Association of apical rocking with super-response to cardiac resynchronisation therapy.

BACKGROUND: Super-responders to cardiac resynchronisation therapy (CRT) show an exceptional improvement in left ventricular ejection fraction (LVEF). Previous studies showed that apical rocking was independently associated with echocardiographic response to CRT. However, little is known about the association between apical rocking and super-response to CRT. OBJECTIVES: To determine the independent association of LV apical rocking with super-response to CRT in a large cohort. METHODS: A cohort of 297 consecutive heart failure patients treated with primary indication for CRT-D were included in an observational registry. Apical rocking was defined as motion of the left ventricular (LV) apical myocardium perpendicular to the LV long axis. 'Super-response' was defined by the top quartile of LVEF response based on change from baseline to follow-up echocardiogram. Best-subset regression analysis identified predictors of LVEF super-response to CRT. RESULTS: Apical rocking was present in 45 % of patients. Super-responders had an absolute mean LVEF increase of 27 % (LVEF 22.0 % ± 5.7 at baseline and 49.0 % ± 7.5 at follow-up). Apical rocking was significantly more common in super-responders compared with non-super-responders (76 and 34 %, P < 0.001). In univariate analysis, female gender (OR 2.39, 95 % CI 1.38-4.11), lower LVEF at baseline (OR 0.91 95 % CI 0.87-0.95), non-ischaemic aetiology (OR 4.15, 95 % CI 2.33-7.39) and apical rocking (OR 6.19, 95 % CI 3.40-11.25) were associated with super-response. In multivariate analysis, apical rocking was still strongly associated with super-response (OR 5.82, 95 % CI 2.68-12.61). Super-responders showed an excellent clinical prognosis with a very low incidence of heart failure admission, cardiac mortality and appropriate ICD therapy. CONCLUSION: Apical rocking is independently associated with super-response to CRT.

Inhomogeneous Longitudinal Cardiac Rotation and Impaired Left Ventricular Longitudinal Strain in Children and Young Adults with End-Stage Renal Failure Undergoing Hemodialysis.

BACKGROUND: Cardiac dysfunction frequently complicates the clinical course of patients with end-stage renal failure (ESRF). Recently, we observed abnormal longitudinal cardiac rotation (LR) among patients with ESRF. In this study, we sought to quantify LR mechanics in patients undergoing hemodialysis (HD). METHODS: Twenty-four subjects, 12 ESRF patients (58% male; age 17.5 ± 4.4 years) receiving HD, and 12 aged-matched controls, were prospectively studied. Patients underwent echocardiographic studies before and after HD. LR mechanics were quantified with two-dimensional speckle tracking echocardiography. Peak systolic left ventricular (LV) longitudinal strain and displacement measurements were obtained in all subjects. RESULTS: LR mechanics were successfully quantified in all subjects using 5 key echocardiographic features of LR. We identified two different inhomogeneous LR motion patterns in 41.7% of ESRF patients, characterized by a delayed timing of LR or increased segmental apical rotation. Inhomogeneous LR patterns were not found in controls. Timing of early-systolic counterclockwise LR increased after HD (P = 0.006). In patients, late-systolic clockwise LR occurred earlier (P = 0.043), and showed a significant prolongation after HD (P = 0.003). Longitudinal strain was significantly impaired in patients (P = 0.015), and further decreased after HD (P < 0.0001). Strong correlations were observed between strain and displacement parameters and LR mechanics. CONCLUSIONS: Quantifying LR using speckle tracking echocardiography was feasible, easy, and reproducible. Inhomogeneous LR motion patterns were demonstrated in a large proportion of patients with ESRF. LV dysfunction seems the most important determinant of inhomogeneous LR. Further studies are required to validate these findings.

Echocardiographic mechanical dyssynchrony predicts long-term mortality in patients with cardiac resynchronisation therapy.

