Quantification Of Dyssynchrony Research Articles

Vectorcardiography-derived index allows a robust quantification of ventricular electrical synchrony

Alteration of muscle activation sequence is a key mechanism in heart failure with reduced ejection fraction. Successful cardiac resynchronization therapy (CRT), which has become standard therapy in these patients, is limited by the lack of precise dyssynchrony quantification. We implemented a computational pipeline that allows assessment of ventricular dyssynchrony by vectorcardiogram reconstruction from the patient’s electrocardiogram. We defined a ventricular dyssynchrony index as the distance between the voltage and speed time integrals of an individual observation and the linear fit of these variables obtained from a healthy population. The pipeline was tested in a 1914-patient population. The dyssynchrony index showed minimum values in heathy controls and maximum values in patients with left bundle branch block (LBBB) or with a pacemaker (PM). We established a critical dyssynchrony index value that discriminates electrical dyssynchronous patterns (LBBB and PM) from ventricular synchrony. In 10 patients with PM or CRT devices, dyssynchrony indexes above the critical value were associated with high time to peak strain standard deviation, an echocardiographic measure of mechanical dyssynchrony. Our index proves to be a promising tool to evaluate ventricular activation dyssynchrony, potentially enhancing the selection of candidates for CRT, device configuration during implantation, and post-implant optimization.

Assessment of cardiac dyssynchrony by cardiac MR: A comparison of velocity encoding and feature tracking analysis.

To investigate whether cardiac magnetic resonance (cardiac MR)-based feature tracking (FT) may be used for robust and rapid quantification of dyssynchrony by measurement of the septal to lateral delay (SLD). Healthy volunteers (n = 18) and patients with mechanical dyssynchrony (n = 17) were investigated. Velocity encoding cardiac MR (VENC) and steady-state free precession (SSFP)-cine sequences were acquired in identical horizontal long axis (HLA) positions using a 1.5T MR scanner. Using FT and VENC cardiac MR software, myocardial velocity curves were calculated for the basal segment of the septal and lateral wall. Based on the quantity of dyssynchrony, the patients were classified into three subgroups (minimal, intermediate, extensive). SLD and patient classification were compared and intra- as well as interobserver variability assessed. VENC and FT SLD measurements showed strong correlation (r = 0.94) and good agreement (mean 1.33 msec; limits of agreement [LoA] -2.96 to 5.63). Dyssynchrony subclassification based on FT was identical to VENC in 83% of the cases. While FT correctly classified all healthy subjects, three patients with mechanical dyssynchrony were misclassified. Compared to VENC, FT showed higher intra- and interobserver variability. VENC: intraobserver: mean 2.5 msec, LoA -17.5 to 22.5; interobserver: mean 1.5 msec, LoA -17.2 to 21.9. FT: intraobserver: mean 2.1 msec, LoA 27.6 to 31.8; interobserver: mean 2.4 msec LoA -31.4 to 34.5. Cardiac MR-based FT analysis may be used for rapid appraisal of left ventricle cardiac dyssynchrony from SSFP images. However, FT results are less accurate and reproducible compared to VENC-based assessment of SLD.

Prinicipal component analysis of myocardial strains to optimize cardiac resynchronization therapy patient selection

Background Cardiac resynchronization therapy (CRT) is effective for selected heart failure (HF) patients but improved methods for identification of mechanical dyssynchrony are needed. Cine displacement encoding with stimulated echoes (DENSE) MRI can be used to obtain high quality strain data for LV dyssynchrony quantification. An ideal dyssynchrony parameter should be time-independent and require minimal user interaction. We hypothesize that the time-independent, data-driven quantification of dyssynchrony using principal component analysis (PCA) will help improve patient selection for CRT. Methods 2D cine DENSE MRI was performed in multiple shortaxis views to obtain LV circumferential strains (Ecc) for HF patients referred for CRT. In order to minimize confounding factors with an influence on CRT response, all patients in this analysis (N = 25) were required to have absence of scar as determined from late gadoliniumenhanced (LGE) MRI, as well as LV lead placement in a late-activated segment with time from QRS onset to the LV lead electrogram at the final lead position at least 50% of the QRS width. CRT response was defined as at least a 15% reduction in the LV end systolic volume 6 months after CRT implantation. Typical cine DENSE imaging parameters for HF patients include field of view = 340 - 400 mm 2 , matrix = 128 × 128, slice thickness = 8 mm, no. of spiral interleaves = 6, fat suppression, temporal resolution = 17 ms and displacement encoding frequency = 0.1 cycles/mm 1 .T he LV Ecc curves were

