Left Ventricular Mechanical Dyssynchrony Research Articles

Influences of radionuclides on left ventricular phase analysis of gated myocardial perfusion single-photon emission computed tomography images in ischemic heart disease.

Phase analysis is expected to improve the accuracy of myocardial ischemia diagnosis in conjunction with myocardial perfusion and wall motion imaging and quantification. Although previous studies have reported perfusion image disagreements in relation to radionuclides, a few reports have examined the influences of radionuclides on phase analysis. We evaluated the influences of different radionuclides on stress-induced left ventricular mechanical dyssynchrony by phase analysis using electrocardiogram (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT) (MPS) imaging in patients with ischemic heart disease (IHD). A total of 202 patients with suspected or known IHD were investigated retrospectively. All the patients underwent coronary arteriography and were subsequently classified into the following groups: 43 patients without any coronary lesion (0VD), 71 patients with single-vessel disease (1VD), 59 patients with two-vessel disease (2VD), and 29 patients with three-vessel disease (3VD). Both stress and rest gated-MPS were performed using 99mTc-methoxyisobutylisonitrile (MIBI)/tetrofosmin (TF) in 118 patients and with 201TlCl in 84 patients. Phase analysis was performed to obtain the peak phase, phase standard deviation (SD), and bandwidth. Finally, we investigated potential differences between the phase analysis indices and the respective radionuclides used. The peak phase did not exhibit any significant differences in the numbers of affected branches in either 99mTc-MPS or 201Tl-MPS during stress or rest MPS. Furthermore, both the phase SD and bandwidth demonstrated a tendency to increase in patients with increased numbers of affected branches. A significant difference was observed in the stress MPS when 99mTc-MIBI/TF was used (p < 0.05), but no significant difference was observed in the stress MPS when 201TlCl was used. Both the phase SD and bandwidth of all patients in 99mTc-MPS during stress were significantly larger than those at rest (p < 0.05). Conversely, both the phase SD and bandwidth of all patients in 201Tl-MPS at stress was significantly smaller than that at rest (p < 0.05). Phase analysis using 99mTc-MPS was considered to be useful for the detection of stress-induced left ventricular mechanical dyssynchrony, although it is necessary to be careful when using 201Tl-MPS.

Comparison between cardiac magnetic resonance and speckle-tracking echocardiography in prediction of cardiac resynchronization therapy outcomes

Background Cardiac resynchronization therapy (CRT) improves quality of life, exercise tolerance, and myocardial function in a considerable number of patients with heart failure (HF) and left bundle branch block. In addition, CRT decreases HF hospitalizations and overall mortality. However, structural, morbidity, and mortality improvements after CRT rate between 40 and 60%. Objective To compare the role of the cardiac magnetic resonance (CMR) and speckle-tracking echocardiography (STE) in expectation of response to CRT. Patients and methods We investigated the predictors of CRT response using CMR measurement of left ventricular (LV) volumes and function, CMR-derived mechanical dyssynchrony, scar percentage, and its relation to the site of LV lead implantation, in comparison with STE in prediction of CRT outcomes. Results A total of 35 patients with HF planned for CRT were included. Echocardiography was used to define the response to CRT (15% reduction in LV end-systolic volume 6 months after implantation). At follow-up, 18 (51.43%) patients were categorized as responders. Echocardiographic speckle-tracking radial strain analysis showed a significant LV dyssynchrony in responders versus nonresponders (radial mid-anteroseptal and posterior wall delays were 245.1 ms and 80.7 ms, respectively) (P&lt;0.0001). LV radial dyssynchrony, as measured by CMR-feature tracking, was significantly higher in responders versus nonresponders (mean of SDt-16 of radial strain were 232.7 ms vs. 180.4 ms, P&lt;0.0001), and median of radial mid-anteroseptal-to-inferolateral wall delay was 375 vs. 125.4 ms, P&lt;0.0001). Late contrast-enhanced CMR was performed for scar assessment. It was noticed that scar percentage of LV mass was much higher in nonresponders (median 6.2 vs. 0%) (P=0.005). Conclusion CMR imaging offers the unique opportunity to predict the CRT outcomes by measurement of LV volumes, LV mechanical dyssynchrony (that well correlated with that of STE), and the total scar percentage and distribution in a single examination.

Comparison of left ventricular mechanical dyssynchrony parameters between exercise and adenosine triphosphate stress tests using gated single-photon emission computed tomography myocardial perfusion imaging.

