Results of the Predictors of Response to CRT (PROSPECT) trial

What Have We Learned in the Last 20 Years About CRT Non-Responders?

Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

Machine learning for multidimensional response and survival after cardiac resynchronization therapy using features from cardiac magnetic resonance

Background

Cardiac resynchronization therapy (CRT) response is complex, and better approaches are required to predict survival and need for advanced therapies.

Objective

The objective was to use machine learning to characterize multidimensional CRT response and its relationship with long-term survival.

Methods

Associations of 39 baseline features (including cardiac magnetic resonance [CMR] findings and clinical parameters such as glomerular filtration rate [GFR]) with a multidimensional CRT response vector (consisting of post-CRT left ventricular end-systolic volume index [LVESVI] fractional change, post-CRT B-type natriuretic peptide, and change in peak VO₂) were evaluated. Machine learning generated response clusters, and cross-validation assessed associations of clusters with 4-year survival.

Results

Among 200 patients (median age 67.4 years, 27.0% women) with CRT and CMR, associations with more than 1 response parameter were noted for the CMR CURE-SVD dyssynchrony parameter (associated with post-CRT brain natriuretic peptide [BNP] and LVESVI fractional change) and GFR (associated with peak VO₂ and post-CRT BNP). Machine learning defined 3 response clusters: cluster 1 (n = 123, 90.2% survival [best]), cluster 2 (n = 45, 60.0% survival [intermediate]), and cluster 3 (n = 32, 34.4% survival [worst]). Adding the 6-month response cluster to baseline features improved the area under the receiver operating characteristic curve for 4-year survival from 0.78 to 0.86 (P = .02). A web-based application was developed for cluster determination in future patients.

Conclusion

Machine learning characterizes distinct CRT response clusters influenced by CMR features, kidney function, and other factors. These clusters have a strong and additive influence on long-term survival relative to baseline features.

Breakthroughs in the treatment of heart failure with mildly reduced and preserved ejection fraction

Historically, only patients with a left ventricular ejection fraction (LVEF) of less than or equal to 40% were considered to have heart failure (HF). However, it was later found that patients could have elevated cardiac filling pressures and the stigmata of HF signs and symptoms with normal LVEF. This subset of patients has undergone multiple taxonomical variations and is now termed heart failure with preserved ejection fraction (HFpEF) with the lower limit of LVEF assigned as roughly ≥40%-50% in clinical trials and ≥50% in HF guidelines. Patients with LVEF 41%-49% did not clearly fit these designations but bear resemblance to both heart failure with reduced ejection fraction (HFrEF) and HFpEF. This cohort was initially assigned the term HFpEF (borderline), which has also undergone several modifications and is currently termed heart failure with mildly reduced ejection fraction (HFmrEF). Earlier landmark HF trials were heavily focused on patients with HFrEF. Only in the last 2 decades has there been an increasing focus on HFpEF with emergence of key drug therapies including sodium-glucose cotransport-2 inhibitors that have shown to improve outcomes across the whole LVEF spectrum. There is yet to be a focused clinical trial to determine therapeutic modalities for HFmrEF; most of the evidence has been extrapolated from subgroup analysis mostly from HFpEF trials. In this review, we provide an overview of the historical basis of HFpEF and HFmrEF and discuss key therapeutic advances in their management.

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.

Clinical and gated SPECT MPI parameters associated with super-response to cardiac resynchronization therapy

PURPOSE

We sought to evaluate the behavior of cardiac mechanical synchrony as measured by phase SD (PSD) derived from gated MPI SPECT (gSPECT) in patients with super-response after CRT and to evaluate the clinical and imaging characteristics associated with super-response.

METHODS

158 subjects were evaluated with gSPECT before and 6 months after CRT. Patients with an improvement of LVEF > 15% and NYHA class I/II or reduction in LV end-systolic volume > 30% and NYHA class I/II were labeled as super-responders (SR).

RESULTS

34 patients were classified as super-responders (22%) and had lower PSD (32° ± 17°) at 6 months after CRT compared to responders (45° ± 24°) and non-responders 46° ± 28° (P = .02 for both comparisons). Regression analysis identified predictors independently associated with super-response to CRT: absence of previous history of CAD (odds ratio 18.7; P = .002), absence of diabetes mellitus (odds ratio 13; P = .03), and history of hypertension (odds ratio .2; P = .01).

CONCLUSION

LV dyssynchrony after CRT implantation, but not at baseline, was significantly better among super-responders compared to non-super-responders. The absence of diabetes, absence of CAD, and history of hypertension were independently associated with super-response after CRT.

Standard care vs. TRIVEntricular pacing in Heart Failure (STRIVE HF): a prospective multicentre randomized controlled trial of triventricular pacing vs. conventional biventricular pacing in patients with heart failure and intermediate QRS left bundle branch block

AIMS

To determine whether triventricular (TriV) pacing is feasible and improves CRT response compared to conventional biventricular (BiV) pacing in patients with left bundle branch block (LBBB) and intermediate QRS prolongation (120-150 ms).

METHODS AND RESULTS

Between October 2015 and November 2019, 99 patients were recruited from 11 UK centres. Ninety-five patients were randomized 1:1 to receive TriV or BiV pacing systems. The primary endpoint was feasibility of TriV pacing. Secondary endpoints assessed symptomatic and remodelling response to CRT. Baseline characteristics were balanced between groups. In the TriV group, 43/46 (93.5%) patients underwent successful implantation vs. 47/49 (95.9%) in the BiV group. Feasibility of maintaining CRT at 6 months was similar in the TriV vs. BiV group (90.0% vs. 97.7%, P = 0.191). All-cause mortality was similar between TriV vs. BiV groups (4.3% vs. 8.2%, P = 0.678). There were no significant differences in echocardiographic LV volumes or clinical composite scores from baseline to 6-month follow-up between groups.

CONCLUSION

Implantation of two LV leads to deliver and maintain TriV pacing at 6 months is feasible without significant complications in the majority of patients. There was no evidence that TriV pacing improves CRT response or provides additional clinical benefit to patients with LBBB and intermediate QRS prolongation and cannot be recommended in this patient group.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov: NCT02529410.

Can nuclear imaging accurately detect scar in ischemic cardiac resynchronization therapy candidates?

BACKGROUND

Accurate scar assessment is crucial in cardiac resynchronization therapy (CRT) candidates, since its presence is a negative predictor for CRT response. Therefore, we assessed the performance of different PET parameters to detect scar in CRT candidates.

METHODS

Twenty-nine CRT candidates underwent 18F-fluorodeoxyglucose (18F-FDG)-PET/computed tomography (CT), resting 13N-NH3-PET/CT and cardiac magnetic resonance (CMR) prior to CRT implantation. Segmental 18F-FDG uptake, late 13N-NH3 uptake and absolute myocardial blood flow (MBF) were evaluated for scar detection using late gadolinium enhancement (LGE) CMR as reference. A receiver operator characteristic (ROC) area under the curve (AUC) ≥0.8 indicated a good accuracy of the methods evaluated.

