Assessment Of Mechanical Dyssynchrony Research Articles

Understanding the Application of Mechanical Dyssynchrony in Patients with Heart Failure Considered for CRT.

Over the past two decades of CRT use, the failure rate has remained around 30-35%, despite several updates in the guidelines based on the understanding from multiple trials. This review article summarizes the role of mechanical dyssynchrony in the selection of heart failure patients for cardiac resynchronization therapy. Understanding the application of mechanical dyssynchrony has also evolved during these past two decades. There is no role of lone mechanical dyssynchrony in the patient selection for CRT. However, mechanical dyssynchrony can complement the electrocardiogram and clinical criteria and improve patient selection by reducing the failure rate. An oversimplified approach to mechanical dyssynchrony assessment, such as just estimating time-to-peak delays between segments, should not be used. Instead, methods that can identify the underlying pathophysiology of HF and are representative of a substrate to CRT should be applied.

Mechanical Dyssynchrony Combined with Septal Scarring Reliably Identifies Responders to Cardiac Resynchronization Therapy.

Background and aim: The presence of mechanical dyssynchrony on echocardiography is associated with reverse remodelling and decreased mortality after cardiac resynchronization therapy (CRT). Contrarily, myocardial scar reduces the effect of CRT. This study investigated how well a combined assessment of different markers of mechanical dyssynchrony and scarring identifies CRT responders. Methods: In a prospective multicentre study of 170 CRT recipients, septal flash (SF), apical rocking (ApRock), systolic stretch index (SSI), and lateral-to-septal (LW-S) work differences were assessed using echocardiography. Myocardial scarring was quantified using cardiac magnetic resonance imaging (CMR) or excluded based on a coronary angiogram and clinical history. The primary endpoint was a CRT response, defined as a ≥15% reduction in LV end-systolic volume 12 months after implantation. The secondary endpoint was time-to-death. Results: The combined assessment of mechanical dyssynchrony and septal scarring showed AUCs ranging between 0.81 (95%CI: 0.74-0.88) and 0.86 (95%CI: 0.79-0.91) for predicting a CRT response, without significant differences between the markers, but significantly higher than mechanical dyssynchrony alone. QRS morphology, QRS duration, and LV ejection fraction were not superior in their prediction. Predictive power was similar in the subgroups of patients with ischemic cardiomyopathy. The combined assessments significantly predicted all-cause mortality at 44 ± 13 months after CRT with a hazard ratio ranging from 0.28 (95%CI: 0.12-0.67) to 0.20 (95%CI: 0.08-0.49). Conclusions: The combined assessment of mechanical dyssynchrony and septal scarring identified CRT responders with high predictive power. Both visual and quantitative markers were highly feasible and demonstrated similar results. This work demonstrates the value of imaging LV mechanics and scarring in CRT candidates, which can already be achieved in a clinical routine.

Mechanical dyssynchrony combined with septal scarring reliably identifies responders to cardiac resynchronization therapy

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Research Foundation Flanders (FWO). Background The presence of mechanical dyssynchrony on echocardiography is associated with reverse remodeling after cardiac resynchronization therapy (CRT). In contrast, recent studies suggest that presence of myocardial scarring – particularly in the septal wall – reduces the effect of CRT. Recently, a combined assessment of mechanical dyssynchrony and septal wall scarring has demonstrated high predictive power for CRT response. However, a direct comparison of different markers of mechanical dyssynchrony has not yet been performed. Aim This study: (I) investigated how well a combined assessment of different markers of mechanical dyssynchrony and septal scarring identifies responders to CRT, and (II) evaluated potential differences in predictive power. Methods In a prospective multicentre study in 170 CRT recipients, septal flash (SF) or apical rocking (ApRock), systolic stretch index (SSI) and lateral-to-septal (LW-S) work difference were assessed on echocardiography. SSI was calculated from longitudinal strain traces of the four-chamber view as the sum of the septal systolic stretch and lateral systolic pre-stretch before aortic valve closure. The LW-S work difference was calculated from the regional work of the lateral wall and septal wall - considering the averaged work from the basal- and mid-ventricular segments in the apical four-chamber view. Myocardial scarring of the septum was quantified on cardiac magnetic resonance imaging (CMR) late gadolinium enhancement (LGE) images (n=125 patients), or excluded based on a coronary angiogram and clinical history (n=45 patients). Myocardial scarring was reported regionally as percentage of total amount of scarred tissue per wall. The study’s endpoint was CRT response, defined as ≥15% reduction in LV end-systolic volume 12 months after CRT implantation. AUC’s from ROC curves were used to investigate the predictive power of the different markers for CRT response. Results The AUC’s for the combined assessment of the markers of mechanical dyssynchrony and septal scarring as predictor of CRT-response were 0.86 (95% CI: 0.79–0.91) for presence of SF or ApRock, 0.81 (95% CI: 0.74–0.88) for SSI, and 0.84 (95% CI: 0.76–0.90) for LW-S work difference (all p<0.0001). No significant difference was observed between the different markers of mechanical dyssynchrony (p>0.05 between all). Conclusions The combined assessment of mechanical dyssynchrony and septal scarring identified CRT responders with high predictive power. Both visual and quantitative markers demonstrated similar results. Our data demonstrates the importance of assessing LV mechanics and scarring in CRT-candidates, which can easily be achieved in clinical routine.

