Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy

Left ventricular pacing in the treatment of pediatric cardiac dysfunction caused by idiopathic complete left bundle branch block

OBJECTIVE

This study aimed to investigate the feasibility and effectiveness of transthoracic epicardial dual-chamber pacemaker implantation in the treatment of cardiac dysfunction caused by idiopathic complete left bundle branch block (CLBBB) in children.

METHODS

Nine children diagnosed with cardiac dysfunction due to idiopathic CLBBB were included in this study. All patients underwent transthoracic epicardial dual-chamber pacemaker implantation. Cardiac function was evaluated using echocardiography during the follow-up. Additionally, intraventricular synchronization parameters were assessed using two-dimensional speckle tracking echocardiography (STE).

RESULTS

Nine children (mean age, 3.0 ± 2.6 years) were included in this study. The median follow-up duration was 2 (interquartile range, 1-3) years. The cardiac function of all patients recovered to normal levels within 1 year postoperatively. The postoperative QRS duration on electrocardiography (142 ± 21 ms) was significantly shorter than that at baseline (106 ± 12 ms) (p < .05). Cardiac dyssynchrony in patients who manifested preoperatively achieved complete correction after pacemaker implantation. The comparison of preoperative and postoperative (last follow-up visit) synchronization parameters were as follows: longitudinal standard deviation of the time to peak strain, 99.0 ± 41.9 versus 36.8 ± 5.0 ms (p = .004); delay time of peak longitudinal strain, 252.2 ± 131.4 versus 35.0 ± 22.9 ms (p = .002); and longitudinal systolic dyssynchrony index, 2.8 ± 0.8% versus 1.0 ± 0.3% (p = .001), respectively.

CONCLUSION

Transthoracic epicardial dual-chamber pacemaker implantation (with left atrial sensing and left ventricular single-site pacing) can be used for the treatment of cardiac dysfunction caused by idiopathic CLBBB in children.

Clinical Utility of Three-Dimensional Speckle-Tracking Echocardiography in Heart Failure

Heart failure (HF) is an extremely major health problem with gradually increasing incidence in developed and developing countries. HF may lead to cardiac remodeling; thus, advanced imaging techniques are required to comprehensively evaluate cardiac mechanics. Recently, three-dimensional speckle-tracking echocardiography (3D-STE) has been developed as a novel imaging technology that is based on the three-dimensional speckle-tracking on the full volume three-dimensional datasets. Three-dimensional speckle-tracking echocardiography allows a more accurate evaluation of global and regional myocardial performance, assessment of cardiac mechanics, detection of subclinical cardiac dysfunction, and prediction of adverse clinical events in a variety of cardiovascular diseases. Therefore, this review summarizes the clinical usefulness of 3D-STE in patients with HF.

Cardiac Resynchronization Therapy Response Assessment with Electromechanical Activation Mapping within 24 Hours of Device Implantation: A Pilot Study

BACKGROUND

Cardiac resynchronization therapy (CRT) response assessment relies on the QRS complex narrowing criterion. Yet one third of patients do not improve despite narrowed QRS after implantation. Electromechanical wave imaging (EWI) is a quantitative echocardiography-based technique capable of noninvasively mapping cardiac electromechanical activation in three dimensions. The aim of this exploratory study was to investigate the EWI technique, sensitive to ventricular dyssynchrony, for informing CRT response on the day of implantation.

METHODS

Forty-four patients with heart failure with left bundle branch block or right ventricular (RV) paced rhythm and decreased left ventricular ejection fraction (LVEF; mean, 25.3 ± 9.6%) underwent EWI without and with CRT within 24 hours of device implantation. Of those, 16 were also scanned while in left ventricular (LV) pacing. Improvement in LVEF at 3-, 6-, or 9-month follow-up defined (1) super-responders (ΔLVEF ≥ 20%), (2) responders (10% ≤ ΔLVEF < 20%), and (3) nonresponders (ΔLVEF ≤ 5%). Three-dimensionally rendered electromechanical maps were obtained under RV, LV, and biventricular CRT pacing conditions. Mean RV free wall and LV lateral wall activation times were computed. The percentage of resynchronized myocardium was measured by quantifying the percentage of the left ventricle activated within 120 msec of QRS onset. Correlations between percentage of resynchronized myocardium and type of CRT response were assessed.

