Three-dimensional Evaluation of Dobutamine-induced Changes in Regional Myocardial Deformation in Ischemic Myocardium Using Ultrasonic Strain Measurements: The Role of Circumferential Myocardial Shortening

Prediction of Deterioration of Left Ventricular Function Using 3-Dimensional Speckle-Tracking Echocardiography in Patients With Left Bundle-Branch Block

Background Previous studies have demonstrated that 2-dimensional (2D) global longitudinal strain (GLS) is associated with cardiovascular outcomes in patients with left bundle-branch block. However, the predictive value of 3-dimensional (3D) speckle-tracking echocardiography has not yet been investigated in these patients. Methods and Results The authors retrospectively identified 290 patients with left bundle-branch block who underwent echocardiography more than twice. Using speckle-tracking echocardiography, 2D-GLS, 3D-GLS, 3D-global circumferential strain, 3D global radial strain, and 3D global area strain were acquired. The association between 2D and 3D strains and the follow-up left ventricular (LV) ejection fraction (LVEF) was analyzed. The study population was divided into 2 sets: a group with preserved LVEF (baseline LVEF ≥40%) and a group with reduced LVEF (baseline LVEF <40%). After a median follow-up of 29.1 months (interquartile range, 13.1-53.0 months), 14.9% of patients progressed to LV dysfunction in the group with preserved LVEF, and 51.0% of patients showed improved LV function in the group with reduced LVEF. Multivariable analysis of 2D and 3D strains revealed that higher 2D-GLS (odds ratio [OR], 0.65 [95% CI, 0.54-0.78], P<0.001) was highly associated with maintaining LVEF in patients with preserved LVEF. However, a lower 3D-global circumferential strain (OR, 0.61 [95% CI, 0.47-0.78], P<0.001) showed a strong association with persistently reduced LVEF in patients with reduced LVEF. Conclusions Although 2D-GLS showed a powerful predictive value for the deterioration of LV function in the preserved LVEF group, 3D strain, especially 3D-global circumferential strain, can be helpful to predict consistent LV dysfunction in patients with left bundle-branch block who have reduced LVEF.

Deterioration of longitudinal, circumferential, and radial myocardial strains during acute coronary flow reduction: which direction of strain should be analyzed for early detection?

Longitudinal myocardial strain is considered to deteriorate in the early ischemic stage compared to circumferential and radial strains because the subendocardial inner oblique fibers are generally directed along the longitudinal axis. However, it is unclear whether the decrease in longitudinal strain precedes a decrease in circumferential and radial strains during acute coronary flow reduction. The left anterior descending artery was gradually narrowed in 13 open-chest dogs. Whole-wall and subendocardial longitudinal, circumferential, and radial strains were analyzed at baseline and during flow reduction. Peak systolic and end-systolic strains, the postsystolic strain index (PSI), and the early systolic strain index (ESI) were measured in the risk area; the decreasing rate in each parameter and the diagnostic accuracy to detect flow reduction were evaluated. Absolute values of peak systolic and end-systolic strains gradually decreased with flow reduction. The decreasing rate and diagnostic accuracy of longitudinal systolic strain were not significantly different from those in other strains, although the diagnostic accuracy of radial systolic strain tended to be lower. PSI and ESI gradually increased with flow reduction. In these parameters, a lower diagnostic accuracy with respect to radial strain was not demonstrated. During acute coronary flow reduction, the decrease in longitudinal systolic strain did not precede that in circumferential systolic strain; however, the decrease in radial systolic strain may be smaller than that of other systolic strains. In contrast, there appeared to be no differences in the PSI and ESI values among the three strains.

