Prevention of non-response to cardiac resynchronization therapy: points to remember

The Prognostic Role of Global Longitudinal Strain and NT-proBNP in Heart Failure Patients Receiving Cardiac Resynchronization Therapy

BACKGROUND

We aimed to evaluate whether baseline GLS (global longitudinal strain), NT-proBNP, and changes in these after cardiac resynchronization therapy (CRT) can predict long-term clinical outcomes and the echocardiographic-based response to CRT (defined by 15% relative reduction in left ventricular end-systolic volume).

METHODS

We enrolled 143 patients with stable ischemic heart failure (HF) undergoing CRT-D implantation. NT-proBNP and echocardiography were obtained before and 6 months after. The patients were followed up (median: 58 months) for HF-related deaths and/or HF hospitalizations (primary endpoint) or HF-related deaths (secondary endpoint).

RESULTS

A total of 84 patients achieved the primary and 53 the secondary endpoint, while 104 patients were considered CRT responders and 39 non-responders. At baseline, event-free patients had higher absolute GLS values (p < 0.001) and lower NT-proBNP serum levels (p < 0001) than those achieving the primary endpoint. A similar pattern was observed in favor of CRT responders vs. non-responders. On Cox regression analysis, baseline absolute GLS value (HR = 0.77; 95% CI, 0.51-1.91; p = 0.002) was beneficially associated with lower primary endpoint incidence, while baseline NT-proBNP levels (HR = 1.55; 95% CI, 1.43-2.01; p = 0.002) and diabetes presence (HR = 1.27; 95% CI, 1.12-1.98; p = 0.003) were related to higher primary endpoint incidence.

CONCLUSIONS

In HF patients undergoing CRT-D, baseline GLS and NT-proBNP concentrations may serve as prognostic factors, while they may predict the echocardiographic-based response to CRT.

Assessing cardiac resynchronization therapy response in heart failure patients: a comparative analysis of efficacy and outcomes between transvenous and epicardial leads

Cardiac resynchronization therapy (CRT) is an effective treatment for selected heart failure (HF) patients. Although transvenous implantation is the standard method, it is not feasible in some patients, so the epicardial lead emerges as an alternative. We aim to compare CRT response, procedure-related complications, and the occurrence of clinical outcomes between patients with transvenous and epicardial leads. In a single-center retrospective study, we enrolled consecutive HF patients submitted to CRT implantation with a defibrillator between 2013 and 2022. Clinical response was defined as an improvement of at least one of the New York Heart Association classes with no occurrence of cardiovascular death or HF hospitalization in the first year of follow-up. Echocardiographic response was attained with an increase in left ventricular ejection fraction 10% or a reduction of left ventricular end-diastolic volume >15% at 6-12 months after CRT implantation. Major adverse cardiovascular events (MACE) (cardiovascular mortality and HF hospitalization) and all-cause mortality were evaluated. From a total of 149 patients, 38% (n=57) received an epicardial lead. Clinical (63% versus 60%, p=0.679) and echocardiographic (63% versus 60%, p=0.679) responses were similar between the transvenous and epicardial groups. Patients in the transvenous group had a shorter hospital stay (2 versus 7 days, p<0.001). Procedure-related complications were comparable between groups (24% versus 28%, p=0.572), but left ventricular lead-related complications were more frequent in the transvenous group (14% versus 2%). During a median follow-up of 4.7 years, the rate of MACE was 30% (n=44), with no differences in both groups (p=0.591), neither regarding HF hospitalization (p=0.917) nor cardiovascular mortality (p=0.060). Nevertheless, the epicardial group had a higher rate of all-cause mortality (35% versus 20%, p=0.005), the majority occurring during long-term follow-up (>12 months), with no deaths in the postoperative period. Considering the comparable rates of CRT response, procedure-related complications, and MACE between groups, we conclude that epicardial lead is a feasible alternative for CRT when transvenous lead implantation is not possible. The occurrence of a higher number of all-cause deaths in epicardial patients in the long-term follow-up was mainly due to infectious complications (unrelated to the lead) and the progression of oncological/chronic diseases.

Value of q waves in lateral and left precordial leads in patients with left bundle branch block to predict the response to cardiac resynchronization therapy

BACKGROUND

The cardiac resynchronization therapy (CRT) non-response rate can reach 30% in heart failure (HF) patients with left bundle branch block (LBBB). This study aimed to evaluate the value of baseline q waves in leads I, V5, or V6 in predicting response to CRT in patients with HF and LBBB.