Can echocardiography facilitate decision-making to CRT?

Abstract Introduction Cardiac resynchronization therapy (CRT) remains underused despite its well-established therapeutic effect and clear guidelines. Among various reasons are the lack of referral, the fear of complications and the high therapy cost. The assessment of mechanical dyssynchrony (MD) on echocardiography has been suggested to aid patient selection. In the past, however, several studies have used old markers of MD producing disappointing results and the use of echocardiography for patient selection became discredited. Promising new markers have been developed since and could aid clinical decision-making for CRT. These should, however, first be thoroughly tested and compared to the old markers. Purpose (I) To confirm the relevance of the new markers of MD for survival free of cardiac death and (II) to compare old and new markers of MD for predicting cardiac death within 5 years post-CRT in patients eligible for CRT according the 2021 ESC guidelines. Methods 222 CRT-patients were analysed retrospectively in a multicentre setting. MD was assessed using three old markers: septal-to-posterior wall-motion-delay (SPWMD), left-ventricular-filling-time/cardiac-cycle ratio (LVFT/RR), and intraventricular mechanical delay (IVMD); and three new markers: systolic stretch index (SSI), myocardial work index (MWI), and visual presence of septal flash or apical rocking (SFoAR). For each marker, patients were categorized using previously published cut-offs as “MD present” (Yes) or “MD not present” (No). Log rank tests were performed on Kaplan-Meier curves for survival free of cardiac death. Cox proportional hazards regressions were used to compute the hazard-ratio (HR) for cardiac death within 5 years after implantation. Results Cardiac death occurred in 37 patients (17%). Patients with MD before CRT according to IVMD (p=0.003), SSI (p<0.001), MWI (p<0.001) or SFoAR (p<0.001) had a significantly better survival. The hazard ratios were 0.34 (95% CI, 0.19–0.75) for IVMD, 0.30 (95% CI, 0.15–0.57) for SSI, 0.26 (95% CI, 0.12–0.54) for MWI and, 0.28 (95% CI, 0.14–0.53) for SFoAR. The other markers for MD were not significant for survival. Conclusion The new markers for dyssynchrony are better than the old. Patients with mechanical dyssynchrony on echocardiography before CRT according to SSI, MWI or SFoAR are 3 to 4 times less likely to die within 5 years after CRT implantation. The presence of one of these markers in patients with a broad QRS (≥130ms) and reduced LVEF (≤35%) should prompt clinicians to refer for or to proceed to CRT. Funding Acknowledgement Type of funding sources: None.