Strain-encoded magnetic resonance: a method for the assessment of myocardial deformation

This study aims to assess the usefulness of strain‐encoded magnetic resonance (SENC) for the quantification of myocardial deformation (‘strain’) in healthy volunteers and for the diagnostic workup of patients with different cardiovascular pathologies. SENC was initially described in the year 2001. Since then, the SENC sequence has undergone several technical developments, aiming at the detection of strain during single‐heartbeat acquisitions (fast‐SENC). Experimental and clinical studies that used SENC and fast‐SENC or compared SENC with conventional cine or tagged magnetic resonance in phantoms, animals, healthy volunteers, or patients were systematically searched for in PubMed. Using ‘strain‐encoded magnetic resonance and SENC’ as keywords, three phantom and three animal studies were identified, along with 27 further clinical studies, involving 185 healthy subjects and 904 patients. SENC (i) enabled reproducible assessment of myocardial deformation in vitro, in animals and in healthy volunteers, (ii) showed high reproducibility and substantially lower time spent compared with conventional tagging, (iii) exhibited incremental value to standard cine imaging for the detection of inducible ischaemia and for the risk stratification of patients with ischaemic heart disease, and (iv) enabled the diagnostic classification of patients with transplant vasculopathy, cardiomyopathies, pulmonary hypertension, and diabetic heart disease. SENC has the potential to detect a wide range of myocardial diseases early, accurately, and without the need of contrast agent injection, possibly enabling the initiation of specific cardiac therapies during earlier disease stages. Its one‐heartbeat acquisition mode during free breathing results in shorter cardiovascular magnetic resonance protocols, making its implementation in the clinical realm promising.

Circumferential strain acquired by CMR early after acute myocardial infarction adds incremental predictive value to late gadolinium enhancement imaging to predict late myocardial remodeling and subsequent risk of sudden cardiac death

PURPOSE

Late adverse myocardial remodeling after acute myocardial infarction (AMI) is strongly associated with sudden cardiac death (SCD). Cardiac magnetic resonance (CMR) performed early after AMI can predict late remodeling and SCD risk with moderate accuracy. This study assessed the ability of CMR-measured circumferential strain (CS) to add incremental predictive information to late gadolinium enhancement (LGE).

METHODS

Patients with an AMI and LVEF < 50% were screened for inclusion. A total of 27 patients, totaling 432 myocardial segments, prospectively underwent CMR 7 ± 5 days after percutaneous coronary intervention (PCI). LGE, microvascular obstruction (MVO), and myocardial CS were measured for each segment. The primary endpoint was late segmental adverse remodeling defined as segmental wall motion score (WMS) > 1 measured by echocardiography 3 months after PCI.

RESULTS

A total of 141 segments experienced the primary endpoint at 3 months. The mean LGE volume was higher in these segments, but LGE was also present in many segments with normal WMS (40 ± 28 versus 20 ± 26%, p < 0.01). Segments that met the primary endpoint also showed greater impairment of CS. Segments with both LGE > 17% and impaired CS >- 7.2% on CMR were more likely to experience late adverse remodeling (73%) as compared to segments with neither (9%, p < 0.001) or one abnormal parameter (36%, p < 0.001). CS >- 7.2% also added incremental accuracy to LGE > 17% for predicting late adverse remodeling (AUC 0.81 from 0.70, p < 0.001).

CONCLUSIONS

When performed early after AMI, LGE is a moderate predictor of late remodeling and CS is a powerful predictor of late myocardial remodeling. When combined, they can predict late remodeling, a surrogate of SCD, with high accuracy.

Evolving new concepts in the assessment of aortic stenosis

Echocardiography has been pivotal in evaluating aortic stenosis (AS) over the past several decades. Recent experience has shown a wide spectrum in the clinical presentation of AS. A better understanding of the underlying hemodynamic principles has resulted in emergence of new subtypes of AS. New treatment modalities have also been introduced, requiring precise evaluation of aortic valve (AV) pathology for implementation of these therapies. This review will discuss new concepts and indices in the use of echocardiography in patients with AS. Specifically, we will address the hemodynamic characteristics, clinical presentation, and management of normal-flow, high-gradient; paradoxical low-flow, low-gradient; and classical low-flow, low-gradient aortic stenoses.

