Ventricular Mechanical Dyssynchrony Research Articles

Low-dose dobutamine induces left ventricular mechanical dyssynchrony in patients with dilated cardiomyopathy and a narrow QRS: A study using real-time three-dimensional echocardiography

AimsThe effects of inotropic agents on left ventricular (LV) synchrony in heart failure patients are still unknown. The purpose of this study was to investigate the effects of dobutamine on LV mechanical dyssynchrony and LV systolic performance in patients with dilated cardiomyopathy (DCM) and a narrow QRS using real-time three-dimensional echocardiography (RT3DE). Methods and resultsThirty-three patients with idiopathic DCM and a narrow QRS underwent low-dose dobutamine stress echocardiography (LDSE) with RT3DE. A time-global LV volume curve and time-regional LV volume curves were derived from RT3DE. Regional LV stroke volumes were summed in each stage, and the dobutamine-induced increase in the sum of regional LV stroke volumes was considered as the sum of regional contractile reserve. Systolic dyssynchrony index (SDI) was calculated as follows: (standard deviation of time to minimal volume for regional LV segments)×100/RR duration. Among the 33 patients, low-dose dobutamine increased global LV stroke volume (SV) in 28 (85%), but decreased global LVSV in the remainder (15%). The sum of regional contractile reserve was modestly correlated with the dobutamine-induced increase in global LVSV (R=0.57, p<0.001). In contrast, low-dose dobutamine increased SDI in 14 (42%) patients without a significant change in QRS duration, and there was an inverse correlation between the increase in SDI and the increase in global LVSV induced by dobutamine (R=−0.67, p<0.001). ConclusionsDobutamine may induce LV mechanical dyssynchrony in a substantial proportion of patients with DCM and a narrow QRS. In such cases, regional LV contractile reserve does not fully contribute to an increase in global LVSV.

THE ASSESSMENT OF MECHANICAL RV DYSSYNCHRONY USING PHASE ANALYSIS OF RNV IMAGING IN SUBJECTS WITH NORMAL AND SEVERELY REDUCED LV FUNCTION

Phase analysis during radionuclide ventriculography (RNV) is an evolving and promising technique for measuring left ventricular (LV) mechanical dyssynchrony. However, the feasibility of phase analysis to assess right ventricle (RV) synchrony in normal population and RV dyssynchrony pre and post

Noncompaction Cardiomyopathy is Associated With Mechanical Dyssynchrony: A Potential Underlying Mechanism for Favorable Response to Cardiac Resynchronization Therapy

BackgroundThe aim of this study was to assess the presence of evidence of ventricular mechanical dyssynchrony in patients with isolated left ventricular noncompaction cardiomyopathy (IVNC) and the potential usefulness of cardiac resynchronization therapy (CRT) in those patients. Methods and ResultsWe studied 25 patients consecutively diagnosed with IVNC and a control group of 50 patients with dilated cardiomyopathy of different etiologies. Mechanical dyssynchrony was assessed by echocardiography by the presence of a septal flash, the time from peak septal to posterior wall displacement, and the time from septal to lateral wall peak systolic velocity. Among the patients with IVNC, 9 received CRT and were followed at 12 months. Overall, dyssynchrony parameters were significantly more frequent in IVNC, regardless of QRS duration. All 9 IVNC patients treated with CRT showed a septal flash, and a favorable response was observed in 8/9 patients (89%) regardless of QRS width. ConclusionsThe presence of mechanical dyssynchrony, amenable to correction with CRT, is common in patients with IVNC, independently from QRS width. This might be related to altered electrical endocardial activation associated with abnormal myocardium and could be the justification for the high response rate to CRT observed in these patients.