Echocardiographic assessment of mechanical dyssynchrony: are the new parameters better?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction - The high cost and important non-response rate are preventing optimal use of cardiac resynchronization therapy (CRT). Assessing mechanical dyssynchrony on echocardiography in candidates for CRT could remove these barriers by improving patient selection. In 2008 the PROSPECT study compared several old parameters of dyssynchrony in search of a reproducible parameter capable of better predicting response to CRT. Unfortunately, the results were disappointing and the assessment of dyssynchrony became discredited. Promising new parameters have been developed but a comparison with the old parameters is currently missing. Purpose - To compare the old and new parameters of mechanical dyssynchrony for (1) their effect on response to CRT as additional selection criteria, (2) predicting favourable long-term outcome after CRT and (3) their reproducibility. Methods - 146 CRT patients were analysed retrospectively in a multicentre setting. Mechanical dyssynchrony was assessed using three old parameters: septal-to-posterior wall motion delay (SPWMD), left ventricular filling time/cardiac cycle ratio (LVFT/RR), and intraventricular mechanical delay (IVMD); and three new parameters: systolic stretch index (SSI), myocardial work index (MWI), and visual presence of septal flash or apical rocking (SFoAR). Response to CRT was defined as a ≥15% decrease in LV end-systolic volume 1 year after CRT. For each parameter patients were categorized using previously published cut-offs as ‘eligible’ or ‘non-eligible’. The ‘non-eligible’ were considered untreated. Results were compared to the guidelines (Fig. 1). The hazard ratio (HR) for cardiac death within 5 years after implantation was computed for all patients (Fig. 2), and intra- and interrater agreement was determined. Results - 73% (n= 107) of patients showed response to CRT. The old parameters maintained less than 75% of the original responders. SFoAR preserved the highest proportion of responders (93%), while reducing the number of non-responders by 39% (Fig. 1). The prediction of cardiac death was significant for SFoAR (HR = 0.29; 95% CI: 0.12-0.74; P = 0.009) and IVMD (HR = 0.32; 95% CI: 0.13-0.79; P = 0.014) (Fig. 2). Intra- and interrater agreement was best for SFoAR (κ = 0.89; 95% CI: 0.67-1.0 and κ = 0.78; 95% CI: 0.50-1.0 respectively). Interrater agreement was poor for all old parameters (κ < 0.6). Conclusion - The new parameters for dyssynchrony are performing better. The visual presence of apical rocking or septal flash provided the most responders to CRT, predicted favourable long-term outcome and was highly reproducible. Our results show that future research should focus on the new parameters. Abstract Figure. Abstract Figure.

Incremental Value of Left Ventricular Mechanical Dyssynchrony Assessment by Nitrogen-13 Ammonia ECG-Gated PET in Patients With Coronary Artery Disease.

Background: Phase analysis is a technique used to assess left ventricular mechanical dyssynchrony (LVMD) in nuclear myocardial imaging. Previous studies have found an association between LVMD and myocardial ischemia. We aim to assess the potential diagnostic value of LVMD in terms of myocardial viability, and ability to predict major adverse cardiac events (MACE), using Nitrogen-13 ammonia ECG-gated positron emission tomography (gPET).Methods: Patients with coronary artery disease (CAD) who underwent Nitrogen-13 ammonia and Fluorine-18 FDG myocardial gPET were enrolled, and their gPET imaging data were retrospectively analyzed. Patients were followed up and major adverse cardiac events (MACE) were recorded. The Kruskal-Wallis test and Mann-Whitney U test were performed to compare LVMD parameters among the groups. Binary logistic regression analysis, receiver operating characteristic (ROC) curve analysis, and multiple stepwise analysis curves were applied to identify the relationship between LVMD parameters and myocardial viability. Kaplan–Meier survival curves and the log-rank test were used to look for differences in the incidence of MACE.Results: In total, 79 patients were enrolled and divided into three groups: Group 1 (patients with only viable myocardium, n = 7), Group 2 (patients with more viable myocardium than scar, n = 33), and Group 3 (patients with less viable myocardium than scar, n = 39). All LVMD parameters were significantly different among groups. The median values of systolic phase standard deviation (PSD), systolic phase histogram bandwidth (PHB), diastolic PSD, and diastolic PHB between Group 1 and Group 3, and Group 2 and Group 3 were significantly different. A diastolic PHB of 204.5° was the best cut-off value to predict the presence of myocardial scar. In multiple stepwise analysis models, diastolic PSD, ischemic extent, and New York Heart Association (NYHA) classification were independent predictive factors of viable myocardium and myocardial scar. The incidence of MACE in patients with diastolic PHB > 204.5° was 25.0%, higher than patients with diastolic PHB <204.5° (11.8%), but the difference was not significant.Conclusions: LVMD generated from Nitrogen-13 ammonia ECG-gated myocardial perfusion imaging had added diagnostic value for myocardial viability assessment in CAD patients. LVMD did not show a definite prognostic value.

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.