Challenges for 'diastology': contributions from Japanese researchers

Diastology is a study to treat diastole of the heart. Transmitral flow and pulmonary venous flow velocities recorded by pulsed Doppler echocardiography provide more important information about left ventricular (LV) diastolic dysfunction [left atrial (LA)-LV coupling] than cardiac catheterization in clinical practice; however, these waveforms are influenced by loading conditions, particularly preload. The early diastolic mitral annular and LV wall motion indices measured by tissue Doppler echocardiography can evaluate LV relaxation abnormality and filling pressure by being relatively preload independent. In addition, the role of concomitant systolic longitudinal dysfunction is well characterized in asymptomatic patients and in patients with heart failure and preserved ejection fraction. Two-dimensional speckle tracking echocardiography is an angle-independent method, and has the potential to evaluate the contraction and relaxation abnormalities in the longitudinal, circumferential, and radial directions of the LV myocardium as well as LV torsion/untwisting and, moreover, deformation of the LA myocardium and large arterial wall. As a result, this new technique can facilitate the early detection of impaired LA-LV-arterial coupling in patients before occurrence of overt heart failure symptoms.

Additive Prognostic Value of Echocardiographic Global Longitudinal and Global Circumferential Strain to Electrocardiographic Criteria in Patients With Heart Failure Undergoing Cardiac Resynchronization Therapy

Background—

Response to cardiac resynchronization therapy is most favorable in patients with heart failure with QRS duration ≥150 ms and left bundle branch block and less predictable in those with QRS width 120 to 149 ms or non–left bundle branch block.

Methods and Results—

We studied 205 patients with heart failure referred for cardiac resynchronization therapy with QRS ≥120 ms and ejection fraction ≤35%. We tested the hypothesis that contractile function using speckle-tracking echocardiographic global circumferential strain (GCS) from 2 short-axis views and global longitudinal strain (GLS) from 3 apical views add prognostic value to electrocardiographic criteria. There were 112 patients (55%) with GLS >−9% and 136 patients (66%) with GCS >−9%. During 4 years, 81 patients reached the combined primary end point (death, circulatory support, or transplant) and 120 reached the secondary end point (heart failure hospitalization or death). Both GLS >−9% and GCS >−9% were associated with increased risk of unfavorable events as follows: for the primary end point (hazard ratio=2.91; 95% confidence interval, 1.88–4.49; P <0.001) and (hazard ratio=3.73; 95% confidence interval, 2.39–5.82; P <0.001) for the secondary end point (hazard ratio=2.10; 95% confidence interval, 1.45–3.05; P <0.001) and (hazard ratio=3.25; 95% confidence interval, 2.23–4.75; P <0.001). In a prespecified subgroup of 120 patients with QRS 120 to 149 ms or non–left bundle branch block, significant associations of baseline GLS and GCS and outcomes remained: P =0.014 and P =0.002 for the primary end point and P =0.049 and P =0.001 for the secondary end point. Global strain measures had additive prognostic value to routine clinical or electrocardiographic parameters ( P <0.001).

Conclusions—

Baseline GCS and GLS were significantly associated with long-term outcome after cardiac resynchronization therapy and had additive prognostic value to routine clinical and electrocardiographic selection criteria for cardiac resynchronization therapy.

Prediction of functional recovery by cardiac magnetic resonance feature tracking imaging in first time ST-elevation myocardial infarction. Comparison to infarct size and transmurality by late gadolinium enhancement

PURPOSE

To investigate whether myocardial deformation imaging, assessed by feature tracking cardiac magnetic resonance (FTI-CMR), would allow objective quantification of myocardial strain and estimation of functional recovery in patients with first time ST-elevation myocardial infarction (STEMI).

