Cardiac Resynchronization Therapy In Patients Research Articles

Interamerican Society of Cardiology (CIFACAH - ELECTROSIAC)/Latin American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of cardiac resynchronization therapy in heart failure.

Epidemiological studies suggest that approximately half of the patients with heart failure (HF) have reduced ejection fraction, while the other half have normal ejection fraction (EF). Currently, international guidelines consider QRS duration greater than 130 ms, in the presence of ventricular dysfunction (EF < 35%), as a criterion for selecting patients for cardiac resynchronization therapy (CRT). CRT helps restore intraventricular and auriculoventricular synchrony, improving left ventricular (LV) performance, reducing functional mitral regurgitation, and inducing reverse LV remodeling. This is evidenced by increased LV filling time and left ventricular ejection fraction, decreased LV end-diastolic and end-systolic volumes, mitral regurgitation, and septal dyskinesia. Because the mechanisms of dyssynchrony may be heterogeneous, no single measure may accurately predict response to CRT. Finally, CRT has been progressively shown to be safe and feasible, improves functional status and quality of life, reversely remodels the LV, decreases the number of hospitalizations, total mortality in patients with refractory HF, LV dysfunction, and intraventricular conduction disorders; is a pacemaker-based therapy for HF and thanks to current technology, safe remote monitoring of almost all types of cardiac devices is possible and provides useful alerts in clinical practice.

Multicenter Study of Survival Benefit of Cardiac Resynchronization Therapy in Pediatric and Congenital Heart Disease

BackgroundEvidence for the efficacy of cardiac resynchronization therapy (CRT) in pediatric and congenital heart disease (CHD) has been limited to surrogate outcomes. ObjectivesThis study aimed to assess the impact of CRT upon the risk of transplantation or death in a retrospective, high-risk, controlled cohort at 5 quaternary referral centers. MethodsBoth CRT patients and control patients were <21 years of age or had CHD; had systemic ventricular ejection fraction <45%; symptomatic heart failure; and significant electrical dyssynchrony (QRS duration z score >3 or single-site ventricular pacing >40%) at enrollment. Patients with CRT were matched with control patients via 1:1 propensity score matching. CRT patients were enrolled at CRT implantation; control patients were enrolled at the outpatient clinical encounter where inclusion criteria were first met. The primary endpoint was transplantation or death. ResultsIn total, 324 control patients and 167 CRT recipients were identified. Mean follow-up was 4.2 ± 3.7 years. Upon propensity score matching, 139 closely matched pairs were identified (20 baseline indices). Of the 139 matched pairs, 52 (37.0%) control patients and 31 (22.0%) CRT recipients reached the primary endpoint. On both unadjusted and multivariable Cox regression analysis, the risk reduction associated with CRT for the primary endpoint was significant (HR: 0.40; 95% CI: 0.25-0.64; P < 0.001; and HR: 0.44; 95% CI: 0.28-0.71; P = 0.001, respectively). On longitudinal assessment, the CRT group had significantly improved systemic ventricular ejection fraction (P < 0.001) and shorter QRS duration (P = 0.015), sustained to 5 years. ConclusionsIn pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplantation-free survival.

Virtual pacing of a patient's digital twin to predict left ventricular reverse remodelling after cardiac resynchronization therapy.