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Positioning of Left Ventricular Pacing Lead Guided by Intracardiac Echocardiography with Vector Velocity Imaging During Cardiac Resynchronization Therapy Procedure

Intraoperative modality for "real-time" left ventricular (LV) dyssynchrony quantification and optimal resynchronization is not established. This study determined the feasibility, safety, and efficacy of intracardiac echocardiography (ICE), coupled with vector velocity imaging (VVI), to evaluate LV dyssynchrony and to guide LV lead placement at the time of cardiac resynchronization therapy (CRT) implant. One hundred and four consecutive heart failure patients undergoing ICE-guided (Group 1, N = 50) or conventional (Group 2, N = 54) CRT implant were included in the study. For Group 1 patients, LV dyssynchrony and resynchronization were evaluated by VVI including visual algorithms and the maximum differences in time-to-peak (MD-TTP) radial strain. Based on the findings, the final LV lead site was determined and optimal resynchronization was achieved. CRT responders were defined using standard criteria 6 months after implantation. Both groups underwent CRT implant with no complications. In Group 1, intraprocedural optimal resynchronization by VVI including visual algorithms and MD-TTP was a predictor discriminating CRT response with a sensitivity of 95% and specificity of 89%. Use of ICE/VVI increased number of and predicted CRT responders (82% in Group 1 vs 63% in Group 2; OR = 2.68, 95% CI 1.08-6.65, P = 0.03). ICE can be safely performed during CRT implantation. "Real-time" VVI appears to be helpful in determining the final LV lead position and pacing mode that allow better intraprocedural resynchronization. VVI-optimized acute resynchronization predicts CRT response and this approach is associated with higher number of CRT responders.

Left ventricular dyssynchrony in patients with left bundle branch block and patients after myocardial infarction: integration of mechanics and viability by cardiac magnetic resonance

To quantify left ventricular (LV) dyssynchrony in patients with left bundle branch block (LBBB) and in patients after myocardial infarction (MI) applying an accelerated three-dimensional (3D) tagging cardiac magnetic resonance (CMR) technique, and to combine dyssynchrony information with viability data obtained by late gadolinium enhancement (LGE) CMR. Thirty-two patients (59 +/- 11 years) after first MI (Pats(MI)), 10 patients (63 +/- 10 years) with LBBB (ejection fraction < 40%; Pats(LBBB<40)), 13 patients (63 +/- 11) with LBBB (ejection fraction >or= 40%; Pats(LBBB >or=40 )), and 15 healthy controls (53 +/- 10 years) underwent 3D tagging CMR and LGE imaging at 1.5 T. As a measure of mechanical LV dyssynchrony, the standard deviation of T(max) over the LV, the circumferential uniformity ratio estimate (CURE) index, and a segmental-based circumferential systolic dyssynchrony index (SDI) were calculated. All three parameters detected significantly increased circumferential dyssynchrony in patients compared with controls. The CURE and SDI showed a good correlation (r = 0.93, P < 0.0001) and detected most severe dyssynchrony in Pats(LBBB<40) (P < 0.001 vs. controls, P < 0.005 vs. Pats(MI)). Systolic dyssynchrony index additionally allowed integration of localized viability information to yield SDI(viable) which was highest in Pats(LBBB<40). Dyssynchrony patterns in the LV can be quantified globally and regionally by 3D tagging CMR. Combination of viability and dyssynchrony information allows for a comprehensive dyssynchrony quantification in patients with LBBB or post-MI. Future studies are required to test the value of the method to predict responsiveness to resynchronization.

A 3D evaluation of dyssynchrony may offer an advantage over a 2D approach; a cardiovascular MRI method for dyssynchrony quantification

Detection of dyssynchrony is primarily performed by EKG and/or tissue Doppler echocardiography, sampling the heart in selected basal segments. Limited approaches for dyssynchrony have been performed by cardiovascular MRI (CMR).