RESULTS

Scar was present in 111 of 464 segments. None of the approaches could reliably identify segments with nontransmural scar, except for 18F-FDG uptake in the lateral wall (AUC 0.83). Segmental transmural scars could be detected with all methods (AUC ≥ 0.8), except for septal 18F-FDG uptake and MBF in the inferior wall (AUC < 0.8). Late 13N-NH3 uptake was the best parameter for transmural scar detection, independent of its location, with a sensitivity of 80% and specificity of 92% using a cutoff of 66% of the maximum tracer activity.

CONCLUSIONS

Late 13N-NH3 uptake is superior to 13N-NH3 MBF and 18F-FDG in detecting transmural scar, independently of its location. However, none of the tested PET parameters was able to accurately detect nontransmural scar.

Global longitudinal strain predicts responders after cardiac resynchronization therapy-a systematic review and meta-analysis

To evaluate the association between baseline global longitudinal strain (GLS) and ΔGLS (difference of baseline GLS and follow-up) and cardiac resynchronization therapy (CRT) response defined either with clinical or with echocardiographic characteristics. This meta-analysis was performed in accordance to both the Meta-Analysis of Observational Studies in Epidemiology and Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Two independent investigators performed a comprehensive systematic search in MedLine, EMBASE and Cochrane databases through September 2019 without limitations. Data analysis was performed by using the Review Manager software (RevMan), version 5.3, and Stata 13 software. A p value of less than 0.05 (two-tailed) was considered statistically significant. Twelve studies (1004 patients, mean age 63.8 years old, males 69.4%) provided data on the association of baseline GLS with the response to CRT therapy. We found that CRT responders had significantly better resting GLS values compared with non-responders [GLS mean difference -2.13 (-3.03, -1.23), p < 0.001, I2 78%]. Furthermore, CRT responders had significantly greater improvement of GLS at follow-up compared with non-responders [ΔGLS mean difference -3.20 (-4.95, -1.45), p < 0.001, I2 66%]. These associations remained significant in a subgroup analysis including only studies with similar CRT response definition. In this meta-analysis, we found that CRT responders had a baseline and ΔGLS significantly higher than the non-responders strengthening the central role of GLS as a tool for selecting candidates for CRT. Furthermore, improved GLS values after CRT may be used to better define CRT responders.

Left ventricular reverse remodelling and its predictors in non-ischaemic cardiomyopathy

Adverse remodelling following an initial insult is the hallmark of heart failure (HF) development and progression. It is manifested as changes in size, shape, and function of the myocardium. While cardiac remodelling may be compensatory in the short term, further neurohumoral activation and haemodynamic overload drive this deleterious process that is associated with impaired prognosis. However, in some patients, the changes may be reversed. Left ventricular reverse remodelling (LVRR) is characterized as a decrease in chamber volume and normalization of shape associated with improvement in both systolic and diastolic function. LVRR might occur spontaneously or more often in response to therapeutic interventions that either remove the initial stressor or alleviate some of the mechanisms that contribute to further deterioration of the failing heart. Although the process of LVRR in patients with new‐onset HF may take up to 2 years after initiating treatment, there is a significant portion of patients who do not improve despite optimal therapy, which has serious clinical implications when considering treatment escalation towards more aggressive options. On the contrary, in patients that achieve delayed improvement in cardiac function and architecture, waiting might avoid untimely implantable cardioverter‐defibrillator implantation. Therefore, prognostication of successful LVRR based on clinical, imaging, and biomarker predictors is of utmost importance. LVRR has a positive impact on prognosis. However, reverse remodelled hearts continue to have abnormal features. In fact, most of the molecular, cellular, interstitial, and genome expression abnormalities remain and a susceptibility to dysfunction redevelopment under biomechanical stress persists in most patients. Hence, a distinction should be made between reverse remodelling and true myocardial recovery. In this comprehensive review, current evidence on LVRR, its predictors, and implications on prognostication, with a specific focus on HF patients with non‐ischaemic cardiomyopathy, as well as on novel drugs, is presented.

Orthodromic and Antidromic Snare Techniques for Left Ventricular Lead Implantation in Cardiac Resynchronization Therapy

The snare technique can be used to overcome unsuitable cardiac venous anatomies for left ventricular (LV) lead implantation in cardiac resynchronization therapy (CRT) procedures. However, limited data exist regarding performance of the snare technique. We classified 262 patients undergoing CRT procedure into the snare (n = 20) or conventional group (n = 242) according to the LV lead implantation method. We compared the safety, efficacy, and composite outcome (all-cause death and heart failure readmission) at 3 years post-implant between the snare and conventional groups. In the snare group, all LV leads were implanted safely using orthodromic (n = 15) or antidromic (n = 5) techniques, and no immediate complications occurred including vessel perforation, tamponade, and lead dislodgement. During follow-up, LV lead threshold and impedance remained stable without requiring lead revision in the snare group. There were no significant between-group differences regarding LV ejection fraction increase (12 ± 13% vs. 12 ± 13%, p = 0.929) and LV end-systolic volume reduction (18 ± 48% vs. 28 ± 31%, p = 0.501). Both groups exhibited comparable CRT-response rates (62.5% vs. 60.6%, p = 1.000). The risk of primary outcome was not significantly different between the two groups (25.9% vs. 30.9%, p = 0.817). In patients who failed conventional LV lead implantation for CRT, the snare technique could be a safe and effective solution to overcome difficult coronary venous anatomy.

Strain-based discoordination imaging during exercise in heart failure with reduced ejection fraction: Feasibility and reproducibility

PURPOSE

Various parameters of mechanical dyssynchrony have been proposed to improve patient selection criteria for cardiac resynchronization therapy, but sensitivity and specificity are lacking. However, echocardiographic parameters are consistently investigated at rest, whereas heart failure (HF) symptoms predominately manifest during submaximal exertion. Although strain-based predictors of response are promising, feasibility and reproducibility during exercise has yet to be demonstrated.

METHODS

Speckle-tracking echocardiography was performed in patients with HF at two separate visits. Echocardiography was performed at rest, during various exercise intensity levels, and during recovery from exercise. Systolic rebound stretch of the septum (SRSsept), systolic shortening, and septal discoordination index (SDI) were calculated.

RESULTS

Echocardiography was feasible in about 70-80% of all examinations performed during exercise. Of these acquired views, 84% of the cine-loops were suitable for analysis of strain-based mechanical dyssynchrony. Test-retest variability and intra- and inter-operator reproducibility at 30% and 60% of the ventilatory threshold (VT) were about 2.5%. SDI improved in the majority of patients at 30% and 60% of the VT, with moderate to good agreement between both intensity levels.

CONCLUSION

Although various challenges remain, exercise echocardiography with strain analysis appears to be feasible in the majority of patients with dyssynchronous heart failure. Inter- and intra-observer agreement of SRSsept and SDI up to 60% of the VT were comparable to resting values. During exercise, the extent of SDI was variable, suggesting a heterogeneous response to exercise. Further research is warranted to establish its clinical significance.