Cardiac resynchronisation therapy (CRT) is an established treatment for patients with symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 35%; HFrEF) and conduction disturbances (QRS duration ≥ 130 ms). The presence of mechanical dyssynchrony (MD) on echocardiography has been hypothesised to be of predictive value in determining indication for CRT. This study investigated the impact of MD (apical rocking [AR] and septal flash [SF]) on long-term survival in CRT recipients. HFrEF patients (n = 425; mean age 63.0 ± 10.6 years, 72.3% male, 60.7% non-ischaemic aetiology) with a guideline-derived indication for CRT underwent device implantation. MD markers were determined at baseline and after a mean follow-up of 11.5 ± 8.0 months; long-term survival was also determined. AR and/or SF were present in 307 (72.2%) participants at baseline. During post-CRT follow-up, AR and/or SF disappeared in 256 (83.4%) patients. Overall mean survival was 95.9 ± 52.9 months, longer in women than in men (109.1 ± 52.4 vs. 90.9 ± 52.4 months; p < 0.001) and in younger (< 60 years) versus older patients (110.6 ± 53.7 vs. 88.6 ± 51.1 months; p < 0.001). Patients with versus without MD markers at baseline generally survived for longer (106.2 ± 52.0 vs. 68.9 ± 45.4 months; p < 0.001), and survival was best in patients with resolved versus persisting MD (111.6 ± 51.2 vs. 79.7 ± 47.6 months p < 0.001). Age and MD at baseline were strong predictors of long-term survival in HFrEF patients undergoing CRT on multivariate analysis. Novel echocardiography MD parameters in HFrEF CRT recipients predicted long-term mediated better outcome, and survival improved further when AR and/or SF disappear after CRT implantation.

A Comparative Analysis of Apical Rocking and Septal Flash: Two Views of the Same Systole?

Heart failure (HF) is a complex medical condition characterized by both electrical and mechanical dyssynchrony. Both dyssynchrony mechanisms are intricately linked together, but the current guidelines for cardiac resynchronization therapy (CRT) rely only on the electrical dyssynchrony criteria, such as the QRS complex duration. This possible inconsistency may result in undertreating eligible individuals who could benefit from CRT due to their mechanical dyssynchrony, even if they fail to fulfill the electrical criteria. The main objective of this literature review is to provide a comprehensive analysis of the practical value of echocardiography for the assessment of left ventricular (LV) dyssynchrony using parameters such as septal flash and apical rocking, which have proven their relevance in patient selection for CRT. The secondary objectives aim to offer an overview of the relationship between septal flash and apical rocking, to emphasize the primary drawbacks and benefits of using echocardiography for evaluation of septal flash and apical rocking, and to offer insights into potential clinical applications and future research directions in this area. Conclusion: there is an opportunity to render resynchronization therapy more effective for every individual; septal flash and apical rocking could be a very useful and straightforward echocardiography resource.

Mechanical dyssynchrony as a selection criterion for cardiac resynchronization therapy: Design of the AMEND-CRT trial.

AIMS: One third of patients do not improve after cardiac resynchronization therapy (CRT). Septal flash (SF) and apical rocking (ApRock) are deformation patterns observed on echocardiography in most patients eligible for CRT. These markers of mechanical dyssynchrony have been associated to improved outcome after CRT in observational studies and may be useful to better select patients. The aim of this trial is to investigate whether the current guideline criteria for selecting patients for CRT should be modified and include SF and ApRock to improve therapy success rate, reduce excessive costs and prevent exposure to device-related complications in patients who would not benefit from CRT. METHODS: The AMEND-CRT trial is a multicentre, randomized, parallel-group, double-blind, sham-controlled trial with a non-inferiority design. The trial will include 578 patients scheduled for CRT according to the 2021 ESC guidelines who satisfy all inclusion criteria. The randomization is performed 1:1 to an active control arm ('guideline arm') or an experimental arm ('echo arm'). All participants receive a device, but in the echo arm, CRT is activated only when SF or ApRock or both are present. The outcome of both arms will be compared after 1 year. The primary outcome measures are the average change in left ventricular end-systolic volume and patient outcome assessed using a modified Packer Clinical Composite Score. CONCLUSIONS: The findings of this trial will redefine the role of echocardiography in CRT and potentially determine which patients with heart failure and a prolonged QRS duration should receive CRT, especially in patients who currently have a class IIa or class IIb recommendation.