Predictors of pacing induced left ventricular dysfunction and cardiomyopathy assessed by three-dimensional echocardiography and speckle tracking strain

BackgroundLong-term RV pacing leads to ventricular dyssynchrony, in the form of LBBB-like morphology, with subsequent detrimental effects on LV structure and function. Three-dimensional echocardiography allowed early detection of volumetric changes associated with PICMP and provided more accurate assessment of mechanical dyssynchrony. Speckle tracking strain is able to identify LV dysfunction even before any reduction in LVEF. Our aim was to study pacing effects on LV function and hemodynamics using 3D echo and speckle tracking strain.ResultsThis was a prospective study of 175 consecutive patients without structural heart disease (LVEF > 50%) presented for permanent pacing. Full-volume 3D echocardiography done before implantation, 1 week, and 6 months together with GLS. Patients were followed for 6 months to detect incidence of PIVD (defined as reduction in LVEF > 10% but still above 50%) and PICMP (defined as decrease in LVEF by 10% from baseline in absence of other known causes of cardiomyopathy resulting in EF< 50%). PIVD and PICMP predictors and risk factors were analyzed. Only 50 patients met study criteria. Twenty-five (50%) patients developed LV systolic dysfunction; of these, 19 (38%) developed PIVD and 6 (12%) developed PICMP. Pre-implantation GLS was significantly lower in the 6 patients who subsequently developed PICMP, compared to those who developed PIVD and the preserved EF group (mean GLS − 15.50 vs. − 21.0, − 20.0 respectively; p = 0.005, 0.033, respectively). At 1 week, GLS was significantly lower in the 25 patients who subsequently developed PIVD, compared to those who did not (GLS − 13.0 vs. − 18.0, respectively; p = 0.002). A reduction of baseline GLS by 15% or more at 1 week was associated with the development of PIVD and PICMP (p = < 0.001). A wider native QRS complex was associated with PIVD and PICMP (p = 0.008, 0.018, respectively). The other predictors were found non-significant.ConclusionPICMP may be more common than previously reported and it may occur shortly after implantation. Pre-implantation GLS is a sensitive parameter for PICMP. One-week GLS, pre-implantation QRS complex width are early predictors for PICMP and PIVD before any reduction in EF.

Echocardiographic assessment of CRT candidates. Does it work equally well in intermediate QRS duration?

Abstract Background The presence of mechanical dyssynchrony – such as apical rocking (ApRock) and septal flash (SF) – on echocardiography is associated with favourable outcome after cardiac resynchronization therapy (CRT). Myocardial scar on the other hand, has a considerable negative impact on CRT response. There is growing evidence that a visual echocardiographic assessment of mechanical dyssynchrony by ApRock, SF and scar predicts CRT response. Little is known however if this works equally well in patients with intermediate QRS duration (120–150ms), where guideline recommendation for CRT is weaker. Methods A total of 400 unselected patients referred for CRT, who fulfil the contemporary guidelines, were enrolled in this multicentre study. Echocardiographic images were visually assessed before CRT implantation, focussing on the presence of ApRock, SF and location and extent of scar segments in the left ventricle (LV), resulting in a CRT response prediction (i.e. Reader Interpretation). Readers were blinded to all patient information other than ischaemic aetiology of heart failure. CRT response was defined as ≥15% reduction in LV end-systolic volume on echocardiography, on average 15 months after device implantation. Results Overall, 321 (80%) patients had a left bundle branch block (LBBB), with an average QRS duration of 166±25ms. Ischemic aetiology of heart failure was found in 131 (33%) patients. Before CRT, ApRock and SF were present in 254 (64%) and 244 (61%) patients, respectively. ApRock and SF alone predicted CRT response with an area under the curve (AUC) of 0.79 (95% CI: 0.74–0.84) and 0.78 (95% CI: 0.73–0.83) (Figure A), while the echocardiographic Reader Interpretation had an AUC of 0.85 (95% CI: 0.81–0.89), with a sensitivity of 89% and a specificity of 82% for the prediction of CRT response (Figure B) (p&amp;lt;0.0001 vs. ApRock and SF alone). A total of 92 patients had a QRS duration of 120–150ms, and 48 of them responded to CRT. In these patients, the AUC of Reader Interpretation was comparable to that of the entire study cohort [0.83 (95% CI: 0.75–0.92)], as was sensitivity and specificity (90% and 79%, respectively, p=0.717 vs. the AUC of the entire cohort) (Figure C). Conclusions A visual assessment of LV function, by means of mechanical dyssynchrony and scar, has an excellent predictive value for CRT response, and requires only apical echocardiographic images. Responders were identified equally well in the challenging subgroup of patients with a QRS duration of 120–150 ms. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): KU Leuven

160 Echocardiographic assessment of CRT candidates. Does additional scar evaluation by MRI improve prediction of response?

