Regional Myocardial Deformation Research Articles

Speckle tracking echocardiography as a predictor of location of ablation sites in candidates to catheter ablation for recurrent ventricular tachycardia

Abstract Background Preoperative imaging is essential before a ventricular tachycardia (VT) ablation procedure, to improve operative outcomes and reduce procedural times. Although MRI is the gold standard, it has several limitations, including patient compliance, possible presence of non-MRI-compatible devices, and long acquisition time. Speckle tracking echocardiography (STE) is a reliable and appealing technique that quantifies regional and global myocardial deformation, as well as layer-specific (endo-, mid- and epicardial) longitudinal strain, without MRI limitations. Purpose This study aimed to evaluate the efficacy of STE in predicting VT ablation sites. Methods In this study, we compared the bull’s eye segmentation of the left ventricle, global and layer-specific, obtained with STE (TomTec Arena), to investigate whether echocardiography can predict the areas of scar and late potential, as identified by electroanatomic mapping (EnSite X mapping, HD Grid mapping catheter, Abbott). Strain analysis and electroanatomic mapping data were matched segment-by-segment to obtain pairs of endocardial strain and bipolar substrate maps, as well as pairs of midmyocardial/epicardial strain and unipolar substrate maps. Results Twenty-three consecutive patients with an indication for catheter ablation for recurrent VT were enrolled. All patients were being treated with beta-blockers, 52% were taking amiodarone, and only 2 patients were on mexiletine. A total of 1170 pairs of bull’s eye segments were available for analysis. A binary logistic mixed-effects model was used to predict the presence of electroanatomical scar based on strain echocardiography data, to account for interpatient variability. The study findings highlighted a close correlation between the bipolar map and endocardial strain values, and between the unipolar map and midmyocardial strain values. Progressively higher (less negative) values of endocardial strain proved predictive of bipolar electroanatomical scar, with an increase in the odds ratio of bipolar electroanatomical scar equal to 6.2% (95% confidence interval 2.5%-10%) for each unit increase in strain values. Similarly, progressively higher values of midmyocardial strain were predictive of unipolar electroanatomical scar, with an increase in the odds ratio of unipolar electroanatomical scar equal to 6.2% (95% confidence interval 1.2%-11.4%) for each unit increase in strain values. Conclusions The data from our study showed an anatomical correspondence between the areas of low potential identified by electroanatomical mapping and the areas of anomalous longitudinal strain. In particular, the endocardial strain correlates with the bipolar map, and the meso-epicardial strain correlates with the unipolar map. These data may prove useful in the appropriate planning of the procedure in patients with an indication for catheter ablation in the context of recurrent VT.

Evaluation of functional significance of intermediate coronary artery lesions noninvasively by tissue doppler echocardiography and single photon emission computed tomography versus invasively by IFR

Background: Myocardial perfusion imaging by single photon emission computed tomography (MPI–SPECT) is noninvasive test that can give an important information for the diagnosis of coronary artery disease (CAD), detect reversible ischemia, quantify defect sizes and help in clinical decisions of interventions as well as assessment of disease prognosis. Tissue Doppler imaging (TDI) emerged as a potential modality for assessing systolic and diastolic LV performance. Strain doppler echocardiography (SDE) is a new tool for measuring regional myocardial deformation excluding the effect of adjacent myocardial tissue. The development of Instantaneous wave-free Ratio (IFR) as a relatively new invasive method for physiological assessment of coronary lesions without the use of pharmacologic hyperemic agents is the golden standard test for assessment of intermediate coronary lesions and guiding the revascularization decision. Methods: This Cross-sectional study was done was conducted on 50 cases with intermediate coronary artery lesions admitted at the Cardiology departments in Benha University, Kobry Elkobba Military Hospital and Air Force Specialized Hospital. All groups were subjected to history and clinical examination, cardiac examination, 12 lead ECG, 2D echocardiography, routine laboratory investigations, coronary angiography with evaluation of intermediate lesion by IFR then TDI and SDE for evaluation the regional myocardial deformation of the segments supplied by the same coronary artery, after that 99mTc-sestamibi (MIBI) SPECT imaging was done to quantify defect size and finally correlation was done between results of IFR, TDI and SPECT to guide the revascularization decision. Results: Pearson’s correlation analysis showed that; Gated single-photon emission computed moderate and severe Ischemia, Sm-velocity, WMSI, DT, had a highly significant positive correlation with IFR value (p < 0.001). E/A ratio, Mean E/e’ velocity ratio, FS, LVEF and LV GLS had a highly significant negative correlation with IFR value (p < 0.001). Conclusions: Instantaneous wave-free Ratio (IFR) modality is a reliable measure to guide functional significance of the intermediate coronary artery lesions for decision making and guiding plan of management. But it is an expensive and invasive modality. On the other hand, SPECT and tissue doppler modalities showed high sensitivity and specificity in the same group of patients with less expensive, non-invasive and no contrast use advantages.