Identifying heart failure (HF) patients who will benefit from cardiac resynchronization therapy (CRT) remains challenging. We evaluated whether virtual pacing in a digital twin (DT) of the patient's heart could be used to predict the degree of left ventricular (LV) reverse remodelling post-CRT. Forty-five HF patients with wide QRS complex (≥130 ms) and reduced LV ejection fraction (≤35%) receiving CRT were retrospectively enrolled. Echocardiography was performed before (baseline) and 6 months after CRT implantation to obtain LV volumes and 18-segment longitudinal strain. A previously developed algorithm was used to generate 45 DTs by personalizing the CircAdapt model to each patient's baseline measurements. From each DT, baseline septal-to-lateral myocardial work difference (MWLW-S,DT) and maximum rate of LV systolic pressure rise (dP/dtmax,DT) were derived. Biventricular pacing was then simulated using patient-specific atrioventricular delay and lead location. Virtual pacing-induced changes ΔMWLW-S,DT and ΔdP/dtmax,DT were correlated with real-world LV end-systolic volume change at 6-month follow-up (ΔLVESV). The DT's baseline MWLW-S,DT and virtual pacing-induced ΔMWLW-S,DT were both significantly associated with the real patient's reverse remodelling ΔLVESV (r = -0.60, P < 0.001 and r = 0.62, P < 0.001, respectively), while correlation between ΔdP/dtmax,DT and ΔLVESV was considerably weaker (r = -0.34, P = 0.02). Our results suggest that the reduction of septal-to-lateral work imbalance by virtual pacing in the DT can predict real-world post-CRT LV reverse remodelling. This DT approach could prove to be an additional tool in selecting HF patients for CRT and has the potential to provide valuable insights in optimization of CRT delivery.

The prevalence of frailty and its effect on the outcome in cardiac resynchronization therapy patients.

Frailty is a complex clinical syndrome associated with aging and comorbidities, which correlates with unfavorable outcomes. However, in heart failure patients, frailty is very common, data is scarce about those, who are eligible for Cardiac Resynchronization Therapy (CRT) implantation. We investigated the incidence of frailty and the association of Frailty Index (FI) with the outcome. Thirty baseline clinical parameters were used by the Rockwood cumulative deficit method to determine patients' FI in our single-center cohort. Based on previous studies, patients with FI ≤ 0.210 were considered as non-frail, those with FI 0.10-0.210 were classified in Frail-1, with FI > 0.10 in Frail-2 groups, respectively. Echocardiographic response after 12months and all-cause mortality were investigated by frailty groups. Among 1004 included patients, 75 (7%) were considered Non-frail, 271 (27%) grouped in Frail-1, and 658 (66%) in Frail-2 with a median FI of 0.36 (0.28-0.43). Patients in Frail-2 group were older, with more comorbidities compared with non-frail patients or those in Group Frail-1. During the median follow-up time of 4.8years, 29 (39%) patients died in the Non-frail, 140 (52%) in Frail-1, and 471 (72%) in the Frail-2 groups (log-rank p < 0.001). Group Frail-2 showed an unfavorable outcome compared to the non-frail (HR 2.49, 95%CI 1.92-3.22; p < 0.001) and the Frail-1 group (1.83, 95%CI 1.55-2.16; p < 0.001). In our HFrEF patients eligible for CRT implantation, patients were exceedingly vulnerable with a high prevalence of frailty. The calculated frailty index was associated with outcome and proved to be prevalent in individual risk stratification.

A new method using deep transfer learning on ECG to predict the response to cardiac resynchronization therapy

Background: Cardiac resynchronization therapy (CRT) has emerged as an effective treatment for heart failure patients with electrical dyssynchrony. However, accurately predicting which patients will respond to CRT remains a challenge. This study explores the application of deep transfer learning techniques to train a predictive model for CRT response. Methods: In this study, the short-time Fourier transform (STFT) technique was employed to transform ECG signals into two-dimensional images. A transfer learning approach was then applied to the MIT-BIT ECG database to pre-train a convolutional neural network (CNN) model. The model was fine-tuned to extract relevant features from the ECG images and then tested on our dataset of CRT patients to predict their response. Results: Seventy-one CRT patients were enrolled in this study. The transfer learning model achieved an accuracy of 72% in distinguishing responders from non-responders in the local dataset. Furthermore, the model showed good sensitivity (0.78) and specificity (0.79) in identifying CRT responders. The performance of our model outperformed clinic guidelines and traditional machine learning approaches. Conclusion: The utilization of ECG images as input and leveraging the power of transfer learning allows for improved accuracy in identifying CRT responders. This approach offers potential for enhancing patient selection and improving the outcomes of CRT.

Indications for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease.