METHODS

Patients with HF (left ventricular ejection fraction ≤35%) and LBBB receiving CRT implantation were retrospectively enrolled. Baseline characteristics and electrocardiogram parameters, including lateral and left precordial q waves were evaluated. Non-response to CRT was defined as the improvement of left ventricular ejection fraction (LVEF) < 5% at a 6-month follow-up.

RESULTS

A total of 132 patients (mean age 63.0 ± 10.4 years, 94 [71.2%] male) were included. Among them, 32 patients with q waves in leads I, V5, or V6 were classified into the qLBBB (+) group, and the rest without q waves in these leads were defined as the qLBBB (-) group. The CRT non-response rate in the qLBBB (+) group was markedly higher than that in the qLBBB (-) group (68.8% vs. 33.3%, p < .001). Multivariable logistic regression analysis revealed that the presence of baseline q waves in leads I, V5, or V6 remained significantly associated with a higher rate of CRT non-response in patients with HF and LBBB (odds ratio: 4.8, 95% confidence interval: 1.5-15.0, p = .007).

CONCLUSION

Any q wave in leads I, V5, or V6 was an independent predictive factor for CRT non-response in patients with HF and LBBB.

Artificial intelligence models in prediction of response to cardiac resynchronization therapy: a systematic review

The aim of the presented review is to summarize the literature data on the accuracy and clinical applicability of artificial intelligence (AI) models as a valuable alternative to the current guidelines in predicting cardiac resynchronization therapy (CRT) response and phenotyping of patients eligible for CRT implantation. This systematic review was performed according to the PRISMA guidelines. After a search of Scopus, PubMed, Cochrane Library, and Embase databases, 675 records were identified. Twenty supervised (prediction of CRT response) and 9 unsupervised (clustering and phenotyping) AI models were analyzed qualitatively (22 studies, 14,258 patients). Fifty-five percent of AI models were based on retrospective studies. Unsupervised AI models were able to identify clusters of patients with significantly different rates of primary outcome events (death, heart failure event). In comparison to the guideline-based CRT response prediction accuracy of 70%, supervised AI models trained on cohorts with > 100 patients achieved up to 85% accuracy and an AUC of 0.86 in their prediction of response to CRT for echocardiographic and clinical outcomes, respectively. AI models seem to be an accurate and clinically applicable tool in phenotyping of patients eligible for CRT implantation and predicting potential responders. In the future, AI may help to increase CRT response rates to over 80% and improve clinical decision-making and prognosis of the patients, including reduction of mortality rates. However, these findings must be validated in randomized controlled trials.

The Value of Left Ventricular Mechanical Dyssynchrony and Scar Burden in the Combined Assessment of Factors Associated with Cardiac Resynchronization Therapy Response in Patients with CRT-D

Background: Cardiac resynchronization therapy (CRT) improves the outcome in patients with heart failure (HF). However, approximately 30% of patients are nonresponsive to CRT. The aim of this study was to determine the role of the left ventricular (LV) mechanical dyssynchrony (MD) and scar burden as predictors of CRT response. Methods: In this study, we included 56 patients with HF and the left bundle-branch block with QRS duration ≥ 150 ms who underwent CRT-D implantation. In addition to a full examination, myocardial perfusion imaging and gated blood-pool single-photon emission computed tomography were performed. Patients were grouped based on the response to CRT assessed via echocardiography (decrease in LV end-systolic volume ≥15% or/and improvement in the LV ejection fraction ≥5%). Results: In total, 45 patients (80.3%) were responders and 11 (19.7%) were nonresponders to CRT. In multivariate logistic regression, LV anterior-wall standard deviation (adjusted odds ratio (OR) 1.5275; 95% confidence interval (CI) 1.1472–2.0340; p = 0.0037), summed rest score (OR 0.7299; 95% CI 0.5627–0.9469; p = 0.0178), and HF nonischemic etiology (OR 20.1425; 95% CI 1.2719–318.9961; p = 0.0331) were the independent predictors of CRT response. Conclusion: Scar burden and MD assessed using cardiac scintigraphy are associated with response to CRT.

Severe sleep apnea as a predictor of failure to respond to cardiac resynchronization therapy

BACKGROUND

The response to cardiac resynchronization therapy (CRT) is suboptimal in one-third of patients.