RESULTS

LV lateral wall activation time was significantly different (P ≤ .05) among all three pacing conditions in the 16 patients: LV lateral wall activation time with CRT in biventricular pacing (73.1 ± 17.6 msec) was lower compared with LV pacing (89.5 ± 21.5 msec) and RV pacing (120.3 ± 17.8 msec). Retrospective analysis showed that the percentage of resynchronized myocardium with CRT was a reliable response predictor within 24 hours of implantation for significantly (P ≤ .05) identifying super-responders (n = 7; 97.7 ± 1.9%) from nonresponders (n = 17; 89.9 ± 9.9%).

CONCLUSION

Electromechanical activation mapping constitutes a valuable three-dimensional visualization tool within 24 hours of implantation and could potentially aid in the timely assessment of CRT response rates, including during implantation for adjustment of lead placement and pacing outcomes.

Characterization of the anisotropic deformation of the right ventricle during open heart surgery

Digital Image Correlation (DIC) was used for studying the anisotropic behavior of the thin walled right ventricle of the human heart. Strains measured with Speckle Tracking Echocardiography (STE) were compared with the DIC data. Both DIC and STE were used to measure longitudinal strains of the right ventricle in the beginning of an open-heart surgery as well as after the cardiopulmonary bypass. Based on the results, the maximum end-systolic strains obtained with the DIC and STE change similarly during the surgery with less than 10% difference. The difference is largely due to the errors in matching the longitudinal direction in the two methods, sensitivity of the measurement to the positioning of the virtual extensometer of in both STE and DIC, and physiological difference of the measurements as the DIC measures the top surface of the heart whereas the STE obtains the data from below. The anisotropy of the RV was measured using full field principal strains acquired from the DIC displacement fields. The full field principal strains cover the entire region of interest instead of just two points as the virtual extensometer approach used by the STE. The principal strains are not direction dependent measures, and therefore are more independent of the anatomy of the patient and the exact positioning of the virtual strain gage or the STE probe. The results show that the longitudinal strains alone are not enough to fully characterize the behavior of the heart, as the deformation of the heart can be very anisotropic, and the anisotropy changes during the surgery, and from patient to patient.

[Myocardial Strain Properties in Patients with Chronic Heart Failure]

Chronic heart failure is the cause of hospitalization of every fifth cardiological patient. Number of patients with heart failure symptoms that have preserved or intermediate left ventricle ejection fraction increases, i.e. grows portion of diastolic heart failure grows. Gray scale myocardial strain techniques provide an opportunity to detect myocardial dysfunction on early stages when absence of clinically significant symptoms are absent and conventional echocardiography is not informative. The goal of this study is to review parameters of myocardial strain and its clinical applicability in patients with chronic heart failure.

Cardiac Resynchronization Therapy Optimization: A Comprehensive Approach

Since the first report on biventricular pacing in 1994, cardiac resynchronization therapy (CRT) has become standard for patients with advanced heart failure (HF) and ventricular conduction delay. CRT improves myocardial function by resynchronizing myocardial contraction, which results in reverse left ventricular remodeling and improves symptoms and clinical outcomes. Despite the accelerated development of CRT device technology and its increased application in treating HF patients, almost one-third of these patients do not respond to the therapy or gain any clinical benefit from device implantation. Over the last decade, multiple cardiac imaging modalities have provided a deeper understanding of myocardial pathophysiology, thereby improving HF treatment management. However, the optimal strategy for improving the CRT response remains debatable. This article provides an updated overview of the electropathophysiology of myocardial dysfunction in ventricular conduction delay and the diagnostic approaches involving the use of multiple modalities.