Evaluation of left ventricular mechanical dyssynchrony in chronic heart failure patients by two-dimensional speckle tracking imaging

The purpose of this study was to evaluate left ventricular mechanical dyssynchrony (LVMD) in chronic heart failure (CHF) patients using two-dimensional speckle tracking imaging (2D-STI), and also to compare the usefulness of three patterns of myocardial deformation in mechanical dyssynchrony assessment. Furthermore, the relationships between left ventricular ejection fraction (LVEF), QRS duration (QRSd), and LVMD were explored. In total, 78 patients and 60 healthy individuals (group 3) were enrolled. The patients were classified into two subgroups: LVEF≤35% (group 1), 35%<LVEF<50% (group 2). All participants underwent two-dimensional echocardiography, and dyssynchrony indices derived from 2D-STI were calculated. According to statistical principles, the cut-off value of LVMD was defined as mean±1.645 SD of the normal population. Dyssynchrony rates were calculated in CHF subgroups and compared within each subgroup, respectively. Compared with group 3, all indices in group 1 were remarkably higher (p<0.05), and some of the indices in group 2 were significantly higher (p<0.05). A significant difference of dyssynchrony rate was noted within both group 1 and group 2 (χ2=25.55, p<0.05 vs. χ2=23.88, p<0.05), and the highest value was derived from the longitudinal index in both subgroups. LVEF was related to all three forms of strain/strain rate (p<0.05), whereas no relationship existed between QRSd and dyssynchrony indices (p>0.05). CHF patients have different extents of LVMD. Longitudinal deformation shows the best detectability of dyssynchrony motion. Left ventricular systolic function was closely related to mechanical dyssynchrony, whereas QRSd showed no significant correlation.

Left ventricular mechanical dyssynchrony in patients with different stages of chronic kidney disease and the effects of hemodialysis

Left ventricular (LV) dyssynchrony is a known cause of mortality in patients with heart failure and may possibly play a similar role in patients with chronic kidney disease (CKD) in whom sudden death is one of the most common and as yet not fully explained cause of death. LV synchronicity and its relationship with increased volume load and various biomarkers was analyzed in 145 patients including 53 patients with CKD stages 3 and 4 and in 92 CKD stage 5 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) using color tissue Doppler imaging and tissue synchronization imaging. The HD patients were evaluated both before and after a single HD session. LV dyssynchrony was defined as a regional difference in time to peak systolic myocardial velocity, between 12 LV segments > 105 milliseconds. LV dyssynchrony was present in 54% of the patients with no difference between CKD 3 and 4 (58%), HD (48%), and PD (51%). LV dyssynchrony was independently associated with LV mass index and increased estimation of LV end-diastolic pressure. A single HD session resulted in significant changes in LV synchronicity variables-with improvement in 50% of the patients-especially in patients with higher myocardial systolic velocities and lower LV mass index. Abnormalities in LV synchronicity are highly prevalent in CKD patients already prior to dialysis treatment and are associated with LV hypertrophy, LV dysfunction and load conditions, underlining the importance of volume status for LV synchronicity in CKD patients.

Mechanical Dyssynchrony is Similar in Different Patterns of Left Bundle-Branch Block

BackgroundLeft bundle-branch block (LBBB) and the presence of systolic dysfunction are the major indications for cardiac resynchronization therapy (CRT). Mechanical ventricular dyssynchrony on echocardiography can help identify patients responsive to CRT. Left bundle-branch block can have different morphologic patterns. ObjectiveTo compare the prevalence of mechanical dyssynchrony in different patterns of LBBB in patients with left systolic dysfunction. MethodsThis study assessed 48 patients with ejection fraction (EF) < 40% and LBBB consecutively referred for dyssynchrony analysis. Conventional echocardiography and mechanical dyssynchrony analysis were performed, interventricular and intraventricular, with ten known methods, using M mode, Doppler and tissue Doppler imaging, isolated or combined. The LBBB morphology was categorized according to left electrical axis deviation in the frontal plane and QRS duration > 150 ms. ResultsThe patients' mean age was 60 ± 11 years, 24 were males, and mean EF was 29% ± 7%. Thirty-two had QRS > 150 ms, and 22, an electrical axis between −30° and +90°. Interventricular dyssynchrony was identified in 73% of the patients, while intraventricular dyssynchrony, in 37%-98%. Patients with QRS > 150 ms had larger left atrium and ventricle, and lower EF (p < 0.05). Left electrical axis deviation associated with worse diastolic function and greater atrial diameter. Interventricular and intraventricular mechanical dyssynchrony (ten methods) was similar in the different LBBB patterns (p = ns). ConclusionIn the two different electrocardiographic patterns of LBBB analyzed, no difference regarding the presence of mechanical dyssynchrony was observed.