Speckle tracking echocardiography for diagnosis of right ventricular failure in children with totally corrected tetralogy of Fallot in Sulaimani, Iraq

ObjectivesThe study was aimed at using speckle tracking echocardiography as a novel technique to diagnose right ventricular failure (RVF) in children with total correction of tetralogy of Fallot (TOF) through surgery. MethodsA quasi-experimental study was performed at the Children's Heart Hospital of Sulaimani for 9 months. A total of 150 children with completely repaired TOF were enrolled to investigate RVF. Conventional echocardiographic data were recorded, including right ventricular (RV) ejection fraction (EF), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI), and RV end-systolic and diastolic volume (RVESV and RVEDV). Additionally, speckle tracking was performed for the regional and longitudinal strain and strain rate in four-chamber apical view. RVF diagnosis was determined on the basis of electrocardiography measurement of P-wave dispersion, T-wave dispersion, and QRS duration. ResultsChildren with repaired TOF who were diagnosed with RVF through conventional echocardiography exhibited abnormalities with respect to children with normal RV function, including a TAPSE of 1.3 ± 0.11 cm, RVEF of 35.5 ± 6.72, RVESV of 69.8 ± 15.13 ml, RVEDV of 110.1 ± 14.13 ml, MPI of 0.60 ± 0.12, and Pmax of 52.4 ± 14.08. The use of speckle tracking in RVF diagnosis revealed a relatively lower longitudinal strain and strain rate (−12.1 ± 2.3 and −0.9 ± 0.3, respectively) in the children with RVF. Moreover, longitudinal right ventricular strain was positively correlated with TAPSE (r = 0.656) and EF (r = 0.675), and negatively correlated with RVEDV (r = −0.684), RVESV (r = −0.718), MPI (r = −0.735), and Pmax (r = −0.767). ConclusionsThe application of speckle tracking with the longitudinal RV strain and strain rate to estimate RV function in children with repaired TOF is a new advanced method that, compared with conventional echo, significantly improves the diagnosis of regional myocardial deformations and cardiac muscle motion velocity.

Prognostic value of CMR regional longitudinal strain beyond global function and tissue characteristics in patients with suspected myocarditis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Cardiovascular magnetic resonance imaging (CMR) feature tracking (FT) regional longitudinal peak strain (RLS) is a novel method to assess regional myocardial deformation. The aim of this study was to investigate the prognostic value of CMR-FT RLS in patients with suspected myocarditis. Purpose Risk-stratification in patients with myocarditis is challenging. While left ventricular ejection fraction (LVEF) and global longitudinal peak strain (GLS) have shown predictive power in patients with myocarditis, the role of RLS is unknown. Methods Patients meeting clinical criteria for suspected myocarditis who were referred for CMR were included. Global/regional functional and CMR tissue characteristics were analyzed and associated with first major adverse cardiac event (MACE, i.e. heart failure hospitalization, sustained ventricular tachycardia, recurrent myocarditis and all-cause death). RLS was defined as following: anterior-/septal-(inferoseptal-/anteroseptal-))/inferior-/lateral-(anterolateral-/inferolateral). Patients with normal versus impaired function (i.e. according to LVEF and GLS) were selected for further sub-analysis. Results 773 consecutive patients met the inclusion criteria and were included in the final analysis. Mean age was 48.3±16 years, 286 (37%) were female, and at a median follow up of 3.5 years, MACE was present in 131 (17%) of all patients. RLS of all regions were associated with outcome in the univaribale analysis. Lateral-, inferolateral- and anterolateral- RLS remained independent, significant outcome predictors after correcting for cardiovascular risk factors and CMR tissue characteristics/function (HR 1.05–1.08, c-statistics 0.711–0.721). In the 394 (51%) patients with normal LVEF and GLS, septal-, inferoseptal- and inferolateral-RLS were all significant independent predictors for MACE after adjustment for cardiovascular risk factors (HR between 1.11 and 1.13 (95%CI: 1.07–1.17, a c-statistics 0.707–0.721 ). In patients with impaired LVEF/GLS only all but anterior and anterolateral-RLS wereas independently associated with outcome. Conclusion Regional longitudinal strain was independently associated with outcome beyond clinical and CMR tissue characteristsics and might therefore represent a more granular marker to refine risk stratification in suspected myocarditis with impaired- or normal left ventricular function.

Regional contributions to impaired myocardial mechanical function in heart failure with preserved ejection fraction.

Hypertensive heart disease (HHD) is recognized as a key clinical precursor to heart failure with preserved ejection fraction (HFPEF). However, pathophysiological transition from HHD to HFPEF is not well understood. We sought determine whether regional differences in impaired myocardial function may underlie the greater mechanical dysfunction seen in HFPEF compared to HHD. We used standardized echocardiography to assess regional myocardial deformation in a cohort of n = 327 adults with preserved left ventricular (LV) ejection fraction (≥45%), including: n = 129 with HFPEF, n = 158 with HHD and no heart failure, and n = 40 normotensive controls. From detailed measurements of LV systolic strain performed in multiple views, we derived and then compared regional measures of basal, mid-ventricular, and apical longitudinal strains. In models adjusting for clinical covariates, basal and mid-ventricular LV myocardial deformation was more impaired in HHD than in controls (P ≤ 0.003), whereas apical deformation was more impaired in HFPEF than in HHD (P = 0.005). In multivariable-adjusted analyses, only apical strain remained independently associated with HFPEF vs. HHD status [odds ratio 1.18 (1.02-1.37), P = 0.030 per 1% decrease in apical strain]. Compared to other regional strains, apical longitudinal strain optimally differentiated HFPEF from HHD (area under the receiver operating curve: apical longitudinal strain = 0.67; mid-ventricular longitudinal strain = 0.59; basal longitudinal strain = 0.60). We found that while apical mechanical function is preserved in HHD, it was impaired in HFPEF and may contribute to the transition from an asymptomatic heart disease to a symptomatic heart disease.

