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.

Imaging in patients with cardiovascular implantable electronic devices: part 1-imaging before and during device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

More than 500 000 cardiovascular implantable electronic devices (CIEDs) are implanted in the European Society of Cardiology countries each year. The role of cardiovascular imaging in patients being considered for CIED is distinctly different from imaging in CIED recipients. In the former group, imaging can help identify specific or potentially reversible causes of heart block, the underlying tissue characteristics associated with malignant arrhythmias, and the mechanical consequences of conduction delays and can also aid challenging lead placements. On the other hand, cardiovascular imaging is required in CIED recipients for standard indications and to assess the response to device implantation, to diagnose immediate and delayed complications after implantation, and to guide device optimization. The present clinical consensus statement (Part 1) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients undergoing implantation of conventional pacemakers, cardioverter defibrillators, and resynchronization therapy devices. The document summarizes the existing evidence regarding the use of imaging in patient selection and during the implantation procedure and also underlines gaps in evidence in the field. The role of imaging after CIED implantation is discussed in the second document (Part 2).

The saga of dyssynchrony imaging: Are we getting to the point

Cardiac resynchronisation therapy (CRT) has an established role in the management of patients with heart failure, reduced left ventricular ejection fraction (LVEF < 35%) and widened QRS (>130 msec). Despite the complex pathophysiology of left ventricular (LV) dyssynchrony and the increasing evidence supporting the identification of specific electromechanical substrates that are associated with a higher probability of CRT response, the assessment of LVEF is the only imaging-derived parameter used for the selection of CRT candidates.

This review aims to (1) provide an overview of the evolution of cardiac imaging for the assessment of LV dyssynchrony and its role in the selection of patients undergoing CRT; (2) highlight the main pitfalls and advantages of the application of cardiac imaging for the assessment of LV dyssynchrony; (3) provide some perspectives for clinical application and future research in this field.

Conclusion

the road for a more individualized approach to resynchronization therapy delivery is open and imaging might provide important input beyond the assessment of LVEF.

Utility of dobutamine stress echocardiography in aortic valve regurgitation and reduced left ventricular function

OBJECTIVE

Predictors for post-operative reverse remodeling in patients with severe aortic regurgitation (AR) and reduced left ventricular ejection fraction (LVEF) are unknown. We performed low-dose dobutamine stress echocardiography (DSE) in patients with severe AR and reduced LVEF to evaluate the relationship between contractile reserve (CR) and reverse remodeling after surgery.

METHODS

In 31 patients with chronic severe AR and reduced LVEF (LVEF < 50%), we performed pre-operative DSE, assessed CR, and examined whether changes in preoperative DSE were associated with improvement of post-operative LVEF after aortic valve surgery.

RESULTS

The pre-operative echocardiographic findings were as follows: left ventricular (LV) end-diastolic dimension: 67 ± 10 mm, LV end-systolic dimension: 52 ± 13 mm, and LVEF: 42 ± 8%. All patients underwent aortic valve surgery. Patients with pre-operative LVEF of ≥45% exhibited a significant increase in LVEF; however, patients with pre-operative LVEF of <45% showed no significant change. When we examined the results of DSE performed in patients with pre-operative LVEF of <45%, ΔLVEF of ≥6% (with CR) during DSE was related to an improvement in post-operative LVEF; ΔLVEF of ≥6% during DSE predicted an improvement in post-operative LVEF, with sensitivity 100%; specificity 78%; and area under curve (AUC) .92.

CONCLUSIONS

DSE might be a helpful tool for predicting post-operative reverse remodeling in patients with severe AR and moderately reduced LVEF.

Multimodality imaging in the diagnosis, risk stratification, and management of patients with dilated cardiomyopathies: an expert consensus document from the European Association of Cardiovascular Imaging

Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery disease sufficient to explain these changes. This is a heterogeneous disease frequently having a genetic background. Imaging is important for the diagnosis, the prognostic assessment and for guiding therapy. A multimodality imaging approach provides a comprehensive evaluation of all the issues related to this disease. The present document aims to provide recommendations for the use of multimodality imaging according to the clinical question. Selection of one or another imaging technique should be based on the clinical condition and context. Techniques are presented with the aim to underscore what is 'clinically relevant' and what are the tools that 'can be used'. There remain some gaps in evidence on the impact of multimodality imaging on the management and the treatment of DCM patients where ongoing research is important.