Cardiac Resynchronization Therapy and Hypertrophic Cardiomyopathy: A Comprehensive Review.

Hypertrophic cardiomyopathy (HCM) is an inherited primary myocardial disease characterized by asymmetrical/symmetrical left ventricle (LV) hypertrophy, with or without LV outflow tract (LVOT) dynamic obstruction, and poor prognosis. Cardiac resynchronization therapy (CRT) has emerged as a minimally invasive tool for patients with heart failure (HF) with decreased LV ejection fraction (LVEF) and prolonged QRS duration of over 120 ms with or without left bundle branch block (LBBB). Several HCM patients are at risk of developing LBBB because of disease progression or secondary to septal myomectomy, while others might develop HF with decreased LVEF, alleged end-stage/dilated HCM, especially those with thin myofilament mutations. Several studies have shown that patients with myectomy-induced LBBB might benefit from left bundle branch pacing or CRT to relieve symptoms, improve exercise capacity, and increase LVEF. Otherwise, patients with end-stage/dilated HCM and prolonged QRS interval could gain from CRT in terms of NYHA class improvement, LV systolic performance increase and, to some degree, LV reverse remodeling. Moreover, several electrical and imaging parameters might aid proper selection and stratification of HCM patients to benefit from CRT. Nonetheless, current available data are scarce and further studies are still required to accurately clarify the view. This review reassesses the importance of CRT in patients with HCM based on current research by contrasting and contextualizing data from various published studies.

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.

Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT.

OBJECTIVES: The aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT. BACKGROUND: MR is very frequent among patients with dilated cardiomyopathy and conduction delay. METHODS: Echocardiograms (pre-CRT and 12 ± 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area. RESULTS: At baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (ΔLV end-systolic volume -35.5% ± 27.2% vs -4.1% ± 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction. CONCLUSIONS: ApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR.

The association of mechanical dyssynchrony and resynchronization therapy with survival in heart failure with a wide QRS complex: a two-world study.

Setting up a randomized trial to assess the association of mechanical dyssynchrony (MD) and the success of cardiac resynchronization therapy (CRT) in heart failure with a wide QRS complex is ethically challenging. We therefore investigated this association in a retrospective cohort study observing different treatment strategies which were chosen based on the availability of health care resources. The survival of 500 patients from six Western European centers treated with CRT was compared to their 137 Eastern European counterparts not treated with CRT, with regard to the presence of MD. MD was visually assessed and was defined as the presence of apical rocking and/or septal flash. Patients were followed for a mean of 26 ± 8 months for the occurrence of death of any cause. As compared with medical therapy alone, CRT was associated with a more favorable survival (hazard ratio (HR), 0.53; 95% confidence interval (CI) 0.35-0.79; P = 0.002). Patients with MD treated by CRT had better survival than patients belonging to all other groups-they showed 72%, 66% and 56% reduction in all-cause mortality, respectively, compared to patients with MD not treated by CRT (HR 0.28; 95% CI 0.17-0.44), patients without MD treated by CRT (HR 0.34; 95% CI 0.22-0.52) and patients without MD not treated by CRT (HR 0.44; 95% CI 0.25-0.76). Patients with wide QRS complex who are treated with CRT have a significantly better survival when MD is present.

Sex-specific difference in outcome after cardiac resynchronization therapy.