Left ventricular mechanical dyssynchrony (LVMD) can be induced after stress test. However, no studies have compared the influence of different stress‑inducing methods on LVMD parameters. The aim of the study was to determine whether there is a difference between exercise and adenosine triphosphate (ATP) stress tests in terms of changes in LVMD parameters assessed using gated single‑photon emission computed tomography myocardial perfusion imaging (GSPECT MPI). A total of190 patients who underwent 99mTc ‑sestamibi GSPECT MPI were consecutively enrolled. Treadmill exercise and ATP stress tests were performed in 95 patients each. Normal myocardial perfusion was defined as the summed stress score (SSS) ≤3 and summed rest score (SRS) ≤3, myocardial ischemia as SSS >3 and SRS ≤3, and myocardial infarction as SSS >3 and SRS >3. Parameters of LVMD, including phase standard deviation (PSD), phase bandwidth (PBW), skewness, and kurtosis were compared. Subtraction was made between values during stress and rest phases to acquire ∆PSD, ∆PBW, ∆skewness, and ∆kurtosis Results: There were no differences in LVMD parameters between the exercise and ATP groups. The same results were obtained in the normal perfusion, ischemia, and infarction subgroups. Furthermore, no differences were observed in ∆PSD (median [interquartile range, IQR], 0.25 [-2.3 to 3.1] vs 0.42 (-1.7 to 3.1]; P = 0.73), ∆PBW (median [IQR], 1 [-7 to 11] vs 1 [-6 to 11]; P = 0.95), ∆skewness (mean [SD], -0.06 [0.63] vs 0 [0.81]; P = 0.53), and ∆kurtosis (median [IQR], -0.47 [-4.2 to 4.3] vs -0.42 [-4.8 to 5.2]; P = 0.73) between the exercise and ATP stress‑inducing methods. There are no differences between the exercise and ATP stress tests in terms of changes in LVMD parameters. Thus, the 2 methods can be used alternatively.

The use of mechanical dyssynchrony for predicting response to cardiac resynchronization therapy in patients with non-ischemic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Aim/Introduction: Assessment of mechanical dyssynchrony by myocardial perfusion gated-SPECT in patients with non-ischemic cardiomyopathy for predict response to cardiac resynchronization therapy (CRT). Materials and Methods We examined 32 patients with non-ischemic cardiomyopathy before and six months after CRT. Left ventricular mechanical dyssynchrony and contractility were assessed for all patients by myocardial perfusion gated-SPECT. The phase standard deviation (PSD), histogram bandwidth (HBW), phase histogram skewness (S) and phase histogram kurtosis (K) were used as an indicator of mechanical dyssynchrony for the both ventricles. Results Mechanical dyssynchrony of both ventricles before CRT was increased in all patients. Median value PSD 53°(41-61°), HBW 176°(136-202°), S 1,62(1,21-1,89), K 2,81(1,21-3,49). Six months after CRT 22(68%) respondents were identified. We divided the patients into two groups (responders and non-responders) and compared phase parameters. It was found that the PSD (44°(35-54°)) and HBW (158°(118-179°) in the responders were significantly lower than in the non-responders (PSD (68°(58-72°); HBW (205°(199-249°)). The value of phase histogram skewness and kurtosis in responders were significantly higher (Responders: S 1,77(1,62-2,02); K 3,03(2,60-3,58). Non-responders: S 1,21(0,93-1,31); K 1,21(0,19-1,46)). We found that all four indicators of mechanical dyssynchrony can predict CRT response according to the results of univariate logistic regression analysis. Moreover, It was found that only phase histogram kurtosis (OR = 1.196, 95% CI 1.04-1.37) is an independent predictor of CRT response according to multivariate logistic regression. Conclusion Radionuclide assessment of mechanical dyssynchrony may be the optimal diagnostic method for selecting patients with non-ischemic cardiomyopathy on CRT.

Impact of early post-stress 99mTc sestamibi ECG-gated SPECT myocardial perfusion imaging on the detection ofischemic LV dyssynchrony: an early step in the stunning cascade.

Transient alterations in ventricular conduction and synchronized cardiac performance have been reported in experimental models of myocardial ischemia. In post-stress 99mTc-sestamibi-gated-SPECT myocardial perfusion imaging (MPI), the time elapsed between tracer injection and image acquisition could influence the detection of ischemic left ventricular mechanical dyssynchrony (LVMD). We aimed at evaluating whether early vs. delayed post-stress MPI improve ischemic LVMD detection using the phase analysis parameters standard deviation (SD) and histogram bandwidth (HB) and to assess the correlation between stress-induced changes in SD and HB and other functional parameters. We prospectively studied 32 control subjects (Group-1) and 60 ischemic patients (Group-2). Stress-induced changes were calculated as stress minus rest (Δ). LVMD was defined as post-stress increases of either SD or HB. Group-2 showed higher ΔSD and ΔHB in early than in delayed images: early ΔSD: 1.63 (-0.37 to 4.83) vs. delayed ΔSD: -0.39 (-3.82 to 1.74); early ΔHB: 2.50 (-4 to 12) vs. ΔHB delayed: -4 (-15.75 to 4), all p < 0.01. ΔSD and ΔHB correlated linearly with ΔLV-ejection-fraction (EF) and ΔLV-end systolic-volume (ESV) in early images, all p < 0.01. Early images detected LVMD in more patients than delayed scans (78% vs. 38%; p < 0.01) All patients with LVEF drop in early post-stress evaluation had LVMD. Early post-stress images improve ischemic LVMD detection. Ischemic LVEF and LVESV changes correlate with ΔSD and ΔHB.