OBJECTIVES

The study aimed to evaluate the impact of sleep-disordered breathing (SDB) on the CRT-induced left ventricular (LV) reverse remodeling and response for CRT in patients with ischemic congestive heart failure (CHF).

METHODS

A total of 37 patients aged 65.43 years (SD 6.05), seven of whom were females, were treated with CRT according to class I European Society of Cardiology recommendations. Clinical evaluation, polysomnography, and contrast echocardiography were performed twice during the six-month follow-up (6M-FU) to assess the effect of CRT.

RESULTS

In 33 patients (89.1%), sleep-disordered breathing (SDB), predominantly central sleep apnea (70.3%) was observed. This include nine patients (24.3%) with an apnea-hypopnea index (AHI) of >30 events/hour. During the 6M-FU, 16 patients (47.1%) responded to CRT by reducing LV end-systolic volume index (LVESVi) by ≥15%. We stated a directly proportional linear relationship between AHI value and LV volume: LVESVi p = 0.004, and LV end-diastolic volume index p = 0.006.

CONCLUSIONS

Pre-existing severe SDB can impair the LV volumetric response to CRT even in an optimally selected group with class I indications for resynchronization, which may have an impact on long-term prognosis.

Global Research Trends on Ventricular Remodeling: A Bibliometric Analysis From 2012 to 2022

Ventricular remodeling is the progressive pathologic change of the original substance and morphology of the ventricle caused by various injuries and has attracted increasing attention in the past decade. This study aims to conduct a bibliometric analysis of articles on ventricular remodeling published in the Web of Science Core Collection database from 2012 to 2022 to understand the current research state in the field of ventricular remodeling and provide insights for clinicians and researchers. As a result, a total of 1710 articles on ventricular remodeling were included. Annual publications have been gradually increasing and have remained at a high level over the past 10 years. The United States of America contributed the most publications, followed by China. Circulation was the most mainstream and authoritative journal focusing on ventricular remodeling. Research hotspot analysis suggested that myocardial infarction was the primary risk factor for ventricular remodeling, and emerging risk factor studies have focused on pulmonary hypertension, aortic stenosis, and diabetes. The mechanisms in the pathogenesis of ventricular remodeling were mainly closely associated with inflammation, apoptosis, oxidative stress, and myocardial fibrosis. Intensive investigation of the interactions between different mechanisms might be a future research direction. In terms of treatment, cardiac resynchronization therapy was a hot topic of research. These findings can help researchers grasp the research status of ventricular remodeling and determine future research directions.

Optimization of Left Ventricle Pace Maker Location Using Echo-Based Fluid-Structure Interaction Models

INTRODUCTION

Cardiac pacing has been an effective treatment in the management of patients with bradyarrhythmia and tachyarrhythmia. Different pacemaker location has different responses, and pacemaker effectiveness to each individual can also be different. A novel image-based ventricle animal modeling approach was proposed to optimize ventricular pacemaker site for better cardiac outcome.

METHOD

One health female adult pig (weight 42.5 kg) was used to make a pacing animal model with different ventricle pacing locations. Ventricle surface electric signal, blood pressure and echo image were acquired 15 min after the pacemaker was implanted. Echo-based left ventricle fluid-structure interaction models were constructed to perform ventricle function analysis and investigate impact of pacemaker location on cardiac outcome. With the measured electric signal map from the pig associated with the actual pacemaker site, electric potential conduction of myocardium was modeled by material stiffening and softening in our model, with stiffening simulating contraction and softening simulating relaxation. Ventricle model without pacemaker (NP model) and three ventricle models with the following pacemaker locations were simulated: right ventricular apex (RVA model), posterior interventricular septum (PIVS model) and right ventricular outflow tract (RVOT model). Since higher peak flow velocity, flow shear stress (FSS), ventricle stress and strain are linked to better cardiac function, those data were collected for model comparisons.

RESULTS

At the peak of filling, velocity magnitude, FSS, stress and strain for RVOT and PIVS models were 13%, 45%, 18%, 13% and 5%, 30%, 10%, 5% higher than NP model, respectively. At the peak of ejection, velocity magnitude, FSS, stress and strain for RVOT and PIVS models were 50%, 44%, 54%, 59% and 23%, 36%, 39%, 53% higher than NP model, respectively. RVA model had lower velocity, FSS, stress and strain than NP model. RVOT model had higher peak flow velocity and stress/strain than PIVS model. It indicated RVOT pacemaker site may be the best location.