AIMS: Observation of better outcome in women after cardiac resynchronization therapy (CRT) has led to controversies about a potential sex-specific response. In this study, we investigated to which extent this sex-specific difference in CRT outcome could be explained by differences in baseline characteristics between both sexes. METHODS AND RESULTS: We retrospectively analysed data from a multicentre registry of 1058 patients who received CRT. Patients were examined by echocardiography before and 12 ± 6 months after implantation. Response was defined as ≥15% reduction of left ventricular end-systolic volume at follow-up. Patient's characteristics at baseline, including New York Heart Association class, ejection fraction, QRS width and morphology, ischaemic aetiology of cardiomyopathy (ICM), number of scarred segments, age at implantation, atrial fibrillation, and mechanical dyssynchrony (Dyss) were analysed. Patients were followed for a median duration of 59 months. Primary end point was all-cause mortality. Women (24% of the population) had less ICM (23% vs. 49%, P < 0.0001), less scarred segments (0.4 ± 1.3 vs. 1.0 ± 2.1, P < 0.0001), more left bundle branch block (LBBB; 87% vs. 80%, P = 0.01), and more Dyss at baseline (78% vs. 57%, P < 0.0001). Without matching baseline differences, women showed better survival (log rank P < 0.0001). After matching, survival was similar (log rank P = 0.58). In multivariable analysis, female sex was no independent predictor of neither volumetric response (P = 0.06) nor survival (P = 0.31). CONCLUSION: Our data suggest that the repeatedly observed better outcome in women after CRT is mainly due to the lower rate ICM and smaller scars. When comparing patients with similar baseline characteristics, the response of both sexes to CRT is similar.

The association of volumetric response and long-term survival after cardiac resynchronization therapy.

AIMS: Clinical experience indicates that limited or no reverse left ventricular (LV) remodelling may not necessarily imply non-response to cardiac resynchronization therapy (CRT). We investigated the association of the extent of LV remodelling, mechanical dyssynchrony, and survival in patients undergoing CRT. METHODS AND RESULTS: In 356 CRT candidates, three blinded readers visually assessed the presence of mechanical dyssynchrony (either apical rocking and/or septal flash) before device implantation and also its correction by CRT 12 ± 3 months post-implantation. To assess LV reverse remodelling, end-systolic volumes (ESV) were measured at the same time points. Patients were divided into four subgroups: no LV remodelling (ESV change 0 ± 5%), mild LV reverse remodelling (ESV reduction 5-15%), significant LV reverse remodelling (ESV reduction ≥15%), and LV volume expansion (ESV increase ≥5%). Patients were followed for all-cause mortality during the median follow-up of 36 months. Patients with LV remodelling as in the above defined groups showed 58, 54, and 84% reduction in all-cause mortality compared to patients with volume expansion. In multivariable analysis, LVESV change remained independently associated with survival, with an 8% reduction in mortality for every 10% decrease in LVESV (P = 0.0039), but an optimal cut-off point could not be established. In comparison, patients with corrected mechanical dyssynchrony showed 71% reduction in all-cause mortality (P < 0.001). CONCLUSION: Volumetric response assessed at 1-year after CRT is strongly associated with long-term mortality. However, an optimal cut-off cannot be established. The association of the correction of mechanical dyssynchrony with survival was stronger than that of any volumetric cut-off.

Long-Term Outcome After CRT in the Presence of Mechanical Dyssynchrony Seen With Chronic RV Pacing or Intrinsic LBBB.

OBJECTIVES: The aim of this study was to compare the volumetric response and the long-term survival after cardiac resynchronization therapy (CRT) in patients with intrinsic left bundle branch block (LBBB) versus chronic right ventricular pacing (RVP) with respect to the presence of mechanical dyssynchrony (MD). BACKGROUND: Chronic RVP induces an iatrogenic LBBB and asynchronous left ventricular contraction that is potentially reversible by upgrading to CRT. METHODS: A total of 914 patients eligible for CRT (117 with conventional pacemakers and 797 with intrinsic LBBB) were included in the study. MD was visually assessed before CRT and was defined as the presence of either apical rocking and/or septal flash on baseline echocardiograms. Patients with a left ventricular end-systolic volume decrease of ≥15% during the follow-up were considered responders. Patients were followed for all-cause mortality during the median follow-up of 48 months (interquartile range: 29 to 66 months). RESULTS: MD was observed in 51% of patients with RVP versus 77% in patients with intrinsic LBBB (p < 0.001). Patients with RVP and MD had a similar likelihood of volumetric response as did patients with intrinsic LBBB and MD (adjusted odds ratio: 0.71; 95% confidence interval: 0.33 to 1.53; p = 0.385). There was no significant difference in long-term survival between patients with RVP and intrinsic LBBB (adjusted hazard ratio: 1.101; 95% confidence interval: 0.658 to 1.842; p = 0.714). Patients with visual MD and either intrinsic LBBB or RVP had a more favorable survival than those without MD (p < 0.001). CONCLUSIONS: The likelihood of volumetric response and a favorable long-term survival of patients with RVP was similar to those of patients with intrinsic LBBB and were mainly determined by the presence of MD and not by the nature of LBBB.