Prognostic value of left ventricular mechanical dyssynchrony in hypertrophic cardiomyopathy patients with low risk of sudden cardiac death.

This study aims to explore the prognostic value of left ventricular mechanical dyssynchrony (LVMD) in hypertrophic cardiomyopathy (HCM) patients with low risk of sudden cardiac death (SCD). This retrospective study was performed in 50 patients with HCM who underwent Tc-99m sestamibi GSPECT-MPI. All patients were at low risk of SCD, defined as HCM risk-SCD scores <6%. Phase SD (PSD) and phase histogram bandwidth (PBW) were measured for assessment of LVMD. The primary endpoint was the composite major adverse cardiovascular events (MACE), including all-cause mortality, rehospitalization of heart failure symptoms, new-onset stroke, and new-onset syncope. Variables with significant difference between MACE group and non-MACE group were further assessed by Cox regression analysis. During follow-up, MACE occurred in 20 patients. Systolic-PSD, systolic-PBW, diastolic-PSD, and diastolic-PBW were all significantly greater in the MACE group. Multivariate analysis revealed that history of syncope, history of atrial fibrillation, and all the four LVMD parameters were independent predictors of MACE. All LVMD parameters showed similar accuracy to predict MACE. Sequential models indicated that both systolic and diastolic LVMD parameters added incremental value beyond atrial fibrillation and syncope. LVMD parameters are independent predictors of MACE, which add incremental prognostic information in patients with HCM risk-SCD scores <6%.

The prognostic value of left ventricular mechanical dyssynchrony in predicting incident atrial fibrillation and ischemic stroke in the general population

Abstract Background Left ventricular mechanical dyssynchrony (LVMD) is a predictor of many cardiovascular outcomes including ventricular arrhythmias. However, the prognostic value of LVMD in predicting incident atrial fibrillation (AF) in participants from the general population is currently unknown. Purpose The aim of this study was to investigate if LVMD can be used to predict AF and ischemic stroke in the general population. Methods A total of 1282 participants (mean age 57±16 years, 42% male) from the general population underwent a health examination including two-dimensional speckle tracking echocardiography. LVMD was calculated as the standard deviation of the regional time-to-peak strain from the three apical views. The primary endpoint was incident AF at follow-up. All participants with known AF and prior stroke at baseline were excluded (n=84). The secondary endpoint consisted of the composite of AF and ischemic stroke. Results During a median follow-up of 16 years, 148 participants (12%) were diagnosed with incident AF and 88 (7%) experienced an ischemic stroke, resulting in 236 (19%) experiencing the composite outcome. The risk of AF increased incrementally with increasing tertile of LVMD, being approximately 2-fold higher in the 3rd tertile as compared to the 1st tertile (HR 1.79; 95% CI (1.22–2.63), p=0.003; figure). LVMD was a univariable predictor of AF with 7% increased risk per 10ms increase in LVMD (per 10ms: HR 1.07; 95% CI (1.03–1.12), p&amp;lt;0.001). The association remained significant even after multivariable adjustment for age, sex, body mass index, hypertension, diabetes, previous ischemic heart disease, systolic blood pressure, diastolic blood pressure, heart rate, smoking, plasma proBNP, left ventricular ejection fraction &amp;lt;50%, global longitudinal strain, left atrial volume index (LAVI) and E/e' (per 10ms increase: HR 1.06; 95% CI (1.01–1.12), p=0.018). LVMD was also a univariable predictor of the composite outcome of AF and ischemic stroke (per 10ms increase: HR 1.07; 95% CI (1.04–1.11), p&amp;lt;0.001). After multivariable adjustment for the same clinical and echocardiographic parameters, LVMD remained an independent predictor of the composite outcome (per 10ms: HR 1.07; 95% CI (1.03–1.11), p=0.001). Additionally, LVMD provided incremental prognostic information with regard to predicting AF as assessed by a significant increase in the net reclassification improvement (NRI) index beyond the CHARGE-AF score (continuous NRI, 0.300; 95% CI, 0.022–0.503). Furthermore, LVMD provided additional incremental prognostic information, when added to both the CHARGE-AF score and the LAVI (continuous NRI, 0.269; 95% CI, 0.004–0.499). Conclusion In a low risk general population, LVMD provides novel prognostic information on the long-term risk of AF and ischemic stroke. In addition, LVMD provides incremental prognostic information beyond the CHARGE-AF score and LAVI in predicting AF in the general population. Funding Acknowledgement Type of funding source: None

Prognostic value of left ventricular mechanical dyssynchrony indices in long-standing type II diabetes mellitus with normal perfusion and left ventricular systolic functions on SPECT-MPI