Left ventricular mechanical dyssynchrony by cardiac magnetic resonance is greater in patients with strict vs. conventional ECG criteria for left bundle branch block

Left ventricular mechanical dyssynchrony by cardiac magnetic resonance is greater in patients with strict vs. conventional ECG criteria for left bundle branch block

Role of Left Ventricular Mechanical Dyssynchrony Assessment in Predicting Major Adverse Cardiac Events after First Anterior Myocardial Infarction

Role of Left Ventricular Mechanical Dyssynchrony Assessment in Predicting Major Adverse Cardiac Events after First Anterior Myocardial Infarction

Paradoxical septal motion from prior coronary artery bypass graft surgery does not impact left ventricular mechanical dyssynchrony by gated myocardial perfusion imaging

BackgroundPhase analysis of gated myocardial perfusion imaging (MPI) provides automated and reproducible assessment of left ventricular (LV) mechanical dyssynchrony (LVMD) (phase standard deviation [SD]). Many patients undergoing gated MPI have history of prior coronary artery bypass graft surgery (CABG). The latter is often associated with paradoxical septal wall motion (PSM). The effect of prior CABG and PSM on LVMD has not been evaluated. Methods and ResultsFrom the single-photon emission computed tomography (SPECT) and positron emission tomography (PET) MPI clinical database maintained at the Cleveland Clinic, we identified 200 consecutive patients with SPECT (100 control with normal LV ejection fraction [EF], MPI, and QRS < 120 ms; and 100 with LVEF < 35%), and 631 patients with LVEF < 35% with gated PET. Patients with QRS ≥ 120 ms, bundle branch block, ventricular pacing or isolated non-CABG surgery were excluded. There were 162 patients with gated SPECT (46 with prior CABG), and 568 with gated PET (220 with prior CABG) that were left for analysis. Phase SD was derived using Emory Cardiac Toolbox (ECTb) (for gated SPECT) and Corridor 4DM (4DM) (for gated SPECT and PET images). Multivariate linear regression analysis was performed to assess whether prior CABG was an independent predictor of worse LV mechanical dyssynchrony. After adjusting for patients’ demographics, co-morbidities, medications, and MPI data, history of prior CABG was not and independent predictor of LV mechanical dyssynchrony (P = .67 with 4DM, P = .97 with ECTb) in patients undergoing gated SPECT or among patients undergoing gated PET imaging (P = .18). ConclusionsAlthough paradoxical septal wall motion is commonly seen after cardiac surgery, prior CABG does not affect or impact LV mechanical dyssynchrony indices measured from gated SPECT or PET images. Whether dyssynchrony measurements with echocardiography that has higher temporal resolution might uncover intraventricular delays, remains to be determined.

Cost-effectiveness of cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) is a pacing treatment for heart failure. It was first proposed in the 1990s for selected patients with drug refractory heart failure, on the basis of...