Heart failure in patients with congenital heart disease (CHD) stems from unique causes compared with the elderly. Patients with CHD face structural abnormalities and malformations present from birth, leading to altered cardiac function and potential complications. In contrast, elderly individuals primarily experience heart failure due to age-related changes and underlying cardiovascular conditions. Cardiac resynchronization therapy (CRT) can benefit patients with CHD, although it presents numerous challenges. The complexities of CHD anatomy and limited access to appropriate venous sites for lead placement make CRT implantation demanding.

Techniques for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease.

Cardiac resynchronization therapy (CRT) for congenital heart disease has shown promising suucess as an adjunct to medical therapy for heart failure. While cardiac conduction defects and need for ventricular pacing are common in congential heart disease, CRT indications, techniques and long term outcomes have not been well establaished. This is a review of the techniques nad short term outcomes of CRT for the following complex congenital heart disease conditions: single ventricle physiology, systemic right ventricle, and the subpulmonic right ventricle.

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

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

Prognostic implications of invasive hemodynamics during cardiac resynchronization therapy: Stroke work outperforms dP/dtmax

Invasive measurements of left ventricular (LV) hemodynamic performance can evaluate acute response to cardiac resynchronization therapy (CRT). The study sought to determine which metric, maximum rate of LV pressure rise (LV dP/dtmax) or LV stroke work (LVSW), is more strongly associated with long-term prognosis. CRT patients were prospectively included from 3 academic centers. Invasive pressure-volume loop measurements during implantation were performed, and LV dP/dtmax and LVSW were determined at baseline and during biventricular pacing (BVP) as well as their relative increase (%Δ). Hazard ratios (HRs) for the primary outcome of 8-year all-cause mortality were derived using Cox proportional hazards. The secondary endpoint was echocardiographic response, defined as 6-month LV end-systolic volume reduction ≥15%. Paired data from 82 patients were analyzed (67% male; age 66 ± 9 years; QRS duration 158 ± 22 ms, median survival time 72 months). Survival was better when LVSW during BVP was ≥4400 mL∙mm Hg (HR 0.21, 95% CI 0.08-0.58, P < .003) or when ΔLVSW% was ≥10% (HR 0.22, 95% CI 0.08-0.65, P=.006). In multivariate analysis, following direct comparison of continuous measures of acute ΔLV dP/dtmax% and ΔLVSW%, only ΔLVSW% remained associated with the primary endpoint (HR 0.982 per percentage point, P = .028). In contrast to LV dP/dtmax (all P > .05), significant associations with echocardiographic response were found for stroke work during BVP (area under the receiver-operating characteristic curve 0.745, P = .001) and ΔLVSW% (area under the receiver-operating characteristic curve 0.803, P < .001). Stroke work, but not LV dP/dtmax, is consistently associated with long-term prognosis and response after CRT. Our results therefore favor the use of stroke work as the hemodynamic parameter to predict long-term outcome after CRT.

Clinical outcomes of left bundle branch area pacing compared with biventricular pacing in patients with heart failure requiring cardiac resynchronization therapy: systematic review and meta-analysis