ObjectiveTo test whether phase analysis indices from SPECT-MPI for left ventricular mechanical dyssynchrony (LVMD) are predictors of major adverse cardiac events (MACEs) in long-standing diabetes mellitus (DM). MethodsA total of 136 DM patients with normal perfusion and left ventricular systolic functions were followed up for about two years and divided into two groups according to the presence and the absence of MACEs. ResultThirteen (9.5%) patients experienced MACEs during follow-up. Patients experiencing MACEs showed significantly higher phase standard deviation (PSD) and wider phase bandwidth (PBW) than those who did not. Moreover, both PSD and PBW showed significant correlations (r = 0.25 and 0.27; P < 0.05) with duration of DM. Logistic regression analysis revealed significant associations of DM duration, microvascular complications, and LVMD indices for predicting MACEs. Kaplan–Meier event-free survival analysis revealed significantly higher rate of MACEs (Logrank = 10.02; P = 0.001) in patients with high PSD and wide PBW. An overall fit model consisting of high-PSD and wide-PBW group was improved with the addition of microvascular complications (χ2 = 15.9; P = 0.03) and further by addition of DM duration of ≥ 15 years (χ2 = 24.3; P = 0.007) as variables. ConclusionLVMD indices are novel prognostic markers in diabetic patients with normal perfusion and left ventricular systolic functions and their increases in magnitudes with DM-duration and in the presence of microvascular complications.

The prognostic value of diastolic and systolic mechanical left ventricular dyssynchrony among patients with coronary artery disease and heart failure

BackgroundPrevalence and prognostic value of diastolic and systolic dyssynchrony in patients with coronary artery disease (CAD) + heart failure (HF) or CAD alone are not well understood. MethodsWe included patients with gated single-photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) between 2003 and 2009. Patients had at least one major epicardial obstruction ≥ 50%. We assessed the association between dyssynchrony and outcomes, including all-cause and cardiovascular death. ResultsOf the 1294 patients, HF was present in 25%. Median follow-up was 6.7 years (IQR 4.9-9.3) years with 537 recorded deaths. Patients with CAD + HF had a higher incidence of dyssynchrony than patients with CAD alone (diastolic BW 28.8% for the HF + CAD vs 14.7% for the CAD alone). Patients with CAD + HF had a lower survival than CAD alone at 10 years (33%; 95% CI 27-40 vs 59; 95% CI 55-62, P < 0.0001). With one exception, HF was found to have no statistically significant interaction with dyssynchrony measures in unadjusted and adjusted survival models. ConclusionsPatients with CAD + HF have a high prevalence of mechanical dyssynchrony as measured by GSPECT MPI, and a higher mortality than CAD alone. However, clinical outcomes associated with mechanical dyssynchrony did not differ in patients with and without HF.

Prognostic Value of Left Ventricular Dyssynchrony Assessed with Nuclear Cardiology in Patients with Known or Suspected Stable Coronary Artery Disease with Preserved Left Ventricular Ejection Fraction.

Left ventricular (LV) mechanical dyssynchrony assessed with phase analysis of electrocardiogram (ECG) -gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is useful for predicting major cardiac events (MCEs) in patients with cardiac dysfunction. However, there is no report on its usefulness in Japanese patients with known or suspected stable coronary artery disease (CAD) with preserved LV ejection fraction (LVEF).We retrospectively investigated 3,374 consecutive patients with known or suspected CAD who underwent rest 201Tl and stress 99mTc-tetrofosmin ECG-gated SPECT MPI and had preserved LVEF (≥ 45%), and followed them up to confirm their prognosis for three years. The composite endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris, and severe heart failure requiring hospitalization. LV mechanical dyssynchrony was evaluated with phase analysis with the Heart Risk View-F software to obtain the phase bandwidth and standard deviation.During the follow-up, 179 patients experienced MCEs: cardiac death (n = 42); non-fatal MI (n = 34); unstable angina pectoris (n = 54); and severe heart failure (n = 49). Results of the multivariate analysis showed age, a history of MI, diabetes mellitus, summed stress score, and stress phase bandwidth to be independent predictors for MCEs. In Kaplan-Meier analysis, prognoses were significantly stratified with the tertiles of stress phase bandwidth.LV mechanical dyssynchrony assessed with ECG-gated SPECT MPI is useful for predicting a prognosis and stratifying the risk of MCEs in Japanese patients with known or suspected stable CAD with preserved LVEF.