The assessment of pressure-volume relationship during exercise stress echocardiography predicts left ventricular remodeling and eccentric hypertrophy in patients with chronic heart failure

BACKGROUND

The contractile response of patients with heart failure (HF) may be assessed by exercise stress echocardiography (ESE)-derived indexes. We sought to test whether ESE parameters are useful to identify the risk of adverse left ventricular (LV) remodeling in patients with chronic HF and reduced or mildly reduced LV ejection fraction (EF).

METHODS

We enrolled 155 stabilized patients (age: 62 ± 11 years, 17% female, coronary artery disease 47%) with chronic HF, LV EF ≤50% and LV end-diastolic volume index > 75 ml/m2. All patients underwent a symptom-limited graded bicycle semi-supine ESE, with evaluation of peak stress LV EF, end-systolic pressure-volume relation (ESPVR, i.e. LV elastance) and cardiac power output to LV mass (CPOM). A complete echocardiographic study was performed at baseline and after 6 ± 3 months. Adverse LV remodeling was defined as the association of eccentric LV hypertrophy (LV mass: ≥115 g/m2 for male and ≥ 95 g/m2 for women, and relative wall thickness < 0.32) with an increase in LV end-systolic volume index ≥10% at six months.

RESULTS

Adverse LV remodeling was detected in 34 (22%) patients. After adjustment for clinical, biochemical and echocardiographic data, peak ESPVR resulted in the most powerful independent predictor of adverse LV remodeling (OR: 12.5 [95% CI 4.5-33]; p < 0.0001) followed by ischemic aetiology (OR: 2.64 [95% 1.04-6.73]; p = 0.04).

CONCLUSION

In patients with HF and reduced or mildly reduced EF, a compromised ESE-derived peak ESPVR, that reflects impaired LV contractility, resulted to be the most powerful predictor of adverse LV remodeling.

Current role of echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure and left ventricular systolic dysfunction. Patients are usually assessed by echocardiography, which provides a number of anatomical and functional information used for cardiac dyssynchrony assessment, prognostic stratification, identification of the optimal site of pacing in the left ventricle, optimization of the CRT device, and patient follow-up. Compared to other cardiac imaging techniques, echocardiography has the advantage to be non-invasive, repeatable, and safe, without exposure to ionizing radiation or nefrotoxic contrast. In this article, we review current evidence about the role of echocardiography before, during, and after the implantation of a CRT device.

Left ventricular contractile reserve by stress echocardiography as a predictor of response to cardiac resynchronization therapy in heart failure: a systematic review and meta-analysis

Background

The presence of left ventricular contractile reserve (LVCR) during stress echo (SE) may provide favorable response to cardiac resynchronization therapy (CRT) in heart failure patients. The aim of the study was to perform a meta-analysis of available SE data in this set of patients.

Methods

From a Pubmed and Advance Google Scholar database web based search scan up to December 2016, we initially identified 5906 records. From this initial set, we removed that did not include SE and duplicate studies. We assessed for eligibility 71 full-text articles assessed for eligibility, and 60 of them did not meet the inclusion criteria as follow: 1) heart failure patients with NYHA class III and IV, depressed ejection fraction (EF <35%) and QRS duration ≥120 ms at study entry; 2) SE with assessment of LVCR; 3) Follow-up data. LVCR during SE was identified as reduction in wall motion score index and/or an increase in EF.

Results

Eleven studies with 861 patients (mean age 67 ± 9 years, ejection fraction 25 ± 6%) were included in the meta-analysis. The type of stress was either exercise (n = 2) or dobutamine (n = 9), the latter with low-dose (10 mcg) in two, intermediate-dose (20 mcg) in five, and high-dose (40 mcg) protocol in two studies. LVCR was detected in 555 patients (63%) and CRT-response was present in 584 (66%). The overall odds ratio for LVCR to predict a favorable CRT response was 2.06 (95%, CI 1.70–2-43), Z score: 11.055, p < 0.001.

Conclusion

The presence of LVCR during SE with either dobutamine or exercise is associated with a greater chance of response to CRT. This parameter is now ready to be tested in a prospective multicenter trial to select patients more likely to benefit from CRT.