TRANSTHORACIC SHOCKS LEAD TO REGIONAL BI-VENTRICULAR DIASTOLIC DYSFUNCTION IN TERRITORIES WITH ACUTE MYOCARDIAL INJURY

<h3>Introduction</h3> Electric defibrillations and cardioversion are standard interventions to terminate arrhythmia. Recent evidence hints to acute post shock myocardial injury. However, that injury may follow unique pathways in every individual. Common functional measures such as ejection fraction are limited in that they represent only global ventricular function. Cardiovascular magnetic resonance feature tracking (CMR-FT) is a technique that can quantify myocardial contraction and relaxation on a regional level. The purpose of this analysis was to investigate the impact of acute myocardial injury after serial transthoracic shocks on regional systolic and diastolic myocardial deformation in a healthy animal model. <h3>Methods</h3> Ten healthy anaesthetized swine were scanned in a 3 Tesla MRI with a standard short axis cine and a clinical T1 mapping sequence in three short axis slices to detect myocardial edema. Five transthoracic shocks with 200 Joules each were applied within five minutes. Five hours post-shock the same images were re-acquired. Six control animals underwent the same protocol without shocks. Changes in regional peak strain as a measure of systolic function, and early diastolic strain rate as a measure of diastolic function were evaluated using CMR-FT analysis in circumferential orientation for both the left (LV) and right ventricle (RV). T1 maps of the LV were analyzed and reported per myocardial AHA segment as a measure of myocardial edema. For the RV, a region of interest (ROI) was contoured in each of the 3 short-axis slices. The regional changes in strain in comparison to the development of myocardial injury (ΔT1 mapping) over the course of 5h were statistically assessed using a mixed effects model accounting for the electrical intervention and multiple measurements per individual. <h3>Results</h3> Global circumferential peak strain worsened in both ventricles (LV: -15.6±3.3% to -13.0±3.6%, p<0.01; RV: -16.1±2.3% to -12.8±4.8%, p=0.03). Additionally, LV early diastolic strain rate slowed from baseline to the 5h timepoint (1.19±0.35 to 0.95±0.37/s, p = 0.02) in shocked animals. Whereas no change was observed for any global strain parameters in the control group. There was no linear association with regional LV peak strain with T1 changes (p=0.97). However, an increase in T1 was colocalized to a reduction in early diastolic strain rate (p = 0.03), where early diastolic strain rate slowed by -0.25/s every 100ms increase in T1. On the other hand, both RV systolic and diastolic function worsened in the presence of increased regional RV T1 with a change in peak strain of 2.7% and a deceleration of diastolic strain rate (–0.42/s) per 100ms increase in RV T1 (p<0.05). <h3>Conclusions</h3> Serial transthoracic shock in a healthy swine model attenuate biventricular systolic function, but it is the development of regional diastolic dysfunction that is associated with the onset of colocalized myocardial edema. Future studies are warranted to assess these effects of electrical interventions in clinical settings.

Computational Analysis of Cardiac Contractile Function.

Heart failure results in the high incidence and mortality all over the world. Mechanical properties of myocardium are critical determinants of cardiac function, with regional variations in myocardial contractility demonstrated within infarcted ventricles. Quantitative assessment of cardiac contractile function is therefore critical to identify myocardial infarction for the early diagnosis and therapeutic intervention. Current advancement of cardiac functional assessments is in pace with the development of imaging techniques. The methods tailored to advanced imaging have been widely used in cardiac magnetic resonance, echocardiography, and optical microscopy. In this review, we introduce fundamental concepts and applications of representative methods for each imaging modality used in both fundamental research and clinical investigations. All these methods have been designed or developed to quantify time-dependent 2-dimensional (2D) or 3D cardiac mechanics, holding great potential to unravel global or regional myocardial deformation and contractile function from end-systole to end-diastole. Computational methods to assess cardiac contractile function provide a quantitative insight into the analysis of myocardial mechanics during cardiac development, injury, and remodeling.

Value of myocardial deformation parameters for detecting significant coronary artery disease.