METHODS

Cardiac magnetic resonance (CMR) imaging was performed in 74 consecutive patients 2-4 days after successfully reperfused STEMI, using a 1.5T CMR scanner (Philips Achieva). Peak systolic circumferential and longitudinal strains were measured using the FTI applied to SSFP cine sequences and were compared to infarct size, determined by late gadolinium enhancement (LGE). Follow-up CMR at 6 months was performed in order to assess residual ejection fraction, which deemed as the reference standard for the estimation of functional recovery.

RESULTS

During the follow-up period 53 of 74 (72%) patients exhibited preserved residual ejection fraction ≥50%. A cut-off value of -19.3% for global circumferential strain identified patients with preserved ejection fraction ≥50% at follow-up with sensitivity of 76% and specificity of 85% (AUC=0.86, 95% CI=0.75-0.93, p<0.001), which was superior to that provided by longitudinal strain (ΔAUC=0.13, SE=0.05, z-statistic=2.5, p=0.01), and non-inferior to that provided by LGE (ΔAUC=0.07, p=NS). Multivariate analysis showed that global circumferential strain and LGE exhibited independent value for the prediction of preserved LV-function, surpassing that provided by age, diabetes and baseline ejection fraction (HR=1.4, 95% CI=1.0-1.9 and HR=1.4, 95% CI=1.1-1.7, respectively, p<0.05 for both).

CONCLUSIONS

Estimation of circumferential strain by FTI provides objective assessment of infarct size without the need for contrast agent administration and estimation of functional recovery with non-inferior accuracy compared to that provided by LGE.

Comparison of quantitative wall-motion analysis and strain for detection of coronary stenosis with three-dimensional dobutamine stress echocardiography

BACKGROUND

Quantitative analysis of wall motion from three-dimensional (3D) dobutamine stress echocardiography (DSE) could provide additional diagnostic information not available from qualitative analysis. In this study, we compare the effectiveness of 3D fractional shortening (3DFS), a measure of wall motion computed from 3D echocardiography (3DE), to strain and strain rate measured with sonomicrometry for detecting critical stenoses during DSE.

METHODS

Eleven open-chest dogs underwent DSE both with and without a critical stenosis. 3DFS was measured from 3DE images acquired at peak stress. 3DFS was normalized by subtracting average 3DFS during control peak stress (∆3DFS). Strains in the perfusion defect (PD) were measured from sonomicrometry, and PD size and location were measured with microspheres.

RESULTS

A ∆3DFS abnormality indicated the presence of a critical stenosis with high sensitivity and specificity (88% and 100%, respectively), and ∆3DFS abnormality size correlated with PD size (R(2) = 0.54). The sensitivity and specificity for ∆3DFS were similar to that for area strain (88%, 100%) and circumferential strain and strain rate (88%, 92% and 88%, 86%, respectively), while longitudinal strain and strain rate were less specific. ∆3DFS correlated significantly with both coronary flow reserve (R(2) = 0.71) and PD size (R(2) = 0.97), while area strain correlated with PD size only (R(2) = 0.67), and other measures were not significantly correlated with flow reserve or PD size.

CONCLUSION

Quantitative wall-motion analysis using ∆3DFS is effective for detecting critical stenoses during DSE, performing similar to 3D strain, and provides potentially useful information on the size and location of a perfusion defect.

Prognostic value of global left ventricular strain for conservatively treated patients with symptomatic aortic stenosis

AIMS

Impaired left ventricular (LV) strain is associated with an increased risk of cardiac events in asymptomatic severe aortic stenosis (AS). We aimed to evaluate the prognostic value of global LV strain in conservatively treated patients with symptomatic AS.