Abstract Background Myocardial scar presence and extent, has a considerable influence on response to cardiac resynchronization therapy (CRT). Apical rocking (ApRock) and septal flash (SF) are associated with favourable outcome after CRT. Little is known however to which extent visual assessment of mechanical dyssynchrony by ApRock, SF and scar predicts CRT response. We therefore investigated, if additional scar assessment by cardiac magnetic resonance imaging (MRI) adds to the predictive value of the visual evaluation of echocardiographic images in CRT candidates. Methods A total of 201 unselected patients referred for CRT, who fulfil the contemporary guidelines for CRT implantation, were enrolled in this prospective multicentre study. Two experienced observers visually assessed echocardiographic images before CRT implantation, focussing on the presence of ApRock, SF and location and extent of scar segments of the left ventricle (LV), resulting in a CRT response prediction (i.e. Integrative Prediction). A third observer provided a consensus reading in case of disagreement. All observers were blinded to all patient information other than the ischaemic aetiology of heart failure. Independent from that, segmental myocardial scar burden was objectified by late gadolinium enhancement (LGE) cardiac MRI (LGE &amp;gt; 50%). CRT response was defined as ≥15% reduction in LV end-systolic volume on echocardiography, one year after device implantation. Results Overall, 69 (34%) patients had an ischaemic aetiology of heart failure. Before CRT, ApRock and SF were present in 129 (64%) and 136 (68%) patients, respectively. ApRock and SF alone predicted CRT response with an area under the curve (AUC) of 0.85 (95% CI: 0.79-0.91) and 0.84 (95% CI: 0.77-0.91) (Figure A), while the echocardiographic Integrative Prediction had an AUC of 0.90 (95% CI: 0.84-0.95), with a sensitivity of 93% and a specificity of 87% for the prediction of CRT response (Figure B) (p &amp;lt; 0.05 vs. ApRock and SF alone). When combining information on ApRock, SF and the number of scarred segments on MRI in a statistical model, the AUC was comparable to the echocardiographic Integrative Prediction [0.90 (95% CI: 0.84-0.96)] as was sensitivity and specificity (91% and 83%, respectively, p = N.S. vs. Integrative Prediction) (Figure C). Conclusions An integrative visual assessment of LV function has an excellent predictive value for CRT response. Our data show, that the echocardiographic estimation of scar burden is sufficiently accurate and cannot be further improved by an additional MRI scar assessment. Abstract 160 Figure.

P5429Mechanical dyssynchrony has a higher predictive value for CRT response than different ECG-based definitions of LBBB

Abstract Background/Aim To investigate the value of baseline assessment of mechanical dyssynchrony (Dyss) in predicting response to cardiac resynchronization therapy (CRT) in comparison to the classic ECG definition of left bundle branch block (LBBB) (Classic-def) as well as the recently proposed Sex- based definition (Sex-def.). Methods The baseline ECGs of 194 patients (31% females, 39% with ischemic cardiomyopathy, mean QRS width 159±25 ms and mean LVEF 29±8%) were investigated for identifying the criteria of LBBB before CRT implantation. Classic-def., defined as notched or slurred QRS complex in at least two of the leads I, aVL, V1, V2, V5 and V6 with a total width of at least 120 ms in addition to the absence of Q wave in lead I, V5 and V6 was identified in 74% of the study population. Sex-def. was identified in 69%, which is a QRS duration of at least 140 and 130 ms for men and women respectively with otherwise the same criteria of the Classic definition. Dyss was defined as the presence of either apical rocking and/or septal flash in 2D echocardiography prior to implantation. Volumetric response to CRT was defined as a reduction of at least 15% of the LV-end systolic volume (ESV) at follow up echocardiography (12±6 months after device implantation). Results Patient with baseline Dyss showed the highest response rates (76%) with a sensitivity of 88%, a specificity of 63% and an area under the curve (AUC) of 0.76 (P&lt;0.001) compared to 70% (sensitivity 82%, specificity 47%, AUC 0.65, P&lt;0.01) in patients with Sex-def. and 65% (sensitivity 84%, specificity 40%, AUC 0.62, P=0.01) in patients with Classic-def. (Figure A). Pairwise comparisons showed that the accuracy of the Sex-def. did not differ significantly from the Classic-def. in response prediction (AUC=0.65 vs. 0.62 for Sex-def. vs. Classic-def. respectively, P=0.27). Alternatively, Dyss showed a significantly higher accuracy in predicting response to therapy (AUC=0.76) as compared to Sex-def. and Classic-def. (P=0.02 and &lt;0.01 respectively, Figure B). Mech. dyssynchrony vs. ECG-based LBBB Conclusion The presence of Apical rocking and/or septal flash before CRT is associated with better response to CRT as compared to various ECG definitions of LBBB. Although a Sex-based definition of LBBB showed a trend of better response to CRT as compared to the Classic definition, it was not statistically significant.

