Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy

Decreased Left Ventricular Systolic Function during the Late Phase after Response to Cardiac Resynchronization Therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) improves cardiac function in patients with heart failure (HF) and dyssynchrony. However, a subset of responders develops a delayed decline in left ventricular (LV) systolic function, referred to as "delayed negative reverse remodeling (DNRR)."

OBJECTIVE

This study aimed to investigate the characteristics and prognosis of DNRR in CRT responders.

METHODS

A total of 203 patients undergoing CRT device implantation were analyzed. Among them, 100 responders were identified based on a ≥5% absolute LV ejection fraction (LVEF) increase and a ≥15% relative LV end-systolic volume (LVESV) reduction at 6 months post-CRT. DNRR was defined as a ≥5% absolute decrease in LVEF at 1 year after treatment response determination.

RESULTS

Of the responders, 22 (22.0%) exhibited DNRR, while 78 (78.0%) were classified as non-DNRR. The DNRR group showed a decline in LVEF from 41.2±8.3% to 32.7±9.6% (p<0.001), while the non-DNRR group showed improvement from 42.8±9.5% to 46.2±10.5% (p<0.001). Multivariate analysis identified LVESV ≥100 mL (odds ratio [OR]: 3.575, p=0.041), paced QRS duration ≥150 ms (OR: 4.427, p=0.023), synchronized LV pacing <85% (OR: 5.753, p=0.043) at 6 months post-CRT, and intraventricular conduction disturbance (OR: 5.593, p=0.018) as independent predictors of DNRR. The DNRR group had significantly worse outcomes, including cardiac death and HF-related hospitalization, compared to the non-DNRR group.

CONCLUSION

Despite an initial response to CRT, a subset of HF patients developed DNRR, which correlated with worse clinical outcomes. Identifying risk factors associated with DNRR may help optimize CRT management and improve long-term patient care.

Could Pulsed Wave Tissue Doppler Imaging Solve the Diagnostic Dilemma of Right Atrial Masses and Pseudomasses? A Case Series and Literature Review

Even if rarely detected, right atrial (RA) masses represent a diagnostic challenge due to their heterogeneous presentation. Para-physiological RA structures, such as a prominent Eustachian valve, Chiari's network, and lipomatous atrial hypertrophy, may easily be misinterpreted as pathological RA masses, including thrombi, myxomas, and vegetations. Each pathological mass should always be correlated with adequate clinical, anamnestic, and laboratory data. However, the differential diagnosis between pathological RA masses may be challenging due to common constitutional symptoms, as in the case of vegetations and myxoma, which present with fever and analogous complications such as systemic embolism. The implementation of transthoracic echocardiography (TTE) with pulsed wave (PW) tissue Doppler imaging (TDI) may improve the visualization and differentiation of intracardiac masses through different color coding of the pathological structure compared to surrounding tissue. More remarkably, PW-TDI can provide a detailed assessment of the specific pattern of motion of each intracardiac mass, with important clinical implications. Specifically, a TDI-derived pattern of incoherent motion is typical of right-sided thrombi, myxomas, and vegetations, whereas right-sided pseudomasses are generally associated with a TDI pattern of concordant motion synchronous with the cardiac cycle. An increased TDI-derived mass peak antegrade velocity may represent an innovative marker of the embolic potential of mobile right-sided pathological masses. During the last two decades, only a few authors have used TTE implemented with PW-TDI for the characterization of intra-cardiac masses' morphology and mobility. Herein, we report two clinical cases of totally different right-sided cardiac masses diagnosed using a multimodality imaging approach, including PW-TDI, followed at our institution. The prevalence and physiopathological characteristics of the most relevant RA masses and pseudomasses encountered in clinical practice are described in the present narrative review. In addition, we will discuss the principal clinical applications of PW-TDI and its potential value in improving the differential diagnosis of pathological and para-physiological right-sided cardiac masses.

Optimizing outcomes from cardiac resynchronization therapy: what do recent data and insights say?

INTRODUCTION

Cardiac Resynchronization Therapy (CRT) is an effective treatment for heart failure (HF) in approximately two-thirds of recipients, with a third remaining CRT 'non-responders.' There is an increasing body of evidence exploring the reasons behind non-response, as well as ways to preempt or counteract it.

AREAS COVERED

This review will examine the most recent evidence regarding optimizing outcomes from CRT, as well as explore whether traditional CRT indeed remains the best first-line therapy for electrical resynchronization in HF. We will start by discussing methods of preempting non-response, such as refining patient selection and procedural technique, before reviewing how responses can be optimized post-implantation. For the purpose of this review, evidence was gathered from electronic literature searches (via PubMed and GoogleScholar), with a particular focus on primary evidence published in the last 5 years.

EXPERT OPINION

Ever-expanding research in the field of device therapy has armed physicians with more tools than ever to treat dyssynchronous HF. Newer developments, such as artificial intelligence (AI) guided device programming and conduction system pacing (CSP) are particularly exciting, and we will discuss how they could eventually lead to truly personalized care by maximizing outcomes from CRT.

Heart Rate Recovery Index and Improved Diastolic Dyssynchrony in Fusion Pacing Cardiac Resynchronization Therapy

Background: Restoring electrical synchrony with cardiac resynchronization therapy (CRT) reverses the heart failure phenotype developed by left-ventricular (LV) dyssynchrony. This study aimed to identify new predictors of response to LV-only fusion pacing CRT. Methods: A select group of patients with CRT-P indications received a right atrium (RA)/LV DDD pacing system. LV dyssynchrony was assessed via offline TDI timing focusing on the temporal difference between peak septal (E″T) and lateral wall (A"T) motion. CRT effectiveness was evaluated at each follow-up, involving the heart rate recovery index (HRRI) parameter (acceleration/deceleration time) derived from exercise testing along with the echocardiographic parameters. Patients were classified into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline initial characteristics: 62 patients (35 male) aged 62 ± 11 y.o. with non-ischemic dilated cardiomyopathy (DCM). Ejection fraction (EF) 27 ± 5.2%; QRS 164 ± 18 ms; 29% had type III diastolic dysfunction (DD), 63% type II DD, and 8% type I DD. Average follow-up was 45 ± 19 months: 34% of patients were SR, 61% R, and 5% NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR, with a shorter deceleration time (DT) during exercise test compared to NR (109 ± 68 ms vs. 330 ± 30 ms; p < 0.0001). The responders present a higher HRRI (2.87 ± 1.47 vs. 0.98 ± 0.08; p = 0.03) compared to NR and a significantly decrease in E"T and A"T from 76 ± 13 ms to 51 ± 11 ms (p < 0.0001). Prolonged DT was associated with an accentuated LV dyssynchrony and nonoptimal response to CRT. Conclusions: The study identified new parameters for assessing responsiveness to LV-only fusion pacing CRT, which could improve candidate selection and CRT implementation.

Successful cardiac resynchronization therapy reduces negative septal work in patient-specific models of dyssynchronous heart failure

In patients with dyssynchronous heart failure (DHF), cardiac conduction abnormalities cause the regional distribution of myocardial work to be non-homogeneous. Cardiac resynchronization therapy (CRT) using an implantable, programmed biventricular pacemaker/defibrillator, can improve the synchrony of contraction between the right and left ventricles in DHF, resulting in reduced morbidity and mortality and increased quality of life. Since regional work depends on wall stress, which cannot be measured in patients, we used computational methods to investigate regional work distributions and their changes after CRT. We used three-dimensional multi-scale patient-specific computational models parameterized by anatomic, functional, hemodynamic, and electrophysiological measurements in eight patients with heart failure and left bundle branch block (LBBB) who received CRT. To increase clinical translatability, we also explored whether streamlined computational methods provide accurate estimates of regional myocardial work. We found that CRT increased global myocardial work efficiency with significant improvements in non-responders. Reverse ventricular remodeling after CRT was greatest in patients with the highest heterogeneity of regional work at baseline, however the efficacy of CRT was not related to the decrease in overall work heterogeneity or to the reduction in late-activated regions of high myocardial work. Rather, decreases in early-activated regions of myocardium performing negative myocardial work following CRT best explained patient variations in reverse remodeling. These findings were also observed when regional myocardial work was estimated using ventricular pressure as a surrogate for myocardial stress and changes in endocardial surface area as a surrogate for strain. These new findings suggest that CRT promotes reverse ventricular remodeling in human dyssynchronous heart failure by increasing regional myocardial work in early-activated regions of the ventricles, where dyssynchrony is specifically associated with hypoperfusion, late systolic stretch, and altered metabolic activity and that measurement of these changes can be performed using streamlined approaches.

Tighter is better: Can a simple and cost-free parameter predict response to cardiac synchronization therapy?

BACKGROUND

Several studies have evaluated the role of QRS duration (QRSd) or QRS narrowing as a predictor of response to cardiac resynchronization therapy (CRT) to reduce nonresponders.

AIM

Our study aimed to determine the correlation between the relative change in QRS index (QI) compared to clinical outcome and prognosis in patients who underwent CRT implantation.

METHODS

A three-centers study involving 398 patients with a CRT device was conducted. Clinical, echocardiographic and pharmacological variables, QRSd before and after CRT implantation and QI were measured.