Abstract Background Biventricular pacing (BVP) is recommended from the most recent ESC guidelines as the first line pacing strategy in patients with heart failure (HF) that require cardiac resynchronization therapy (CRT). (1) Many studies have shown its beneficial effects regarding morbidity and mortality in this population. (2, 3) However, 10% of patients cannot be treated by BVP due to unsuitable coronary sinus vein, while 30-40% are non-responders to BVP and experience no benefit from this treatment.(4) Left bundle branch area pacing (LBBAP) is a new pacing modality (5) that can achieve narrow QRS and improve left ventricular function in patients with HF, by engaging the intrinsic conduction pathway of the heart. Also, it appears to have better results in electrical and mechanical synchrony compared with BVP. Purpose We conducted a systematic review and meta-analysis to compare the two pacing modalities in terms of hard clinical outcomes, in patients with heart failure that require CRT. Methods Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science databases were systematically searched for studies comparing LBBAP with BVP for CRT in patients with HF. Outcomes of interest were all-cause mortality, Heart Failure Hospitalizations (HFH) and New York Heart Association (NYHA) class improvement. Two independent investigators identified studies, extracted data, and assessed the risk of bias using the Cochrane Risk of Bias 2 tool for randomized clinical trials and the Newcastle-Ottawa-Scale for observational studies. Pairwise meta-analysis was conducted using random and fixed effects models. Risk Ratios (RRs) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were used to report dichotomous and continuous variables respectively. Heterogeneity was assessed with the I² statistic. Results In total, 764 studies were retrieved and finally 9 trials with 992 individuals (365 in LBBAP and 627 in BVP group) were included in the analysis. The mean follow-up duration was 13 ± 5.82 months and the average procedural success rate in the LBBAP group was 89.8%. The baseline characteristics were similar between the two groups. Pooled analysis showed that the two methods had no difference in terms of all-cause mortality (RR:0.87 CI 95%:0.38 to 2.02; I²=0%; p=0.750, Figure 1) with 8 (2.4%) vs 17 (2.9%) events occurring in LBBAP and BVP group respectively. However, LBBAP was found to have significantly lower risk for HFH (RR:0.58 CI 95%:0.38 to 0.91; I²=0%; p=0.020, Figure 2A) and to achieve more improvement in NYHA class compared with BVP (WMD: -0.40, CI 95%: -0.68 to -0.12; I²=72%; p=0.005; Figure 2B). Conclusions To the best of our knowledge this is the first meta-analysis that assesses exclusively the clinical outcomes of LBBAP compared to BVP in such an important number of patients. LBBAP presents better outcomes in HFH and NYHA class improvement, but it has no difference in all-cause mortality in comparison with BVP.Figure 1.All-cause mortalityFigure 2.A.HFH B.NYHA class improvement

Does scar burden predict sudden cardiac death in patients with cardiac resynchronization therapy? - A Systematic Review and Meta-Analysis

Abstract Background Based on latest guidelines, scar burden assessment may have a crucial role in appropriate device choice in cardiac resynchronization therapy (CRT), but no randomized controlled trials have been made yet.1 Scar burden is associated with a higher prevalence of ventricular arrhythmias (VA) and sudden cardiac death (SCD).2 Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately evaluate the extent of myocardial scar.3. Purpose Our aim is to investigate the association between scar burden and SCD risk in cardiac resynchronization therapy patients. Methods We performed a systematic literature search on MEDLINE using the PubMed, Embase, Scopus, and CENTRAL databases. Heart failure patients with reduced ejection fraction and CRT therapy were collected. The primary endpoint was sudden cardiac death events. Meta-analyses were performed using the META and DMETAR packages in R, using a random-effects model. The risk of bias was assessed using Quips tool and the quality of evidence was evaluated using the GRADE assessment. Results 18 eligible articles have been included in our study, with a total of 2917 patients, of whom 830, 1324, and 391 have been implanted with an ICD, CRT-D, CRT-P respectively. Altogether 59,05 % of the total population were LGE-CMR positive. The average proportion of appropriate ICD shock was 15,65 % per the total population during the median follow-up time of 39,45 months. Based on the univariant analysis of 14 articles, the cumulative hazard ratio of developing sudden cardiac death events, in the scar burden positive population compared to scar burden negative was 1,95 with CI: 1,29- 2,96 p&amp;lt;0,001. The multivariant analysis shows the HR of 1,88 with CI: 1,20- 2,93 p&amp;lt;0,001. There were 4 articles using the competing risk model which is considered to be the highest evidence level. Based on that analysis we found only a trend with a HR of 1,55 CI: 0,75-2,92. Calculating from the event numbers based on 8 eligible articles, the high scar burden group had 5.55 higher odds of getting SCD events. (OR: 5.55. CI 2,52-12,22 p&amp;lt;0,001). Conclusion In our meta-analysis, LGE-CMR was associated with a trend toward appropriate device therapy and can identify a subgroup of patients with an increased risk of life-threatening VA. Based on our results performing an MRI before device implantation might be important to select high-risk patients for SCD.Forest plot O.R.Forest plot uni. H.R.