Assessment of mechanical dyssynchrony can improve the prognostic value of guideline-based patient selection for cardiac resynchronization therapy.

To determine if incorporation of assessment of mechanical dyssynchrony could improve the prognostic value of patient selection based on current guidelines. Echocardiography was performed in 1060 patients before and 12 ± 6 months after cardiac resynchronization therapy (CRT) implantation. Mechanical dyssynchrony, defined as the presence of apical rocking or septal flash was visually assessed at the baseline examination. Response was defined as ≥15% reduction in left ventricular end-systolic volume at follow-up. Patients were followed for a median of 59 months (interquartile range 37-86 months) for the occurrence of death of any cause. Applying the latest European guidelines retrospectively, 63.4% of the patients had been implanted with a Class I recommendation, 18.2% with Class IIa, 9.4% with Class IIb, and in 9% no clear therapy recommendation was present. Response rates were 65% in Class I, 50% in IIa, 38% in IIb patients, and 40% in patients without a clear guideline-based recommendation. Assessment of mechanical dyssynchrony improved response rates to 77% in Class I, 75% in IIa, 62% in IIb, and 69% in patients without a guideline-based recommendation. Non-significant difference in survival among guideline recommendation classes was found (Log-rank P = 0.2). Presence of mechanical dyssynchrony predicted long-term outcome better than guideline Classes I, IIa, IIb (Log-rank P < 0.0001, 0.006, 0.004, respectively) and in patients with no guideline recommendation (P = 0.02). Comparable results were observed using the latest American Guidelines. Our data suggest that current guideline criteria for CRT candidate selection could be improved by incorporating assessment of mechanical asynchrony.

Left ventricular mechanical dyssynchrony assessment in long-standing type II diabetes mellitus patients with normal gated SPECT-MPI

BackgroundAssessment of left ventricular mechanical dyssynchrony (LVMD) using phase analysis of gated SPECT-MPI is well established. However, there is little information about the influence of diabetes mellitus on phase analysis. The present work was to evaluate the LVMD in longstanding type II diabetes mellitus (DM) patients with normal gated SPECT-MPI. MethodsRetrospective analysis of 146 (86 type II diabetics for > 5 years’ duration and 60 nondiabetics) consecutive patients with normal gated SPECT-MPI and adequate LVEF was done. Sixty age- and sex-matched nondiabetic served as control. LVMD was determined from the cutoff values (> mean + 2 SD) observed for phase standard deviation (PSD) and phase bandwidth (PBW) from the control subjects. Multivariate logistic regression analysis was applied to assess the correlation between various confounding factors. ResultsLVMD was detected in 24 (28%) diabetic patients with the pre-defined cut-off values for PSD (> 10.8) and PBW (> 35.6) derived from the controls. Hyperlipidemia, overweight/obesity, duration of DM and its long-term complications were independently associated with LVMD, with long-term complications being the highest risk factor (OR 28.00; P < .001). ConclusionThe evolution time of the patients with type II diabetes mellitus affects the left ventricular mechanical synchrony.

Combined myocardial deformation to predict cardiac resynchronization therapy response in nonischemic cardiomyopathy.

20-30% of patients do not benefit from cardiac resynchronization therapy (CRT) when the established selection criteria were applied. We hypothesized that a combined assessment of mechanical dyssynchrony, myocardial deformation, and diastolic function would identify patients who would benefit most from CRT. In 36 CRT patients, clinical evaluation and echocardiography were performed before and after CRT. Patients were classified into three subgroups according to their amount of response: echocardiographic responders, clinical responders, and nonresponders. Radial dyssynchrony and left ventricular (LV) global longitudinal, radial, and circumferential peak strain was assessed by speckle-tracking image. Diastolic function was quantified by conventional echocardiography. In addition to left bundle branch block, nonspecific intraventricular conduction disturbance with intraventricular dyssynchrony could also improve LV remodeling. Echocardiographic responders had better global longitudinal strain, global circumferential peak strain, and global radial strain at baseline which significantly increased at 12-month follow-up. An improvement in estimates of LV filling pressure and a decrease in mitral regurgitation and left atrial dimensions were observed only in echocardiographic responders to CRT. Patients with clinical but without echocardiographic response showed a significant improvement in atrioventricular (AV) synchrony and a nonsignificant improvement in other parameters. The nonresponder group did not improve the AV and intraventricular dyssynchrony. CRT could not improve restrictive filling pattern with normal filling time. Overall, those patients with AV and intraventricular dyssynchrony and those with best contractile function and short diastolic filling time of restrictive filling pattern at baseline demonstrated the greatest benefit from CRT. Mechanical dyssynchrony, contractile function, and filling pattern are important determinants of the benefits in CRT.