The electrocardiographic characteristics of septal flash in patients with left bundle branch block

AIMS

In patients with systolic heart failure and left bundle branch block (LBBB), septal flash (SF) movement has been described by echocardiography. We evaluated the prevalence of SF in LBBB and non-LBBB patients and evaluated whether specific electrocardiographic (ECG) characteristics within LBBB are associated with the presence of SF on echocardiography.

METHODS AND RESULTS

One hundred and four patients with probable LBBB on standard 12-lead ECG were selected, 40 patients with non-LBBB served as controls. Left bundle branch block and non-LBBB were defined, according to the most recent guidelines. The presence of SF was assessed by echocardiography. Strict LBBB criteria were met in 93.3% of the patients. Septal flash was present in 45.2% of LBBB patients and was not present in non-LBBB patients. This was more prevalent in patients without anterior ischaemic cardiomyopathy (ICMP) compared with those with anterior ICMP (P = 0.008). The duration of QRS was longer in SF patients compared with that of non-SF patients (P < 0.05). The presence of a mid-QRS notching in more than two consecutive leads was a good predictor for the presence of SF (P = 0.01), and when combined with an absent R-wave in lead V1, the presence of SF is very likely (P = 0.001).

CONCLUSION

Our data show that SF is present in 45.2% of LBBB patients, whereas it was absent in patients with non-LBBB. Patients with SF fulfilled more LBBB criteria compared with LBBB patients without SF. Our findings raise the provocative question of whether the presence of SF identifies patients with 'true LBBB' and whether this echocardiographic finding might be considered as a selection parameter in cardiac resynchronization therapy.

Echocardiography and cardiac resynchronisation therapy, friends or foes?

Echocardiography is used in cardiac resynchronisation therapy (CRT) to assess cardiac function, and in particular left ventricular (LV) volumetric status, and prediction of response. Despite its widespread applicability, LV volumes determined by echocardiography have inherent measurement errors, interobserver and intraobserver variability, and discrepancies with the gold standard magnetic resonance imaging. Echocardiographic predictors of CRT response are based on mechanical dyssynchrony. However, parameters are mainly tested in single-centre studies or lack feasibility. Speckle tracking echocardiography can guide LV lead placement, improving volumetric response and clinical outcome by guiding lead positioning towards the latest contracting segment. Results on optimisation of CRT device settings using echocardiographic indices have so far been rather disappointing, as results suffer from noise. Defining response by echocardiography seems valid, although re-assessment after 6 months is advisable, as patients can show both continuous improvement as well as deterioration after the initial response. Three-dimensional echocardiography is interesting for future implications, as it can determine volume, dyssynchrony and viability in a single recording, although image quality needs to be adequate. Deformation patterns from the septum and the derived parameters are promising, although validation in a multicentre trial is required. We conclude that echocardiography has a pivotal role in CRT, although clinicians should know its shortcomings.

Low-dose dobutamine stress echo for reverse remodeling prediction after cardiac resynchronization

PURPOSE

Cardiac resynchronization therapy (CRT) is a valuable option for patients with heart failure and wide QRS to reduce electromechanical dyssynchrony (DYS). High non-responders rate (30%) urges the need to improve selection of candidates for CRT. We hypothesized that low-dose dobutamine stress echocardiography (DSE) can help unmask dyssynchronous motion. The aim of this study is comparison between dyssynchrony index at rest and during low-dose dobutamine stress to predict left ventricular reverse remodeling after CRT.

PATIENTS AND METHODS

Prospectively, 57 consecutive patients (37 male) aged 61.8±9 who qualified for CRT according to current guidelines were enrolled. Two dimensional echocardiography and tissue Doppler imaging (TDI) were performed before and 6 month after CRT to assess reverse remodeling (rLV). Additionally DSE was performed before CRT. DYS was assessed at rest (DYSr) and peak DSE (DYSd) separately, as a difference between time to peak systolic velocity (Ts) of septum and lateral wall. Ts was corrected for heart rate.