2043 Could a novel 3D evaluation of dyssynchrony offer an advantage over a 2D approach? A cardiovascular MRI method for dyssynchrony quantification

2043 Could a novel 3D evaluation of dyssynchrony offer an advantage over a 2D approach? A cardiovascular MRI method for dyssynchrony quantification

Quantification of Regional Left Ventricular Dyssynchrony by Magnetic Resonance Imaging

Cardiac resynchronization therapy is an established treatment in patients with symptomatic heart failure and intraventricular conduction delay. Electrical dyssynchrony is typically adopted to represent myocardial activation dyssynchrony, which should be compensated by cardiac resynchronization therapy. One third of the patients, however, does not respond to the therapy. Therefore, imaging modalities aimed at the mechanical dyssynchrony estimation have been recently proposed to improve patient selection criteria. This paper presents a novel fully automated method for regional mechanical left ventricular dyssynchrony quantification in short-axis magnetic resonance imaging. The endocardial movement is described by time-displacement curves with respect to an automatically determined reference point. Different methods are proposed for time-displacement curve analysis aimed at the regional contraction timing estimation. These methods were evaluated in two groups of subjects with (nine patients) and without (six patients) left bundle branch block. The contraction timing standard deviation showed a significant increase for left bundle branch block patients with all the methods. A novel method based on phase spectrum analysis may be however preferred due to a better specificity (99.7%) and sensitivity (99.0%). In conclusion, this method provides a valuable prognostic indicator for heart failure patients with dyssynchronous ventricular contraction and it opens new possibilities for regional timing analysis.

Patients with Ischemic Cardiomyopathy Have Higher Degrees of Dyssynchrony Than Patients with Non-Ischemic Cardiomyopathy as Measured by Phase Analysis of Gated SPECT Perfusion Imaging

Introduction: Cardiac resynchronization therapy (CRT) is used for the treatment of patients with severe heart failure. Approximately 30% of patients do not respond to CRT when QRS duration is used to measure dyssynchrony. We compared the degree of dyssynchrony as measured by phase analysis of gated SPECT perfusion imaging in subjects with ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM), and we describe the relationship between resting perfusion defects and myocardial ischemia and the quantification of dyssynchrony.

Cross-correlation Quantification of Dyssynchrony: A New Method for Quantifying the Synchrony of Contraction and Relaxation in the Heart

Quantification of left ventricular dyssynchrony using Doppler tissue imaging may improve selection of patients who will benefit from cardiac resynchronization therapy. Most methods used to quantify dyssynchrony use a time-to-peak analysis, which is quantitatively simplistic and requires manual identification of systole and selection of peak velocities. We developed and tested a new, highly automatable dyssynchrony parameter, cross-correlation delay (XCD), that does not require identification of systole or manual selection of peak systolic velocities. XCD uses all velocity data points from 3 consecutive beats (approximately 420 points). We tested XCD on 11 members of a positive control group (responders to cardiac resynchronization therapy with a >or=15% reduction in left ventricular end-systolic volume) and 12 members of a negative control group (normal 12-lead electrocardiogram and 2-dimensional echocardiogram findings). We compared XCD to septal-to-lateral delay in time-to-peak (SLD), maximum difference in the basal 2- or 4-chamber times to peak (MaxDiff), and SD of the 12 basal and midwall times-to-peak (Ts-SD). XCD and Ts-SD were significantly different between the positive and negative control groups (both P <or= .0001). SLD and MaxDiff demonstrated no difference between the positive and negative control groups. XCD and Ts-SD were superior to SLD and MaxDiff in discriminating between positive and negative control groups (both P < .01 by receiver operating characteristic comparison). XCD, SLD, MaxDiff, and Ts-SD demonstrated dyssynchrony in 0%, 50%, 58%, and 50% of the negative control group, respectively. XCD was the only parameter that decreased after resynchronization in the positive control group (from 160 +/- 88-69 +/- 61 milliseconds, P = .003). XCD is superior to existing parameters at discriminating patients with left ventricular dyssynchrony from those with normal function.