METHODS AND RESULTS

This cohort study retrospectively reviewed symptomatic AS patients who were treated conservatively or surgically between July 2007 and April 2010. We measured their global longitudinal strain (GLS) and global circumferential strain (GCS). Clinical events were defined as readmission for heart failure or all-cause death for 2 years. GLS and GCS could predict a worse outcome in the conservatively treated group at cut-offs of =-16.5% (77% sensitivity and 67% specificity) and =-22.2% (92% sensitivity and 83% specificity), respectively. By univariate Cox regression analysis, age, logistic EuroSCORE, aortic valve area, GLS, and GCS were significant predictors. When adjusted for age, logistic EuroSCORE, and aortic valve area, impaired GLS and GCS were independently associated with a higher risk of clinical events.

CONCLUSION

In conservatively treated patients with symptomatic AS, impaired GLS and GCS were associated with an increased risk of cardiac events during a 2-year follow-up. Global LV strain may help to define a higher risk subset; therefore, a larger and prospective observation study would be necessary.

Strain-encoded cardiac magnetic resonance during high-dose dobutamine stress testing for the estimation of cardiac outcomes: comparison to clinical parameters and conventional wall motion readings

OBJECTIVES

The purpose of this study was to determine the prognostic value of strain-encoded magnetic resonance imaging (SENC) during high-dose dobutamine stress cardiac magnetic resonance imaging (DS-MRI) compared with conventional wall motion readings.

BACKGROUND

Detection of inducible ischemia by DS-MRI on the basis of assessing cine images is subjective and depends on the experience of the readers, which may influence not only the diagnostic classification but also the risk stratification of patients with ischemic heart disease.

METHODS

In all, 320 consecutive patients with suspected or known coronary artery disease underwent DS-MRI, using a standard protocol in a 1.5T MR scanner. Wall motion abnormalities (WMA) and myocardial strain were assessed at baseline and during stress, and outcome data including cardiac deaths, nonfatal myocardial infarctions ("hard events"), and revascularization procedures performed >90 days after the MR scans were collected.

RESULTS

Thirty-five hard events occurred during a 28 ± 9 month follow-up period, including 10 cardiac deaths and 25 nonfatal myocardial infarctions, and 32 patients underwent coronary revascularization. Using a series of Cox proportional-hazards models, both resting and inducible WMA offered incremental information for the assessment of hard cardiac events compared to clinical variables (chi-square = 13.0 for clinical vs. chi-square = 26.1 by adding resting WMA, p < 0.001, vs. chi-square = 39.3 by adding inducible WMA, p < 0.001). Adding visual SENC or quantitative strain rate reserve to this model further improved the prediction of outcome (chi-square = 50.7 vs. chi-square = 52.5, p < 0.001 for both). In a subset of patients (n = 175) who underwent coronary angiography, SENC yielded significantly higher sensitivity for coronary artery disease detection (96% vs. 84%, p < 0.02), whereas specificity and accuracy were not significantly different (88% vs. 94% and 93% vs. 88%, p = NS for both).

CONCLUSIONS

Strain-encoded MRI aids the accurate identification of patients at high risk for future cardiac events and revascularization procedures, beyond the assessment of conventional atherogenic risk factors and resting or inducible WMA on cine images. (Strain-Encoded Cardiac Magnetic Resonance Imaging as an Adjunct for Dobutamine Stress Testing; NCT00758654).

Systolic-diastolic coupling of myocardial deformation of the left ventricle in children with left ventricular noncompaction

Disruption of the myocardial architecture in left ventricular noncompaction (LVNC) may alter myocardial deformation. We evaluated LV myocardial deformation and tested the hypothesis that tight systolic-diastolic coupling occurs in LVNC. Longitudinal and circumferential strain and strain rates (SRs) as determined by speckle tracking echocardiography in nine children aged 5.6 ± 5.5 years was compared with those in nine controls. Left ventricular systolic myocardial deformation parameters were correlated with ejection fraction and indices of diastolic deformation. Compared with controls, patients had lower global LV systolic longitudinal strain (P = 0.008), systolic SR (P = 0.05) and early diastolic SR (P < 0.001). Similarly, LV systolic circumferential strain (base, P = 0.04; papillary muscle level, P = 0.01; apex, P = 0.04), systolic SR (base, P = 0.04) and early diastolic SR (papillary muscle level, P = 0.004, apex, P = 0.02) were lower in patients than in controls. Among patients, the LV ejection fraction correlated with global longitudinal systolic strain and SR and circumferential systolic strain and SR at all levels (all P < 0.05). Positive correlations existed between early diastolic and systolic SRs in corresponding dimensions (longitudinal r = 0.80, P = 0.01; circumferential at base, r = 0.91, P = 0.001; papillary muscle level, r = 0.96, P < 0.001; apex r = 0.98, P = <0.001). In conclusion, LV myocardial deformation is reduced in the longitudinal and circumferential dimensions and manifests tight systolic-diastolic coupling in children with LVNC.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.