QRS Narrowing Following CRT Implantation: Predictors, Dynamics, and Association with Improved Long-Term Outcome

Background: Heart failure (HF) patients with wide QRS often benefit from cardiac resynchronization therapy (CRT), although QRS narrowing does not always occur. The current study investigates the incidence and predictors for QRS narrowing following CRT and its long-term impact on clinical outcomes. Methods: Among individuals undergoing clinically indicated CRT, pre-and post-implantation electrocardiographs were meticulously analyzed for QRS duration change. All-cause mortality and the composite of mortality and HF hospitalizations were retrieved. Results: For 104 patients, mean age 67 years, 25% females, QRS narrowed within days by 20.2 ± 24.7 ms. In 55/104 (53%) QRS narrowed by ≥20 ms (“acute narrowing”). Female gender and baseline QRS predicted acute narrowing. Acute narrowing persisted for 1−6 weeks in 18/20 (90%) and 3−12 months in 21/31 (68%) of patients. During the average follow-up of 41 months, 29/104 (28%) died and 50/104 (48%) met the composite outcome. In a multivariable analysis including comorbidities and cardiac history, prolonged baseline PR interval (HR 1.015, CI 1.008−1.021, p < 0.001) and acute narrowing < 20 ms (HR 3.243, CI 1.593−6.603, p = 0.001) were significant and independent predictors for the composite outcome. Conclusions: Post-CRT acute QRS narrowing ≥ 20 ms is independently associated with favorable long-term outcomes and might be considered as a novel measure for procedural success.

Desynchronization Strain Patterns and Contractility in Left Bundle Branch Block through Computer Model Simulation

Left bundle branch block (LBBB) is associated with specific septal-to-lateral wall activation patterns which are strongly influenced by the intrinsic left ventricular (LV) contractility and myocardial scar localization. The objective of this study was to propose a computational-model-based interpretation of the different patterns of LV contraction observed in the case of LBBB and preserved contractility or myocardial scarring. Two-dimensional transthoracic echocardiography was used to obtain LV volumes and deformation patterns in three patients with LBBB: (1) a patient with non-ischemic dilated cardiomyopathy, (2) a patient with antero-septal myocardial scar, and (3) a patient with lateral myocardial scar. Scar was confirmed by the distribution of late gadolinium enhancement with cardiac magnetic resonance imaging (cMRI). Model parameters were evaluated manually to reproduce patient-derived data such as strain curves obtained from echocardiographic apical views. The model was able to reproduce the specific strain patterns observed in patients. A typical septal flash with pre-ejection shortening, rebound stretch, and delayed lateral wall activation was observed in the case of non-ischemic cardiomyopathy. In the case of lateral scar, the contractility of the lateral wall was significantly impaired and septal flash was absent. In the case of septal scar, septal flash and rebound stretch were also present as previously described in the literature. Interestingly, the model was also able to simulate the specific contractile properties of the myocardium, providing an excellent localization of LV scar in ischemic patients. The model was able to simulate the electromechanical delay and specific contractility patterns observed in patients with LBBB of ischemic and non-ischemic etiology. With further improvement and validation, this technique might be a useful tool for the diagnosis and treatment planning of heart failure patients needing CRT.

The efficacy and safety outcomes of cardiac resynchronization therapy in patients with heart failure in Thailand: Phramongkutklao experience

BACKGROUND

Cardiac resynchronization therapy (CRT) is one of the crucial treatments in patients with symptomatic heart failure reduced ejection fraction. This study aimed to report the efficacy and safety of CRT implantation in treating patients with heart failure. The responders and related outcomes were also analyzed.

METHODS

Medical records of all patients with CRT implantation, because of heart failure treatment indication, in Phramongkutklao Hospital between 2008 and 2019 were reviewed. Free from death and heart failure hospitalization were analyzed as composited efficacy outcomes with survival analysis. Follow-up echocardiography was used to define a responder. The safety outcomes were reported using descriptive data. Cox-proportional hazard model analysis was used for the responder as a predictor of outcomes.

RESULTS

A total of 152 patients underwent CRT implantation because of heart failure. 77.63% were male, the mean age of 65.9 ± 13.19 years, 59.85% were diagnosed with ischemic cardiomyopathy, mean LVEF of 22.69 ± 7.51%, and QRS duration of 147 ± 21 ms. Mean Follow-up was 41 months. The composited efficacy outcomes were 91.7%, 54.8%, and 35.4% at 1, 5, and 10 years, respectively. CRT-related complications were found in 12 patients (7.89%). 71.30% of patients who were responders had lower death or heart failure hospitalization when compared to non-responders (HR: 0.43, 95% CI: 0.24-0.78).

CONCLUSION

The efficacy and safety in CRT treating patients in our center were consistent with the previous randomized and observational studies. The responder rate remained the same as in previous trials but was a strong predictor for better outcomes.

A rapid electromechanical model to predict reverse remodeling following cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an effective therapy for patients who suffer from heart failure and ventricular dyssynchrony such as left bundle branch block (LBBB). When it works, it reverses adverse left ventricular (LV) remodeling and the progression of heart failure. However, CRT response rate is currently as low as 50-65%. In theory, CRT outcome could be improved by allowing clinicians to tailor the therapy through patient-specific lead locations, timing, and/or pacing protocol. However, this also presents a dilemma: there are far too many possible strategies to test during the implantation surgery. Computational models could address this dilemma by predicting remodeling outcomes for each patient before the surgery takes place. Therefore, the goal of this study was to develop a rapid computational model to predict reverse LV remodeling following CRT. We adapted our recently developed computational model of LV remodeling to simulate the mechanics of ventricular dyssynchrony and added a rapid electrical model to predict electrical activation timing. The model was calibrated to quantitatively match changes in hemodynamics and global and local LV wall mass from a canine study of LBBB and CRT. The calibrated model was used to investigate the influence of LV lead location and ischemia on CRT remodeling outcome. Our model results suggest that remodeling outcome varies with both lead location and ischemia location, and does not always correlate with short-term improvement in QRS duration. The results and time frame required to customize and run this model suggest promise for this approach in a clinical setting.

Evolving concept of dyssynchrony and its utility

The role of electromechanical dyssynchrony in heart failure gained prominence in literature with the results of trials of cardiac resynchronization therapy (CRT). CRT has shown to significantly decrease heart failure hospitalization and mortality in heart failure patients with dyssynchrony. Current guidelines recommend the use of electrical dyssynchrony based on a QRS > 150 ms and a left bundle branch block pattern on surface electrocardiogram to identify dyssynchrony in patients who will benefit from CRT implantation. However, predicting response to CRT remains a challenge with nearly one-third of patients gaining no benefit from the device. Multiple echocardiographic measures of mechanical dyssynchrony have been studied over the past two decade. However, trials where mechanical dyssynchrony used as an additional or lone criteria for CRT failed to show any benefit in the response to CRT. This shows that a deeper understanding of cardiac mechanics should be applied in the assessment of dyssynchrony. This review discusses the evolving role of imaging techniques in assessing cardiac dyssynchrony and their application in patients considered for device therapy.