Functional mitral regurgitation and ventricular arrhythmias in patients with cardiac resynchronization therapy

Abstract Introduction In patients with heart failure (HF), the occurrence of ventricular arrhythmias (VAs) is associated with prognosis, and advanced HF can cause VAs. In HF patients developed moderate to severe functional mitral regurgitation (FMR), a transcatheter mitral valve repair therapy has significantly reduced the hospitalization and mortality rates compared to guideline-directed medical therapy. Although the mechanisms of arrhythmias are multiple, it is unclear whether FMR is involved in the development of VAs advanced HF patients. Methods and results We retrospectively examined 176 cardiac resynchronization therapy (CRT) patients (78% men, median age 67 years) without FMR before CRT implanted between 2010 and 2018. Worsening FMR was defined as developing moderate to severe FMR after CRT. During median follow-up of 40 (quartile range, 23-60) months, worsening FMR was detected in 26 (15%) patients at a median of 30 (quartile range, 12–75) months after CRT implantation. There was no difference in age, New York Heart Association functional class, QRS width before CRT and the rate of responders between patients with and without worsening FMR. Patients with worsening FMR had a tendency of larger left ventricular end-systolic dimension (58 [53-68] vs. 53 [47-60] mm, p&amp;lt;0.10), a significantly higher rate of female (38% vs. 19%, p&amp;lt;0.05) and a significantly larger left atrial volume index (LAVI) (63 [43-81] vs. 48 [35-62] ml/m2, p&amp;lt;0.05). By multivariate logistic regression analysis, female gender (odds ratio 4.3) and baseline LAVI (odds ratio 1.04 per a ml/m2 increase) were independent factors associated with worsening FMR. There was a significantly higher incidence of HF hospitalization (50% vs 15%, log-rank P&amp;lt;0.05) (Figure 1) and a higher incidence of VAs, defined as sustained ventricular tachyarrhythmias requiring implantable-cardioverter defibrillator therapy or external defibrillation, in patients with worsening FMR than patients without worsening FMR (65% vs 38%, log-rank P&amp;lt;0.05) (Figure 2). Multivariate analysis showed that worsening FMR was independently associated with the development of VAs (hazard ratio 2.77, 95% confidence interval 1.13-6.83). Conclusions In patients with HF and CRT, female gender and baseline LAVI were associated with worsening FMR after CRT. We need to pay attention to changes in the FMR that can be associated with developing VAs after CRT implantation.

Associations of 2013 and 2021 ESC definitions of left bundle-branch block with mechanical dyssynchrony and CRT-induced reverse remodeling

Abstract Background In 2021, a new and stricter ECG-based definition of LBBB was proposed and implemented in the European Society of Cardiology (ESC) guidelines on cardiac pacing and cardiac resynchronization therapy (CRT). Aim To investigate the association between the 2021 and the 2013 LBBB definitions with CRT-induced left ventricular (LV) reverse remodeling, as well as mechanical dyssynchrony. Methods CRT patients (n=191) were retrospectively investigated. Pre-CRT digitally stored ECGs were analyzed and categorized according to the LBBB definition of 2013 (LBBB-2013) and the 2021 (LBBB-2021). Mechanical dyssynchrony (Dyss) was assessed pre-CRT using 2D-echocardiography and was defined as the presence of apical rocking and/or septal flash. CRT-induced LV reverse remodeling was measured as the relative change of left ventricular end systolic volume (LVESV) at 12 ± 6 months after CRT compared to baseline. Results Patients’ characteristics were as follows; age 70 ± 10 years, 69% males and NYHA class 2.7 ± 0.5. QRS width was 156 ± 18 ms and LVEF 33 ± 11%, and 52% had ischemic etiology. Dyss was present in 59% of the population. The percentage of the cohort that was considered to have LBBB was considerably lower according to the LBBB-2021 than according to the LBBB-2013 (18 vs. 57% respectively). Similarly, percentages of patients with LBBB+Dyss were 16 and 46% according to LBBB-2021 and LBBB-2013 respectively, with a respective Kappa coefficient of 0.16 and 0.47 (Figure A). At CRT follow up, LBBB-2013 patients showed significantly more LV reverse remodeling compared to non-LBBB patients (P &amp;lt; 0.001), while there was no significant difference between patients with LBBB-2021 and non-LBBB (P = 0.09, Figure B). Conclusion The LBBB definition proposed in the 2021 ESC guidelines excludes many patients from a class I indication for CRT. It is less associated with mechanical dyssynchrony and with CRT-induced LV reverse remodeling than the 2013 LBBB definition. Therefore, the new LBBB definition appears to be counterproductive with regards to selection of CRT patients.