Importance of Mean Platelet Volume in Predicting Cardiac Mechanics Parameters and Carotid-Intima Media Thickness in Children With End-Stage Renal Disease and Comparison With Healthy Children

Cardiovascular disease (CVD) is the major cause of death in children with ESRD. Echocardiography and Doppler ultrasound are useful devices for diagnosing cardiovascular abnormalities in such patients. However, they are expensive, difficult to perform as a routine, and not available in many centers. Therefore, finding a more accessible and inexpensive method for CVD evaluation biomarkers is needed. The aim of this study was to evaluate the relationship between mean platelet volume (MPV) as a routine hematological parameter with cardiac mechanics characteristics in children with ESRD. Forty-two children under dialysis and 60 age- and sex-matched healthy subjects as control group were enrolled in the study. Carotid-intima media thickness (CIMT) and echocardiographic parameters were measured in both groups. In addition, hematological and biochemical variables were evaluated in blood samples of participants. MPV was significantly higher in patients than in controls. CIMT, left ventricular mass index (LVMI), end diastolic diameter, strain rate, and global longitudinal strain were significantly different between the two groups. MPV was positively correlated with LVMI and inversely with ejection fraction. In receiver operating characteristic (ROC) curve analysis, the area under the ROC curve (AUC) values for MPV in predicting left ventricular hypertrophy (LVH) and abnormal CIMT were 0.65 (P = 0.07) and 0.53 (P = 0.74), respectively. MPV was correlated with some cardiac abnormalities in children with ESRD. However, it could not show appropriate predictive values in diagnosing LVH and subclinical atherosclerosis. Further studies with prospective design could shed more light in this topic.

The Many Faces of Heart Failure

Heart failure is a heterogeneous clinical syndrome stemming from cardiac overload and injury that leads to considerable morbidity and mortality. This review highlights the many faces of heart failure, a major and growing public health problem, including its causes, classification, underlying pathophysiology, and variable progression. An individualized, patient-centered treatment approach that focuses on guideline-directed pharmacologic and device therapies is required for optimal management of this complex syndrome.

Basic and advanced echocardiographic evaluation of myocardial dysfunction in sepsis and septic shock

Sepsis continues to be a leading cause of mortality and morbidity in the intensive care unit. Cardiovascular dysfunction in sepsis is associated with worse short- and long-term outcomes. Sepsis-related myocardial dysfunction is noted in 20%-65% of these patients and manifests as isolated or combined left or right ventricular systolic or diastolic dysfunction. Echocardiography is the most commonly used modality for the diagnosis of sepsis-related myocardial dysfunction. With the increasing use of ultrasonography in the intensive care unit, there is a renewed interest in sepsis-related myocardial dysfunction. This review summarises the current scope of literature focused on sepsis-related myocardial dysfunction and highlights the use of basic and advanced echocardiographic techniques for the diagnosis of sepsis-related myocardial dysfunction and the management of sepsis and septic shock.

Echocardiography for the management of patients with biventricular pacing: Possible roles in cardiac resynchronization therapy implementation

Cardiac resynchronization therapy (CRT) is an established therapeutic option for the subset of patients with heart failure (HF), reduced ejection fraction (EF), and dyssynchrony evidenced by electrocardiography. Benefit from CRT has been proven in many clinical trials, yet a sizeable proportion of these patients with wide QRS do not respond to this intervention, despite the updated practice guidelines. Several echocardiographic indices, targeting mechanical rather than electrical dyssynchrony, have been suggested to address this issue, but research so far has not succeeded in providing a single and simple measurement with adequate sensitivity and specificity for identification of responders. While there is still ongoing research in this field, echocardiography proves helpful in other aspects of CRT implementation, such as site selection for left ventricular (LV) lead pacing and optimization of pacing parameters during follow-up visits.