RESULTS

rLV defined as decrease ≥15% of LVESV at follow-up was found in 38 (67%) patients. DYSr and DYSd were independent predictors of rLV (OR=1.04, Cl ±1.02-1.06, p<0.02 and OR=1.05, Cl±1.03-1.08, p<0.0002 respectively). ROC analysis found that DYSr>42ms and DYSd>59ms had sensitivity of 70% and 87%, specificity of 61% and 78%, and accuracy of 70% and 84% respectively for prediction of reverse remodeling LV. Area under Receiver Operating Characteristic Curve for DYSd was higher than for DYSr (0.89 vs 0.71, p<0.007).

CONCLUSION

Exercise intraventricular dyssynchrony assessed by dobutamine stress echo is a strong independent predictor of cardiac resynchronization therapy response.

Mechanical abnormalities detected with conventional echocardiography are associated with response and midterm survival in CRT

OBJECTIVES

Our aim was to identify "correctable abnormalities" using conventional grayscale and blood-pool Doppler echocardiography and evaluate their ability to predict both response and midterm survival.

BACKGROUND

Identification of mechanical abnormalities that may be corrected with cardiac resynchronization therapy (CRT) is useful for predicting echocardiographic response at 1-year follow-up.

METHODS

A total of 200 CRT patients were included. Clinical evaluation and echocardiography were performed before and after CRT to assess the presence of the mechanical abnormalities of interest (septal flash, abnormal ventricular filling, or exaggerated interventricular dependence). Response to CRT was defined as a reduction in left ventricular (LV) end-systolic volume (ESV) ≥15%. Four subgroups of extent of response were defined: LVESV reduction >26.68% (extensive remodeling); LVESV reduction 6.8% to 26.68% (slight remodeling); LVESV reduction <6.8% (no remodeling) and clinical response; and LVESV reduction <6.8% without clinical response or the occurrence of death or heart transplantation. Midterm cardiovascular survival was evaluated (mean follow-up 38 ± 19 months).

RESULTS

The presence of a correctable abnormality was independently associated with a better rate (odds ratio: 0.03 [95% confidence interval (CI): 0.01 to 0.10], p < 0.001) and extent of response to CRT (n = 59 [96.7%] for the extensive remodeling subgroup vs. n = 53 [85.5%] for the slight remodeling subgroup vs. n = 19 [47.5%] for the no remodeling with clinical response subgroup vs. n = 17 [45.9%] for the no remodeling without clinical response subgroup, p = 0.0001), as well as with increased midterm survival (hazard ratio: 0.11 [95% CI: 0.2 to 0.6]). Other independent predictors included creatinine level and LV end-systolic diameter for response; New York Heart Association functional class IV, creatinine, LV end-systolic diameter, and transmurality index for extent of response; and New York Heart Association functional class IV for cardiovascular mortality.

CONCLUSIONS

The presence of a correctable abnormality evaluated by conventional echocardiography is associated with LV reverse remodeling and better survival at midterm follow-up. Clinical characteristics and myocardial viability also have an influence.

Novel dyssynchrony evaluation by M-mode imaging in left bundle branch block and the application to predict responses for cardiac resynchronization therapy

BACKGROUND

To determine an appropriate M-mode method in assessing left ventricular (LV) dyssynchrony in left bundle branch block (LBBB), and to assess feasibility of the method to predict cardiac resynchronization therapy (CRT) responses.

METHODS AND RESULTS

Fifty-one patients with LBBB were enrolled. Among them 31 patients underwent CRT. In addition to original septal to posterior wall motion delay (SPWMD), first peak-SPWMD was proposed as time of difference between the first septal displacement and the maximum displacement of the posterior. If an early septal point was not present, anatomical M-mode was used to visualize an early septal displacement spreading scan-area until inferoseptal wall. CRT responders were defined as LV end-systolic volume reduction (>15%) at 6 months after CRT. Twenty patients (65%) were identified as CRT responders. First peak-SPWMD in responders was significantly higher than those in nonresponders, although SPWMD did not differ between groups. Strong predicting ability of first peak-SPWMD was revealed (first peak-SPWMD: 80/90/83%; SPWMD: 35/100/58%), and area under the curve in receiver operating characteristic analysis of first peak-SPWMD (0.88) was significantly higher than that of SPWMD (0.61) (p<0.05).

CONCLUSION

In patients with LBBB, time differences between early septal and delayed displacement of posterolateral wall on M-mode images were the appropriate dyssynchrony parameter, and could improve the predictive ability for CRT responses.