Impact of right ventricular dilation on left ventricular myocardial deformation in patients after surgical repair of tetralogy of fallot

Left ventricular (LV) dysfunction is 1 of the major determinants of late adverse clinical outcomes in patients after surgical repair of tetralogy of Fallot (TOF). The aim of this study was to test the hypothesis that LV myocardial deformation is impaired in patients after TOF repair and related to right ventricular (RV) dilation and exercise capacity. Longitudinal, radial, and circumferential LV myocardial deformation was determined using speckle-tracking echocardiography in 23 postoperative patients with TOF and compared to that of 23 age-matched controls. Relations between LV strain and strain rate (SR) and RV volumes and exercise parameters were determined in patients. Compared to controls, patients had reduced global LV longitudinal, radial, and circumferential strain (all p values <0.05). Patients with significantly increased RV end-systolic volume (>2 SDs higher than normal; n = 17) had reduced global LV circumferential strain (p = 0.048) and SR (p = 0.038), but similar longitudinal and radial speckle-tracking echocardiographic parameters, compared to those without (n = 6). RV end-systolic volume was correlated inversely with global LV circumferential strain and SR (r = -0.58, p = 0.004, and r = -0.58, p = 0.005, respectively), while RV end-diastolic volume was correlated only with global LV circumferential strain (r = -0.43, p = 0.047). In patients, the LV ejection fraction was correlated with global LV circumferential strain (r = 0.54, p = 0.01) and SR (r = 0.66, p = 0.001) but not with longitudinal or radial speckle-tracking echocardiographic parameters. Using multivariate analysis, global LV circumferential SR (beta = 0.66, p = 0.001) and male gender (beta = 0.46, p = 0.012) were identified as independent predictors of peak oxygen consumption. In conclusion, the negative impact of RV dilation on LV function relates to its influence on LV circumferential strain and SR in patients after TOF repair.

Strain-encoded cardiac MR during high-dose dobutamine stress testing: comparison to cine imaging and to myocardial tagging

PURPOSE

To investigate regional strain response during high-dose dobutamine stress cardiac magnetic resonance imaging (DS-CMR) using myocardial tagging and Strain-Encoded MR (SENC).

MATERIALS AND METHODS

Stress induced ischemia was assessed by wall motion analysis, by tagged CMR and by SENC in 65 patients with suspected or known CAD who underwent DS-CMR in a clinical 1.5 Tesla scanner. Coronary angiography deemed as the standard reference for the presence or absence of CAD (> or =50% diameter stenosis) in all patients.

RESULTS

SENC and conventional tagging detected abnormal strain response in six and five additional patients, respectively, who were missed by cine images and proved to have CAD by angiography (P < 0.05 for SENC versus cine, P = 0.06 for tagging versus cine and p = NS for SENC versus tagging). On a per-vessel level, wall motion analysis on cine images showed high specificity (95%) but moderate sensitivity (70%) for the detection of CAD. Tagging and SENC yielded significantly higher sensitivity of 81% and 89%, respectively (P < 0.05 for tagging and P < 0.01 for SENC versus wall motion analysis, and p = NS for SENC versus tagging), while specificity was equally high (96% and 94%, respectively, P = NS for all).