Introduction: The study aimed to evaluate the diagnostic value of global and regional myocardial deformation parameters derived from two-dimensional speckle-tracking echocardiography to detect functionally significant coronary artery stenosis. Methods: Dobutamine stress echocardiography and cardiac magnetic resonance myocardial perfusion imaging (CMR-MPI) were performed on 145 patients with a moderate and high probability of coronary artery disease (CAD) and LVEF≥55%. Significant CAD was defined as>50% stenosis of the left main stem,>70% stenosis in a major coronary vessel, or in the presence of intermediate stenosis (50-69%) validated as hemodynamically significant by CMRMPI. Patients were divided in two groups: non-pathological (48.3%) vs pathological (51.7%), according to CAG and CMR-MPI results. Afterwards, off-line speckle-tracking analysis was performed to analyse myocardial deformation parameters. Results: There were no differences in myocardial deformation parameters at rest between groups, except global longitudinal strain (GLS) and global radial strain (GRS) were significantly lower in the CAD (+) group: -21.3±2.2 vs.-16.3±2.3 (P<0.001) and 39.7±23.2 vs. 24.5±15.8 (P<0.001). GLS and regional longitudinal strain rate (SR) had the highest diagnostic value at high dobutamine dose with AUC of 0.902 and 0.878, respectively. At early recovery, GLS was also found to be the best myocardial deformation parameter with a sensitivity of 78%, specificity 67%, AUC 0.824. Conclusion: Global and regional myocardial deformation parameters are highly sensitive and specific in detecting functionally significant CAD. The combination of deformation parameters and WMA provides an incremental diagnostic value for patients with a moderate and high probability of CAD, especially the combination with regional longitudinal SR.

A Lumped Two-Compartment Model for Simulation of Ventricular Pump and Tissue Mechanics in Ischemic Heart Disease.

Introduction: Computational modeling of cardiac mechanics and hemodynamics in ischemic heart disease (IHD) is important for a better understanding of the complex relations between ischemia-induced heterogeneity of myocardial tissue properties, regional tissue mechanics, and hemodynamic pump function. We validated and applied a lumped two-compartment modeling approach for IHD integrated into the CircAdapt model of the human heart and circulation. Methods: Ischemic contractile dysfunction was simulated by subdividing a left ventricular (LV) wall segment into a hypothetical contractile and noncontractile compartment, and dysfunction severity was determined by the noncontractile volume fraction (). Myocardial stiffness was determined by the zero-passive stress length ( and nonlinearity () of the passive stress-sarcomere length relation of the noncontractile compartment. Simulated end-systolic pressure volume relations (ESPVRs) for 20% acute ischemia were qualitatively compared between a two- and one-compartment simulation, and parameters of the two-compartment model were tuned to previously published canine data of regional myocardial deformation during acute and prolonged ischemia and reperfusion. In six patients with myocardial infarction (MI), the was automatically estimated using the echocardiographic LV strain and volume measurements obtained acutely and 6 months after MI. Estimated segmental values at the baseline and 6-month follow-up were compared with percentage late gadolinium enhancement (LGE) at 6-month follow-up. Results: Simulation of 20% of shifted the ESPVR rightward while moderately reducing the slope, while a one-compartment simulation caused a leftward shift with severe reduction in the slope. Through tuning of the , , and , it was found that manipulation of the alone reproduced the deformation during acute ischemia and reperfusion, while additional manipulations of and were required to reproduce deformation during prolonged ischemia and reperfusion. Out of all segments with LGE>25% at the follow-up, the majority (68%) had higher estimated at the baseline than at the follow-up. Furthermore, the baseline correlated better with percentage LGE than did at the follow-up. Conclusion: We successfully used a two-compartment model for simulation of the ventricular pump and tissue mechanics in IHD. Patient-specific optimizations using regional myocardial deformation estimated the in a small cohort of MI patients in the acute and chronic phase after MI, while estimated values closely approximated the extent of the myocardial scar at the follow-up. In future studies, this approach can facilitate deformation imaging–based estimation of myocardial tissue properties in patients with cardiovascular diseases.

Abstract 11382: Left and Right Ventricular Strain Mechanics in Fetal Arrhythmia

Introduction: Assessment of ventricular mechanics in fetuses with tachyarrhythmia poses significant challenges. Strain analysis measures myocardial deformation and has been shown to be a very sensitive marker of ventricular systolic dysfunction compared to traditional measurements. Global and regional myocardial deformation has not been well described in fetuses with arrhythmias. Hypothesis: We hypothesize that left and right ventricular myocardial mechanics are impaired in fetuses with tachyarrhythmias compared to normal fetuses in sinus rhythm. Methods: Retrospective review of fetuses with tachyarrhythmia (groups 1 and 2) and gestational age (GA) matched normal fetuses with normal cardiac anatomy (group 3) from 2000 to 2018 at a single institution, with IRB approval. Fetuses with isolated ectopy and congenital heart disease were excluded from all groups. Strain analysis was performed using VVI software. Arrhythmia type, medications, cardiovascular profile score and postnatal outcome were collected. Results: 18 fetuses with tachyarrhythmia with GA between 21 to 36.5 weeks were analyzed; 18 fetuses of similar GA with normal cardiac anatomy in sinus rhythm served as controls. 3 fetuses were delivered close to term and did not have strain assessment in sinus rhythm. Both LV global longitudinal strain (-4.44 ± 2.82%) and strain rate (-1.24 ± 0.85%) and RV global longitudinal strain (-6.76 ± 2.09%) and strain rate (-1.41 ± 0.55%) were reduced in tachyarrhythmia (Group 1) and recovered when in sinus rhythm (Group 2) but still reduced compared to controls (Group 3). Global longitudinal velocity was not different between patients in Group 2 and 3 (Table &amp; Fig 1). Conclusions: Strain parameters remain abnormal in fetuses with tachyarrhythmia despite conversion to sinus rhythm when compared to GA matched controls. Serial evaluation of strain will help guide therapy and monitor ventricular function in this patient population.