RESULTS

In a 6-month follow-up, a significant improvement in left ventricular ejection fraction (LVEF), left ventricular end-diastolic and systolic volumes (LVEDV and LVESV) were observed. QI was related to reverse remodeling (multiple r-squared: 0.48, adjusted r-squared: 0.43, p = .001), and the cut-off value that best predicted LV reverse remodeling after 6 months of CRT was 12.25% (AUC 0.7, p = .001). At 24 months, a statistically significant difference was found between patients with a QI ≤ 12.25% and those with a QI > 12.25% regarding NYHA class worsening (p = .04). The mean of the QI of patients who died from cardiovascular causes was lower than patients who died of other causes (p = .0179). A correlation between pre-CRT QRSd/LVEDV and QI was observed (r = + 0.20; p = .0003). A higher QRSd/LVEDV ratio was associated with an improved LVEF, LVEDV, and LVESV (p < .0001) at follow-up.

CONCLUSIONS

QI narrowing after CRT was related to greater echocardiographic reverse remodeling and a lower rate of adverse events (death or cardiovascular hospitalizations). The QI can improve the prediction of adverse events in a population with CRT regardless of comorbidities according to the Charlson Comorbidity Index. QI could be used to predict CRT response.

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.

Clinical significance of regional constructive and wasted work in patients receiving cardiac resynchronization therapy

Background

Previous studies have shown that global constructive work (CW) and wasted work (WW) predict response to cardiac resynchronization therapy (CRT). This study evaluated the predictive value of regional CW and WW for reverse remodeling and clinical outcomes after CRT.

Methods

We performed a prospective study involving 134 CRT candidates with left bundle branch block and left ventricular ejection fraction ≤35%. Global and regional CW and WW were calculated using pressure-strain loop analysis. CRT response was defined by reverse remodeling as a reduction of ≥15% in left ventricular end-systolic volume after six months.

Results

At six-month follow-up, 92 (69%) patients responded to CRT. Of the regional CW and WW measures, lateral wall (LW) CW and septal WW were most strongly and significantly correlated with reverse remodeling. At multivariate analysis, LW CW and septal WW were both independent determinants of reverse remodeling. When LW CW and septal WW were included in the model, global CW and WW were not independently associated with reverse remodeling. LW CW and septal WW predicted reverse remodeling with an area under the curve (AUC) of 0.783 (95% CI: 0.700-0.866) and 0.737 (95% CI: 0.644-0.831), respectively. Using both variables increased the AUC to 0.832 (95% CI: 0.755-0.908). Both LW CW ≤878 mmHg% (HR 2.01; 95% CI: 1.07-3.79) and septal WW ≤181 mmHg% (HR 2.60; 95% CI: 1.38-4.90) were significant predictors of combined death and HF hospitalization at two-year follow-up.

Conclusion

LW CW and septal WW before CRT are important determinants of reverse remodeling and clinical outcomes.

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.

Multimodality Imaging for Selecting Candidates for CRT: Do We Have a Single Alley to Increase Responders?

Cardiac resynchronization therapy has evolved in recent years to provide a reduction of morbidity and mortality for many patients with heart failure. Its application and optimization is an evolving field and its use requires a multidisciplinary approach for patient and device selection, technical preprocedural planning, and optimization. While echocardiography has always been considered the first line for the evaluation of patients, additional imaging techniques have gained increasing evidence in recent years. Today different details about heart anatomy, function, dissynchrony can be investigated by magnetic resonance, cardiac computed tomography, nuclear imaging, and more, with the aim of obtaining clues to reach a maximal response from the electrical therapy. The purpose of this review is to provide a practical analysis of the single and combined use of different imaging techniques in the preoperative and perioperative phases of cardiac resynchronization therapy, underlining their main advantages, limitations, and information provided.

Impact of sacubitril/valsartan and gliflozins on cardiac resynchronization therapy response in ischemic and non-ischemic heart failure patients

AIMS

Angiotensin receptor-neprilysin inhibitor (ARNi) and sodium-glucose co-transporter 2 inhibitor (SGLT2i) improve outcomes in heart failure with reduced ejection fraction (HFrEF) patients, however their effects in cardiac resynchronization therapy (CRT) recipients have been scarcely explored. This study investigated whether ARNi and SGLT2i 1) improve the rate of clinical and echocardiographic CRT response and 2) have different impact based on the ischemic or non-ischemic etiology.

METHODS

HFrEF patients referred for CRT implant were grouped in no treatment (group 1), only ARNi (group 2) and both ARNi and SGLT2i (group 3). Clinical and echocardiographic response were evaluated at 12 months.

RESULTS

A total of 178 patients were enrolled. At one-year follow-up, 74.4% patients in group 2 (p = 0.031) and 88.9% in group 3 (p = 0.014) were classified as clinical responders vs 54.5% in the no treatments group. In multivariable analysis, ARNi/SGLT2i use was an independent predictor of CRT response (OR 3.72; CI 95%, 1.40-10.98; p = 0.011), confirmed in both groups 2 and 3. At 12 months, the median Δ LVEF increase was 6% and 8.5% in groups 2 and 3 respectively, vs 4.5% in group 1 (p = 0.042 and p = 0.029) with significantly more echocardiographic responders in groups 2 and 3 (76% and 78% vs 50%, p = 0.003 and p = 0.036). Significantly more ischemic HFrEF patients than non-ischemic were considered clinical and echocardiographic responders in the treatment groups.

CONCLUSIONS

ARNi alone or in combination with SGLT2i in CRT patients improves the clinical and echocardiographic response at 12 months. Ischemic patients seem to benefit more from these treatments.

Predictors and outcomes of cardiac dyssynchrony among patients with heart failure attending Benjamin Mkapa Hospital in Dodoma, central Tanzania: A protocol of prospective-longitudinal study

INTRODUCTION

Cardiac Dyssynchrony is prevalent among patients with heart failure with high cost of care and potentially poor outcomes. Nevertheless, little is known about cardiac dyssynchrony among heart failure patients, especially in developing countries. This study aims at assessing the predictors and outcomes of cardiac dyssynchrony among heart failure patients attending the cardiology department at Benjamin Mkapa Referral Hospital in Dodoma, central Tanzania.

METHODS

The study will follow a prospective longitudinal design involving participants aged 18 years and above with heart failure attending the Cardiology Department at Benjamin Mkapa Hospital. Heart failure will be identified based on Framingham's score and patients will be enrolled and followed up for six months. Baseline socio-demographic and clinical characteristics will be taken during enrollment. Outcomes of interest at six months include worsening of heart failure, readmission and death. Continuous data will be summarized as Mean (SD) or Median (IQR), and categorical data will be summarized using proportions and frequencies. Binary logistic regression will be used to determine predictors and outcomes of Cardiac Dyssynchrony among patients with heart failure.

A machine learning method integrating ECG and gated SPECT for cardiac resynchronization therapy decision support

PURPOSE

Cardiac resynchronization therapy (CRT) has been established as an important therapy for heart failure. Mechanical dyssynchrony has the potential to predict responders to CRT. The aim of this study was to report the development and the validation of machine learning models which integrate ECG, gated SPECT MPI (GMPS), and clinical variables to predict patients' response to CRT.

METHODS

This analysis included 153 patients who met criteria for CRT from a prospective cohort study. The variables were used to model predictive methods for CRT. Patients were classified as "responders" for an increase of LVEF ≥ 5% at follow-up. In a second analysis, patients were classified as "super-responders" for an increase of LVEF ≥ 15%. For ML, variable selection was applied, and Prediction Analysis of Microarrays (PAM) approach was used to model response while Naïve Bayes (NB) was used to model super-response. These ML models were compared to models obtained with guideline variables.

RESULTS

PAM had AUC of 0.80 against 0.72 of partial least squares-discriminant analysis with guideline variables (p = 0.52). The sensitivity (0.86) and specificity (0.75) were better than for guideline alone, sensitivity (0.75) and specificity (0.24). Neural network with guideline variables was better than NB (AUC = 0.93 vs. 0.87) however without statistical significance (p = 0.48). Its sensitivity and specificity (1.0 and 0.75, respectively) were better than guideline alone (0.78 and 0.25, respectively).

CONCLUSIONS

Compared to guideline criteria, ML methods trended toward improved CRT response and super-response prediction. GMPS was central in the acquisition of most parameters. Further studies are needed to validate the models.

Cardiovascular imaging in conduction system pacing: What does the clinician need?

Permanent pacemakers are used for symptomatic bradycardia and biventricular pacing (BVP)-cardiac resynchronization therapy (BVP-CRT) is established for heart failure (HF) patients traditionally. According to guidelines, patients' selection for CRT is based on QRS duration (QRSd) and morphology by surface electrocardiogram (ECG). Cardiovascular imaging techniques evaluate cardiac structure and function as well as identify pathophysiological substrate changes including the presence of scar. Cardiovascular imaging helps by improving the selection of candidates, guiding left ventricular (LV) lead placement, and optimization devices during the follow-up. Conduction system pacing (CSP) includes His bundle pacing (HBP) and left bundle branch pacing (LBBP) which is screwed into the interventricular septum. CSP maintains and restores ventricular synchrony in patients with native narrow QRSd and left bundle branch block (LBBB), respectively. LBBP is more feasible than HBP due to a wider target area. This review highlights the role of multimodality cardiovascular imaging including fluoroscopy, echocardiography, cardiac magnetic resonance (CMR), myocardial scintigraphy, and computed tomography (CT) in the pre-procedure assessment for CSP, better selection for CSP candidates, the guidance of CSP lead implantation, and the optimization of devices programming after the procedure. We also compare the different characteristics of multimodality imaging and discuss their potential roles in future CSP implantation.