On the Importance of Image Gating for the Assay of Left Ventricular Mechanical Dyssynchrony Using SPECT

The potential of SPECT for quantifying left ventricular mechanical dyssynchrony is increasingly appreciated. We sought to examine the incidence and impact of image gating errors on this quantification and to test a possible solution for affected studies. First, to establish whether and how gating error alone could affect the measurement of dyssynchrony, we performed a prospective study in which patients with pacemakers were studied twice: during normal rhythm without gating error and with gating error caused by pacemaker-induced dysrhythmia. Second, to understand the pattern and magnitude of gating error during our typical imaging practice, we retrospectively examined studies from a separate cohort of 64 patients who were referred for dyssynchrony evaluation. Third, to understand whether studies with gating error could be repaired for the purpose of quantifying dyssynchrony, we tested a correction algorithm on the pacemaker-induced dysrhythmia image set to see whether it repaired this set so as to approximate the patients' normal rhythm image data. We subsequently applied this algorithm to the 64-patient cohort. Pacemaker-induced gating error caused a spurious decrease in dyssynchrony magnitude. Among the 64-patient cohort, similar gating errors were common, and an inverse exponential relationship between gating-error magnitude and dyssynchrony magnitude was observed. The correction algorithm accurately repaired the pacemaker-induced dysrhythmia image set; when it was applied to the 64-patient cohort, the magnitude of the postcorrection increase in dyssynchrony magnitude was proportional to the magnitude of the gating error. Gating errors cause a spurious reduction in SPECT assay of dyssynchrony magnitude. In our standard imaging practice, gating errors were common. Post hoc correction appears to be feasible.

Novel Indices for Left-Ventricular Dyssynchrony Characterization Based on Highly Automated Segmentation From Real-Time 3-D Echocardiography

Cardiac resynchronization therapy (CRT) using a biventricular pacemaker is an invasive and expensive treatment option for left ventricular mechanical dyssynchrony (LVMD). The CRT candidate selection is a crucial issue due to the unreliability of the current standard CRT indicators. Real-time three-dimensional (3-D) echocardiography (RT3DE) provides four-dimensional (4-D) (3-D+time) information about the LV and is suitable for LVMD assessment. In this article, the complex left ventricle (LV) shape and motion of 50 RT3DE datasets are represented by novel 4-D descriptors — 4-D sphericity, volume and shape, from which novel indices were derived by principal component analysis (PCA) and subsequently analyzed by a support vector machine (SVM) classifier to assess their capability of LVMD characterization and CRT outcome prediction. These novel indices outperformed clinical indices and have promising capabilities in disease characterization and great potential in CRT outcome prediction. To enable efficient quantitative RT3DE analysis, a segmentation method was developed to combine the powers of active shape models and optimal graph search. Various aspects of the method were designed to handle varying RT3DE image quality among datasets and LV segments. An application with graphical user interface was developed to provide the user with simple and intuitive control. The developed method was robust to inter-observer variability and produced very good accuracy — 3.2±1.1 mm absolute surface positioning error, <1 mm mean signed error and <5% mean volume difference. The computer method’s classification performance was compared with the independent standard, showing that the 4-D shape modal indices were not only the most capable of all tested options when employed for disease characterization but also the least sensitive to segmentation imperfections.

Comparison of three-dimensional echocardiographic software packages for assessment of left ventricular mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy

We directly compared TomTec and QLAB software packages for the three-dimensional echocardiographic (3DE) assessment of left ventricular (LV) dyssynchrony including their ability to predict response to cardiac resynchronization therapy (CRT) in patients with ischaemic and non-ischaemic cardiomyopathy. A total of 140 heart failure patients with the LVEF ≤35% and 60 healthy volunteers underwent 3DE. A subgroup of 60 patients underwent CRT and were evaluated before and 6-12 months after implantation. The systolic dyssynchrony index (SDI) was derived from the dispersion of time to minimum regional volume for all 16 LV segments and measured with both software packages and compared using Pearson's correlation and Bland-Altman analysis. Measurements of SDI were significantly higher using TomTec compared with QLAB in both patients (10.9 ± 3.8 vs. 9.7 ± 3.9, P < 0.001) and healthy volunteers (4.1 ± 0.8 vs. 2.4 ± 1, P < 0.001), with large biases and wide limits of agreement. A moderate correlation (r = 0.65, P < 0.001) was observed between both software packages in patients while their inter-observer and intra-observer reliability were good. Of the 60 patients undergoing CRT, reverse remodelling as a measure of response was observed in 41 patients (68%). The optimal SDI cut-off value to predict response to CRT was higher for TomTec than for QLAB (8.8 vs.7.3%, P < 0.001) and demonstrated better sensitivity and specificity (93 and 61%, respectively) compared with QLAB (88 and 33%, respectively). Response prediction in patients with non-ischaemic cardiomyopathy was excellent with a sensitivity and specificity of 95 and 100% for TomTec and 70 and 83% for QLAB using similar cut-off values of 9.1 and 9.2%, respectively. Different 3DE software packages for the assessment of mechanical dyssynchrony should not be used interchangeably until better software standardization is achieved. Dyssynchrony assessment with 3DE for the prediction of response to CRT seems particularly useful in patients with non-ischaemic cardiomyopathy.

Predictors and incremental prognostic value of left ventricular mechanical dyssynchrony response during stress-gated positron emission tomography in patients with ischemic cardiomyopathy

ObjectivesThe study sought to investigate whether there is stress-induced worsening of left ventricular mechanical dyssynchrony (LVMD) in patients with ischemic cardiomyopathy (ICM), determine the predictors of LVMD response (LVMDR) and its incremental prognostic value. BackgroundThe effect of stress physiology on LVMD in patients with ICM has not been adequately evaluated, and the prognostic value of abnormal LVMDR beyond traditional predictors of mortality remains uncertain. Methods489 consecutive patients with ICM, LV ejection fraction (EF) <35% undergoing rest/stress Rb-82 gated PET were evaluated. LVMD was determined by phase analysis (SD) from gated rest and peak stress images; LVMDR was defined as stress SD − rest SD, and stratified by tertiles. All-cause mortality was the primary outcome. Linear regression was performed to determine the predictors of LVMDR, and Cox proportional hazard modeling to assess its independent prognostic value. Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were performed to determine incremental value of abnormal LVMDR. ResultsIndependent predictors of worse LVMD at peak stress were perfusion defect size (PDS) and resting heart rate; while higher resting LVEF, LVEF reserve and rest phase SD were associated with lower LVMDR. Over a mean follow-up of 2.0 ± 1.4 years, 123 patients (25%) died. After multivariate analysis, LVMDR was an independent predictor of all-cause mortality (HR 1.19[1.01;1.38], per 10° increase, P = .04) and reclassified 18% of patients with IDI 1.4% (P = .02) and NRI 9% (P = .057). ConclusionIn patients with ICM, an increase of LVMD during peak gating stress as compared to rest was an independent predictor of all-cause mortality, and had a modest incremental prognostic value. Future studies are needed to validate our findings.

Utility of Combined Assessment of Baseline Dyssynchrony and Its Acute Improvement to Predict Long-Term Outcomes After Cardiac Resynchronization Therapy

Although left ventricular (LV) mechanical dyssynchrony can predict the response to cardiac resynchronization therapy (CRT), the presence of baseline LV dyssynchrony might not be the only determinant of the response to CRT. The objectives of the present study were to test the hypothesis that a combined assessment of baseline LV dyssynchrony and its acute improvement can produce a more accurate prediction of the long-term outcomes after CRT. We studied 121 patients with heart failure undergoing CRT. LV dyssynchrony was determined by measuring the anteroseptal-to-posterior wall time delay using the speckle-tracking radial strain (≥130 ms was predefined as significant) and was assessed at baseline and 7 ± 3 days after CRT. Long-term unfavorable outcome events were tracked for 5 years. Acute improvement in LV dyssynchrony of ≥33% was predictive of the long-term outcome with an area under the curve of 0.67 (p = 0.0024). Using this cutoff value, the Kaplan-Meier curve showed that patients with acute improvement in LV dyssynchrony experienced fewer cardiovascular events than those without (log-rank p = 0.0002). The event-free survival of patients whose baseline LV dyssynchrony was ≥130 ms and whose acute improvement in LV dyssynchrony was ≥33% was greater than that of the patients with baseline LV dyssynchrony of ≥130 ms but with acute improvement in LV dyssynchrony of <33% (88% vs 65%, p = 0.012). In conclusion, the combined assessment of baseline LV dyssynchrony and its acute improvement after CRT produced a more accurate prediction of long-term outcomes after CRT.