CONCLUSION

This preliminary study indicated that RVOT model had the best performance among the four models compared. This modeling approach could be used as "virtual surgery" to try various pacemaker locations and avoid risky and dangerous surgical experiments on real patients.

Left Bundle Branch Area Pacing vs. Biventricular Pacing for Cardiac Resynchronization Therapy: A Meta-Analysis

Background: Left bundle branch area pacing (LBBAP) is a recently proposed method for conduction system pacing. We performed a meta-analysis of controlled studies to compare the clinical outcome in patients who received LBBAP vs. biventricular pacing (BVP) for cardiac resynchronization therapy (CRT).

Methods: PubMed, Embase, and Cochrane's Library databases were searched for relevant controlled studies. A random-effect model incorporating the potential heterogeneity was used to synthesize the results.

Results: Four non-randomized controlled studies including 249 patients with heart failure (HF) for CRT were included, and the patients were followed for 6–12 months. Compared with BVP, LBBAP was associated with significantly shortened QRS duration [mean difference (MD): −29.18 ms, 95% confidence interval (CI): −33.55–24.80, I² = 0%, P < 0.001], improved left ventricular ejection fraction (MD: 6.93%, 95% CI: 4.69–9.17, I² = 0%, P < 0.001), reduced left ventricular end-diastolic dimension (MD: −2.96 mm, 95% CI: −5.48 to −0.44, I² = 0%, P = 0.02), and improved New York Heart Association class (MD: −0.54, 95% CI: −0.84 to −0.24, I² = 65%, P < 0.001). Moreover, patients who received LBBAP were more likely to achieve echocardiographic [odds ratio (OR): 5.04, 95% CI: 2.17–11.69, I² = 0%, P < 0.001] and clinical (OR: 7.33, 95% CI: 1.62–33.16, I² = 0%, P = 0.01) CRT responses.

Conclusion: Current evidence from non-randomized studies suggests that LBBAP appears to be a promising method for CRT, which is associated with more remarkable improvements of symptoms and cardiac function in HF patients with indication for CRT.

Real-World Economic Burden Among Patients With And Without Heart Failure Worsening After Cardiac Resynchronization Therapy

INTRODUCTION

Although cardiac resynchronization therapy (CRT) has the potential to improve cardiac function in patients with heart failure (HF), a considerable portion of patients do not respond to therapy. This study assessed the economic burden among patients with and without HF worsening after receiving CRT in real-world practice.

METHODS

In this retrospective claims-based study using Optum's de-identified Clinformatics^® Data Mart Database (January 2007-December 2018), adults who received CRT were stratified into two cohorts based on whether they showed evidence of HF worsening within 180 days post-CRT implantation. Inverse probability of treatment weighting (IPTW) was used to adjust for confounding, accounting for demographics (e.g., age, sex), the Quan-Charlson Comorbidity Index, other clinical characteristics, healthcare resource utilization (HRU), and healthcare costs during the 180 days pre-CRT (baseline period). Annualized all-cause and congestive HF-related HRU and healthcare costs from payer and patient perspectives were assessed from day 181 post-CRT (follow-up period), and compared between cohorts using incidence rate ratios (IRRs) and cost ratios (CRs).

RESULTS

This study included 12,753 patients (n = 4785 with HF worsening; n = 7968 without). Mean age was 72 years and roughly two-thirds were male. Baseline characteristics were balanced between cohorts post-IPTW. During follow-up, patients with HF worsening had significantly greater annual all-cause inpatient [adjusted IRR (95% confidence interval) = 1.55 (1.44, 1.66), p < 0.001], outpatient [adjusted IRR = 1.46 (1.32, 1.61), p < 0.001], and emergency department [adjusted IRR = 1.31 (1.22, 1.41), p < 0.001] visits. Mean annual total per patient payer-paid amounts were significantly higher for patients with HF worsening versus without HF worsening [adjusted CR = 1.68 (1.56, 1.80), p < 0.001]. Annual patient-paid medical costs were also higher for patients with HF worsening [adjusted CR = 1.31 (1.25, 1.38), p < 0.001]. Results were similar for congestive HF-related HRU and costs.

CONCLUSIONS

The incremental economic burden among patients with HF worsening following CRT is substantial. Efforts aimed at CRT optimization may help reduce this burden.