Abstract 15668: The Incidence and Predictors of Delayed and Late Response to Cardiac Re-Synchronization Therapy

Background: The incidence and predictors of delayed response to cardiac resynchronization therapy (CRT) have not been well established. Our study aimed to investigate the incidence and predictors of delayed and late response in CRT patients. Research Question: What patient-specific characteristics are associated with delayed or late response to CRT? Goal/Aim: To investigate the incidence and predictors of delayed and late response in CRT patients. Methods: We conducted a retrospective analysis of 201 patients who underwent CRT implantation with placement of a CS lead. Patients meeting the enrollment criteria were categorized into three groups: Group A comprised conventional responders with a response observed at the 6-month follow-up, Group B consisted of delayed responders with a response seen between 6 months and 1-year follow-up, and Group C included late responders with a response observed after 1 year of follow-up. CRT response was defined as an absolute increase of ≥ 5% in left ventricular ejection fraction. All echocardiograms were performed at the same institution. Only patients who were defined as responders to CRT were included in the analysis. Results: Among the patients analyzed, 59 patients (67.2 ± 12.3 years, 39 male) achieved a conventional response to CRT, while 40 patients (69.6 ± 9.5 years, 30 male) experienced a delayed response, and 29 patients exhibited a late response (66.1 ± 11.4 years, 18 male). The mean follow-up time was 267 days (± 341 days). The incidence of delayed and late responses was 19.9% and 14.43%, respectively. In univariable logistic regression analysis, a history of coronary artery disease (p = 0.047) was associated with delayed and late CRT responses. Conclusions: Our findings demonstrate a significant proportion of patients experiencing delayed and late responses to CRT. This study suggests the need for reconsidering the waiting time for CRT response, particularly in patients with a history of coronary artery disease. Keywords: cardiac resynchronization therapy, delayed response, heart failure

Abstract 14660: The Effect of Sacubitril/Valsartan Therapy on Hospitalization and Mortality in Patients Non-Respondent to Cardiac Resynchronization Therapy