Electrical and mechanical dyssynchrony in patients with right bundle branch block

BackgroundThough fairly benign reputation, the right bundle branch block (RBBB) can cause left ventricular mechanical dyssynchrony (LVMD). Still, the relationship between electrical disturbance and LVMD is partly unclear among these patients. MethodsThirty patients with RBBB and 60 matching controls were studied with vector electrocardiography and myocardial perfusion imaging phase analysis. RBBB group was divided into those with and those without LVMD. ResultsPrevalence of LVMD among RBBB patients was 50% and among controls 22%. Odds ratio (OR) for LVMD in patients with RBBB vs controls without RBBB was 3.6 (95% CI 1.4 to 9.3). Ejection fraction (EF), end-systolic volume, the angle between QRS and T vectors, and the QRS angle in the sagittal plane were significantly different between RBBB patients with and without LVMD. The QRS duration was comparable in these groups. EF associated independently with LVMD, explaining 60% of its variation. A cut-off value of EF ≤ 55% detected LVMD in 100% specificity (sensitivity of 47%). ConclusionHalf of the patients with RBBB had LVMD. The OR for LVMD between RBBB and normal ECG was 3.6. It seems that EF, rather than electrical parameters, is the main determinant of LVMD. This information might be useful when evaluating indications for cardiac resynchronization therapy.

The clinical usefulness of phase analysis in detecting coronary artery disease using dipyridamole thallium-201-gated myocardial perfusion imaging with a cadmium-zinc-telluride camera

BackgroundPrevious studies have demonstrated left ventricular mechanical dyssynchrony (LVMD) in patients with severe coronary artery disease (CAD) with ≥ 70% stenosis. The aim of this study was to evaluate the clinical usefulness of stress/rest LVMD in the diagnosis of CAD with ≥ 50% stenosis using dipyridamole thallium-201 (Tl-201) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera. Methods and ResultsA total of 476 patients without known CAD who underwent dipyridamole Tl-201 MPI and coronary angiography within 6 months were retrospectively reviewed. LVMD parameters including phase standard deviation and phase histogram bandwidth, phase skewness and phase kurtosis, as well as myocardial perfusion and myocardial stunning were assessed in post-stress and rest MPI. Relationships between the presence of CAD on coronary angiography and single photon emission computerized tomography (SPECT) parameters were evaluated. The presence of perfusion abnormalities was the best diagnostic tool in detecting CAD. Although less left ventricular synchrony was observed post-stress in the CAD group compared to the non-CAD group, no significant dyssynchrony was noted. ConclusionsThe addition of phase analysis to help diagnose CAD in Tl-201-gated SPECT with dipyridamole stress may have limited value in patients with CAD with ≥ 50% stenosis.

Biventricular pacemaker therapy improves exercise capacity in patients with non-obstructive hypertrophic cardiomyopathy via augmented diastolic filling on exercise.

AimsTreatment options for patients with non‐obstructive hypertrophic cardiomyopathy (HCM) are limited. We sought to determine whether biventricular (BiV) pacing improves exercise capacity in HCM patients, and whether this is via augmented diastolic filling.Methods and resultsThirty‐one patients with symptomatic non‐obstructive HCM were enrolled. Following device implantation, patients underwent detailed assessment of exercise diastolic filling using radionuclide ventriculography in BiV and sham pacing modes. Patients then entered an 8‐month crossover study of BiV and sham pacing in random order, to assess the effect on exercise capacity [peak oxygen consumption (VO2)]. Patients were grouped on pre‐specified analysis according to whether left ventricular end‐diastolic volume increased (+LVEDV) or was unchanged/decreased (–LVEDV) with exercise at baseline. Twenty‐nine patients (20 male, mean age 55 years) completed the study. There were 14 +LVEDV patients and 15 –LVEDV patients. Baseline peak VO2 was lower in –LVEDV patients vs. +LVEDV patients (16.2 ± 0.9 vs. 19.9 ± 1.1 mL/kg/min, P = 0.04). BiV pacing significantly increased exercise ΔLVEDV (P = 0.004) and Δstroke volume (P = 0.008) in –LVEDV patients, but not in +LVEDV patients. Left ventricular ejection fraction and end‐systolic elastance did not increase with BiV pacing in either group. This translated into significantly greater improvements in exercise capacity (peak VO2 + 1.4 mL/kg/min, P = 0.03) and quality of life scores (P = 0.02) in –LVEDV patients during the crossover study. There was no effect on left ventricular mechanical dyssynchrony in either group.ConclusionSymptomatic patients with non‐obstructive HCM may benefit from BiV pacing via augmentation of diastolic filling on exercise rather than contractile improvement. This may be due to relief of diastolic ventricular interaction.Clinical Trial Registration: ClinicalTrials.gov NCT00504647.

Synergistic prognostication of left ventricular hypertrophy and three-dimensional mechanical dyssynchrony in heart failure.