Radiation Exposure Should Not Limit Bone Scintigraphy with 18F-NaF

1817 Objectives The prevalence of left ventricular mechanical dyssynchrony (LVMD) in stable angina pectoris (AP) has not been fully clarified. The aim of this study was to assess the presence and severity of LVMD in stable AP. Methods A total of 201 patients (age 69 ± 11, 137 males) with suspected ischemic heart disease underwent stress/rest gated myocardial perfusion SPECT (GMPS). For the evaluation of LVMD, histogram bandwidth (HBW) and phase standard deviation (PSD) were determined by GMPS using phase analysis. LVMD at stress and rest were compared among three groups: 103 normal patients (NG) [summed stress score (SSS) 50 %], 54 patients with ischemia (IG) [SSS > 3, summed difference score (SDS) > 1, and summed rest score (SRS) 3 and SDS Results The measured LVMD parameters (HBW and PSD) in NG, IG, and pMIG are summarized in the figure. At stress, both HBW and PSD in IG were significantly greater than those in NG (p Conclusions In patients with stable AP, LVMD was demonstrated to be enhancement at stress, and was found to be detectable equally well with prior MI

The Contribution of Echocardiography in Discerning Responders to Cardiac Resynchronization Therapy

Cardiac resynchronisation therapy (CRT) has been established as a therapeutic intervention in chronic heart failure and is proven to help improve symptoms, cardiac size and function as well as improve rehospitalisation and mortality. Current selection criteria for CRT are ECG based but there is mounting evidence that cardiac imaging may be a more accurate selection tool. This abstract examines some of the commonly used echocardiography techniques for quantifying left ventricular mechanical dyssynchrony to select potential responders to CRT.

Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of 201Tl gated SPECT myocardial perfusion imaging

In (201)Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use (201)Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest (201)Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, ≥5, summed rest score, SRS, <5), infarct group (N = 16, SSS ≥5, SRS ≥5) and normal group (N = 34, SSS <5, SRS <5). LV dyssynchrony parameters were calculated by phase analysis, and compared between the stress and rest images. In the ischemia group, LV dyssynchrony was significantly larger during stress than during rest. On the contrary, LV dyssynchrony during stress was significantly smaller than during rest in the normal and infarct groups. LV dyssynchrony during rest was significantly larger in the infarct group than in the normal and ischemia groups. There were no significant differences in LV dyssynchrony during rest between the normal and ischemia groups. Stress-induced myocardial ischemia caused dyssynchronous contraction in the ischemic region, leading to a deterioration in LV synchrony. Normal myocardium had more synchronous contraction during stress. The different dyssynchrony pattern between ischemic and normal myocardium early post-stress may aid the diagnosis of coronary artery disease using (201)Tl gated SPECT MPI.