Background: Non-responders to Cardiac Resynchronization Therapy (CRT-NR) have poor prognosis. Sacubitril/valsartan (SV) treatment improved the outcomes of heart failure patients with reduced left ventricular (LV) ejection fraction (HFrEF) in randomized trials; however, limited data are available on the specific cohort of CRT-NRs. Aim of the study: We have compared heart failure hospitalization (HFH) and mortality rates in three patient cohorts: CRT-NR patients on S/V versus on ACEi/ARB and general HFrEF patients on S/V. Methods: 275 HF patients, including 70 CRT-NRs receiving S/V at least for 6 months (Group I); 70 CRT-NRs on ACEi/ARB treatment (Group II); and 135 HFrEF patients without CRT indication on S/V therapy at least for 6 months (Group III) were included. CRT-NR was defined as a less than 10% improvement in left ventricular ejection fraction (LVEF) 6 months after device implantation. Rates of HFH and the composite of all-cause mortality/heart transplantation/LVAD therapy were compared with a mean follow-up of 21.5 months. A subgroup analysis was also performed in patients on S/V (Groups I and III) who demonstrated a more versus less than 10% increase in LVEF after 6 months of S/V treatment (S/V super-responders versus S/V moderate responders, respectively). Results: HFH rates were similar in Groups I and III (28.5% vs. 28.1%, respectively; p&gt;0.05), while significantly higher (54.2%) in Group II (p=0.02). No significant difference in the composite mortality endpoint was demonstrated between the three groups (22.8% vs. 24.2% vs. 22.2%, p=0.08). On S/V treatment, 13 out of the 70 (18.5%) CRT-NR patients (Group I) and 24 out of the 135 (17.8%) HFrEF patients (Group III) were found to be SV super-responders. Comparing these 37 patients with the 168 S/V moderate responders, neither the HFH (24.3% vs 30.9%, p=0.07), nor the composite mortality rates (24.3% vs 23.2%, p=0.53) demonstrated significant differences. Conclusion: S/V treatment in CRT-NRs improved hospitalization rates similarly to what was observed in a general HFrEF population. No benefit in mortality rates was demonstrated in this cohort. The extent of change in LVEF on S/V was not predictive of a better response on HFH or mortality.

Abstract 18037: Left Bundle Branch Area versus Biventricular Pacing in Cardiac Resynchronization Therapy: A Systematic Review and Meta-Analysis

Introduction: Cardiac resynchronization therapy (CRT) through biventricular pacing (BVP) is the standard treatment for heart failure with reduced ejection fraction (HFrEF) and left bundle-branch block (LBBB). Left bundle-branch area pacing (LBBAP) has emerged as a potentially more effective approach. However, its superiority over BVP remains unclear. Hypothesis: Is LBBAP more effective and safer than BVP for CRT in patients with HFrEF? Methods: We systematically searched PubMed, Embase, and Cochrane for randomized controlled trials (RCTs) or observational studies that reported adjusted effect estimates (i.e propensity score-matched populations or multivariate analysis), comparing the efficacy and safety of LBBAP versus BVP. We applied the random-effects model to calculate adjusted hazard ratio (aHR) and mean difference (aMD), with the corresponding 95% confidence interval. Heterogeneity was assessed using I 2 statistics. Statistical analysis was performed using R version 4.2.1. Results: Our analysis included 7 studies, yielding 2,743 patients, of whom 1,164 (42.4%) were assigned to LBBAP group. Compared with BVP, LBBAP was associated with a significant reduction of the composite of overall mortality and heart failure hospitalizations (aHR 0.67; 95% CI 0.56-0.80; I 2 =0%; p&lt;0.001; Figure 1A). Additionally, LBBAP demonstrated a significant increase in LVEF (aMD 5.77%; 95% CI 2.94-8.60; I 2 =68%; p&lt;0.001; Figure 1B) and shortening of QRS duration (aMD -25.71 ms; 95% CI -35.87 to -15.55; I 2 =0%; p&lt;0.001; Figure 2A) compared with BVP. Sub-analysis of patients with LBBB also demonstrated a significant reduction of the composite of overall mortality and heart failure hospitalizations (aHR 0.64; 95% CI 0.49 to 0.85; I 2 =0%; p&lt;0.001; Figure 2B) in LBBAP. Conclusions: This meta-analysis of RCTs and multivariable adjusted studies suggests that LBBAP is superior to BVP in patients with HFrEF undergoing CRT for both electrophysiological and clinical outcomes.