Mechanical dyssynchrony assessment with speckle tracking echocardiography in patients before cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) represents one of the treatment used in congestive heart failure. Current guidelines for this therapy include: widening of the QRS complex, left bundle branch block, NYHA functional class, ejection fraction. However, CRT is not effective for everyone. Unfortunately, there are some patients with heart failure who do not benefit from CRT therapy. For these reasons, a large number of studies have evaluated clinical utility of two-dimensional speckle tracking echocardiography (2D STE). Mechanical dyssynchrony assessed by imaging methods, such as STE, might be able to lead to a better selection of patients who are candidates to CRT and can predict response to it. However it is not known, which potential dyssynchrony parameter is a most promising for predicting benefits from cardiac resynchronization therapy.

Clinical values of left ventricular mechanical dyssynchrony assessment by gated myocardial perfusion SPECT in patients with acute myocardial infarction and multivessel disease.

The aim of this study was to evaluate the prognostic value of additional evaluation of left ventricular mechanical dyssynchrony (LVMD) by gated myocardial perfusion single-photon emission computed tomography (GMPS) in patients with acute myocardial infarction (MI) and multivessel disease. One hundred and nine acute MI patients with >50% stenosis in at least one non-culprit artery who underwent GMPS within 2weeks were enrolled. All patients underwent successful revascularization of the culprit arteries. Those with previous MI, atrial fibrillation, or frequent ventricular premature complexes, cardiac devices, significant patient motion, or procedure-related events were excluded. Phase standard deviation (PSD) and phase histogram bandwidth (PBW) were measured for assessment of LVMD. Patients were followed up for a median of 26months after index MI, for composite major adverse cardiac events (MACE), which consisted with all-cause death, unplanned hospitalization due to heart failure and severe ventricular arrhythmias (sustained ventricular tachycardia or ventricular fibrillation). Independent predictors of MACE were evaluated. MACE occurred in 22 patients (20%). Stress PSD (53.3 ± 17.3° vs. 35.3 ± 18.9°; p <0.001), stress PBW (147.6 ± 54.6° vs. 96.8 ± 59.2°; p = 0.001) and resting PBW (126.8 ± 37.5° vs. 96.6 ± 48.9°; p = 0.001) were significantly higher in patients with MACE compared to those without. Multivariate analysis revealed that stress PSD ≥45.5° and stress PBW ≥126.0° were predictive of MACE, as well as suboptimal non-culprit artery revascularization (SNR) and renin-angiotensin system (RAS) blockade medication. Higher stress PSD and stress PBW were associated with poorer prognosis both in patients with and without SNR, and those with RAS blockade medication, but not in those without RAS blockade medication. LVMD measured by GMPS showed added prognostic value in acute MI with multivessel disease. GMPS could serve as a comprehensive evaluation imaging tool in patients with acute MI and multivessel disease.

New Automatic Tools to Identify Responders to Cardiac Resynchronization Therapy

New echocardiographic parameters (apical rocking [AR], septal flash [SF]) are intended to detect patternsspecific to responders to cardiac resynchronization therapy (CRT). The patterns are visually recognized and qualitatively described, requiring experience and training. Speckle-tracking echocardiography can reflect SF and AR by using newly developed, dedicated parameters, such as start systolic index (SSI) and peak longitudinal displacement (PLD). The aim of this study was to investigate whether SSI and PLDcan identifypotential CRT responders. In 125 patients, echocardiograms from before and 9±3months after CRT were retrospectively analyzed with dedicated EchoPAC prerelease software. From speckle-tracking baseline images, color-coded bull's-eye displays of SSI and PLD were generated. Cutoff values for both parameters were derived from 25 randomly selected patients and applied to the remaining 100 patients to identify CRTresponse, defined as a decrease in end-systolic volume of ≥15% during follow-up. The performance of SSI and PLD was compared with the visual assessment of AR and SF by expert and novice readers. Expert readers detected 77 patients with AR, identifying CRT responders with sensitivity and specificity of 85±2% and 82±2%, respectively. Novice readers reached 74±7% sensitivity and 55±11% specificity,while the sensitivity and specificity of the quantitative analysis were 72±3% and 84±4% for SSI and 80±1% and 75±2% for PLD, respectively. New speckle-tracking-based quantitative assessment of mechanical dyssynchrony by SSI and PLD performs comparably in identifying CRT responders as visual analysis by expert readers and performs significantly better than novice readers.