Three-dimensional speckle tracking echocardiography for the assessment of left ventricular function and mechanical dyssynchrony

Objective Evaluation of left ventricular (LV) function and dyssynchrony is of vital importance. A newly-developed three-dimensional (3D) speckle tracking echocardiography (STE) has the potential to circumvent limitations of two-dimensional STE. Our study was to evaluate LV function and dyssynchrony by 3D-STE.Methods and results Fifty-two non-ischaemic dilated cardiomyopathy patients (DCM) with complete left bundle-branch block and 55 healthy subjects were enrolled. Of these patients, 24 underwent cardiac resynchronization therapy (CRT). 3D-STE was performed before and 1 month after CRT. We measured 3D (3DS), longitudinal (LS), circumferential (CS) and radial (RS) strain of the LV. LV dyssynchrony was evaluated by the standard deviation of time to peak negative value of 3D strain (3DS-SD) and time to reach the minimum regional volume of 16 segments (SDI) related to the heartcycle. DCM patients had signifi cantly lower global 3DS (–17.12 ± 6.70% vs –38.38 ± 4.28%, P< 0.01), signifi cantly greater 3DS-SD (11.11 ± 5.14% vs 4.04 ± 1.43%, P< 0.01) and SDI (9.69 ± 4.82% vs 4.23 ± 1.33%, P< 0.01) than normal volunteers. 3DS, LS, CS, RS had an excellent correlation with LV ejection fraction (LVEF) (r2= –0.94, –0.91, -0.93, 0.89, respectively, P< 0.01 for all). 3DS-SD correlated well with SDI (ICC = 0.85). For mild, moderate and severe systolic dysfunction, 3DS-SDs were 4.56 ± 1.53%, 9.87 ± 2.58%, and 14.55 ± 4.71%, respectively (P < 0.01) and SDIs were 4.46 ± 1.27%, 8.19 ± 2.35%, and 12.83 ± 4.87%, respectively (P < 0.01), but independently of QRS width. After CRT therapy, global 3DS (–13.12 ± 2.63% to –14.06 ± 2.53%, P= 0.025), 3DSSDs (12.99 ± 3.92% to 11.53 ± 4.53%, P= 0.015) and SDIs (10.85 ± 3.74% to 9.50 ± 4.63%, P= 0.013) were markedly improved.Conclusion When image quality is optimal, 3D STE seems to be a promising approach assessing LV function and dyssynchrony.

Evaluation of left ventricular systolic dyssynchrony in chronic heart failure patients by two-dimensional speckle tracking imaging

Objective To evaluate the left ventricular mechanical dyssynchrony in patients with chronic heart failure(CHF)by two dimensional speckle tracking imaging(2D-STI).Methods 37 CHF patients were enrolled in this study.According to left ventricular ejection fraction(LVEF),the patienst were classified into two subgroups:group A,LVEF≤ 35 ％;group B,35 ％＜LVEF＜50 ％.35 healthy volunteers constituted the control group(group C).Standard 2D images were acquired in the 2-,3-and 4-apical views as well as the parasternal short-axis views at the level of the mitral valve and papillary muscles.The time to peak-systolic strain and strain rate were measured for each segment in the level of the mitral valve and papillary muscles in Qlab software.Dyssychrony parameters were defined as the standard deviation and the maximal time delay of the time to peak-systolic strain and strain rate for 12 segments.Parameters were compared among the three groups respectively.The correlation between dyssynchrony parameters and LVEF were analysed in CHF patients.The cut-off value of each parameter were derived from group C based on statistical principles.Dyssychrony rate of each parameter were calculated in group A and B,and compared within each group respectively.Results Compared with group C,all the dyssychrony parameters in group A were significant higher(P＜0.05),and part of the parameters(Tsl-12SD,Tsl-12Dif,Tslr-12SD,Tslr-12Dif and Tsr-12SD)in group B were remarkable higher(P＜0.05).Dyssychrony parameters in CHF patients correlated closely with LVEF(P＜0.05).Significant differences among dyssychrony rates were noted in both group A and B(P＜0.05),and Ts1-12SD showed the highest value in both subgroups.Conclusions 2D-STI is useful in quantifying left ventricular systolic dyssychrony in CHF patients,and the longitudinal parameters are more efficient to detect mechanical dyssychrony than the radial parameters and circumferential parameters. Key words: Echocardiography; Heart failure,congestive; Ventricular function,left; Speckle tracking imaging