Myocardial Perfusion SPECT Imaging Radiomic Features and Machine Learning Algorithms for Cardiac Contractile Pattern Recognition

A U-shaped contraction pattern was shown to be associated with a better Cardiac resynchronization therapy (CRT) response. The main goal of this study is to automatically recognize left ventricular contractile patterns using machine learning algorithms trained on conventional quantitative features (ConQuaFea) and radiomic features extracted from Gated single-photon emission computed tomography myocardial perfusion imaging (GSPECT MPI). Among 98 patients with standard resting GSPECT MPI included in this study, 29 received CRT therapy and 69 did not (also had CRT inclusion criteria but did not receive treatment yet at the time of data collection, or refused treatment). A total of 69 non-CRT patients were employed for training, and the 29 were employed for testing. The models were built utilizing features from three distinct feature sets (ConQuaFea, radiomics, and ConQuaFea + radiomics (combined)), which were chosen using Recursive feature elimination (RFE) feature selection (FS), and then trained using seven different machine learning (ML) classifiers. In addition, CRT outcome prediction was assessed by different treatment inclusion criteria as the study's final phase. The MLP classifier had the highest performance among ConQuaFea models (AUC, SEN, SPE = 0.80, 0.85, 0.76). RF achieved the best performance in terms of AUC, SEN, and SPE with values of 0.65, 0.62, and 0.68, respectively, among radiomic models. GB and RF approaches achieved the best AUC, SEN, and SPE values of 0.78, 0.92, and 0.63 and 0.74, 0.93, and 0.56, respectively, among the combined models. A promising outcome was obtained when using radiomic and ConQuaFea from GSPECT MPI to detect left ventricular contractile patterns by machine learning.

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 &lt; 35%) and widened QRS (&gt;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.

Considering Diastolic Dyssynchrony as a Predictor of Favorable Response in LV-Only Fusion Pacing Cardiac Resynchronization Therapy

Background: CRT improves systolic and diastolic function, increasing cardiac output. Aim of the study: to assess the outcome of LV diastolic dyssynchrony in a population of fusion pacing CRT. Methods: Diastolic dyssynchrony was measured by offline speckle-tracking-derived TDI timing assessment of the simultaneity of E″ and A″ basal septal and lateral walls. New parameters introduced: E″ and, respectively, A″ time (E″T/A″T) as the time difference between E″ (respectively, A″) peak septal and lateral wall. Patients were divided into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline characteristics: 62 pts (62 ± 11 y.o.) with idiopathic DCM, EF 27 ± 5.2%; 29% type III diastolic dysfunction (DD), 63% type II, 8% type I. Average follow-up 45 ± 19 months: LVEF 37 ± 7.9%, 34%SR, 61%R, 5%NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR with significant LV reverse remodeling (LV end-diastolic volume 193.7 ± 81 vs. 243.2 ± 82 mL at baseline, p < 0.0028) and lower LV filling pressures (E/E' 13.2 ± 4.6 vs. 11.4 ± 4.5, p = 0.0295). DD profile improved in 65% of R with a reduction in E/E' ratio (21 ± 9 vs. 14 ± 4 ms, p < 0.0001). Significant cut-off value calculated by ROC curve for LV diastolic dyssynchrony is E″T > 80 ms and A″T > 30 msec. Conclusions: The study identifies the cut-off values of diastolic dyssynchrony parameters as predictors of favorable outcomes in responders and super-responder patients with fusion CRT pacing. These findings may have important implications in patient selection and follow-up.

Prognostic value of non-alcoholic fatty liver disease fibrosis score in patients undergoing cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) is an effective option in the treatment of patients with heart failure and wide QRS. Non-alcoholic fatty liver disease (NAFLD) fibrosis score (NFS) has been shown to predict cardiac events in several patient populations. However, the relationship between NFS and response to CRT has not been investigated. The aim of the study was to investigate the predictive role of NFS in the assessment of response after CRT.

METHODS

Three hundred thirty-six patients with heart failure undergoing CRT were prospectively studied. Liver fibrosis were assessed according to the non-alcoholic fatty liver disease fibrosis score (NFS), which includes age, body mass index, impaired fasting glycemia or diabetes mellitus, aspartate aminotransferase /alanine aminotransferase ratio, platelets, and albumin. Echocardiographic response to CRT was defined by a ≥15% reduction in left ventricular end-systolic volume at six months at follow-up.

RESULTS

Two hundred thirty-eight patients (71%) had CRT response after 6 months of follow-up. Receiver-operator characteristic curve analysis showed NFS cutoff value of < -1.12 for predicting CRT response with a sensitivity of 70.4% and a specificity of 52.9%. The patients were also divided into four groups according to the quartiles of NFS. The proportion of response to CRT was increased with lower level of NFS value. Multivariate logistic regression analysis demonstrated the NFS score < -1.12 and LVIDs were independent predictors of the CRT response. In the second model of analysis which included NFS, quartiles demonstrated that fourth NFS quartile and LVIDs were independent predictors of CRT response.

CONCLUSION

Liver fibrosis assessed by NFS can provide valuable information to predict reverse remodeling in patients undergoing CRT. The present study supports monitoring of NFS to improve preoperative risk stratification of these patients.

Myocardial Work in Echocardiography

Myocardial work is an emerging tool in echocardiography that incorporates left ventricular afterload into global longitudinal strain analysis. Myocardial work correlates with myocardial oxygen consumption, and work efficiency can also be assessed. Myocardial work has been evaluated in a variety of clinical conditions to assess the added value of myocardial work compared to left ventricular ejection fraction and global longitudinal strain. This review showcases the current use of myocardial work in adult echocardiography and its possible role in cardiac pathologies.

Does types of atrial fibrillation matter in the impairment of global and regional left ventricular mechanics and intra-ventricular dyssynchrony?

Background

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which is associated with cardiac dysfunction. This study aimed to compare the impairment severity of left ventricular strain and intra-ventricular dyssynchrony using echocardiography-derived velocity vector imaging in patients with different types of AF without heart failure.

Methods

168 non-valvular AF patients with normal left ventricular ejection fraction (98 paroxysmal AF patients and 70 persistent AF patients) and 86 healthy control subjects were included in this study. Regional and global left ventricular longitudinal and circumferential strain were measured. Time to regional peak longitudinal strain was measured and the standard deviation of all 12 segments (SDT-S) was used as a measure of intra-ventricular dyssynchrony.

Results

Significantly lower GLS (−18.71 ± 3.00% in controls vs. −17.10 ± 3.01% in paroxysmal AF vs. −12.23 ± 3.25% in persistent AF, P &lt; 0.05) and GCS (−28.75 ± 6.34% in controls vs. −24.43 ± 6.86% in paroxysmal AF vs. −18.46 ± 6.42% in persistent AF, P &lt; 0.01) were observed in either persistent AF subjects or paroxysmal AF subjects compared with healthy control subjects (P &lt; 0.05). The impairment was much worse in persistent AF subjects compared with paroxysmal AF subjects (P &lt; 0.001). Intraventricular dyssynchrony was found in both persistent AF patients and paroxysmal AF patients, and it’s worse in persistent AF patients (52 ± 18 ms in controls, 61 ± 17 ms in paroxysmal AF, and 70 ± 28 ms in persistent AF, P &lt; 0.05). Multivariate regression analysis revealed AF types were independent risk factors of GLS, GCS, and intraventricular dyssynchrony.

Conclusion

AF types were not only associated with impaired longitudinal and circumferential left ventricle mechanics but also intra-ventricular mechanical dyssynchrony. Worse systolic mechanics and intra-ventricular dyssynchrony were found in patients with persistent AF compared with these in patients with paroxysmal AF.

Evaluation of Cardiac Mechanical Dyssynchrony in Heart Failure Patients Using Current Echo-Doppler Modalities

BACKGROUND

Current guidelines indicate electrical dyssynchrony as the major criteria for selecting patients for cardiac resynchronization therapy, and 25-35% of patients exhibit unfavorable responses to cardiac resynchronization therapy (CRT). We aimed to evaluate different cardiac mechanical dyssynchrony parameters in heart failure patients using current echo-Doppler modalities and we analyzed their association with electrical dyssynchrony.

METHODS

The study included 120 heart failure with reduced ejection fraction (HFrEF) who underwent assessments for left ventricular mechanical dyssynchrony (LVMD) and interventricular mechanical dyssynchrony (IVMD).

RESULTS

Patients were classified according to QRS duration: group I with QRS < 120 ms, group II with QRS 120-149 ms, and group III with QRS ≥ 150 ms. Group III had significantly higher IVMD, LVMD indices, TS-SD speckle-tracking echocardiography (STE) 12 segments (standard deviation of time to peak longitudinal strain speckle tracking echocardiography in 12 LV-segments), and LVMD score compared with group I and group II. Group II and group III were classified according to QRS morphology into left bundle branch block (LBBB) and non-LBBB subgroups. LVMD score, TS-SD 12 TDI, and TS-SD 12 STE had good correlations with QRS duration.