Effect of low dose intracoronary alteplase on global circumferential strain (myocardial strain CMR substudy from the T-TIME trial)

Abstract Background Microvascular obstruction affects half of patients with ST-segment elevation myocardial infarction (STEMI) and confers an adverse prognosis. Feature-tracking (FT) cardiac magnetic resonance (CMR) allows myocardial strain assessment from standard cine images without the need for specialist sequences. Myocardial strain reflects both systolic and diastolic function allowing the assessment of both global and regional myocardial deformation. Strain recovery is impaired in patients with microvascular obstruction. There is growing evidence to suggest that global circumferential strain may offer incremental value beyond traditional CMR endpoints. Purpose We aimed to determine whether a therapeutic strategy involving low-dose intracoronary alteplase improves global circumferential strain in STEMI. Methods Between March 17, 2016, and December 21, 2017, 440 patients presenting at 11 hospitals in the United Kingdom within 6 hours of STEMI were randomised in a 1:1:1 dose-ranging trial design. Participants were randomly assigned to treatment with placebo (n=151), alteplase 10mg (n=144), or alteplase 20mg (n=145). The primary outcome was the amount of microvascular obstruction (%left ventricular mass) quantified by CMR at 2–7 days. Global circumferential strain was a prespecified secondary endpoint measured at 2–7 days and 3 months. Troponin T AUC was measured at 0, 2, and 24 hours post reperfusion. Patients were followed up to 1 year with all events adjudicated by an independent committee. Results Among the 440 patients who were randomised (mean age 60.5 years; 85% male), the primary endpoint was achieved in 396 (90%), all patients were followed up to 1 year for clinical events. The amount (mean, standard deviation) of microvascular obstruction was not different between the groups (2.3% vs. 2.6% vs. 3.5% left ventricular mass); p=0.28. Global circumferential strain was worse in patients receiving alteplase. −23.1% (placebo) vs −20.6 (10mg alteplase) vs −22.0% (20mg alteplase); mean difference for both doses combined vs placebo: 1.8% (95% CI 0.5, 3.2), p=0.009. There were no differences between groups in the other CMR endpoints including LV ejection fraction (LVEF). The area-under-the-curve for troponin T measured in 317 (72%) patients was increased in both treatment groups compared to placebo, mean difference 1.53 (95% CI: 1.16, 2.01), p=0.002. There were no differences in MACE at 1 year; placebo n=16 (10.6%), 10mg alteplase n=22 (15.3%), 20mg alteplase group n=15 (10.3%). Conclusion In patients presenting within 6 hours of STEMI, low-dose intracoronary alteplase compared with placebo did not reduce microvascular obstruction. There was a reduction in global circumferential strain and an increase in Troponin T AUC supporting an increase in myocardial injury early after reperfusion in patients receiving alteplase. There was no differences in MACE at one year suggesting no long-term clinical sequelae. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): T-TIME was supported by grant 12/170/4 from the Efficacy and Mechanism Evaluation (EME) programme of the National Institute for Health Research (NIHR-EME). Boehringer-Ingelheim U.K. Ltd. provided the study drugs (alteplase 10mg, 20mg), matched placebo, and sterile water for injection. Study recruitment flowchartTable- Study endpoints

Myocardial deformation techniques as potential tools to detect arrhythmogenic cardiomyopathy in early stages of the disease

Abstract Introduction Arrhythmogenic Cardiomyopathy (ACM) is a life-threatening entity which predispose to malignant arrhythmias and sudden cardiac death even in early stages of the disease. Deformation techniques obtained by echocardiography are promising tools which can identify subtle pathologic changes in the myocardial wall. Our aim is to investigate how myocardial deformation parameters may be affected throughout ACM spectrum. Methods A cohort of ACM 45 subjects, was characterized using advanced transthoracic echocardiography and divided into groups according to left ventricle ejection fraction (LVEF). Twenty-three healthy volunteers were also included as control group (CG). We analyzed regional wall motion abnormalities and left ventricular myocardial deformation parameters by 2D Speckle Tracking, such as global longitudinal strain (GLS), mechanical dispersion (MD) [standard deviation (SD) and range (delta)]. Results 23 (51,1%) of the ACM cohort were men, with a mean age of 43,13±16,55 years. Next-generation sequencing identified a potential pathogenic mutation in 37 (82,2%) of the patients. Those ACM subjects with low LVEF (ACM-L) presented lower GLS values when compared to those with normal LVEF (ACM-N) (−16,17±2,68% vs. ACM-N −19,39±2,97%; p&amp;lt;0.001) with no significant differences in MD parameters. ACM-N showed no differences in GLS regarding to CG, but significant differences were found when analyzing MD values, with pathological dispersion times in the ACM-N group (ACM-N DMSD 50,50±20,39ms vs. CG 37,35±17,15ms; p=0,016; ACM-N DMDelta 167,4583±75,07ms vs CG 125±49,13ms; p=0,033). Conclusions MD may be an additive tool for identifying ACM patients in early stages of the disease when LVEF is still preserved. Funding Acknowledgement Type of funding sources: None.