AimsIn this study, we investigated the prognostic interplay of left ventricular hypertrophy and mechanical dyssynchrony (LVMD), both of which can be measured three‐dimensionally by gated myocardial perfusion imaging (MPI), in patients with chronic systolic heart failure (HF).Methods and resultsIn 829 consecutive HF patients with reduced left ventricular ejection fraction less than 50%, LVMD was evaluated as a standard deviation (phase SD) of regional onset of mechanical contraction phase angles. A phase histogram was created by Fourier phase analysis applied to regional time‐activity curves obtained by gated MPI. Left ventricular mass index (LVMI) was measured by Corridor 4DM version 6.0. Patients were followed up with a primary endpoint of lethal cardiac events (CE) for a mean interval of 34 months. CE were documented in 223 (27%) of the HF patients. The CE group had a greater phase SD and a greater LVMI than those in the non‐CE group. Patients in the CE group had a more advanced age, greater New York Heart Association (NYHA) functional class, left ventricular cavity size, and left atrial diameter or septal E/e' and lower kidney or cardiac function than did patients in the non‐CE group. Phase SD > 37 and LVMI > 122.7 g/m2 were identified as optimal cut‐off values by receiver operating characteristic analyses for discrimination of the most increased risk HF subgroup from others (P < 0.0001). When classified into four patient subgroups using both cut‐off values, HF patients with phase SD > 37 (LVMD) and LVMI > 122.7g/m2 had the highest CE rate among the subgroups (P < 0.0001). Univariate analysis and subsequent multivariate analysis with a Cox proportional hazards model showed that phase SD and LVMI were significant independent predictors of CE with hazard ratios of 1.038 (confidence interval [CI], 1.024–1.051, P < 0.0001) and 1.005 (CI, 1.001–1.008, P = 0.0073), respectively, as well as conventional clinical parameters such as age, NYHA class, estimated glomerular filtration rate (eGFR), and BNP concentration. Patients with increased phase SD and LVMI had incrementally improved prognostic values of clinical parameters including age, NYHA functional class, eGFR, and BNP with increases in the global χ2 value: 5.9 for age; 139.5 for age and NYHA; 157.9 for age, NYHA, and eGFR; 163.9 for age, NYHA, eGFR, and BNP; 183.4 for age, NYHA, eGFR, BNP, and phase SD; and 192.5 for age, NYHA, eGFR, BNP, phase SD, and LVMI.ConclusionsThree‐dimensionally assessed LVMD has independent prognostic values and can improve the risk stratification of chronic HF patients synergistically in combination with conventional clinical parameters.

Left ventricular mechanical dyssynchrony assessment in obese patients using the cadmium-zinc telluride SPECT camera.

The use of phase analysis techniques to assess left ventricular mechanical dyssynchrony (LVMD) has been well documented. However, artifacts have reduced the accuracy of the assessment due to soft tissue attenuation, so little information is available about the effects of obesity on LVMD. The aim of this study was to evaluate LVMD in patients with simple obesity by SPECT with a new cadmium-zinc telluride (CZT) detector and to explore the effects of obesity on left ventricular wall motion. We retrospectively analyzed 95 patients with myocardial perfusion imaging (MPI) images without perfusion defects, of which 55 were diagnosed with simple obesity (BMI > 30), and 40 non-obese patients (BMI < 25) matched for age and sex were used as controls. The five-point method was used to analyze the MPI images of the two groups, and the complete cardiac function parameters including phase bandwidth (PBW) and phase standard deviation (PSD) were obtained. Although the PBW values of the two groups were within the normal range (cut-off value > 90°), the PBW (35.4 ± 28 vs 24.9 ± 7.5, P < .001; 36.6 ± 18.4 vs 28.7 ± 9.1, P = 0.01) and PSD (8.7 ± 7.6 vs 5.9 ± 2, P = 0.02; 9.2 ± 4.9 vs 7.1 ± 2.7, P = 0.01) of the obese group were larger than the control group under both stressing and resting, and the difference was statistically significant. CZT-SPECT can effectively assess LVMD in obese patients, and they are more likely to develop LVMD, which may be related to their left ventricular volume.

Functional mitral regurgitation determinants in dilated cardiomyopathy

Functional mitral regurgitation (FMR) is a frequent condition in the setting of dilated cardiomyopathy (DCM) and its physiopathological mechanisms are complex. The aim of this study was to determine the influence of left ventricular remodeling and mechanical dyssynchrony on the occurence of FMR in non-ischemic DCM. Prospective study involving 52 patients (mean age = 57 ± 10 years, sex-ratio = 1.8) with non-ischemic DCM. Two groups were compared: the group with FMR (group MR+ = 31 patients) and that without FMR (group MR- = 21 patients). Mean QRS duration was 141 ± 29 ms, 63% of patients had complete left bundle branch block (LBBB), with no significant difference between the 2 groups. Echocardiographic parameters representing left ventricular systolic function were similar in 2 groups except for cardiac output which was lower in the group MR+ (3.3 ± 1l/min vs. 4 ± 1.3l/min. P = 0.02). For mitral deformation indices, tenting area (3.6 ± 1cm 2 vs. 2.5 ± 0.8cm 2 ; P = 0.005) and tenting height (1.5 ± 0.3 cm vs. 1 ± 0.2 cm; P < 0.001) were significantly larger in group MR+. For dyssynchrony indices, only temporal longitudinal dyssynchrony was associated to FMR ( P = 0.04). In the group MR+, more criteria of intraventricular dyssynchrony were noted (3.4 ± 1.4) than in group MR- (2,4 ± 1.4; P = 0.01). FMR severity was well correlated to tenting area ( r = 0.66; P < 0.001) and tenting height ( r = 0.67; P < 0.01). However, parameters representing left ventricular systolic and diastolic function were not good determinants of FMR severity and dyssynchrony indices were not at all associated to FMR severity. This study showed that only the mitral deformation indices were well correlated to both the presence and the severity of FMR. Left ventricular remodeling indices were not good determinants of FMT. However, the intra ventricular dyssynchrony indices were associated to the presence of FMR and not to its severity.