CONCLUSIONS

HFrEF patients with wide QRS duration (> 150 ms) had more evident LVMD compared with patients with narrow or intermediate QRS. Those patients with intermediate QRS duration (120-150 ms) had substantial LVMD assessed by both TDI and 2D STE, regardless of QRS morphology. Subsequently, we suggest that LVMD indices might be employed as additive criteria to predict CRT response in that patient subgroup. Electrical and mechanical dyssynchrony were strongly correlated in HFrEF patients.

Cardiac remodelling - Part 2: Clinical, imaging and laboratory findings. A review from the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology

In patients with heart failure, the beneficial effects of drug and device therapies counteract to some extent ongoing cardiac damage. According to the net balance between these two factors, cardiac geometry and function may improve (reverse remodelling, RR) and even completely normalize (remission), or vice versa progressively deteriorate (adverse remodelling, AR). RR or remission predict a better prognosis, while AR has been associated with worsening clinical status and outcomes. The remodelling process ultimately involves all cardiac chambers, but has been traditionally evaluated in terms of left ventricular volumes and ejection fraction. This is the second part of a review paper by the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology dedicated to ventricular remodelling. This document examines the proposed criteria to diagnose RR and AR, their prevalence and prognostic value, and the variables predicting remodelling in patients managed according to current guidelines. Much attention will be devoted to RR in patients with heart failure with reduced ejection fraction because most studies on cardiac remodelling focused on this setting.

A Mild Dyssynchronous Contraction Pattern Detected by SPECT Myocardial Perfusion Imaging Predicts Super-Response to Cardiac Resynchronization Therapy

Background

Using single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) with phase analysis (PA), we aimed to identify the predictive value of a new contraction pattern in cardiac resynchronization therapy (CRT) response.

Methods

Left ventricular mechanical dyssynchrony (LVMD) was evaluated using SPECT MPI with PA in non-ischemic dilated cardiomyopathy (DCM) patients with left bundle branch block (LBBB) indicated for CRT. CRT super-response was defined as LV ejection fraction (EF) ≥50% or an absolute increase of LVEF >15%. The LV contraction was categorized as the mild dyssynchronous pattern when the phase standard deviation (PSD) ≤ 40.3° and phase histogram bandwidth (PBW) ≤ 111.9°, otherwise it was defined as severe dyssynchronous pattern which was further characterized as U-shaped, heterogeneous or homogenous pattern.

Results

The final cohort comprised 74 patients, including 32 (43.2%) in mild dyssynchronous group, 17 (23%) in U-shaped group, 19 (25.7%) in heterogeneous group, and 6 (8.1%) in homogenous group. The mild dyssynchronous group had lower PSD and PBW than U-shaped, heterogeneous, and homogenous groups (P < 0.0001). Compared to patients with the heterogeneous pattern, the odds ratios (ORs) with 95% confidence intervals (CIs) for CRT super-response were 10.182(2.43–42.663), 12.8(2.545–64.372), and 2.667(0.327–21.773) for patients with mild dyssynchronous, U-shaped, and homogenous pattern, respectively. After multivariable adjustment, mild dyssynchronous group remained associated with increased CRT super-response (adjusted OR 5.709, 95% CI 1.152–28.293). Kaplan-Meier curves showed that mild dyssynchronous group demonstrated a better long-term prognosis.

Conclusions

The mild dyssynchronous pattern in patients with DCM is associated with an increased CRT super-response and better long-term prognosis.

Ventricular Arrhythmias in Seniors with Heart Failure: Present Dilemmas and Therapeutic Considerations: A Systematic Review

BACKGROUND

Heart Failure (HF) is a global public health problem, which affects over 23 million people worldwide. The prevalence of HF is higher among seniors in the USA and other developed countries. Ventricular Arrhythmias (VAs) account for 50% of deaths among patients with HF. We aim to elucidate the factors associated with VAs among seniors with HF, as well as therapies that may improve the outcomes.

METHODS

PubMed, Web of Science, Scopus, Cochrane Library databases, Science Direct, and Google Scholar were searched using specific keywords. The reference lists of relevant articles were searched for additional studies related to HF and VAs among seniors as well as associated outcomes.

RESULTS

The prevalence of VAs increases with worsening HF. A 24-hour Holter electrocardiogram may be useful in risk stratifying patients for device therapy if they do not meet the criterion of low ventricular ejection fraction. Implantable Cardiac Defibrillators (ICDs) are superior to anti-arrhythmic drugs in reducing mortality in patients with HF. Guideline-Directed Medical Therapy (GDMT) together with device therapy may be required to reduce symptoms. In general, the proportion of seniors on GDMT is low. A combination of ICDs and cardiac resynchronization therapy may improve outcomes in selected patients.

CONCLUSION

Seniors with HF and VAs have high mortality even with the use of device therapy and GDMT. The holistic effect of device therapy on outcomes among seniors with HF is equivocal. More studies focused on seniors with advanced HF as well as therapeutic options are, therefore, required.

Comparison of the Acute Effects of Different Pacing Sites on Cardiac Synchrony and Contraction Using Speckle-Tracking Echocardiography

Background: Cardiac pacing in patients with bradyarrhythmia may employ variable pacing sites, which may have different effects on cardiac function. Left bundle branch pacing (LBBP) is a new physiological pacing modality, and the acute outcomes on cardiac mechanical synchrony during LBBP remain uncertain. We evaluated the acute effects of four pacing sites on cardiac synchrony and contraction using speckle-tracking echocardiography, and comparisons among four different pacing sites were rare.

Methods: We enrolled 21 patients with atrioventricular block or sick sinus syndrome who each sequentially underwent acute pacing protocols, including right ventricular apical pacing (RVAP), right ventricular outflow tract pacing (RVOP), His bundle pacing (HBP), and left bundle branch pacing (LBBP). Electrocardiograms and echocardiograms were recorded at baseline and during pacing. The interventricular mechanical delay (IVMD), the standard deviation of the times to longitudinal peak strain during 17 segments (PSD), and the Yu index were used to evaluate ventricular mechanical synchrony. Layer-specific strain was computed using two-dimensional speckle tracking technique to provide in-depth details about ventricular synchrony and function.

Results: Left ventricular ejection fraction (LVEF) and tricuspid annulus plane systolic excursion (TAPSE) were significantly decreased during RVAP and RVOP but were not significantly different during HBP and LBBP compared with baseline. RVAP and RVOP significantly prolonged QRS duration, whereas HBP and LBBP showed non-significant effects. IVMD and PSD were significantly increased during RVAP but were not significantly different during RVOP, HBP, or LBBP. LBBP resulted in a significant improvement in the IVMD and Yu index compared with RVAP. No significant differences in mechanical synchrony were found between HBP and LBBP.

Conclusion: Among these pacing modalities, RVAP has a negative acute impact on cardiac synchrony and contraction. HBP and LBBP best preserve physiological cardiac synchrony and function.

Septal Flash as a Predictor of Cardiac Resynchronization Therapy Response: A Systematic Review and Meta-Analysis

Cardiac resynchronization therapy (CRT) in heart failure patients has been shown to improve patient outcomes in some but not all patients. A few studies have identified that septal flash on imaging is associated with response to CRT, but there has yet to be systematic review to evaluate the consistency of the finding across the literature. A search of MEDLINE and EMBASE was conducted to identify studies, which evaluate septal flash and its association with CRT response. Studies that met the inclusion criteria were statistically pooled with random-effects meta-analysis and heterogeneity was assessed using the I2 statistic. A total of nine studies were included with 2307 participants (mean age 76 years, 67% male). Septal flash on imaging before CRT implantation was seen in 53% of patients and the proportion of CRT responders from the included studies varied from 52% to 77%. In patients who were CRT responders, septal flash was seen in 40% of patients compared to 10% in those deemed to be CRT nonresponders. Meta-analysis of eight of the nine included studies suggests that the presence of septal flash at preimplant was associated with an increased likelihood of CRT response (relative risk 2.55 95% confidence interval 2.04-3.19, P < 0.001, I2 = 51%). Septal flash was also reported to be associated with left ventricular reverse remodeling, but the association with survival and symptomatic improvement was less clear. Septal flash is a well-defined and distinctive contraction pattern that is easily recognizable on cardiac imaging. Septal flash may be associated with CRT response and should be evaluated in the patients that are considered for CRT devices.

Prevalence, clinical and instrumental features of left bundle branch block-induced cardiomyopathy: the CLIMB registry

AIMS

Although increasingly recognized as a distinct pathological entity, left bundle branch block-induced cardiomyopathy (LBBB-ICMP) is not included among the possible aetiologies of acquired dilated cardiomyopathies (DCM). While diagnostic criteria have been proposed, its recognition remains principally retrospective, in the presence of clinical and instrumental red flags. We aimed to assess the prevalence and clinical and instrumental features of LBBB-ICMP in a large cohort of patients with DCM.