The Role of Echocardiography in the Optimization of Cardiac Resynchronization Therapy: Current Evidence and Future Perspectives

Background:

Cardiac resynchronization therapy (CRT) has become a mainstay in the management of heart failure. Up to one-third of patients who received resynchronization devices do not experience the full benefits of CRT. The clinical factors influencing the likelihood to respond to the therapy are wide QRS complex, left bundle branch block, female gender, non-ischaemic cardiomyopathy (highest responders), male gender, ischaemic cardiomyopathy (moderate responders) and narrow QRS complex, non-left bundle branch block (lowest, non-responders).

Objective:

This review provides a conceptual description of the role of echocardiography in the optimization of CRT.

Method:

A literature survey was performed using PubMed database search to gather information regarding CRT and echocardiography.

Results:

A total of 70 studies met selection criteria for inclusion in the review. Echocardiography helps in the initial selection of the patients with dyssynchrony, which will benefit the most from optimal biventricular pacing and provides a guide to left ventricular (LV) lead placement during implantation. Different echocardiographic parameters have shown promise and can offer the possibility of patient selection, response prediction, lead placement optimization strategies and optimization of device configurations.

Conclusion:

LV ejection fraction along with specific electrocardiographic criteria remains the cornerstone of CRT patient selection. Echocardiography is a non-invasive, cost-effective, highly reproducible method with certain limitations and accuracy that is affected by measurement errors. Echocardiography can assist with the identification of the appropriate electromechanical substrate of CRT response and LV lead placement. The targeted approach can improve the haemodynamic response, as also the patient-specific parameters estimation.

Echocardiographic Techniques of Deformation Imaging in the Evaluation of Maternal Cardiovascular System in Patients with Complicated Pregnancies

Cardiovascular diseases (CVD) represent the leading cause of maternal mortality and morbidity. Knowledge of CVD in women is constantly evolving and data are emerging that female-specific risk factors as complications of pregnancy are conditions associated with an increased risk for the long-term development of CVD. Echocardiography is a safe and effective imaging technique indicated in symptomatic or asymptomatic pregnant women with congenital heart diseases who require close monitoring of cardiac function. Deformation imaging is an echocardiographic technique used to assess myocardial function by measuring the actual deformation of the myocardium through the cardiac cycle. Speckle-tracking echocardiography (STE) is a two-dimensional (2D) technique which has been found to be more accurate than tissue Doppler to assess both left ventricular (LV) and right ventricular (RV) myocardial function. The use of 2D STE however might present some technical issues due to the tomographic nature of the technique and the motion in the three-dimensional space of the myocardial speckles. This has promoted the use of 3D STE to track the motion of the speckles in the 3D space. This review will focus on the clinical value of the new echocardiographic techniques of deformation imaging used to assess the maternal cardiovascular system in complicated pregnancies.

Risk stratification in patients with heart failure: the value of considering both global longitudinal left ventricular strain and mechanical dispersion

In previous studies, mechanical dispersion (MD) predicted ventricular arrhythmias independently of left ventricular ejection fraction (LVEF). Moreover, the combination of MD and global longitudinal strain (GLS) increased the prediction of arrhythmic events. We investigated the prognostic value of a new 2-dimensional strain index, GLS/MD, in patients with heart failure (HF). We analyzed 340 consecutive HF outpatients in sinus rhythm. Echocardiography was performed at 1.6 ± 0.4 months after hospital discharge. The end point included sudden cardiac death, ventricular fibrillation, and sustained ventricular tachycardia (SCD/VA). During the follow-up period (36 ± 9 months), SCD/VA occurred in 48 patients (14.1%). A multivariate Cox regression analysis, which included LVEF, early diastolic transmitral / mitral annular velocity ratio (E/E'), GLS, MD, and GLS/MD in the model, revealed that GLS/MD was the best independent predictor of SCD/VA (HR = 3.22, 95% confidence interval = 1.72-6.15, p = 0.03). Separate inclusion of LVEF, systolic mitral annular velocity, E/E', GLS, and MD together with GLS/MD showed that GLS/MD remained the best predictor of SCD/VA (each p < 0.05). The optimal GLS/MD cutoff value to predict SCA/VA was -0.20%/ms (80% sensitivity, 76% specificity). Irrespective of LVEF, free survival was significantly better in patients with GLS/MD ≤ -0.2%/ms (log-rank test, p < 0.001). In conclusion, GLS/MD may improve cardiovascular risk stratification in subjects with HF.