Coexistence of dynamic mitral regurgitation and dynamic left ventricular dyssynchrony in a patient with repeated episodes of acute pulmonary edema: improvement with cardiac resynchronization therapy

A 69-year-old woman with idiopathic dilated cardiomyopathy and chronic heart failure experienced repeated hospital admissions for acute pulmonary edema with no recognizable precipitating factor. Worsening mitral regurgitation was triggered by exercise echocardiography and significant intraventricular dyssynchrony was elicited by low-dose dobutamine stress echocardiography. After cardiac resynchronization therapy she remained free of hospitalizations for 12 months. This case highlights the dynamic nature of both functional mitral regurgitation and left ventricular dyssynchrony and illustrates how in some patients stress echocardiography can help to clarify clinical scenarios and help with the challenging task of selecting patients who will benefit from cardiac resynchronization therapy.

Association between presystolic ventricular flash and left ventricular functional recovery after cardiac resynchronization therapy

The presence of septal flash (SF), an early inward/outward motion of the ventricular septum, has been reported to predict a fair response to cardiac resynchronization therapy (CRT) in patients with heart failure. Using speckle tracking echocardiography, we investigated whether the extent of pre-CRT SF was associated with left ventricular (LV) functional recovery after CRT device implantation. Fifteen patients with left bundle branch block with a mean LV ejection fraction of 23 ± 9% were enrolled in this study. The extent of presystolic ventricular flash (PSVF), which was defined if there was a peak in the radial strain curve in the preejection period, was semiquantified by counting the number of PSVF-positive segments. Patients underwent radial strain analysis before and between 3 and 6 months after CRT. After CRT device implantation, LV end-diastolic and end-systolic volumes were decreased, LV ejection fraction was increased, and LV filling time corrected by RR interval was increased. The number of PSVF-positive segments at baseline showed a graded association with improvement in both LV ejection fraction and LV filling time. In conclusion, the finding that a larger number of PSVF-positive segments before CRT predicted fair LV functional recovery after CRT suggests that PSVF may represent a substrate that is amenable to functional response to CRT.

CT imaging of myocardial scars with collagen-targeting gold nanoparticles

In the setting of myocardial ischemia, recovery of myocardial function by revascularization procedures depends on the extent of coronary disease and myocardial scar burden. Currently, computed tomographic (CT) imaging offers superior evaluation of coronary lesions but lacks the capability to measure the transmural extent of myocardial scar. Our work focuses on determining if collagen-targeting gold nanoparticles (AuNPs) can effectively target myocardial scar and provide adequate contrast for CT imaging. AuNPs were coated with a collagen-homing peptide, collagen adhesin (CNA35). Myocardial scar was created in mice by occlusion/reperfusion of the left anterior descending coronary artery. Thirty days later, un-gated CT imaging was performed. Over 6h, CNA35-AuNPs provided uniform and prolonged opacification of the vascular structures (100-130 HU). In mice with larger scar burden, focal contrast enhancement was detected in the myocardium, which was not apparent within that of control mice. Histological staining confirmed myocardial scar formation and accumulation of AuNPs.

FROM THE CLINICAL EDITOR

This team of investigators presents a collagen-targeting gold nanoparticle-based approach that enables the imaging of myocardial scars via CT scans in a rodent model. This information would enable clinicians to judge the recovery potential of myocardium more accurately than the current CT-scan based approaches.

Atlas-based quantification of myocardial motion abnormalities: added-value for understanding the effect of cardiac resynchronization therapy

Statistical atlases may help improving the analysis of cardiac wall-motion abnormalities. This study aims at demonstrating the clinical value of such a method to better understand the effect of cardiac resynchronization therapy (CRT). We compared an atlas of normal septal motion built using apical four-chamber two-dimensional echocardiographic sequences from healthy volunteers with 88 patients undergoing CRT at baseline and at 12 months follow-up. Abnormal motion was quantified locally using a p value based on a statistical distance to normality. Reduction ≥15% in left ventricle end-systolic volume defined CRT response. Responders showed significantly higher reduction of abnormalities (p ≤ 0.001). Non-responders conserved abnormal septal motion at the end of the isovolumic contraction (IVC). A specific inward-outward motion of the septum during IVC predominated in responders and was corrected at follow-up. The method is of interest to characterize patterns of mechanical dyssynchrony and to study the link between their evolution and CRT response.