P1303 Pseudo-severe aortic stenosis due to mechanical dyssynchrony in a patient with low contractile reserve

Abstract Introduction Aortic stenosis characterization in patients with low flow – low gradient stenosis (LF-LG) and reduced left ventricular (LV) ejection fraction (EF) is challenging. In this subgroup, pseudo- severe stenosis should be properly identified, as these patients are treated conservatively with heart failure therapy. Its identification relies mainly on preserved contractile reserve seen during dobutamine echocardiography. We present a patient with low contractile reserve and pseudo-severe stenosis due to mechanical dyssynchrony. Case presentation 83-years old patient with ischemic heart disease and chronic kidney disease was admitted to our department due to progressive exertional dyspnea. In 2014 he underwent dual-chamber pacemaker (PM) implantation due to sick sinus syndrome and was programmed to asynchronous pacing mode (VVI mode) in 2016 as atrial electrode dysfunction was observed. Coronary angiogram was normal. Echocardiography showed enlarged left ventricle (LV EDV 180 ml), reduced EF (33%) and signs of mechanical dyssynchrony. Peak aortic valve velocity was 2.5 m/s, mean pressure gradient (MPG) 13 mmHg and AVA 1.0 cm2. Stroke volume was reduced (SVI 28 ml/m2). LF-LG aortic stenosis was suspected. Stress echocardiography using dobutamine at peak infusion of 15 mcg/kg/min showed low contractile reserve (EF 37%, SVI 33 ml/m2) with no significant changes in aortic valve parameters (MPG 29 mmHg, AVA 0.9 cm2). However, significant masurement disparity was noted and at least partly contributed to atrio-ventricular (A-V) and inter-ventricular dyssynchrony because of asynchronous VVI pacing. To overcome A-V and intraventricular dyssynchrony we decided for atrial lead reposition and upgrade to cardiac resynchronization therapy (CRT-P). After six months of CRT, normalization of EF and improvement of exercise capacity were observed. Furthermore, additional evaluation of aortic valve showed only moderate stenosis (peak velocity 2,8 m/s, MPG 18 mmHg and AVA 1.4 cm2). Stroke volume was normal (SVI 48 ml/m2). Consequently, we postponed potential surgical or interventional treatment of the aortic valve. Conclusion Considerable LV mechanical dyssynchrony could interfere with determining the severity of aortic stenosis. As demonstrated in the present case report, special considerations should be taken in patients with notable LV dyssynchrony and low contractile reserve as it may not be overcome with dobutamine stress echocardiography as recommended by the current guidelines.

The effect of renal transplantation on left ventricular function, electrocardiography, and mechanical synchrony by gated myocardial perfusion imaging

BackgroundDepressed left ventricular ejection fraction (LVEF), LV mechanical dyssynchrony (LVMD), and prolonged QTc interval predict poor outcomes in end-stage renal disease (ESRD). Renal transplantation improves mortality in ESRD patients but the effects of transplantation on these indices remain undefined. MethodsWe identified patients with myocardial perfusion imaging (MPI) before and after renal transplantation. A control group consisted of ESRD patients who underwent 2 MPIs but did not receive a transplant. Changes in LVEF, LVMD indices [phase standard deviation (SD) and bandwidth (BW)] by MPI, and electrocardiogram (ECG) indices were determined. ResultsThe study population consisted of 32 ESRD patients (53% male, 50 ± 11 years, 59% African American, 65% diabetic). The second MPI was performed 31 months (13-59 months) after renal transplantation. LVEF (72 ± 10% vs. 67 ± 10%, P < 0.001) but not SD (22 ± 15° vs. 22 ± 11°, P = 0.9) or BW (58 ± 35° vs. 57 ± 29°, P = 0.9) improved after transplantation. There were no changes in these indices in the control group. QTc (425 ± 30 ms vs. 447 ± 32 ms, P = <0.001) but not QRS (90 ± 21 ms vs. 90 ± 21 ms, P = 0.9) improved significantly after renal transplantation. ConclusionsLVEF and QTc improved after renal transplantation but LVMD indices and QRS did not change, which suggests that LVMD and electrical dyssynchrony may be irreversible in ESRD.

