detection of regional LV systolic and diastolic dysfunctions, with preserved ejection fraction as well as additional RV and atrial involvement, in obese children. Obesity may negatively influence atrial and ventricular function, as measured by 2D speckle tracking echocardiography. Obese children, though they are apparently healthy, may have subclinical myocardial dysfunction.

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Abstract 964: Effect of Volume Overload on Left Ventricular Torsion and Extra Cellular Matrix

Circulation ◽

10.1161/circ.116.suppl_16.ii_190-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Hosakote M Nagaraj ◽

Thomas S Denney ◽

Steven G Lloyd ◽

David Calhoun ◽

Inmaculada Aban ◽

...

Keyword(s):

Picric Acid ◽

Three Dimensional ◽

Volume Overload ◽

Left Ventricular ◽

Deformation Model ◽

Data Set ◽

Left Ventricular Torsion ◽

Tissue Tagging ◽

Ventricular Torsion ◽

Longitudinal Strains

Background: Muscle fibers are arranged in a spiral network and are connected by extracellular matrix (ECM). LV torsion is increased in the pressure overloaded heart where there is an increase in ECM. However, torsion and its relation to ECM have not been systematically studied in the volume overloaded heart. Hypothesis: The volume overloaded heart has a decrease in LV torsion due a loss of ECM. Methods: Primary mitral regurgitation (MR) (n=29), resistant hypertension (HTN) (n=77) and normal volunteers (NL) (n±37) were studied. Comprehensive cardiac magnetic resonance imaging (MRI) with tissue tagging was performed and analyzed using three-dimensional data set. Torsion was computed by fitting a B-spline deformation model in prolate-spheroidal coordinates to the tag line data. A subset of MR subjects had LV collagen assessed by picric acid Sirius red from biopsy samples taken at the time of surgery. Results: LV ejection fraction was 65% in MR and 70% in HTN. MR demonstrated eccentric remodeling and HTN demonstrated concentric remodeling. HTN had significantly higher torsion angle and systolic twist compared to NL and MR. This was associated with a simultaneous decrease in longitudinal strain. In contrast, MR patients had similar torsion indices, circumferential and longitudinal strains compared to NL. LV biopsy in MR demonstrated a decrease in interstitial collagen compared to NL. Conclusions: As opposed to the pure volume overloaded heart, LV torsional forces are increased in the pressure overloaded heart. This difference may be related to a rearrangement of the laminar structure due to a differential effect on ECM in the volume overloaded versus the pressure overloaded heart.

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