Cardiac rehabilitation - The answer for the second chance

In the United States and worldwide, the leading cause of death in females is cardiovascular disease (CVD). However, compared to males, females have overall higher mortality rates, especially within the first few years of having an acute myocardial infarction (AMI). Despite the increased awareness of CVD in females and established benefits of cardiac rehabilitation (CR) programs, there is still delayed initiation of care, under-recognition of atypical presentations of angina in females, under referral of females to CR, and under-representation of females in CVD trials. In this paper, we will investigate the barriers to female participation in CR, explore the fundamental differences in physiology between males and females, and current limitations in CVD trials where females are under-represented. Finally, we aim to provide potential methods to increase enrollment of females in CR and CR related trials.

Multipoint left ventricular pacing effects on hemodynamic parameters and functional status: HUMVEE single-arm clinical trial (NCT03189368)

OBJECTIVES

The aim of this study was to assess the capacity of optimized multipoint pacing (MPP) over optimized cardiac resynchronization therapy (CRT), in terms of clinical, functional, and echocardiographic parameters among patients with dyssynchronous heart failure (HF).

METHODS

Eighty patients (Caucasian, 77.5% male, 68.4 ± 10.1 years, and 53.8% ischemic cardiomyopathy) sequentially received optimized CRT and optimized MPP over 6- and 12-month periods in a single-arm clinical trial. Clinical, laboratory, and echocardiographic assessment was conducted at baseline and after the completion of each step.

RESULTS

Significant additive effects of optimized MPP over optimized CRT were noted with regard to 6-min walking distance (baseline/optCRT/optMPP: 293 ± 120 m vs 367 ± 94 m vs 405 ± 129 m and p < 0.001), NYHA class (2.36 vs 2.19 vs 1.45 and p < 0.001), VTIlvot (14.25 ± 3.2 cm vs 16.2 ± 4 cm vs 17.5 ± 3.4 cm and p < 0.001), stroke volume (48 ± 13.5 ml vs 55 ± 15 ml vs 59 ± 15 ml and p < 0.001), left ventricular ejection fraction (LVEF) (29% ± 7.1% vs 33% ± 7.3% vs 37% ± 7.7% and p < 0.001), maximal left atrial volume (77.2 ± 34.2 ml vs 74.2 ± 39.5 ml vs 67.7 ± 32 ml and p = 0.02), pulmonary artery systolic pressure (35.9 mmHg vs 33.5 mmHg vs 31 mmHg and p < 0.001), and right ventricular strain (-8.3% ± 6.9% vs -8.8% ± 6.6% vs -11.8% ± 6.1% and p = 0.022). With regard to VAC, stroke work (SW), and CP as percentages of maximal, there was a significant difference detected as compared to baseline for both CRT and MPP. Additive effects persisted only if suitable MPP dipoles were present. Exploratory analysis revealed that ischemic cardiomyopathy continued to exhibit significant differences that favor MPP, whereas nonischemic cardiomyopathy had similar findings with regard to total left atrial strain and quality of life.

CONCLUSIONS

Optimized MPP showed significant improvements in hemodynamic parameters and ventricular function in patients with HF over optimized CRT. The beneficial effect was more prominent in men and in those with rather reduced LVEF, consistent with findings that suggest a beneficial trend in VAC and CP with more homogeneous depolarization offered by optimized MPP.

Four-dimensional flow magnetic resonance imaging visualizes reverse vortex pattern and energy loss increase in left bundle branch block

AIMS

This study aimed to investigate the intraventricular blood flow pattern of patients with left bundle branch block (LBBB) using four-dimensional flow magnetic resonance imaging (4D-flow MRI).

METHODS AND RESULTS

We performed 4D-flow MRI for 16 LBBB patients (LBBB group) and 16 propensity score-matched patients with a normal QRS duration (non-LBBB group). The energy loss (EL) in the left ventricle was evaluated. In both groups, blood flow from the mitral valve to the apex of the heart and left ventricular (LV) outflow tract during LV diastole were observed. Vortices were also observed in both groups. There were two patterns of vortices: unidirectional clockwise rotation and counterclockwise rotation taking place from the mid-diastole to the systole (reverse pattern). The reverse pattern was observed significantly more frequently in the LBBB group (LBBB 94% vs. non-LBBB 19%, P < 0.001). The interobserver agreement for the streamline analysis was good (kappa = 0.68). The maximum EL was significantly higher in the LBBB group [LBBB 12 (11-15) mW vs. non-LBBB 8.0 (6.2-9.7) mW, P < 0.001].

CONCLUSION

Left bundle branch block patients may suffer from inefficient LV haemodynamics reflected by non-physiological counterclockwise vortices and increased EL. Thus, the shape of the vortices and EL in the left ventricle can serve as markers of LV mechanical dyssynchrony in LBBB patients and could be investigated as predictors of response to cardiac resynchronization therapy.

Anodal Capture for Multisite Pacing with a Quadripolar Left Ventricular Lead: A Feasibility Study

Background: Up to 40% of patients are CRT non-responders. Multisite pacing, using a unique quadripolar lead, also called multipoint/multipole pacing (MPP), is a potential alternative. We sought to determine the feasibility of intentional anodal capture using a single LV quadripolar lead, to reproduce MPP without the need of a specific algorithm (so-called “pseudo MPP”). Methods: Consecutive patients implanted with a commercially available CRT device and a quadripolar LV lead in our department were prospectively included. The electric charge (Q, in Coulomb) of RV and LV pacing spikes were calculated for all available LV pacing configurations at the threshold. The best MPP was defined as the configuration with the lowest consumption (Q_RV + Q_{best LV1} + Q_{best LV2}). The best “pseudo MPP” (Q_RV + Q_{LV1–LV2 with anodal capture}) and best BVp (Q_RV + Q_{best LV}) were also calculated. A theoretical longevity was estimated for each configuration at the threshold without a safety margin. Results: A total of 235 configurations were tested in 15 consecutive patients. “Pseudo-MPP” was feasible in 80% of patients with 3.1 ± 2.6 vectors available per-patient and LV_proximal-LV_distal (most distant electrodes) vectors were available in 47% of patients. Each MPP pacing spike electrical charge was comparable to “pseudo-MPP” (18,428 ± 6863 µC and 20,528 ± 5509 µC, respectively, p = 0.15). Theoretical longevity was 6.2 years for MPP, 5.6 years for “pseudo-MPP” and 13.7 years for BVp. Conclusions: “Pseudo MPP” using intentional anodal capture with a quadripolar left ventricular lead, mimicking conventional multisite pacing, is feasible in most of CRT patients, with comparable energy consumption. Further studies on their potential clinical impact are needed.

Does mechanical dyssynchrony in addition to QRS area ensure sustained response to cardiac resynchronization therapy?

Aims

Judicious patient selection for cardiac resynchronization therapy (CRT) may further enhance treatment response. Progress has been made by using improved markers of electrical dyssynchrony and mechanical discoordination, using QRS_AREA, and systolic rebound stretch of the septum (SRSsept) or systolic stretch index (SSI), respectively. To date, the relation between these measurements has not yet been investigated.