[Echocardiographic assessment of myocardial function during His bundle and right ventricular pacing]

INTRODUCTION

In patients with pacemaker (PM) therapy, His bundle stimulation (HBS) may lead to a more synchronous activation of the left ventricle (LV) than conventional right ventricular stimulation (RVS). In this study, we investigated to which extent this effect can be objectified by means of contemporary echocardiographic functional imaging.

METHODS

In all, 15 RVS patients (6 women, mean age 76.6 ± 4.1 years) and 15 HBS patients (6 women, mean age 74.6 ± 3.7 years) underwent echocardiography with and without cardiac pacing. Besides LV end-diastolic volume (EDV), ejection fraction (EF), and global strain (GLS), we measured global and regional myocardial work and LV efficiency based on noninvasive pressure-strain loops.

RESULTS

In all HBS patients, optimization of PM settings resulted in immediate changes in myocardial function parameters. With pacing, RVS patients showed a higher decrease in EF and GLS than HBS patients. Global LV work and LV work efficiency decreased significantly only in RVS patients.

CONCLUSION

Changes in regional and global myocardial function can by proven and quantified by functional echocardiography. In patients under PM therapy, HBS shows functional advantages in comparison to conventional RVS.

Short-term and intermediate-term performance and safety of left bundle branch pacing

Introduction

Left bundle branch pacing (LBBP) is a promising new method for patients with pacing indications. This study aims to evaluate the safety and feasibility of LBBP in a relatively longer time span.

Methods and Results

A total of 164 patients were recruited for LBBP in this study. Among these patients, 148 patients had pacing indications due to symptomatic bradycardia while the other 16 patients had indications for cardiac resynchronization therapy (CRT). LBBP was successful in 89.0% (146/164) of all recruited patients. Intracardiac and surface electrographic parameters and image data were documented during the LBBP procedure. The mean paced QRS duration (pQRSD) and the mean stimulus to left ventricular activation time (stim‐LVAT) was 106.0 ± 12.9 ms and 64.4 ± 13.7 ms respectively. Left bundle branch (LBB) potentials were recorded in 89 patients. Forty‐three of whom had sick sinus syndrome (SSS), and 46 had atrioventricular block (AVB). The presence of LBB potential was more common in patients with SSS (82.7% vs 57.5%, P = .002). No significant differences in pQRSD, stim‐LVAT, or capture threshold were detected between patient groups with or without LBB potential. Patients were followed up at 1 month, 3 months, 6 months, and 1 year after the procedure. Pacing parameters and the echocardiographic data remained stable within a mean follow‐up period of 8.6 ± 4.3 months. No serious complication caused by this procedure was found in this study.

Conclusions

Successful LBBP carried an aspect of short pQRSD and stim‐LVAT while the LBB potential was not the prerequisite and necessary feature. The LBBP procedure had a high success rate with satisfied and stable lead parameters during short and intermediate‐term observations.

First in human: the effects of biventricular pacing on cardiac output in severe pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) carries high morbidity and mortality despite available treatment options. In severe PAH, right ventricular (RV) diastolic pressure overload leads to interventricular septal bowing, hindering of left ventricular diastolic filling and reduced cardiac output (CO). Some animal studies suggest that pacing may mitigate this effect. We hypothesized that eliminating late diastole via ventricular pacing could improve CO in human subjects with severe PAH. Using minimal to no sedation, we performed transvenous acute biventricular (BiV) pacing and right heart catheterization in six patients with symptomatic PAH. Hemodynamic measurements were taken at baseline and during BiV pacing at various 20-ms intervals of V-V timing. We compared baseline CO to (1) CO while pacing the RV first by 80 ms (mimicking RV-only pacing), and then to (2) CO during pacing at the V-V timing that resulted in the highest CO. All participants were female, PASP 74 ± 14 mmHg, QRS duration 104 ± 20 ms. Compared with baseline, the CO decreased when the RV was paced first by 80 ms (7.2 ± 1.0 vs. 6.2 ± 1.1 L/min, p = 0.028). Pacing with optimal V-V timing produced CO similar to baseline (7.2 ± 1.0 vs. 7.4 ± 1.4, p = 0.92). Two patients (33%) met the predefined endpoint of a 15% increase in CO during pacing at the optimal V-V timing. In symptomatic PAH, V-V optimized acute BiV pacing does not consistently improve CO. However, acute BiV pacing did improve CO in a subset of this cohort. Further research is needed to identify predictors of response to cardiac resynchronization therapy in this population.