METHODS AND RESULTS

We analysed a cohort of 242 DCM patients from a two-centre registry. Inclusion criteria were age > 18, non-ischaemic or non-valvular DCM, and LBBB on electrocardiogram. LBBB-ICMP was defined according to previously proposed diagnostic criteria: (i) neither family history nor clinically identifiable potential causes for DCM; (ii) negative genetic testing; (iii) echocardiographic features including non-severe chamber dilation, normal absolute and relative wall thickness, marked dyssynchrony, and normal right ventricular function; and (iv) absence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). From the entire cohort, we identified 30 subjects (similar in terms of New York Heart Association class I or II in 80% vs. 75%, P = 0.56; QRS width of 150 ± 22 vs. 151 ± 24 ms, P = 0.82; and cardiac remodelling of baseline end-diastolic diameter 66 ± 8 vs. 65 ± 10 mm, P = 0.53) with a comprehensive dataset including CMR and genetic testing, required to verify the presence of the diagnostic criteria proposed for LBBB-ICMP. The main characteristics of this subgroup were 73% males, age 45 ± 13 years, left ventricular ejection fraction (LVEF) 30 ± 10%, LGE in 38% of patients, and QRS complex of 150 ± 22 ms. Patients were under guideline-directed medical therapy, and 57% of them were treated with cardiac resynchronization therapy (CRT). Two patients (6.67%, 50% males, age 53 ± 13 years) fulfilled the diagnostic criteria proposed for LBBB-ICMP. After a follow-up of 44 (12-76) months, LVEF was normal and QRS width significantly reduced (from 154 ± 25 to 116 ± 52 ms) in patients with LBBB-ICMP. Both patients were under optimal medical treatment, and one was implanted with CRT-D. Neither of the two patients experienced death, malignant ventricular arrhythmia, or heart failure hospitalization at follow-up.

CONCLUSIONS

Left bundle branch block-induced cardiomyopathy emerges as a distinct pathological entity, promptly identifiable in a minority but not negligible proportion of patients with newly diagnosed DCM and LBBB, using a series of diagnostic criteria including CMR and genetic testing. Further studies are needed to better elucidate the clinical course of LBBB-ICMP.

The physiological effects of cardiac resynchronization therapy on aortic and pulmonary flow and dynamic and static components of systemic impedance

Background

Patients who improve following cardiac resynchronization therapy (CRT) have left ventricular (LV) remodeling and improved cardiac output (CO). Effects on the systemic circulation are unknown.

Objective

To explore the effects of CRT on aortic and pulmonary blood flow and systemic afterload.

Methods

At CRT implant patients underwent a noninvasive assessment of central hemodynamics, including wave intensity analysis (n = 28). This was repeated at 6 months after CRT. A subsample (n = 11) underwent an invasive electrophysiological and hemodynamic assessment immediately following CRT. CRT response was defined as reduction in LV end-systolic volume ≥15% at 6 months.

Results

In CRT responders (75% of those in the noninvasive arm), there was a significant increase in CO (from 3 ± 2 L/min to 4 ± 2 L/min, P = .002) and LV dP/dt_max (from 846 ± 162 mm Hg/s to 958 ± 194 mm Hg/s, P = .001), immediately after CRT in those in the invasive arm. They demonstrated a significant increase in aortic forward compression wave (FCW) both acutely and at follow-up. The relative change in LV dP/dt_max strongly correlated with changes in the aortic FCW (R _s 0.733, P = .025). CRT responders displayed a significant reduction in afterload, and a decrease in systemic vascular resistance and pulse wave velocity acutely; there was a significant decrease in acute pulmonary afterload measured by the pulmonary FCW and forward expansion wave.

Conclusion

Improved cardiac function following CRT is attributable to a combination of changes in the cardiac and cardiovascular system. The relative importance of these 2 mechanisms may then be important for optimizing CRT.

Left ventricular dyssynchrony assessment using tissue synchronization imaging in acute myocardial infarction

Objectives:

To assess left ventricular (LV) dyssynchrony in patients with ST elevation myocardial infarction (STEMI).

Background:

Mechanical synchronization disorder leads to a decrease in LV ejection fraction (LVEF) and stroke volume, an abnormal distribution of wall tension, and increase in workload during cardiac contraction.

Methods:

We enrolled 56 participants, 36 with acute STEMI and 20 healthy controls. The automatically color-coded time to peak myocardial velocity was measured using a 6mm sample volume, manually positioned within the two-dimensional-tissue strain image of the 12 basal and middle LV segments.

Results:

A significant delay was found between the septal-lateral and septal-posterior walls in patients with STEMI compared to patients in the control group (36.36 vs. −6.0ms, P = 0.036; and 42.7 vs. 23.94ms, P = 0.042, respectively). Furthermore, all segment maximum differences and all segment standard deviation (SD; dyssynchrony index) were found to be significantly higher in the STEMI group (131.28 vs. 95.45ms, P = 0.013; and 44.47 vs. 26.45ms, P = 0.001, respectively). A significant delay between the septal-lateral walls and septal-posterior walls, all segment maximum difference, and all segment SD (dyssynchrony index) were found in patients with complicated STEMI (70.89 vs. 15.83ms, P = 0.038; 57.44 vs. 19.06ms, P = 0.040; 138.11 vs. 100.0ms, P = 0.035; and 45.44 vs. 32.50ms, P = 0.021, respectively). There was a significant negative correlation between tissue synchronization imaging parameters and LVEF, and a positive correlation with LV end systolic dimension.

Conclusion:

Patients with acute STEMI showed significant LV dyssynchrony, which was an independent predictor of inhospital complications.

Left-ventricular dyssynchrony in viable myocardium by myocardial perfusion SPECT is predictive of mechanical response to CRT

OBJECTIVES

Gated myocardial perfusion SPECT (GMPS) provides a one-stop-shop evaluation for cardiac resynchronization therapy (CRT). However, conflicting results have been observed regarding whether the baseline left-ventricular (LV) mechanical dyssynchrony as assessed by phase analysis on GMPS was predictive of therapeutic response to CRT. Since dyssynchrony parameters by phase analysis spuriously increased by scarred myocardium, the purpose of this study was to explore the value of dyssynchrony after stripping off the scar region in correlation to mechanical response to CRT.

METHODS

Forty-seven patients following standard indications for CRT received GMPS with phase analysis as pre-CRT evaluation. A decrease of end-systolic volume (ESV) > 15% on follow-up echocardiography after CRT was considered as a mechanical response to CRT. Myocardial regions with less than 50% of maximal activity on GMPS were considered as a scar. The phase standard deviation (PSD) and histogram bandwidth (BW) without or with stripping off scar were assessed by phase analysis of GMPS and were used for evaluation of LV dyssynchrony of all myocardium or only the viable myocardium, respectively.

RESULTS

No significant difference was noted between mechanical responders (31 of 47 patients, 66%) and nonresponders ( 16 of 47 patients, 34%) for PSD (48.6° ± 19.4° vs 43.9° ± 20.7°, p = 0.46) and BW (225° ± 91.1° vs 163.5° ± 94.6°, p = 0.38) of the entire myocardium. However, responders had significantly larger PSD (40.5° ± 15.7° vs 30.5° ± 13.2°, p = 0.03) and borderlinely larger BW (215° ± 91.2° vs. 139.5° ± 78.2°, p = 0.05) than non-responders after stripping off scar. Logistic regression analysis showed that scar area and PSD after stripping off scar were independent predictors of mechanical response.

CONCLUSIONS

Our result showed that LV dyssynchrony of the entire myocardium did not predict response to CRT. However, LV dyssynchrony only in the viable myocardium was a significant predictor of CRT mechanical response.

Echocardiographic view and feature selection for the estimation of the response to CRT

Cardiac resynchronization therapy (CRT) is an implant-based therapy applied to patients with a specific heart failure (HF) profile. The identification of patients that may benefit from CRT is a challenging task and the application of current guidelines still induce a non-responder rate of about 30%. Several studies have shown that the assessment of left ventricular (LV) mechanics by speckle tracking echocardiography can provide useful information for CRT patient selection. A comprehensive evaluation of LV mechanics is normally performed using three different echocardioraphic views: 4, 3 or 2-chamber views. The aim of this study is to estimate the relative importance of strain-based features extracted from these three views, for the estimation of CRT response. Several features were extracted from the longitudinal strain curves of 130 patients and different methods of feature selection (out-of-bag random forest, wrapping and filtering) have been applied. Results show that more than 50% of the 20 most important features are calculated from the 4-chamber view. Although features from the 2- and 3-chamber views are less represented in the most important features, some of the former have been identified to provide complementary information. A thorough analysis and interpretation of the most informative features is also provided, as a first step towards the construction of a machine-learning chain for an improved selection of CRT candidates.

Long-term cardiac reverse remodeling after cardiac resynchronization therapy

INTRODUCTION

The benefit of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with reduced left ventricular ejection fraction (LVEF) have been observed in the first year. However, there are few data on long-term follow-up and the effect of changes of LVEF on mortality. This study aimed to assess the LV remodeling after CRT implantation and the probable effect of changes in LVEF with repeated measures on mortality over time in a real-world registry.

METHODS

Among our cohort of 328 consecutive CRT patients, mixed model effect analysis have been made to describe the temporal evolution of LVEF and LVESV changes over time up with several explanatory variables. Besides, the effect of LVEF along time on the probability of mortality was evaluated using joint modeling for longitudinal and survival data.