How to improve outcomes: should we put more emphasis on programming and medical care and less on patient selection?

Many factors contribute to the pathophysiology and progression of heart failure (HF), offering the potential for many synergistic therapeutic approaches to its management. For patients, who have systolic HF, prolonged QRS and receiving guideline-indicated pharmacological therapy, cardiac resynchronization therapy (CRT) may provide additional benefits in terms of symptom improvement and mortality reduction. Nevertheless, in many patients, moderate or severe symptoms may persist or recur after CRT implantation due to either the severity or progression of the underlying disease, the presence of important co-morbidities or suboptimal device programming. Identifying and, where possible, treating the reasons for persistent or recurrent symptoms in patients who have received CRT is an important aspect of patient care. The present review summarizes the available evidence on this topic.

Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study

BACKGROUND

Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task.

AIMS

The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response.

METHODS

This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%.

RESULTS

A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders.

CONCLUSION

The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.

Echocardiographic prediction of outcome after cardiac resynchronization therapy: conventional methods and recent developments

Echocardiography plays an important role in patient assessment before cardiac resynchronization therapy (CRT) and can monitor many of its mechanical effects in heart failure patients. Encouraged by the highly variable individual response observed in the major CRT trials, echocardiography-based measurements of mechanical dyssynchrony have been extensively investigated with the aim of improving response prediction and CRT delivery. Despite recent setbacks, these techniques have continued to develop in order to overcome some of their initial flaws and limitations. This review discusses the concepts and rationale of the available echocardiographic techniques, highlighting newer quantification methods and discussing some of the unsolved issues that need to be addressed.

Assessment of cardiac dynamics during stress echocardiography by the peak power output-to-left ventricular mass ratio

Peak cardiac power-to-mass and peak mass-to-power are variables that couple cardiac power output with left ventricular (LV) mass at peak exercise or during maximal inotropic stimulation. Quantitative stress echocardiography enables the calculation of power output according to the formula: 133 × 10–6 × stroke volume per second (ml) × mean blood pressure (BP; mmHg) × heart rate. Power-to-mass may be calculated as LV power output per 100 g of LV mass: 100 g × LV power output divided by LV mass (W/100 g). Conversely, mass-to-power may be estimated by dividing LV mass index by LV power output (g/m2/W). With a little rearrangement of the formulas we can write: power-to-mass (W/100 g) = 0.222 × cardiac output (l/min) × mean BP (mmHg)/LV mass (g) and mass-to-power (g/m2/W) = LV mass index/0.00222 × cardiac output (l/min) × mean BP (mmHg). These parameters reflect the energy delivery of ventricular myocardium with respect to potential energy that is stored in LV mass. The assessment of peak power-to-mass and peak mass-to-power indices may be useful to distinguish compensatory versus maladaptive remodeling in patients with LV dysfunction. When the integrity of myocardial structure is compromised, a disproportion becomes apparent between maximal cardiac power output and LV mass and this leads to either a reduction of peak power-to-mass or an increase of peak mass-to-power. Preliminary reports have demonstrated the usefulness and the prognostic value of peak power-to-mass and peak mass-to-power in patients with LV systolic dysfunction and coronary artery disease.

A spatiotemporal statistical atlas of motion for the quantification of abnormal myocardial tissue velocities

In this paper, we present a new method for the automatic comparison of myocardial motion patterns and the characterization of their degree of abnormality, based on a statistical atlas of motion built from a reference healthy population. Our main contribution is the computation of atlas-based indexes that quantify the abnormality in the motion of a given subject against a reference population, at every location in time and space. The critical computational cost inherent to the construction of an atlas is highly reduced by the definition of myocardial velocities under a small displacements hypothesis. The indexes we propose are of notable interest for the assessment of anomalies in cardiac mobility and synchronicity when applied, for instance, to candidate selection for cardiac resynchronization therapy (CRT). We built an atlas of normality using 2D ultrasound cardiac sequences from 21 healthy volunteers, to which we compared 14 CRT candidates with left ventricular dyssynchrony (LVDYS). We illustrate the potential of our approach in characterizing septal flash, a specific motion pattern related to LVDYS and recently introduced as a very good predictor of response to CRT.