Methods and results

A total of 240 CRT patients were prospectively enrolled from six centres. Patients underwent standard 12-lead electrocardiography, and echocardiography, at baseline, 6-month, and 12-month follow-up. QRS_AREA was derived using vectorcardiography, and SRSsept and SSI were measured using strain-analysis. Reverse remodelling was measured as the relative decrease in left ventricular end-systolic volume, indexed to body surface area (ΔLVESVi). Sustained response was defined as ≥15% decrease in LVESVi, at both 6- and 12-month follow-up. QRS_AREA and SRSsept were both strong, multivariable adjusted, variables associated with reverse remodelling. SRSsept was associated with response, but only in patients with QRS_AREA ≥ 120 μVs (AUC = 0.727 vs. 0.443). Combined presence of SRSsept ≥ 2.5% and QRS_AREA ≥ 120 μVs significantly increased reverse remodelling compared with high QRS_AREA alone (ΔLVESVi 38 ± 21% vs. 22 ± 21%). As a result, 92% of left bundle branch block (LBBB)-patients with combined electrical and mechanical dysfunction were ‘sustained’ volumetric responders, as opposed to 51% with high QRS_AREA alone.

Conclusion

Parameters of mechanical dyssynchrony are better associated with response in the presence of a clear underlying electrical substrate. Combined presence of high SRSsept and QRS_AREA, but not high QRS_AREA alone, ensures a sustained response after CRT in LBBB patients.

Prognostic Significance of Left Ventricular Dyssynchrony Assessed with Nuclear Cardiology for the Prediction of Major Cardiac Events after Revascularization

Objective This retrospective study was aimed at determining whether or not stress phase bandwidth (SPBW), a left ventricular (LV) mechanical dyssynchrony index, predicts major cardiac events (MCEs) and stratifies the risk of those in patients with coronary artery disease (CAD) who undergo revascularization. Methods Patients were followed up to confirm the prognosis for at least one year. The SPBW was calculated by a phase analysis using the Heart Risk View-F software program. The composite endpoint was the onset of MCEs, consisting of cardiac death, non-fatal myocardial infarction, unstable angina pectoris, and severe heart failure requiring hospitalization. Patients The study subjects were 332 patients with CAD who underwent coronary angiography and revascularization after confirming ≥5% ischemia detected by rest ²⁰¹Tl and stress ^99mTc-tetrofosmin electrocardiogram-gated single-photon emission computed tomography myocardial perfusion imaging. Results During the follow-up, 35 patients experienced MCEs of cardiac death (n=5), non-fatal myocardial infarction (n=3), unstable angina pectoris (n=11), and severe heart failure requiring hospitalization (n=16). A receiver operating characteristics analysis indicated that the optimal cut-off value of the SPBW was 52° for predicting MCEs, and the MCE rate was significantly higher in the patients with an SPBW >52° than in those with an SPBW ≤52°. Results of the multivariate analysis showed the SPBW and estimated glomerular filtration rate to be independent predictors for MCEs. In addition, the cut-off value of the SPBW significantly stratified the risk of MCEs according to the results of the Kaplan-Meier analysis. Conclusion Evaluating the SPBW before revascularization may help predict future MCEs in patients with CAD who intended to undergo treatment.

Contemporary ICD Use in Patients with Heart Failure

Despite constant breakthroughs in heart failure (HF) therapy, the population of HF patients resume to grow and is linked to increased mortality and morbidity. Ventricular arrhythmias (VA) are one of the leading causes of mortality in HF subjects. Implantable cardioverter-defibrillators (ICDs) are currently the gold standard in treatment, preventing arrhythmic sudden cardiac death (SCD) episodes. However, the death rates related to HF remain elevated, as not all HF subjects benefit equally. Cardiac resynchronization therapy (CRT) has emerged as a novel approach for HF patients. These devices have been thoroughly investigated in major randomized controlled studies but continue to be underutilized in various countries. This review discusses the use of ICD in HF populations on top of treatments.

First-Phase Ejection Fraction Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes

OBJECTIVES

The aim of this study was to examine the value of first-phase ejection fraction (EF1), to predict response to cardiac resynchronization therapy (CRT) and clinical outcomes after CRT.

BACKGROUND

CRT is an important treatment for patients with chronic heart failure. However, even in carefully selected cases, up to 40% of patients fail to respond. EF1, the ejection fraction up to the time of maximal ventricular contraction, is a novel sensitive echocardiographic measure of early systolic function and might relate to response to CRT.

METHODS

An initial retrospective study was performed in 197 patients who underwent CRT between 2009 and 2018 and were followed to determine clinical outcomes at King's Health Partners in London. A validation study (n = 100) was performed in patients undergoing CRT at Barts Heart Centre in London.

RESULTS

Volumetric response rate (reduction in end-systolic volume ≥15%) was 92.3% and 12.1% for those with EF1 in the highest and lowest tertiles (P < 0.001). A cutoff value of 11.9% for EF1 had >85% sensitivity and specificity for prediction of response to CRT; on multivariate binary logistic regression analysis incorporating previously defined predictors, EF1 was the strongest predictor of response (odds ratio [OR]: 1.56 per 1% change in EF1; 95% CI: 1.37-1.78; P < 0.001). EF1 was also the strongest predictor of improvement in clinical composite score (OR: 1.11; 95% CI: 1.04-1.19; P = 0.001). Improvement in EF1 at 6 months after CRT implantation (6.5% ± 5.8% vs 1.8% ± 4.3% in responders vs nonresponders; P < 0.001) was the best predictor of heart failure rehospitalization and death after median follow-up period of 20.3 months (HR: 0.81; 95% CI: 0.73-0.90; P < 0.001). In the validation cohort, EF1 was a similarly 1strong predictor of response (OR: 1.45; 95% CI: 1.23-1.70; P < 0.001) as in the original cohort.

CONCLUSIONS

EF1 is a promising marker to identify patients likely to respond to CRT.

The importance of early evaluation after cardiac resynchronization therapy to redefine response: Pooled individual patient analysis from 5 prospective studies

BACKGROUND

Cardiac resynchronization therapy (CRT) reduces mortality and improves outcomes in appropriately selected patients with heart failure (HF); however, response may vary.

OBJECTIVE

We sought to correlate 6-month CRT response assessed by clinical composite score (CCS) and left ventricular end-systolic volume index (LVESVi) with longer-term mortality and HF hospitalizations.

METHODS

Individual patient data from 5 prospective CRT studies-MIRACLE, MIRACLE ICD, InSync III Marquis, PROSPECT, and Adaptive CRT-were pooled. Classification of CRT response status using CCS and LVESVi were made at 6 months. Kaplan-Meier analyses were used to assess time to mortality. Cox proportional hazards regression models were used to compute hazard ratios (HRs) for the 3 levels of CRT response: improved, stabilized, and worsened. Adjusted models controlled for baseline factors known to influence both CRT response and mortality. HF-related hospitalization was compared between CRT response categories using incidence rate ratios.