The Impact of Function-Flow Interaction on Left Ventricular Efficiency in Patients with Conduction Abnormalities: A Particle Image Velocimetry and Tissue Doppler Study.

BACKGROUND: The aims of this study were to assess the influence of left bundle branch block (LBBB)-like conduction abnormalities on left ventricular (LV) blood flow patterns and to characterize their potential impact on LV efficiency by measuring the changes in vortex formation and energy dissipation in the left ventricle using echocardiographic particle image velocimetry. METHODS: Thirty-six subjects were prospectively studied, including 20 patients with pacemakers, six patients with LBBB, and 10 healthy control subjects, all of whom had normal ejection fractions (>50%). In patients with pacemakers, data were acquired in both DDD and AAI modes. Standard grayscale, tissue Doppler myocardial imaging, and contrast-enhanced echocardiographic particle image velocimetric data were acquired, and LV flow patterns were analyzed using dedicated software. Dyssynchrony was quantified by measuring apical transverse motion. RESULTS: Apical transverse motion was significantly higher in patients with LBBB compared with normal control subjects (mean, 4.9 ± 1.9 vs 1.0 ± 0.7 mm; P < .001). Quantitative measures of vortex energy dissipation (relative strength, vortex relative strength, and vortex pulsation correlation) were significantly higher in patients with LBBB (2.05 ± 0.54, 0.53 ± 0.13, and 0.87 ± 0.47, respectively) compared with control subjects (1.48 ± 0.28, 0.33 ± 0.05, and 0.24 ± 0.51, respectively) (P < .02 for all). Vortex duration time in relation to the entire cardiac cycle was shorter in patients with LBBB than in control subjects (28% vs 44%). All findings in both groups were comparable with DDD and AAI. CONCLUSION: LV flow pattern analysis by echocardiographic particle image velocimetry reveals that conduction delay due to LBBB or pacemaker stimulation in the right ventricle (DDD) disturbs the transfer of kinetic energy during the cardiac cycle and causes less efficient LV function. These data contribute to a better understanding of hemodynamic consequences of conduction delays and may help in the optimization of therapeutic approaches.

Association of apical rocking with long-term major adverse cardiac events in patients undergoing cardiac resynchronization therapy.

AIMS: Correctly identifying patients who will benefit from cardiac resynchronization therapy (CRT) is still challenging. 'Apical rocking' is observed in asynchronously contracting ventricles and is associated with echocardiographic response to CRT. The association of apical rocking and long-term clinical outcome is however unknown at present. We assessed the predictive value of left ventricular (LV) apical rocking on a long-term clinical outcome in patients treated with CRT. METHODS AND RESULTS: Consecutive heart failure patients treated with primary indication for CRT-D between 2005 and 2009 were included in a prospective registry. Echocardiography was performed prior to CRT to assess apical rocking, defined as motion of the LV apical myocardium perpendicular to the LV long axis. Major adverse cardiac event (MACE) was defined as combined end point of cardiac death and/or heart failure hospitalization and/or appropriate therapy (ATP and/or ICD shocks). All echocardiograms were assessed by independent cardiologists, blinded for clinical data. Multivariable analyses were performed to adjust for potential confounders. Two hundred and ninety-five patients with echocardiography prior to implantation were included in the final analyses. Apical rocking was present in 45% of the study patients. Apical rocking was significantly more common in younger patients, females, patients with sinus rhythm, non-ischaemic cardiomyopathy, and in patients with LBBB and wider QRS duration. During a mean clinical follow-up of 5.2 ± 1.6 years, 92 (31%) patients reached the end point of the study (MACE). Patients with MACE had shorter QRS duration, had more ischaemic cardiomyopathy, and were more often on Amiodarone. In univariate analyses, MACE was associated with shorter QRS duration, ischaemic aetiology, and the absence of apical rocking. After multivariable analyses, apical rocking was associated with less MACE (hazards ratio, HR 0.44, 95% confidence interval, CI 0.25-0.77). CONCLUSION: Apical rocking is an independent predictor of a favourable long-term outcome in CRT-D patients.