Time-modified OSEM algorithm for more robust assessment of left ventricular dyssynchrony with phase analysis in ECG-gated myocardial perfusion SPECT

BackgroundIn ordered subsets expectation maximization (OSEM) reconstruction of electrocardiography (ECG)-gated myocardial perfusion single-photon emission computed tomography (SPECT), it is often assumed that the image acquisition time is constant for each projection angle and ECG bin. Due to heart rate variability (HRV), this assumption may lead to errors in quantification of left ventricular mechanical dyssynchrony with phase analysis. We hypothesize that a time-modified OSEM (TOSEM) algorithm provides more robust results.MethodsList-mode data of 44 patients were acquired with a dual-detector SPECT/CT system and binned to eight ECG bins. First, activity ratio (AR)—the ratio of total activity in the last OSEM-reconstructed ECG bin and first five ECG bins—was computed, as well as standard deviation SDR-R of the accepted R–R intervals; their association was evaluated with Pearson correlation analysis. Subsequently, patients whose AR was higher than 90% were selected, and their list-mode data were rebinned by omitting a part of the acquired counts to yield AR values of 90%, 80%, 70%, 60% and 50%. These data sets were reconstructed with OSEM and TOSEM algorithms, and phase analysis was performed. Reliability of both algorithms was assessed by computing concordance correlation coefficients (CCCs) between the 90% data and data corresponding to lower AR values. Finally, phase analysis results assessed from OSEM- and TOSEM-reconstructed images were compared.ResultsA strong negative correlation (r = -0.749) was found between SDR-R and AR. As AR decreased, phase analysis parameters obtained from OSEM images decreased significantly. On the contrary, reduction of AR had no significant effect on phase analysis parameters obtained from TOSEM images (CCC > 0.88). The magnitude of difference between OSEM and TOSEM results increased as AR decreased.ConclusionsTOSEM algorithm minimizes the HRV-related error and can be used to provide more robust phase analysis results.

Assessment of Left Ventricular Asynchrony after Permanent Cardiac Pacing by Using Speckle Tracking Echocardiography

AbstractBackground: Echocardiography is important in assessing Left Ventricular (LV) Mechanical Dysynchrony (LVMD) and left ventricular function after permanent pacemaker. At present, Real-Time Three Dimensional Echocardiography (RT3DE) and tissue Doppler imaging (TDI) are the most sensitive and commonly used techniques for the quantification of LVMD. Global longitudinal strain (GLS) and LV dyssynchrony as-sessment enables us to detect early signs of LV dysfunction after cardiac pacing.Aim of Study: To evaluate LV mechanical dyssynchrony and LV function in different pacing modes after permanent cardiac pacing by using TDI and speckle tracking echocardi-ography and to correlate these changes with other clinical, electrocardiographic and echocardiographic data.Patients and Methods: Seventy patients were enrolled in this prospective cross sectional observational study, (mean age 60.99±13.77 years, 42 females), in Mansoura Specialized Medical Hospital over a period of 1 year from April 2018 to April 2019. All patients were assessed by thorough history taking, clinical examination, 12 lead surface ECG, echocar-diography, 2D speckle tracking echocardiography STE to assess GLS and tissue Doppler imaging TDI.Results: Regarding diastolic function by pulsed wave Doppler PWD: There was significant decrease in E/e¢ ratio (p<0.001 *), significant increase in myocardial performance index Tei index (p<0.001 *). Regarding internal dimensions and systolic function: There was significant increase in the following: Left Atrial Dimension (LAD) (p=0.001*), Left Ventricular End Systolic Dimension LVESD (p<0.001*) and Left Ventricular End Diastolic Dimension LVEDD (p<0.001 *) while there was significant decrease in ejection fraction EF (p<0.001 *) and fractional shortening FS (p<0.001 *). Regarding parameters of LV dysynchrony: There was significant increase in the following: Aortic preejection delay APED (p<0.001*), interventricular mechanical delay (p<0.001 *) and septal posterior wall motion delay SPWMD by M mode (p<0.001 *). Regarding parameters assessed by tissue synchronization imaging TSI: There was significant increase in the following: SD-Ts (p=0.001 *) and all segments Max delay (p=0.027*). Regarding parameters assessed by STE: There was significant decrease in global longitudinal strain GLS (p=0.034*) while there was significant increase in TP-SD by STE (p<0.001*).Also, there was significant decrease in global longitudinal strain GLS (p<0.001*) and significant increase in TP-SD by STE (p=0.001*) in DDD group. While there was significant decrease in global longitudinal strain GLS (p<0.001 *) and significant increase in TP-SD by STE (p<0.001*) in VVI group.Conclusion: GLS and 2D STE can help in the detection of subclinical left ventricular dysfunction after permanent pacemaker implantation before appearance of symptoms. Also, cardiac pacing leads to LVMD whatever the pacing mode is which may needs later on upgrading to cardiac resynchronization therapy CRT.