Using three-dimensional echocardiography to guide left ventricle lead position in cardiac resynchronization therapy: does it make any difference

BACKGROUND

Cardiac resynchronization therapy (CRT) is an effective treatment for patients with advanced heart failure. Nearly 30% of candidates are inadequate responders. Proper patient selection, left ventricle (LV) lead placement optimization, and optimization of the programming of the CRT device are important approaches to improve outcome of CRT. We examined the role of three-dimensional (3D) echocardiography in determining the optimal LV lead position as a method of optimizing CRT response.

METHODS

Forty-seven patients with a mean age of 60.2 ± 11.1 years including five (10.6%) females, all having advanced CHF (EF <35%, LBBB >120 mesc, or non-LBBB >150 msec, with NYHA II-III or ambulatory class IV) were enrolled. Detailed history (NYHA class, Minnesota living with heart failure questionnaire), clinical examination, 6-min walk test, and standard 2D echocardiography were done in all cases. 3D echo detailed analysis of the LV 16 segments was done to determine the latest wall to reach the minimal systolic volume. Multisite pacing was done blind to the 3D echo data achieving a stable LV lead position in mid LV segment. This exact fluoroscopic site was determined (in two orthogonal views) and correlated with 3D most delayed area using a resized 16-segment schema. Patients were classified retrospectively into group A with concordance between the delayed LV area and LV lead position and group B with discordance between both. Patients were followed up after 3-6 (5.1 ± 1.8) months. Patients with reduction of 2D LV end-systolic volume of ≥10% at follow-up were termed volumetric responders. Poorly echogenic patients and those with decompensated NYHA class IV, sustained atrial arrhythmias, and rheumatic or congenital heart diseases were excluded.

RESULTS

LV lead placement was concordant in 22 (46.8%) cases. After the follow-up period, 31 (65.9%) of the study population were considered volumetric responders with no significant difference among both groups (14 (63.3%) in group A vs 17 (68%) in group B, p > 0.05). CRT insertion resulted in significant improvement of NYHA class in 36 (76.5%) cases, 6-min walk test (447.2 ± 127.0 vs 369.6 ± 87.5 m, p < 0.01), MLHFQ (58.1 ± 19.7 vs 69.6 ± 13.5, p < 0.01), QRS duration (131.2 ± 13.8 vs 149.4 ± 16 msec, p < 0.01), 2D LV EF 33.0 ± 9.5 vs 25.3 ± 6.5, p < 0.001), LVESV (156.0 ± 82.9 vs177.6 ± 92.7 ml, p < 0.05), and 3D LVEF (29.1 ± 9.0 vs 23.6 ± 5.9, p < 0.001) irrespective of the etiology of heart failure. However, there were no significant differences between both groups regarding the same parameters (6-min walk test 470.8 ± 128.7 vs 428.3 ± 126.8 m, MLHFQ 56.8 ± 20.0 vs 58.11 ± 19.0, QRS duration 129.9 ± 12.4 vs 132.1 ± 15.1 msec, 2D LVEF 30.9 ± 8.3 vs 34.58 ± 10.9, LVESV 173.0 ± 110.0 vs 143.0 ± 67.9, 3D LVEF 26 ± 8 vs 31 ± 9, for groups A and B, respectively, p < 0.05).

CONCLUSIONS

Standard anatomical LV lead placement remains a simple, practical, and effective method in patients undergoing CRT. 3D echocardiography-guided LV lead placement added no clinical benefit compared to standard techniques.