RESULTS

The study population included 328 patients (253 men; 70.2 ± 9.5 years) in 4.2 (2.9) years follow-up. There was an increase in LVEF of 11% and a reduction in LVESV of 42 mL during the first year. These changes are more important during the first year, but slight changes remain during the follow-up. The largest reduction in LVESV occurred in patients with left bundle branch block (LBBB) and the smallest reduction in patients with NYHA IV. The smallest increase in LVEF was an ischemic etiology, longer QRS, and LV electrode in a nonlateral vein. Besides, the results showed that the LVEF profiles taken during follow-up after CRT were associated with changes in the risk of death.

CONCLUSION

Reverse remodeling of the left ventricle is observed especially during the first year, but it seems to be maintained later after CRT implantation in a contemporary cohort of patients. Longitudinal measurements could give us additional information at predicting the individual mortality risk after adjusting by age and sex compared to a single LVEF measurement after CRT.

Are SPECT MPI measures of dyssynchrony dyssynchronous?

BACKGROUND

Assessment of left ventricular mechanical dyssynchrony (LVMD) from gated SPECT myocardial perfusion imaging (MPI) aims to aid selection of patients for cardiac resynchronization therapy (CRT), using either the standard deviation of left ventricular phase (PSD) ≥ 43° or phase histogram bandwidth (HBW) of > 38° and > 30.6° in males and females, respectively. We observed dyssynchrony parameters might be affected by test type and alignment.

METHODS

We reviewed 242 patients who underwent gated SPECT MPI with use of the Emory Cardiac Toolbox comparing PSD and HBW at rest and stress for Pearson correlation, and substitutability with Bland-Altman analysis.

RESULTS

There is statistically significant difference in the mean PSD and HBW during rest vs stress (33.4 ± 17.4° vs 20.7 ± 13.5° and 97.7 ± 59.6° vs 59.4 ± 45.4°, respectively, P < 0.001). Proper valve plane alignment rendered smaller values (i.e., less dyssynchrony) in both phase SD and HBW (16.8 ± 13.5) vs (22.2 ± 14.7) (P = 0.011), and (47.0 ± 38.2) vs (60.7 ± 48.0) (P = 0.023), respectively.

CONCLUSION

Proper alignment and test type, particularly low-dose rest vs high-dose stress, should be considered when assessing LVMD using SPECT MPI.

Comparative efficacy of image-guided techniques in cardiac resynchronization therapy: a meta-analysis

Background

Several studies have illustrated the use of echocardiography, magnetic resonance imaging, and nuclear imaging to optimize left ventricular (LV) lead placement to enhance the response of cardiac resynchronization therapy (CRT) in heart failure patients. We aimed to conduct a meta-analysis to determine the incremental efficacy of image-guided CRT over standard CRT.

Methods

We searched PubMed, Cochrane library, and EMBASE to identify relevant studies. The outcome measures of cardiac function and clinical outcomes were CRT response, concordance of the LV lead to the latest sites of contraction (concordance of LV), heart failure (HF) hospitalization, mortality rates, changes of left ventricular ejection fraction (LVEF), and left ventricular end-systolic volume (LVESV).

Results

The study population comprised 1075 patients from eight studies. 544 patients underwent image-guided CRT implantation and 531 underwent routine implantation without imaging guidance. The image-guided group had a significantly higher CRT response and more on-target LV lead placement than the control group (RR, 1.33 [95% CI, 1.21 to 1.47]; p < 0.01 and RR, 1.39 [95% CI, 1.01 to 1.92]; p < 0.05, respectively). The reduction of LVESV in the image-guided group was significantly greater than that in the control group (weighted mean difference, − 12.46 [95% CI, − 18.89 to − 6.03]; p < 0.01). The improvement in LVEF was significantly higher in the image-guided group (weighted mean difference, 3.25 [95% CI, 1.80 to 4.70]; p < 0.01). Pooled data demonstrated no significant difference in HF hospitalization and mortality rates between two groups (RR, 0.89 [95% CI, 0.16 to 5.08]; p = 0.90, RR, 0.69 [95% CI, 0.37 to 1.29]; p = 0.24, respectively).

Conclusions

This meta-analysis indicates that image-guided CRT is correlated with improved CRT volumetric response and cardiac function in heart failure patients but not with lower hospitalization or mortality rate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02061-y.

Associations of the Prognostic Nutritional Index with the Cardiac Function and Survival after Cardiac Resynchronization Therapy

Objective The relationship between changes in the nutritional status after cardiac resynchronization therapy (CRT) and the prognosis has not been fully elucidated. We aimed to evaluate the changes in the nutritional status as assessed by the prognostic nutritional index (PNI) and their associations with the improvement in the cardiac function and subsequent clinical outcomes. Methods The study population consisted of 119 patients with a CRT-device. They were divided into 2 groups, based on whether their PNI had increased at 6 months after CRT-device implantation (positive ΔPNI group, n=73) or not (negative ΔPNI group, n=46). The left ventricular (LV) end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were measured before and six months after CRT-device implantation. We compared the changes in the cardiac function and prevalence of adverse events (re-hospitalization due to worsening heart failure or all cause death) between the two groups. Results In the positive ΔPNI group, the LVEDV (186±93 mL vs. 149±71 mL, p<0.05) and LVESV (134±75 mL vs. 98±62 mL, p<0.05) were significantly decreased 6 months after CRT-device implantation. In addition, the LVEF (31±11% vs. 37±12%, p<0.05) was significantly increased after CRT-device implantation. In the negative ΔPNI group, no significant changes were observed in any echocardiographic parameters. During a median follow-up period of 914 days, there were 67 (56.3%) adverse events. In the Kaplan-Meier analysis, the positive ΔPNI group was associated with a lower risk of adverse events than the negative ΔPNI group (50.6% vs. 65.2%, log-rank p=0.042). Conclusion Our results suggest that improvement in the cardiac function after CRT-device implantation is associated with increases in the PNI, resulting in favorable outcomes.

Left bundle branch block without a typical contraction pattern is associated with increased risk of ventricular arrhythmias in cardiac resynchronization therapy patients

Cardiac resynchronization therapy (CRT) reduces the risk of ventricular arrhythmias (VA) in heart failure (HF) patients with left bundle branch block (LBBB) while the effect is less clear among non-LBBB patients. This study aimed to investigate if absence of LBBB features whether by echocardiography or strict ECG criteria would identify patients at risk of developing VA in a cohort with LBBB according to conventional ECG criteria. Two hundred six CRT candidates were prospectively included from 2 centers. Prior to CRT presence of a typical LBBB contraction pattern was identified using longitudinal strain in the apical 4-chamber view. All preimplantation ECGs were categorized as LBBB or non-LBBB according to Strauss´ strict criteria. Primary end-point was defined as any appropriate antitachycardia pacing (ATP) or shock therapy within 2 years after CRT implantation. A total of 129 (63%) patients had a typical LBBB contraction pattern, while 134 (66%) met the strict ECG criteria. Over 2 years, 45 patients (22%) experienced VA. Absence of a typical LBBB contraction pattern was independently associated with an increased risk of VA (hazard ratio ([HR] 1.89; 95% CI 1.04 to 3.44; p: 0.036). Strict LBBB was not independently associated with the occurrence of VA. Fulfilling neither strict ECG nor echocardiographic criteria for LBBB was associated with a 3.3-fold increase in risk of VA ([HR] 3.34; 95% CI 1.75 to 6.94; (p < 0.001). The risk of VA was almost 2-fold higher if a typical LBBB contraction pattern was absent prior to CRT.

Cardiac resynchronization therapy with or without defibrillation: a long-standing debate

Cardiac resynchronization therapy (CRT) was shown to improve cardiac function, reduce heart failure hospitalizations, improve quality of life and prolong survival in patients with severe left ventricular dysfunction and intraventricular conduction disturbances, mainly left bundle branch block, on optimal medical therapy with ACE-inhibitors, β-blockers and mineralocorticoid receptor antagonists up-titrated to maximum tolerated evidence-based doses. CRT can be achieved by means of pacemaker systems (CRT-P) or devices with defibrillation capabilities (CRT-D). CRT-Ds offer an undoubted advantage in the prevention of arrhythmic death, but such an advantage may be of lesser degree in non-ischemic heart failure aetiologies. Moreover, the higher CRT-D hardware complexity compared to CRT-P may predispose to device/lead malfunctions and the higher current drainage may cause a shorter battery duration with consequent premature replacements and the well-known incremental complications. In a period of financial constraints, also device costs should be carefully evaluated, with recent reports suggesting that CRT-Ps may be favoured over CRT-Ds in patients with non-ischemic cardiomyopathy and no prior history of cardiac arrhythmias from a cost-effectiveness point of view. The choice between a CRT-P or a CRT-D device should be patient-tailored whenever straightforward defibrillator indications are not present. The Goldenberg score may facilitate this decision-making process in ambiguous settings. Age, comorbidities, kidney disease, atrial fibrillation, advanced functional class, inappropriate therapy risk, implantable device infections and malfunctions are factors potentially reducing the expected benefit from defibrillating capabilities. Future prospective, randomized controlled trials are warranted to directly compare the efficacy and safety of CRT-Ps and CRT-Ds.