The Predictive Value of Right Ventricular Longitudinal Strain in Pulmonary Hypertension, Heart Failure, and Valvular Diseases.

Right ventricular (RV) systolic function has an important role in the prediction of adverse outcomes, including mortality, in a wide range of cardiovascular (CV) conditions. Because of complex RV geometry and load dependency of the RV functional parameters, conventional echocardiographic parameters such as RV fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE), have limited prognostic power in a large number of patients. RV longitudinal strain overcame the majority of these limitations, as it is angle-independent, less load-dependent, highly reproducible, and measure regional myocardial deformation. It has a high predictive value in patients with pulmonary hypertension, heart failure, congenital heart disease, ischemic heart disease, pulmonary embolism, cardiomyopathies, and valvular disease. It enables detection of subclinical RV damage even when conventional parameters of RV systolic function are in the normal range. Even though cardiac magnetic resonance-derived RV longitudinal strain showed excellent predictive value, echocardiography-derived RV strain remains the method of choice for evaluation of RV mechanics primarily due to high availability. Despite a constantly growing body of evidence that support RV longitudinal strain evaluation in the majority of CV patients, its assessment has not become the part of the routine echocardiographic examination in the majority of echocardiographic laboratories. The aim of this clinical review was to summarize the current data about the predictive value of RV longitudinal strain in patients with pulmonary hypertension, heart failure and valvular heart diseases.

Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart

BackgroundInhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear.ObjectiveThe purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology.MethodsIn 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models.ResultsIncreased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01).ConclusionMechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.

Myocardial Deformation Assessed by MR Feature Tracking in Groups of Patients With Ischemic Heart Disease.

Global myocardial strain assessments have been shown to provide useful measures of contractility in many diseases, but whether feature tracking (FT)-derived strain at rest can differentiate ischemic myocardium from infarcted and remote myocardium in patients with coronary artery disease (CAD) remains unclear. To evaluate the performance of magnetic resonance imaging FT-derived strain in the detection of regional myocardial deformation in ischemic, infarcted, and apparent normal myocardium in CAD. Retrospective POPULATION: A total of 109 patients with CAD. Steady-state free-precession rest cine, T1-weighted saturation-recovery fast gradient echo stress/rest perfusion, and two-dimensional phase-sensitive inversion recovery breath-hold late gadolinium enhancement (LGE) tests were performed at 3.0 T. Based on perfusion and LGE images, left ventricular (LV) myocardial segments of CAD patients were categorized into ischemic, infarcted, and negative groups. The FT longitudinal (LS) and circumferential strain (CS) of normal subjects and the three CAD groups were calculated. Z-scores of each segment of CAD patients were calculated. χ2 testing, analysis of variance (ANOVA), and Kruskal-Wallis tests. Z-scores were used to compare the strain between CAD groups. There were significant differences in global LS (GLS) and CS (GCS) between healthy controls (GLS: -19.0% ± 1.4%, GCS, -20.9% ± 1.8%), ischemia (GLS: -17.4% ± 2.1%, GCS, -19.6% ± 1.9%), infarction (GLS: -16.4% ± 1.9%, GCS, -17.8% ± 1.9%), and negative patients (GLS: -17.7% ± 1.4%, GCS, -20.9% ± 2.4%) (all P < 0.05). There were significant differences in regional LS and CS between ischemic (LS, -16.1% ± 5.0%, CS, -18.7% ± 5.0%), infarcted (LS, -14.8% ± 5.2%, CS, -15.3% ± 4.8%), and negative segments (LS, -17.6% ± 5.2%, CS, -19.8% ± 4.8%) (all P < 0.05). The differences in the z-scores of regional LS and CS between the ischemic, infarcted, and negative segments were also significant (all P < 0.05). FT-derived rest strain indices of the LV myocardium of CAD patients were higher compared to healthy controls and varied between ischemic, infarcted, and negative segments. 4 TECHNICAL EFFICACY: Stage 5.

Assessment of myocardial deformation in patients with a singule left ventricle using CMR feature tracking and speckle tracking echcardiography