RESULTS

Among a total of 1603 patients, 1426 and 1165 were evaluated in the CCS and LVESVi outcome assessments, respectively. Mortality was significantly lower for patients in the improved (CCS: HR 0.22; 95% confidence interval [CI] 0.15-0.31; LVESVi: HR 0.40; 95% CI 0.27-0.60) and stabilized (CCS: HR 0.38; 95% CI 0.24-0.61; LVESVi: HR 0.41; 95% CI 0.25-0.68) groups than in the worsened group for both measures after adjusting for potential confounders.

CONCLUSION

Patients with a worsened CRT response status have a high mortality rate and HF hospitalizations. Stabilized patients have a more favorable prognosis than do worsened patients and thus should not be considered CRT nonresponders.

Automated Analysis of Doppler Echocardiographic Videos as a Screening Tool for Valvular Heart Diseases

OBJECTIVES

This study sought to develop a deep learning (DL) framework to automatically analyze echocardiographic videos for the presence of valvular heart diseases (VHDs).

BACKGROUND

Although advances in DL have been applied to the interpretation of echocardiograms, such techniques have not been reported for interpretation of color Doppler videos for diagnosing VHDs.

METHODS

We developed a 3-stage DL framework for automatic screening of echocardiographic videos for mitral stenosis (MS), mitral regurgitation (MR), aortic stenosis (AS), and aortic regurgitation (AR) that classifies echocardiographic views, detects the presence of VHDs, and, when present, quantifies key metrics related to VHD severities. The algorithm was trained (n = 1,335), validated (n = 311), and tested (n = 434) using retrospectively selected studies from 5 hospitals. A prospectively collected set of 1,374 consecutive echocardiograms served as a real-world test data set.

RESULTS

Disease classification accuracy was high, with areas under the curve of 0.99 (95% CI: 0.97-0.99) for MS; 0.88 [95% CI: 0.86-0.90] for MR; 0.97 [95% CI: 0.95-0.99] for AS; and 0.90 [95% CI: 0.88-0.92]) for AR in the prospective test data set. The limits of agreement (LOA) between the DL algorithm and physician estimates of metrics of valve lesion severities compared to the LOAs between 2 experienced physicians spanned from -0.60 to 0.77 cm² vs -0.48 to 0.44 cm² for MV area; from -0.27 to 0.25 vs -0.23 to 0.08 for MR jet area/left atrial area; from -0.86 to 0.52 m/s vs -0.48 to 0.54 m/s for peak aortic valve blood flow velocity (Vmax); from -10.6 to 9.5 mm Hg vs -10.2 to 4.9 mm Hg for average peak aortic valve gradient; and from -0.39 to 0.32 vs -0.31 to 0.32 for AR jet width/left ventricular outflow tract diameter.

CONCLUSIONS

The proposed deep learning algorithm has the potential to automate and increase efficiency of the clinical workflow for screening echocardiographic images for the presence of VHDs and for quantifying metrics of disease severity.

Radial strain imaging-guided lead placement for improving response to cardiac resynchronization therapy in patients with ischaemic cardiomyopathy: the raise cardiac resynchronization therapy trial

AIMS

To evaluate the benefit of speckle tracking radial strain imaging (STRSI)-guided left ventricular (LV) lead (LVL) positioning in cardiac resynchronization therapy (CRT) in patients (pts) with ischaemic cardiomyopathy with CRT indication.

METHODS AND RESULTS

We conducted a prospective randomized controlled trial. Patients were enrolled in nine centres with 2:1 randomization into two groups (guided vs. control). Patients underwent STRSI to identify the optimal LV position from six LV segments at midventricular level. Implantation via STRSI was attempted for recommended segment in the guided group only. Follow-up included echocardiography (6 months) and clinical evaluation (6 and 12 months). The primary endpoint was comparison % reduction in LV end-systolic volume at 6 months with baseline. Secondary endpoints included hospitalizations for heart failure and death, and improvement in additional echocardiographic measurements and quality of life score. A total of 172 patients (115 guided vs. 57 control) were enrolled. In the guided group, 60% of the implanted LV leads were adjudicated to be successfully located at the recommended segment, whereas in the control group 44% reached the best STRSI determined segment. There was no difference between the groups in any of the primary or secondary endpoints at 6 and 12 months.

CONCLUSION

Our findings suggest that echo-guided implantation of an LV lead using STRSI does not improve the clinical or echocardiographic response compared with conventional implantation.

Regional contributions to left ventricular stroke volume determined by cardiac magnetic resonance imaging in cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) restores ventricular synchrony and induces left ventricular (LV) reverse remodeling in patients with heart failure (HF) and dyssynchrony. However, 30% of treated patients are non-responders despite all efforts. Cardiac magnetic resonance imaging (CMR) can be used to quantify regional contributions to stroke volume (SV) as potential CRT predictors. The aim of this study was to determine if LV longitudinal (SVlong%), lateral (SVlat%), and septal (SVsept%) contributions to SV differ from healthy controls and investigate if these parameters can predict CRT response.

METHODS

Sixty-five patients (19 women, 67 ± 9 years) with symptomatic HF (LVEF ≤ 35%) and broadened QRS (≥ 120 ms) underwent CMR. SVlong% was calculated as the volume encompassed by the atrioventricular plane displacement (AVPD) from end diastole (ED) to end systole (ES) divided by total SV. SVlat%, and SVsept% were calculated as the volume encompassed by radial contraction from ED to ES. Twenty age- and sex-matched healthy volunteers were used as controls. The regional measures were compared to outcome response defined as ≥ 15% decrease in echocardiographic LV end-systolic volume (LVESV) from pre- to 6-months post CRT (delta, Δ).

RESULTS

AVPD and SVlong% were lower in patients compared to controls (8.3 ± 3.2 mm vs 15.3 ± 1.6 mm, P < 0.001; and 53 ± 18% vs 64 ± 8%, P < 0.01). SVsept% was lower (0 ± 15% vs 10 ± 4%, P < 0.01) with a higher SVlat% in the patient group (42 ± 16% vs 29 ± 7%, P < 0.01). There were no differences between responders and non-responders in neither SVlong% (P = 0.87), SVlat% (P = 0.09), nor SVsept% (P = 0.65). In patients with septal net motion towards the right ventricle (n = 28) ΔLVESV was - 18 ± 22% and with septal net motion towards the LV (n = 37) ΔLVESV was - 19 ± 23% (P = 0.96).

CONCLUSIONS

Longitudinal function, expressed as AVPD and longitudinal contribution to SV, is decreased in patients with HF scheduled for CRT. A larger lateral contribution to SV compensates for the abnormal septal systolic net movement. However, LV reverse remodeling could not be predicted by these regional contributors to SV.