Left ventricular global longitudinal strain in predicting CRT response: one more J-shaped curve in medicine

The aim of the study was: (1) to verify the hypothesis that left ventricular global longitudinal strain (LVGLS) may be of additive prognostic value in prediction CRT response and (2) to obtain such a LVGLS value that in the best optimal way enables to characterize potential CRT responders. Forty-nine HF patients (age 66.5 ± 10 years, LVEF 24.9 ± 6.4%, LBBB 71.4%, 57.1% ischemic aetiology of HF) underwent CRT implantation. Transthoracic echocardiography was performed prior to and 15 ± 7 months after CRT implantation. Speckle-tracking echocardiography was performed to assess longitudinal left ventricular function as LVGLS. The response to CRT was defined as a ≥ 15% reduction in the left ventricular end-systolic volume (∆LVESV). Thirty-six (73.5%) patients responded to CRT. There was no linear correlation between baseline LVGLS and ∆LVESV (r = 0.09; p = 0.56). The patients were divided according to the percentile of baseline LVGLS: above 80th percentile; between 80 and 40th percentile; below 40th percentile. Two peripheral groups (above 80th and below 40th percentile) formed “peripheral LVGLS” and the middle group was called “mid-range LVGLS”. The absolute LVGLS cutoff values were − 6.07% (40th percentile) and − 8.67% (80th percentile). For the group of 20 (40.8%) “mid-range LVGLS” patients mean ΔLVESV was 33.3 ± 16.9% while for “peripheral LVGLS” ΔLVESV was 16.2 ± 18.8% (p < 0.001). Among non-ischemic HF etiology, all “mid-range LVGLS” patients (100%) responded positively to CRT (in “peripheral LVGLS”—55% responders; p = 0.015). Baseline LVGLS may have a potential prognostic value in prediction CRT response with relationship of inverted J-shaped pattern. “Mid-range LVGLS” values should help to select CRT responders, especially in non-ischemic HF etiology patients.

Value of intraventricular dyssynchrony assessment by gated-SPECT myocardial perfusion imaging in the management of heart failure patients undergoing cardiac resynchronization therapy (VISION-CRT)

BACKGROUND

Placing the left ventricular (LV) lead in a viable segment with the latest mechanical activation (vSOLA) may be associated with optimal cardiac resynchronization therapy (CRT) response. We assessed the role of gated SPECT myocardial perfusion imaging (gSPECT MPI) in predicting clinical outcomes at 6 months in patients submitted to CRT.

METHODS

Ten centers from 8 countries enrolled 195 consecutive patients. All underwent gSPECT MPI before and 6 months after CRT. The procedure was performed as per current guidelines, the operators being unaware of gSPECT MPI results. Regional LV dyssynchrony (Phase SD) and vSOLA were automatically determined using a 17 segment model. The lead was considered on-target if placed in vSOLA. The primary outcome was improvement in ≥1 of the following: ≥1 NYHA class, left ventricular ejection fraction (LVEF) by ≥5%, reduction in end-systolic volume by ≥15%, and ≥5 points in Minnesota Living With Heart Failure Questionnaire (MLHFQ).

RESULTS

Sixteen patients died before the follow-up gSPECT MPI. The primary outcome occurred in 152 out of 179 (84.9%) cases. Mean change in LV phase standard deviation (PSD) at 6 months was 10.5°. Baseline dyssynchrony was not associated with the primary outcome. However, change in LV PSD from baseline was associated with the primary outcome (OR 1.04, 95% CI 1.01-1.07, P = .007). Change in LV PSD had an AUC of 0.78 (0.66-0.90) for the primary outcome. Improvement in LV PSD of 4° resulted in the highest positive likelihood ratio of 7.4 for a favorable outcome. In 23% of the patients, the CRT lead was placed in the vSOLA, and in 42% in either this segment or in a segment within 10° of it. On-target lead placement was not significantly associated with the primary outcome (OR 1.53, 95% CI 0.71-3.28).

CONCLUSION

LV dyssynchrony improvement by gSPECT MPI, but not on-target lead placement, predicts clinical outcomes in patients undergoing CRT.

Prognostic value of integrative analysis of electrical and mechanical dyssynchrony in patients with acute heart failure

BACKGROUND

Left ventricular mechanical dyssynchrony has been shown to provide significant clinical values for chronic heart failure (HF) and cardiac resynchronization therapy (CRT). The purpose of this study was to evaluate whether electrical dyssynchrony combined with mechanical dyssynchrony has an incremental benefit over electrical dyssynchrony or mechanical dyssynchrony alone to predict clinical events in patients with acute heart failure (AHF).

METHODS

Ninety-six AHF patients who received standard 12-lead ECG, gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and echocardiography were enrolled. Thirty-two normal subjects were collected as the control group to get the normal database of mechanical dyssynchrony. The end point is the composite of all-cause death and heart transplantation. Electrical dyssynchrony was defined as QRS duration > 120 ms. Mechanical dyssynchrony was defined as > mean + 2 × SD phase standard deviation (PSD) or phase bandwidth (PBW) based on our normal database.

RESULTS

During the follow-up of 28 ± 10 months, complete data were obtained in 92 patients. 26 (28.3%) Patients who reached the end point were classified into the event group. There were no significant differences in PSD or PBW between the event and non-event groups. However, PBW > 77.76° was independently associated with the end point in the univariate and multivariate analysis (hazard ratio 2.92, 95% confidence interval 1.00-8.47, P = .049; hazard ratio 3.89, 95% confidence interval 1.01-14.97, P = .048). The Kaplan-Meier curve with a log-rank test showed that the end point rate was significantly higher in the patients with PBW > 77.76° (log-rank P = .039). Moreover, the ROC curve analysis showed that the area under the curve (AUC) for predicting end point events by the integrative analysis of QRS > 120 ms and PBW > 77.76° was significantly improved compared to QRS duration > 120 ms (AUC: 0.75 vs 0.68, P = .001) or PBW > 77.76° (AUC: 0.75 vs 0.62, P = .049), respectively. The model of combined electrical and mechanical dyssynchrony yielded a further significantly improved risk prediction for adverse events in the global χ2.

CONCLUSIONS

The combination of QRS duration > 120 ms and PBW > 77.76° was an independent predictor of all-cause death and heart transplantation in AHF patients. The integrative analysis of electrical and mechanical dyssynchrony provides incremental prognostic value for clinical use.

Cardiovascular Imaging Applications in Clinical Management of Patients Treated with Cardiac Resynchronization Therapy

Cardiovascular imaging techniques, including echocardiography, nuclear cardiology, multi-slice computed tomography, and cardiac magnetic resonance, have wide applications in cardiac resynchronization therapy (CRT). Our aim was to provide an update of cardiovascular imaging applications before, during, and after implantation of a CRT device. Before CRT implantation, cardiovascular imaging techniques may integrate current clinical and electrocardiographic selection criteria in the identification of patients who may most likely benefit from CRT. Assessment of myocardial viability by ultrasound, nuclear cardiology, or cardiac magnetic resonance may guide optimal left ventricular (LV) lead positioning and help to predict LV function improvement by CRT. During implantation, echocardiographic techniques may guide in the identification of the best site of LV pacing. After CRT implantation, cardiovascular imaging plays an important role in the assessment of CRT response, which can be defined according to LV reverse remodeling, function and dyssynchrony indices. Furthermore, imaging techniques may be used for CRT programming optimization during follow-up, especially in patients who turn out to be non-responders. However, in the clinical settings, the use of proposed functional indices for different imaging techniques is still debated, due to their suboptimal feasibility and reproducibility. Moreover, identifying CRT responders before implantation and turning non-responders into responders at follow-up remain challenging issues.

Comparison of the dyssynchrony parameters recorded with gated SPECT in ischemic cardiomyopathy according to their repeatability at rest and to their ability to detect a synchrony reserve under dobutamine infusion

BACKGROUND

This study aimed to determine whether the repeatability of dyssynchrony assessment using gated myocardial perfusion SPECT (GSPECT) allows the detection of synchrony reserve during low-dose dobutamine infusion.

METHODS AND RESULTS

Sixty-one patients with ischemic cardiomyopathy and LV ejection fraction < 50% were prospectively included in 10 centers. Each patient underwent two consecutive rest GSPECT with 99mTc-labeled tracer (either tetrofosmin or sestamibi) to assess the repeatability of LV function and dyssynchrony parameters, followed by a GSECT acquisition during low-dose dobutamine infusion. LV dyssynchrony was assessed using QGS software through histogram bandwidth (BW), standard deviation of the phase (SD), and entropy. Repeatability was assessed with Lin's concordance correlation coefficient (CCC). Entropy showed a higher CCC (0.80) compared to BW (0.68) and SD (0.75). On average, dobutamine infusion yielded to improve both BW (P = .049) and entropy (P = .04) although significant improvements, setting outside the 95% confidence interval of the repeatability analysis, were documented in only 6 and 4 patients for BW and entropy, respectively.

CONCLUSIONS

A synchrony reserve may be documented in patients with ischemic cardiomyopathy through the recording of BW and entropy with low-dose dobutamine GSPECT, with the additional advantage of a higher repeatability for entropy.