Abstract Funding Acknowledgements Type of funding sources: None. Background Patients with a single ventricle are at risk for ventricular dysfunction in the long-term follow-up during and after completion of the total cavopulmonary connection (TCPC). Hence a detailed assessment of ventricular function is of high clinical relevance in those patients. Echocardiography and cardiovascular magnetic resonance (CMR) are routinely used to examine ventricular function with newer techniques, such as tissue tracking, enabling to determine regional and global myocardial deformation. Studies focusing on patients with a single left ventricle (SLV) are sparse. We assessed LV function in a larger cohort of SLV patients by using CMR feature tracking (FT) and speckle tracking echocardiography (STE). Methods 56 SLV patients (mean age 12.0.5 ± 8.1 years) who underwent CMR as part of a routine clinical examination were included. The study population consisted of 20 patients with double inlet left ventricle (DILV), 25 patients with tricuspid atresia (TA) and 11 patients with various diagnoses. 36 patients had an echocardiographic examination within 3 months of the CMR study. Left ventricular longitudinal, circumferential and radial strain and strain rate were measured from short axis stacks at basal, midventricular and apical levels as well as from 4-chamber-views using FT. LV end-diastolic and end-systolic volumes (LVEDV, LVESV), ejection fraction (LVEF) and myocardial mass were determined from short axis images. 2D-STE was used to measure global peak systolic longitudinal strain and strain rate. In a subgroup analysis we compared patients with a DILV with patients who had TA. Results Apart from two patients, all patients were in NYHA class I. LVEF was preserved in the total group of patients (LVEF 56.1 ± 8.4%) and correlated well with global and regional circumferential strain (r= -0.38 to -0.74, p &amp;lt; 0.01), global radial strain (r= 0.33, p &amp;lt; 0.05) and global longitudinal strain values (r= -0.31, p &amp;lt; 0.05). There was a mild association between LVEF and age at Fontan completion (r= -0.28, p = 0.04). There was no significant difference between the results for global longitudinal strain from FT and STE in the entire patient group. In the subgroup analysis there was no difference in LVEF, LV volumes and global strain and strain rate values from FT and STE between patients with DILV and TA. Conclusion SLV patients in this study had a preserved ejection fraction along with an overall good health. The correlation of global and regional strain values derived from CMR FT with LVEF demonstrates that FT might be valuable to assess ventricular function in SLV patients during long-term follow-up.

Regional Amyloid Burden Differences Evaluated Using Quantitative Cardiac MRI in Patients with Cardiac Amyloidosis.

ObjectiveThis study aimed to investigate the regional amyloid burden and myocardial deformation using T1 mapping and strain values in patients with cardiac amyloidosis (CA) according to late gadolinium enhancement (LGE) patterns.Materials and MethodsForty patients with CA were divided into 2 groups per LGE pattern, and 15 healthy subjects were enrolled. Global and regional native T1 and T2 mapping, extracellular volume (ECV), and cardiac magnetic resonance (CMR)-feature tracking strain values were compared in an intergroup and interregional manner.ResultsOf the patients with CA, 32 had diffuse global LGE (group 2), and 8 had focal patchy or no LGE (group 1). Global native T1, T2, and ECV were significantly higher in groups 1 and 2 than in the control group (native T1: 1384.4 ms vs. 1466.8 ms vs. 1230.5 ms; T2: 53.8 ms vs. 54.2 ms vs. 48.9 ms; and ECV: 36.9% vs. 51.4% vs. 26.0%, respectively; all, p < 0.001). Basal ECV (53.7%) was significantly higher than the mid and apical ECVs (50.1% and 50.0%, respectively; p < 0.001) in group 2. Basal and mid peak radial strains (PRSs) and peak circumferential strains (PCSs) were significantly lower than the apical PRS and PCS, respectively (PRS, 15.6% vs. 16.7% vs. 26.9%; and PCS, −9.7% vs. −10.9% vs. −15.0%; all, p < 0.001). Basal ECV and basal strain (2-dimensional PRS) in group 2 showed a significant negative correlation (r = −0.623, p < 0.001). Group 1 showed no regional ECV differences (basal, 37.0%; mid, 35.9%; and apical, 38.3%; p = 0.184).ConclusionQuantitative T1 mapping parameters such as native T1 and ECV may help diagnose early CA. ECV, in particular, can reflect regional differences in the amyloid deposition in patients with advanced CA, and increased basal ECV is related to decreased basal strain. Therefore, quantitative CMR parameters may help diagnose CA and determine its severity in patients with or without LGE.

Assessment of diastolic dysfunction: comparison of different cardiovascular magnetic resonance techniques.

AimsHeart failure with preserved ejection fraction is still a diagnostic and therapeutic challenge, and accurate non‐invasive diagnosis of left ventricular (LV) diastolic dysfunction (DD) remains difficult. The current study aimed at identifying the most informative cardiovascular magnetic resonance (CMR) parameters for the assessment of LVDD.Methods and resultsWe prospectively included 50 patients and classified them into three groups: with DD (DD+, n = 15), without (DD−, n = 26), and uncertain (DD±, n = 9). Diagnosis of DD was based on echocardiographic E/E′, invasive LV end‐diastolic pressure, and N‐terminal pro‐brain natriuretic peptide. CMR was performed at 1.5 T to assess LV and left atrial (LA) morphology, LV diastolic strain rate (SR) by tissue tracking and tagging, myocardial peak velocities by tissue phase mapping, and transmitral inflow profile using phase contrast techniques. Statistics were performed only on definitive DD+ and DD− (total number 41). DD+ showed enlarged LA with LA end‐diastolic volume/height performing best to identify DD+ with a cut‐off value of ≥0.52 mL/cm (sensitivity = 0.71, specificity = 0.84, and area under the receiver operating characteristic curve = 0.75). DD+ showed significantly reduced radial (inferolateral E peak: DD−: −14.5 ± 6.5%/s vs. DD+: −10.9 ± 5.9%/s, P = 0.04; anterolateral A peak: DD−: −4.2 ± 1.6%/s vs. DD+: −3.1 ± 1.4%/s, P = 0.04) and circumferential (inferolateral A peak: DD−: 3.8 ± 1.2%/s vs. DD+: 2.8 ± 0.8%/s, P = 0.007; anterolateral A peak: DD−: 3.5 ± 1.2%/s vs. DD+: 2.5 ± 0.8%/s, P = 0.048) SR in the basal lateral wall assessed by tissue tracking. In the same segments, DD+ showed lower peak myocardial velocity by tissue phase mapping (inferolateral radial peak: DD−: −3.6 ± 0.7 ms vs. DD+: −2.8 ± 1.0 ms, P = 0.017; anterolateral longitudinal peak: DD−: −5.0 ± 1.8 ms vs. DD+: −3.4 ± 1.4 ms, P = 0.006). Tagging revealed reduced global longitudinal SR in DD+ (DD−: 45.8 ± 12.0%/s vs. DD+: 34.8 ± 9.2%/s, P = 0.022). Global circumferential and radial SR by tissue tracking and tagging, LV morphology, and transmitral flow did not differ between DD+ and DD−.ConclusionsLeft atrial size and regional quantitative myocardial deformation applying CMR identified best patients with DD.