CONCLUSION

Both the direct color-coded visualization of strain on CMR images and the generation of additional visual markers within the myocardium with tagged CMR represent useful adjuncts for DS-CMR, which may provide incremental value for the detection of CAD in humans. J. Magn. Reson.

Strain and strain rate imaging by echocardiography - basic concepts and clinical applicability

Echocardiographic strain and strain-rate imaging (deformation imaging) is a new non-invasive method for assessment of myocardial function. Due to its ability to differentiate between active and passive movement of myocardial segments, to quantify intraventricular dyssynchrony and to evaluate components of myocardial function, such as longitudinal myocardial shortening, that are not visually assessable, it allows comprehensive assessment of myocardial function and the spectrum of potential clinical applications is very wide. The high sensitivity of both tissue Doppler imaging (TDI) derived and two dimensional (2D) speckle tracking derived myocardial deformation (strain and strain rate) data for the early detection of myocardial dysfunction recommend these new non-invasive diagnostic methods for extensive clinical use. In addition to early detection and quantification of myocardial dysfunction of different etiologies, assessment of myocardial viability, detection of acute allograft rejection and early detection of allograft vasculopathy after heart transplantation, strain and strain rate data are helpful for therapeutic decisions and also useful for follow-up evaluations of therapeutic results in cardiology and cardiac surgery. Strain and strain rate data also provide valuable prognostic information, especially prediction of future reverse remodelling after left ventricular restoration surgery or after cardiac resynchronization therapy and prediction of short and median-term outcome without transplantation or ventricular assist device implantation of patients referred for heart transplantation.The Review explains the fundamental concepts of deformation imaging, describes in a comparative manner the two major deformation imaging methods (TDI-derived and speckle tracking 2D-strain derived) and discusses the clinical applicability of these new echocardiographic tools, which recently have become a subject of great interest for clinicians.

Strain-encoded cardiac MRI as an adjunct for dobutamine stress testing: incremental value to conventional wall motion analysis

BACKGROUND

High-dose dobutamine stress MRI is safe and feasible for the diagnosis of coronary artery disease (CAD) in humans. However, the assessment of cine scans relies on the visual interpretation of regional wall motion, which is subjective. Recently, strain-encoded MRI (SENC) has been proposed for the direct color-coded visualization of myocardial strain. The purpose of our study was to compare the diagnostic value of SENC with that provided by conventional wall motion analysis for the detection of inducible ischemia during dobutamine stress MRI.

METHODS AND RESULTS

Stress-induced ischemia was assessed by wall motion analysis and by SENC in 101 patients with suspected or known CAD and in 17 healthy volunteers who underwent dobutamine stress MRI in a clinical 1.5-T scanner. Quantitative coronary angiography deemed as the standard reference for the presence or absence of significant CAD (> or =50% diameter stenosis). On a coronary vessel level, SENC detected inducible ischemia in 86 of 101 versus 71 of 101 diseased coronary vessels (P<0.01 versus cine) and showed normal strain response in 189 of 202 versus 194 of 202 vessels with <50% stenosis (P=NS versus cine). On a patient level, SENC detected inducible ischemia in 63 of 64 versus 55 of 64 patients with CAD (P<0.05 versus cine) and showed normal strain response in 32 of 37 versus 34 of 37 patients without CAD (P=NS versus cine). Quantification analysis demonstrated a significant correlation between strain rate reserve and coronary artery stenosis severity (r(2)=0.56, P<0.001), and a cutoff value of strain rate reserve of 1.64 was deemed as a highly accurate marker for the detection of > or =50% stenosis (area under the curve, 0.96; SE, 0.01; 95% CI, 0.94 to 0.98; P<0.001).

CONCLUSIONS

The direct color-coded visualization of strain on MR images is a useful adjunct for dobutamine stress MRI, which provides incremental value for the detection of CAD compared with conventional wall motion readings on cine images.