Endocardial left ventricular pacing

Cardiac resynchronization therapy (CRT) is an effective treatment for dyssynchronous heart failure; however, 30–50% of patients fail to improve after implant. Endocardial left ventricular (LV) pacing is an alternative therapy for patients who do not respond to conventional CRT or in whom placement of a lead via the coronary sinus is not possible. It enables pacing at a wide variety of sites, without restrictions due to coronary sinus anatomy, and there is evidence of superior electrical resynchronization and hemodynamic response compared with conventional epicardial CRT. In this article, we discuss the potential advantages and disadvantages of endocardial LV pacing compared with conventional CRT, review the evidence for the delivery of endocardial LV pacing using both lead-based and leadless systems, and explore possible future directions of this novel technology.

Non-invasive simulated electrical and measured mechanical indices predict response to cardiac resynchronization therapy

BACKGROUND

Cardiac Resynchronization Therapy (CRT) in dyssynchronous heart failure patients is ineffective in 20-30% of cases. Sub-optimal left ventricular (LV) pacing location can lead to non-response, thus there is interest in LV lead location optimization. Invasive acute haemodynamic response (AHR) measurements have been used to optimize the LV pacing location during CRT implantation. In this manuscript, we aim to predict the optimal lead location (AHR>10%) with non-invasive computed tomography (CT) based measures of cardiac anatomical and mechanical properties, and simulated electrical activation times.

METHODS

Non-invasive measurements from CT images and ECG were acquired from 34 patients indicated for CRT upgrade. The LV lead was implanted and AHR was measured at different pacing sites. Computer models of the ventricles were used to simulate the electrical activation of the heart, track the mechanical motion throughout the cardiac cycle and measure the wall thickness of the LV on a patient specific basis.

RESULTS

We tested the ability of electrical, mechanical and anatomical indices to predict the optimal LV location. Electrical (RV-LV delay) and mechanical (time to peak contraction) indices were correlated with an improved AHR, while wall thickness was not predictive. A logistic regression model combining RV-LV delay and time to peak contraction was able to predict positive response with 70 ± 11% accuracy and AUROC curve of 0.73.

CONCLUSION

Non-invasive electrical and mechanical indices can predict optimal epicardial lead location. Prospective analysis of these indices could allow clinicians to test the AHR at fewer pacing sites and reduce time, costs and risks to patients.

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.

Analysis of Differences in Assessment of Left Ventricular Function on Echocardiography and Nuclear Perfusion Imaging

Two widely used methods for left ventricular (LV) ejection fraction (EF) determination, echocardiography (echo) and gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), often have wide limits of agreement. Factors influencing discrepancies between core laboratory echo and MPI LVEF determinations were examined in a large series of heart failure (HF) subjects and normal controls. 879 HF and 101 control subjects had core lab analyses of echo and MPI (mean time between procedures 7-8 days). LVEF differences were analyzed using one-way analysis of variance and Bland-Altman plots. Relationships between LVEF differences and patient characteristics and outcome endpoints (mortality and arrhythmias) were explored with logistic regression, Cox proportional hazards models, and Kaplan-Meier survival analyses. There was a systematic difference between the 2 modalities; echo LVEF was higher with more severe LV dysfunction, MPI LVEF higher when systolic function was normal. LVEF results were within ±5% in only 37% of HF and 23% of control subjects. Considering discordance around the LVEF threshold 35%, there was disagreement between the 2 methods in 305 HF subjects (35%). Male gender (odds ratio (OR) = 0.200), atrial fibrillation (OR = 2.314), higher body mass index (OR = 1.051) and lower LV end-diastolic volume (OR = 0.985) were the strongest predictors of methodologic discordance. Cardiac event rates were highest if both LVEF values were ≤35% and lowest when both LVEF values were >35%. In conclusion, substantial disagreements between LVEF results by echo and MPI are common. HF patients with LVEF ≤35% by both techniques have the highest 2-year event risk.

Mechanical dyssynchrony: How do we measure it, what it means, and what we can do about it

Left ventricular mechanical dyssynchrony (LVMD) is defined by a difference in the timing of mechanical contraction or relaxation between different segments of the left ventricle (LV). Mechanical dyssynchrony is distinct from electrical dyssynchrony as measured by QRS duration and has been of increasing interest due to its association with worse prognosis and potential role in patient selection for cardiac resynchronization therapy (CRT). Although echocardiography is the most used modality to assess LVMD, some limitations apply to this modality. Compared to echo-based modalities, nuclear imaging by gated single-photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) has clear advantages in evaluating systolic and diastolic LVMD. GSPECT MPI can determine systolic and diastolic mechanical dyssynchrony by the variability in the timing in which different LV segments contract or relax, which has prognostic impact in patients with coronary artery disease and heart failure. As such, by targeting mechanical dyssynchrony instead of electrical dyssynchrony, GSPECT MPI can potentially improve patient selection for CRT. So far, few studies have investigated the role of diastolic dyssynchrony, but recent evidence seems to suggest high prevalence and more prognostic impact than previously recognized. In the present review, we provide an oversight of mechanical dyssynchrony.

Myocardial Work by Echocardiography: Principles and Applications in Clinical Practice

Left ventricular (LV) global longitudinal strain (GLS) has established itself in the last decade as a reliable, more objective method for the evaluation of LV systolic function, able to detect subtle abnormalities in LV contraction even in the presence of preserved ejection fraction (EF). However, recent studies have demonstrated that GLS, similar to LV EF, has important load dependency. Non-invasive myocardial work (MW) quantification has emerged in the last years as an alternative tool for myocardial function assessment. This new method, incorporating measurement of strain and LV pressure, has shown to overcome GLS and LV EF limitations and provide a loading-independent evaluation of myocardial performance. The presence of a commercially available echocardiographic software for the non-invasive MW calculation has allowed the application of this new method in different settings. This review sought to provide an overview on the current knowledge of non-invasive MW estimation, showing its potential applications and possible added value in clinical practice.

Shortening of time-to-peak left ventricular pressure rise (Td) in cardiac resynchronization therapy

Aims

We tested the hypothesis that shortening of time‐to‐peak left ventricular pressure rise (Td) reflect resynchronization in an animal model and that Td measured in patients will be helpful to identify long‐term volumetric responders [end‐systolic volume (ESV) decrease >15%] in cardiac resynchronization therapy (CRT).

Methods

Td was analysed in an animal study (n = 12) of left bundle‐branch block (LBBB) with extensive instrumentation to detect left ventricular myocardial deformation, electrical activation, and pressures during pacing. The sum of electrical delays from the onset of pacing to four intracardiac electrodes formed a synchronicity index (SI). Pacing was performed at baseline, with LBBB, right and left ventricular pacing and finally with biventricular pacing (BIVP). We then studied Td at baseline and with BIVP in a clinical observational study in 45 patients during the implantation of CRT and followed up for up to 88 months.