Marked Disparity in Regional and Transmural Cardiac Mechanics in the Athlete’s Heart

Regional heterogeneity of the human heart plays an important role in left ventricular (LV) and right ventricular (RV) function and may contribute to enhanced myocardial efficiency in the athlete's heart. This study comprehensively characterized regional and transmural myocardial tissue deformation (strain) in recreationally active (RA) and endurance-trained (ET) men to determine if regional nonuniformity evolves alongside morphological adaptations associated with endurance training. Echocardiography was used to measure LV and RV global, regional (apical, mid, basal) and transmural (endocardial, epicardial) longitudinal strain in 30 endurance-trained (ET) (age, 31 ± 2 yr; body mass index, 23.1 ± 0.5 kg·m; V˙O2peak, 60.2 ± 6.5 mL·kg·min) and 30 RA (age: 29 ± 2 yr; body mass index, 23.4 ± 0.4 kg·m; V˙O2peak: 42.6 ± 4.6 mL·kg·min). Nonuniformity was characterized using apex-to-base and transmural (endocardial-to-epicardial) strain gradients. Global longitudinal strain was similar in ET and RA in the left (-17.4% ± 0.4% vs -17.8% ± 0.5%, P = 0.662) and right ventricle (-25.8% ± 0.8% vs 26.4% ± 1.0%, P = 0.717). The apex-to-base strain gradient was greater in ET than RA in the left (-6.5% ± 0.7% vs -2.7% ± 0.8%, P = 0.001) and right ventricle (-9.6% ± 1.8% vs -3.0% ± 1.6%, P = 0.010). The LV transmural strain gradient was greater than RV in both groups, but similar in ET and RA (-4.7% ± 0.2% vs -4.7% ± 0.2%, P = 0.850), whereas RV transmural strain gradient was greater in ET than RA (-3.4% ± 0.3% vs -1.6% ± 0.4%, P = 0.003). RV apex-to-base and transmural strain gradients correlated with RV end-diastolic area (R = 0.536 & 0.555, respectively, P < 0.01) and V˙O2peak (R = 0.415 & 0.677, respectively, P < 0.01). Transmural nonuniformity is more pronounced in the left ventricle than the RV free wall; however, RV functional nonuniformity develops markedly after endurance training. Differences in myocardial architecture and exercise-induced wall stress in the left and right ventricles are possible explanations for the marked functional nonuniformity throughout the myocardium and in response to endurance exercise training.

Association between genetic variants in the HIF1A-VEGF pathway and left ventricular regional myocardial deformation in patients with hypertrophic cardiomyopathy.

Information on genetic etiology of pediatric hypertrophic cardiomyopathy (HCM) rarely aids in risk stratification and prediction of disease onset. Little data exist on the association between genetic modifiers and phenotypic expression of myocardial performance, hampering an individual precision medicine approach. Single-nucleotide polymorphism genotyping for six previously established disease risk alleles in the hypoxia-inducible factor-1α-vascular endothelial growth factor pathway was performed in a pediatric cohort with HCM. Findings were correlated with echocardiographic parameters of systolic and diastolic myocardial deformation measured by two-dimensional (2-D) speckle-tracking strain. Twenty-five children (6.1 ± 4.5 years; 69% male) with phenotypic and genotypic (60%) HCM were included. Out of six risk alleles tested, one, VEGF1 963GG, showed an association with reduced regional systolic and diastolic left ventricular (LV) myocardial deformation. Moreover, LV average and segmental systolic and diastolic strain and strain rate were significantly reduced, as assessed by the standardized difference, in patients harboring the risk allele. This is the first study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial function, with the VEGF1 963GG allele associated with reduced LV systolic and diastolic myocardial performance. While studies are needed to link this information to adverse clinical outcomes, this knowledge may help in risk stratification and patient management in HCM. Risk allele in the VEGF gene impacts on LV myocardial deformation phenotype in children with HCM. LV 2-D strain is significantly reduced in patients with risk allele compared to non-risk allele patients within HCM patient groups. Describes that deficiencies in LV myocardial performance in children with HCM are associated with a previously identified risk allele in the angiogenic transcription factor VEGF. First study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial deformation measured by 2-D strain in children with HCM.