Cardiac resynchronisation therapy in patients with left bundle branch block with residual conduction

Aim

To evaluate whether left bundle branch block with residual conduction (rLBBB) is associated with worse outcomes after cardiac resynchronisation therapy (CRT).

Methods

All consecutive CRT implants at our institution between 2006 and 2013 were identified from our local device registry. Pre- and post-implant patient specific data were extracted from clinical records.

Results

A total of 690 CRT implants were identified during the study period. Prior to CRT, 52.2% of patients had true left bundle branch block (LBBB), 19.1% a pacing-induced LBBB (pLBBB), 11.2% a rLBBB, 0.8% a right bundle branch block (RBBB), and 16.5% had a nonspecific intraventricular conduction delay (IVCD) electrocardiogram pattern. Mean age at implant was 67.5 years (standard deviation [SD] = 10.6), mean left ventricular ejection fraction (LV EF) was 25.7% (SD = 7.9%), and mean QRS duration was 158.4 ms (SD = 32 ms). After CRT, QRS duration was significantly reduced in the LBBB (p < 0.001), pLBBB (p < 0.001), rLBBB (p < 0.001), RBBB (p = 0.04), and IVCD groups (p = 0.03). LV EF significantly improved in the LBBB (p < 0.001), rLBBB (p = 0.002), and pLBBB (p < 0.001) groups, but the RBBB and IVCD groups showed no improvement. There was no significant difference in mortality between the LBBB and rLBBB groups. LV EF post-CRT, chronic kidney disease, hyperkalaemia, hypernatremia, and age at implant were significant predictors of mortality.

Conclusion

CRT in patients with rLBBB results in improved LV EF and similar mortality rates to CRT patients with complete LBBB. Predictors of mortality post-CRT include post-CRT LV EF, presence of CKD, hyperkalaemia, hypernatremia, and older age at implant.

Intraventricular synchronism assessment by gated-SPECT myocardial perfusion imaging in cardiac resynchronization therapy. Does cardiomyopathy type influence results?

Purpose

To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI).

Methods

Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a ^99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ).

Results

No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up.

Conclusion

CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.

Evaluation of ivabradine in left ventricular dyssynchrony and reverse remodeling in patients with chronic heart failure

OBJECTIVES

Ivabradine is a pharmacological agent used in patients with heart failure and sinus rhythm. Its only known pharmacological effect is to slow the heart rate. In this study, we investigated the impact of ivabradine on dyssynchrony parameters in heart failure patients.

METHODS

In this study, we assigned 55 patients taking medication for heart failure to receive ivabradine in addition (Group I). Twenty healthy volunteers comprised Group II. Echocardiographic measurements (dyssynchrony, left ventricular volumes and left ventricular ejection fraction) were taken at baseline, 1 month, and 3 months.

RESULTS

A total of 32 heart failure patients in Group I completed the study. There was significant improvement in dyssynchrony parameters after ivabradine treatment in Group I. Interventricular dyssynchrony (IVD) decreased from 42.0 ± 24.4 milliseconds at baseline to 33.6 ± 20.7 milliseconds at 1 month (P = .001) and to 30.7 ± 19.4 milliseconds at 3 months (P < .001). Septal to posterior wall motion delay decreased from 90.3 ± 21.4 milliseconds to 83.9 ± 26.9 milliseconds (P = .011) at 1 month and to 81.5 ± 27.3 milliseconds at 3 months (P = .001). Septal to lateral Ts delay (Ts-SL) decreased from 42.7 ± 24.5 milliseconds to 35.8 ± 22.6 milliseconds at 1 month (P < .001) and to 34.8 ± 22.4 milliseconds at 3 months (P = .002). Left ventricular end-systolic volume (LVESV) decreased from 139.4 ± 42.2 mL to 135.3 ± 39.6 mL at 1 month (P = .006) and to 123.3 ± 39.5 mL at 3 months (P < .001).

CONCLUSION

The addition of ivabradine to heart failure treatment improves cardiac dyssynchrony parameters in chronic systolic heart failure patients with sinus rhythm.

Multi-Modality Imaging in Dilated Cardiomyopathy: With a Focus on the Role of Cardiac Magnetic Resonance

Heart failure (HF) is recognized as a leading cause of morbidity and mortality worldwide. Dilated cardiomyopathy (DCM) is a common phenotype in patients presenting with HF. Timely diagnosis, appropriate identification of the underlying cause, individualized risk stratification, and prediction of clinical response to treatment have improved the prognosis of DCM over the last few decades. In this article, we reviewed the current evidence on available imaging techniques used for DCM patients. In this direction, we evaluated appropriate scenarios for the implementation of echocardiography, nuclear imaging, and cardiac computed tomography, and we focused on the primordial role that cardiac magnetic resonance (CMR) holds in the diagnosis, prognosis, and tailoring of therapeutic options in this population of special clinical interest. We explored the predictive value of CMR toward left ventricular reverse remodeling and prediction of sudden cardiac death, thus guiding the decisions for device therapy. Principles underpinning the use of state-of-the-art CMR techniques such as parametric mapping and feature-tracking strain analysis are also provided, along with expectations for the anticipated future advances in this field. We also attempted to correlate the evidence with clinical practice, with the intent to address questions on selecting the optimal imaging method for different indications and clinical needs. Overall, we recommend a comprehensive assessment of DCM patients at baseline and at follow-up intervals depending on the clinical status, with the addition of CMR as a second-line modality to other imaging techniques. We also provide an algorithm to guide the detailed imaging approach of the patient with DCM. We expect that future guidelines will upgrade their clinical recommendations for the utilization of CMR in DCM, which is expected to further improve the quality of care and the outcomes. This review provides an up-to-date perspective on the imaging of dilated cardiomyopathy patients and will be of clinical value to training doctors and physicians involved in the area of heart failure.

Fragmented QRS is associated with intraventricular dyssynchrony and independently predicts nonresponse to cardiac resynchronization therapy-Systematic review and meta-analysis

BACKGROUND

Fragmented QRS (fQRS) is postulated to be associated with ventricular dyssynchrony and might be able to predict a nonresponse to cardiac resynchronization therapy (CRT) implantation. In this systematic review and meta-analysis, we aim to assess whether fQRS can be a marker of intraventricular dyssynchronies in patients with ischemic and nonischemic cardiomyopathy and whether it is an independent predictor of nonresponse in patients receiving CRT.

METHODS

We performed a comprehensive search on topics that assesses fQRS and its association with intraventricular dyssynchrony and nonresponse to CRT up until September 2019.

RESULTS

Fragmented QRS is associated with intraventricular dyssynchrony (OR 10.34 [3.39, 31.54], p < .001; I2 : 80% with sensitivity 76.8%, specificity 77%, LR+ 3.3, and LR- 0.3). Subgroup analysis showed that fQRS is associated with intraventricular dyssynchrony in patients with narrow QRS complex (OR 20.92 [12.24, 35.73], p < .001; I2 : 0%) and nonischemic cardiomyopathy (OR of 19.97 [12.12, 32.92], p < .001; I2 : 0%). Fragmented QRS was also associated with a higher time-to-peak myocardial sustained systolic (Ts-SD) (OR 15.19 [12.58, 17.80], p < .001; I2 : 0% and positive Yu index (OR 15.61 [9.07, 26.86], p < .001; I2 : 0%). Fragmented QRS has a pooled adjusted OR of OR of 1.70 [1.35, 2.14], p < .001; I2 : 62% for association with a nonresponse to CRT. QRS duration is found to be higher in nonresponders group mean difference -8.54 [-13.38, -3.70], p < .001; I2 : 70%.

CONCLUSION

Fragmented QRS is associated with intraventricular dyssynchrony and is independently associated with nonresponse to cardiac resynchronization therapy.

Increases in repolarization heterogeneity predict left ventricular systolic dysfunction and response to cardiac resynchronization therapy in patients with left bundle branch block

INTRODUCTION

This study aimed to investigate the association between T-wave morphology and impaired left ventricular ejection fraction (LVEF) in patients with complete left bundle branch block (cLBBB), and the predictive value of T-wave morphology for response to cardiac resynchronization therapy (CRT).

METHODS AND RESULTS

We enrolled 189 patients with cLBBB on electrocardiogram performed between January 2007 and December 2011 who underwent standard echocardiography. Repolarization parameters, including the QRS-to-T angle (TCRT), T-wave morphology dispersion (TMD), T-wave loop area (PL), and T-wave residuum (TWR), were reconstructed from digital standard 12-lead electrocardiograms by T-wave morphology analysis. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume at 12 months after CRT implantation. The clinical outcome endpoint was a composite of heart failure hospitalization, heart transplantation, or death during follow up (mean, 5.8 years). On logistic regression, a higher heart rate, longer QRS duration, increased TMD, and larger TWR were all independently associated with LVEF < 40%. Among 40 patients who underwent CRT, those with a larger TMD (P = .007), larger PL (P = .025), and more negative TCRT (P = .015) had better response to CRT. A large TMD (P = .018) and large PL (P = .003) were also independent predictors of the clinical outcome endpoint.

CONCLUSIONS

Increases in repolarization heterogeneity in patients with cLBBB are associated with impaired LVEF. A large TMD and large PL may be useful as additional predictors of response to CRT, improving patient selection for CRT.