Results

We found a strong relationship between Td and SI in the animals (R = 0.84, P < 0.01). Td and SI increased from narrow QRS at baseline (Td = 95 ± 2 ms, SI = 141 ± 8 ms) to LBBB (Td = 125 ± 2 ms, SI = 247 ± 9 ms, P < 0.01), and shortened with biventricular pacing (BIVP) (Td = 113 ± 2 ms and SI = 192 ± 7 ms, P < 0.01). Prolongation of Td was associated with more wasted deformation during the preejection period (R = 0.77, P < 0.01). Six patients increased ESV by 2.5 ± 18%, while 37 responders (85%) had a mean ESV decrease of 40 ± 15% after more than 6 months of follow‐up. Responders presented with a higher Td at baseline than non‐responders (163 ± 26 ms vs. 121 ± 19 ms, P < 0.01). Td decreased to 156 ± 16 ms (P = 0.02) with CRT in responders, while in non‐responders, Td increased to 148 ± 21 ms (P < 0.01). A decrease in Td with BIVP to values similar or below what was found at baseline accurately identified responders to therapy (AUC 0.98, P < 0.01). Td at baseline and change in Td from baseline was linear related to the decrease in ESV at follow‐up. All‐cause mortality was high among six non‐responders (n = 4), while no patients died in the responder group during follow‐up.

Conclusions

Prolongation of Td is associated with cardiac dyssynchrony and more wasted deformation during the preejection period. Shortening of a prolonged Td with CRT in patients accurately identifies volumetric responders to CRT with incremental value on top of current guidelines and practices. Thus, Td carries the potential to become a biomarker to predict long‐term volumetric response in CRT candidates.

Optimal CRT Implantation-Where and How To Place the Left-Ventricular Lead?

Purpose of Review

Cardiac resynchronization therapy (CRT) represents a well-established and effective non-pharmaceutical heart failure (HF) treatment in selected patients. Still, a significant number of patients remain CRT non-responders. An optimal placement of the left ventricular (LV) lead appears crucial for the intended hemodynamic and hence clinical improvement. A well-localized target area and tools that help to achieve successful lead implantation seem to be of utmost importance to reach an optimal CRT effect.

Recent Findings

Recent studies suggest previous multimodal imaging (CT/cMRI/ECG torso) to guide intraprocedural LV lead placement. Relevant benefit compared to empirical lead optimization is still a matter of debate. Technical improvements in leads and algorithms (e.g., multipoint pacing (MPP), adaptive algorithms) promise higher procedural success. Recently emerging alternatives for ventricular synchronization such as conduction system pacing (CSP), LV endocardial pacing, or leadless pacing challenge classical biventricular pacing.

Summary

This article reviews current strategies for a successful planning, implementation, and validation of the optimal CRT implantation. Pre-implant imaging modalities offer promising assistance for complex cases; empirical lead positioning and intraoperative testing remain the cornerstone in most cases and ensure a successful CRT effect.

Device-Based Solutions to Improve Cardiac Physiology and Hemodynamics in Heart Failure With Preserved Ejection Fraction

Characterized by a rapidly increasing prevalence, elevated mortality and rehospitalization rates, and inadequacy of pharmaceutical therapies, heart failure with preserved ejection fraction (HFpEF) has motivated the widespread development of device-based solutions. HFpEF is a multifactorial disease of various etiologies and phenotypes, distinguished by diminished ventricular compliance, diastolic dysfunction, and symptoms of heart failure despite a normal ejection performance; these symptoms include pulmonary hypertension, limited cardiac reserve, autonomic imbalance, and exercise intolerance. Several types of atrial shunts, left ventricular expanders, stimulation-based therapies, and mechanical circulatory support devices are currently under development aiming to target one or more of these symptoms by addressing the associated mechanical or hemodynamic hallmarks. Although the majority of these solutions have shown promising results in clinical or preclinical studies, no device-based therapy has yet been approved for the treatment of patients with HFpEF. The purpose of this review is to discuss the rationale behind each of these devices and the findings from the initial testing phases, as well as the limitations and challenges associated with their clinical translation.

Gated single-photon emission computed tomography myocardial perfusion imaging phase analysis as an imaging biomarker for mortality prediction in heart failure patients undergoing cardiac resynchronization therapy

OBJECTIVE

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in heart failure patients. The purpose of this study was to assess the value of gated myocardial perfusion single-photon emission computed tomography (GMPS) phase analysis for predicting survival in heart failure patients undergoing CRT.

METHODS

This retrospective cohort study evaluated heart failure patients who underwent GMPS prior to CRT. Phase histogram bandwidth (PHB) and phase SD (PSD) were calculated using GMPS data. Cox proportional hazards model was used to identify independent predictors of overall survival (OS).

RESULTS

A total of 35 patients (age 65.1 ± 13.3, 27 men and 8 women), who were followed for mean of 4.1 ± 2.9 years, were enrolled in the study. PSD of greater than 45° was found to be an independent predictor of poor OS (hazard ratio = 12.63, P = 0.011) when compared with age (hazard ratio = 1.00, P = 0.922), gender (hazard ratio = 0.31, P = 0.155), NYHA class (hazard ratio = 0.45, P = 0.087), QRS duration greater than 150 ms (hazard ratio = 2.38, P = 0.401), pre-CRT left ventricular ejection fraction (LVEF) (hazard ratio = 0.95, P = 0.175) and etiology of heart failure (hazard ratio = 1.42, P = 0.641). Furthermore, PHB greater than 140° was also found to be an independent predictor of poor OS (hazard ratio = 5.63, P = 0.040) when compared with age, gender, NYHA class, QRS duration greater than 150 ms, pre-CRT LVEF and etiology of heart failure.

CONCLUSIONS

PSD and PHB, measured by GMPS, may serve as biomarkers for the prediction of survival in patients undergoing CRT.

Left atrial strain is a predictor of left ventricular systolic and diastolic reverse remodelling in CRT candidates

AIMS

The left atrium (LA) has a pivotal role in cardiac performance and LA deformation is a well-known prognostic predictor in several clinical conditions including heart failure with reduced ejection fraction. The aim of this study is to investigate the effect of cardiac resynchronization therapy (CRT) on both LA morphology and function and to assess the impact of LA reservoir strain (LARS) on left ventricular (LV) systolic and diastolic remodelling after CRT.

METHODS AND RESULTS

Two hundred and twenty-one CRT-candidates were prospectively included in the study in four tertiary centres and underwent echocardiography before CRT-implantation and at 6-month follow-up (FU). CRT-response was defined by a 15% reduction in LV end-systolic volume. LV systolic and diastolic remodelling were defined as the percent reduction in LV end-systolic and end-diastolic volume at FU. Indexed LA volume (LAVI) and LV-global longitudinal (GLS) strain were the main parameters correlated with LARS, with LV-GLS being the strongest determinant of LARS (r = -0.59, P < 0.0001). CRT induced a significant improvement in LAVI and LARS in responders (both P < 0.0001). LARS was an independent predictor of both LV systolic and diastolic remodelling at follow-up (r = -0.14, P = 0.049 and r = -0.17, P = 0.002, respectively).

CONCLUSION

CRT induces a significant improvement in LAVI and LARS in responders. In CRT candidates, the evaluation of LARS before CRT delivery is an independent predictor of LV systolic and diastolic remodelling at FU.