IMPACT OF BASELINE AND CHANGE IN MECHANICAL DYSSYNCHRONY ON LONG-TERM Outcomes IN THE RESYNCHRONIZATION-DEFIBRILLATION FOR AMBULATORY HEART FAILURE TRIAL (RAFT)

IMPACT OF BASELINE AND CHANGE IN MECHANICAL DYSSYNCHRONY ON LONG-TERM Outcomes IN THE RESYNCHRONIZATION-DEFIBRILLATION FOR AMBULATORY HEART FAILURE TRIAL (RAFT)

Computer-based assessment of ventricular mechanical synchrony from magnetic resonance imaging.

Cardiac resynchronization therapy (CRT) has revolutionized the care of a substantial portion of patients with advanced heart failure (HF). From current guideline (NYHA III or IV heart failure, left ventricular ejection fraction ≤35% and ECG QRS duration ≥ 120 ms), CRT improves clinical status in about 70% of those treated. Ideally, the ability to accurately predict likelihood of response will enhance the quality of treatment. This study aims to develop an automated method to assess left ventricular mechanical synchrony from magnetic resonance imaging (MRI), which has been considered as gold standard cardiac imaging for ventricular structure and function assessment. 26 healthy volunteers (age ranges from 24 years to 73 years) were prospectively recruited and underwent standard MRI scans. MRI images (e.g. 2-chamber, 3-chamber and 4-chamber views) were processed and atrioventricular junction (AVJ) motions were auto-tracked during cardiac cycle. The myocardial velocities Sm1 and Sm2 at systolic phase; Em and Am at early and late mitral filing phase, were derived respectively. The time to these measures (e.g., TSm1, TSm2, TEm and TAm) were determined and ventricular synchrony indices TSm1-SD-6, TSm2-SD-6, TEm-SD-6 and TAm-SD-6 (standard deviations of TSm1, TSm2, TEm and TAm for 6 AVJ points) were assessed and correlated with age. The computational time per dataset is approximately 5 minutes. One-way ANOVA analysis found that there were no significant differences in time to peak velocities in 6 segments. Second, linear regression analysis found that there were no significant correlation between TSm2-SD-6 and TAm-SD-6 with age, and fair positive correlation between TSm1-SD-6 and TEm-SD-6 with age. In this prospective study, noninvasive ventricular synchrony derived from typically acquired MRI images offers a novel method that may enable ventricular mechanical dyssynchrony assessment in heart failure.

Left Ventricular Dyssynchrony by Three-Dimensional Echocardiography: Current Understanding and Potential Future Clinical Applications.

Left ventricular mechanical dyssynchrony is an important prognostic factor for patients with symptomatic systolic heart failure and has emerged as a therapeutic target for cardiac resynchronization therapy (CRT). However, approximately one-third of patients fail to improve after CRT based on current guideline recommendations and electrocardiographic criteria. Two-dimensional echocardiography and tissue Doppler-based techniques have shown variable results in assessment of left ventricular (LV) dyssynchrony and have limited value in clinical practice. Three-dimensional echocardiography (3DE) is an appealing novel imaging modality that has been recently used in quantitative evaluation of global and regional LV function. There is accumulating evidence that 3DE measurement of LV systolic dyssynchrony index may potentially play a role in predicting the short- and long-term response to CRT and further improve patient selection for CRT. New developments in 3DE speckle tracking technique and strain analysis may further improve the accuracy of LV mechanical dyssynchrony assessment in this population. In addition, recent studies suggest that mechanical dyssynchrony is present in patients with LV hypertrophy and diastolic heart failure. Three-dimensional echocardiographic assessment of dyssynchrony may aid in diagnosis and in predicting long-term outcome in these patients. We will summarize current understanding of 3DE techniques and parameters in assessment of LV mechanical dyssynchrony in the population of patients with systolic heart failure, LV hypertrophy, and diastolic heart failure. A number of the novel 3DE techniques described in this review are early in their stage of development, and they will continue to evolve and need further testing in large multicenter studies.