Relationship of visually assessed apical rocking and septal flash to response and long-term survival following cardiac resynchronization therapy (PREDICT-CRT).

AIMS: Apical rocking (ApRock) and septal flash (SF) are often observed phenomena in asynchronously contracting ventricles. We investigated the relationship of visually assessed ApRock and SF, reverse remodelling, and long-term survival in cardiac resynchronization therapy (CRT) candidates. METHODS AND RESULTS: A total of 1060 patients eligible for CRT underwent echocardiographic examinations before and 12 ± 6 months after device implantation. Three blinded physicians were asked to visually assess the presence of ApRock and SF before device implantation and also their correction by CRT 12 ± 6 months post-implantation. Patients with a left ventricular (LV) end-systolic volume decrease of ≥15% during the first year of follow-up were regarded as responders. Patients were followed for a median period of 46 months (interquartile range: 27-65 months) for the occurrence of death of any cause. If corrected by CRT, visually assessed ApRock and SF were associated with reverse remodelling with a sensitivity of 84 and 79%, specificity of 79 and 74%, and accuracy of 82 and 77%, respectively. ApRock (hazard ratio [HR] 0.40, 95% confidence interval [CI] 0.30-0.53, P < 0.0001) and SF (HR 0.45 [CI 0.34-0.61], P < 0.001) were independently associated with lower all-cause mortality after CRT and had an incremental value over clinical variables and QRS width for identifying CRT responders. Both the absence of ApRock/SF and unsuccessful correction of ApRock/SF despite CRT were associated with a high risk for non-response and an unfavourable long-term survival. CONCLUSION: A specific LV mechanical dyssynchrony pattern, characterized by ApRock and SF, is associated with a more favourable long-term survival after CRT. Both parameters are also indicators of an effective therapy.

Cardiovascular magnetic resonance features of mechanical dyssynchrony in patients with left bundle branch block.

Patients with left bundle branch block (LBBB) can exhibit mechanical dyssynchrony which may contribute to heart failure; such patients may benefit from cardiac resynchronization treatment (CRT). While cardiac magnetic resonance imaging (CMR) has become a common part of heart failure work-up, CMR features of mechanical dyssynchrony in patients with LBBB have not been well characterized. This study aims to investigate the potential of CMR to characterize mechanical features of LBBB. CMR examinations from 43 patients with LBBB on their electrocardiogram, but without significant focal structural abnormalities, and from 43 age- and gender-matched normal controls were retrospectively reviewed. The following mechanical features of LBBB were evaluated: septal flash (SF), apical rocking (AR), delayed aortic valve opening measured relative to both end-diastole (AVOED) and pulmonic valve opening (AVOPVO), delayed left-ventricular (LV) free-wall contraction, and curvatures of the septum and LV free-wall. Septal displacement curves were also generated, using feature-tracking techniques. The echocardiographic findings of LBBB were also reviewed in those subjects for whom they were available. LBBB was significantly associated with the presence of SF and AR; within the LBBB group, 79 % had SF and 65 % had AR. Delayed AVOED, AVOPVO, and delayed LV free-wall contraction were significantly associated with LBBB. AVOED and AVOPVO positively correlated with QRS duration and negatively correlated with ejection fraction. Hearts with electrocardiographic evidence of LBBB showed lower septal-to-LV free-wall curvature ratios at end-diastole compared to normal controls. CMR can be used to identify and evaluate mechanical dyssynchrony in patients with LBBB. None of the normal controls showed the mechanical features associated with LBBB. Moreover, not all patients with LBBB showed the same degree of mechanical dyssynchrony, which could have implications for CRT.