Issue Highlights

HomeCirculationVol. 113, No. 7Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published21 Feb 2006https://doi.org/10.1161/circ.113.7.919Circulation. 2006;113:919DETECTION OF DIVERSE BACTERIAL SIGNATURES IN ATHEROSCLEROTIC LESIONS OF PATIENTS WITH CORONARY HEART DISEASE, by Ott et al.In this issue of Circulation, Ott and colleagues systematically evaluated the presence and spectrum of bacteria in coronary atherosclerotic lesions based on their molecular phylogeny signatures. A high overall bacterial diversity of more than 50 different species was detected in catheter-based atherectomy tissues from 38 patients, indicating diverse bacterial colonization of arterial lesions. The findings of this study have important implications for the infection hypothesis in the pathophysiology of coronary atherosclerosis—namely, diverse bacterial colonization may be more important than a single pathogen. Although large randomized trials have failed to show a benefit for specific antibiotics in the treatment of coronary heart disease, this study suggests the possibility of a far more complex biology in which diverse bacterial agents colonizing atheromatous lesions are in a position to act as additional factors modulating disease progression. See p 929.NOVEL SPECKLE-TRACKING RADIAL STRAIN FROM ROUTINE BLACK-AND-WHITE ECHOCARDIOGRAPHIC IMAGES TO QUANTIFY DYSSYNCHRONY AND PREDICT RESPONSE TO CARDIAC RESYNCHRONIZATION THERAPY, by Suffoletto et al.Mechanical dyssynchrony is increasingly being recognized as an important contributor to left ventricular (LV) dysfunction in patients with depressed LV systolic function. Quantification of dyssynchrony has potential diagnostic, therapeutic, and prognostic importance. In this issue of Circulation, Suffoletto and colleagues describe a novel technique in which radial strain at several points of the LV is measured using speckle tracking. Dyssynchrony by this technique correlates with tissue Doppler, is less angle dependent than the Doppler approach, and correlates well with the acute hemodynamic and chronic response. Lead placement that was found to be concordant with the site of the latest mechanical activation by speckle tracking was associated with greater improvement in ejection fraction. This study helps to further clarify quantification of LV dyssynchrony and brings us closer to identifying optimal candidates for resynchronization and perhaps to directed placement of the left ventricular lead where anatomically feasible. See p 960.EFFECT OF POSTEROLATERAL SCAR TISSUE ON CLINICAL AND ECHOCARDIOGRAPHIC IMPROVEMENT AFTER CARDIAC RESYNCHRONIZATION THERAPY, by Bleeker et al.One cause of a poor response to cardiac resynchronization therapy (CRT) may be scarring of the posterolateral segments of the LV, resulting in ineffective resynchronization. Bleeker et al evaluated 40 consecutive patients with chronic coronary artery disease and conventional indications for CRT: NYHA class IV symptoms of heart failure, LV ejection fraction 120 ms, and left bundle-branch block. Contrast-enhanced magnetic resonance imaging identified 14 patients with a transmural posterolateral scar. In contrast to patients without a posterolateral scar, these patients did not improve clinically or with regard to echocardiographic measures of LV function or dyssynchrony. These results suggest that contrast-enhanced MRI can be used to identify patients with transmural posterolateral scar who will not respond to CRT. See p 969.Visit http://circ.ahajournals.org:Clinician UpdateInflammatory Biomarkers in Acute Coronary Syndrome: Part II: Acute-Phase Reactants and Biomarkers of Endothelial Cell Activation. See p e152.Images in Cardiovascular MedicineBidirectional Ventricular Tachycardia Caused by Digitalis Toxicity. See p e156.Hibernating Myocardium Identified by Cardiovascular Magnetic Resonance and Positron Emission Tomography. See p e158.Carcinoid Heart Disease. See p e160. Download figureDownload PowerPointBook ReviewA Change of Heart. See p e162.CorrespondenceSee p e164. Previous Back to top Next FiguresReferencesRelatedDetails February 21, 2006Vol 113, Issue 7 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.113.7.919 Originally publishedFebruary 21, 2006 PDF download Advertisement