Abstract 11565: Clinical Implications of Left Atrial Size and Its Changes After Cardiac Resynchronization Therapy in Patients With Heart Failure

Background: Little evidence is available regarding the impact of left atrial (LA) diameter, especially its changes after cardiac resynchronization therapy (CRT), on the prognosis of patients with heart failure (HF). Objective: To investigate the association of LA diameter and its changes with all-cause mortality and HF hospitalization in HF patients with CRT. Methods: This cohort study retrospectively included 488 HF patients with CRT, who were assessed with echocardiography at baseline and 6 months after CRT. The multivariate Cox proportional hazards regression models were used to examine the specific association of LA diameter and its changes with all-cause mortality and HF hospitalization. Results: Non-linear associations were found for LA diameter with all-cause mortality ( P = 0.006 for nonlinearity) and HF hospitalization ( P = 0.02 for nonlinearity). The positive association of LA diameter with all-cause mortality (HR, 1.88; 95% CI, 1.42-2.49) and HF hospitalization (HR, 1.72; 95% CI, 1.32-2.22) only in the range of LA diameter &lt;45 mm. There was a positive association of LA diameter changes with all-cause mortality (HR, 1.29; 95% CI, 1.12-1.48) and HF hospitalization (HR, 1.28; 95% CI, 1.13-1.45). LA adverse remodeling (LAAR) was associated with an increased risk of all-cause mortality (HR, 2.35; 95% CI, 1.46-3.79) and HF hospitalization (HR, 2.18; 95% CI, 1.40-3.41). Conclusions: LA enlargement and LAAR were associated with an unfavorable outcome in HF patients with CRT. These findings suggest that monitoring LA diameter and its changes has potential clinical implications for HF treatment.

Abstract 16252: A Survival Analysis in Patients With Tricuspid Regurgitation and Cardiac Resynchronization Therapy

Introduction: Cardiac resynchronization therapy (CRT) is a well established treatment in heart failure with reduced ejection fraction. It involves simultaneous pacing of the left and right ventricles to restore ventricular synchrony, leading to increased cardiac output and contractility. The impact of CRT on tricuspid regurgitation (TR) severity has not been evaluated. Studies have shown that up to 22% of CRT recipients have significant TR, and of these patients only 41% will improve to no or mild TR. For a majority of patients who have persistent significant TR despite CRT, long term outcomes are put into question. Hypothesis: Tricuspid regurgitation adversely affects the response and survival of CRT patients. Goals: To analyze the prevalence of TR in a cohort of patients admitted to The Christ Hospital who have undergone CRT. To assess the association between TR after CRT and long-term survivability. Methods: This is a retrospective cohort study conducted at The Christ Hospital in Cincinnati Ohio. 13292 patients diagnosed with tricuspid regurgitation (mild to severe) in total were included. 184 of these patients underwent CRT, and survival probability was measured against the no CRT group. Kaplan meier method was used for analysis. Results: Survival probabilities at 1 year, 2 years, and 3 years for patients with CRT = 0.769, 0.661, and 0.558 respectively. Patients without CRT = 0.911, 0.863, and 0.826 respectively. Hazard ratio = 2.84 (2.33, 3.47) compared to solely tricuspid regurgitation. Conclusions: Patients with TR without CRT had greater survival rates up to three years compared to TR with CRT. The risk of death in the TR with CRT was 2.84 times higher than the no CRT group. It can be further investigated why the no CRT group had a greater survival rate than CRT. Limitations include variable assessments of TR due to the subjective nature of grading TR. Future research could investigate the difference between primary (device-related) and secondary TR in this cohort.

Acute Hemodynamic Effect of a NovelDual-Vein, Multisite Biventricular Pacing Configuration.

Biventricular pacing (BVP) from multiple left ventricular (LV) sites could enhance the efficacy of cardiac resynchronization therapy (CRT) by engaging a greater myocardial mass. The goal of this study was to evaluate the acute hemodynamic effect of various multisite pacing (MSP) configurations against conventional BVP. Twenty patients with nonischemic dilated cardiomyopathy and left bundle branch block (mean age: 59 ± 14 years; LV ejection fraction: 27% ± 6%; native QRS: 171 ± 16 milliseconds) were investigated during a routine CRT implant procedure. In addition to conventional right atrial and right ventricular leads, 2 quadripolar leads were placed in the distant coronary venous branches. LV hemodynamics was evaluated by using a micromanometer-tipped catheter during atrioventricular BVP with 4 LV lead configurations: single-lead conventional BVP; single-lead multipoint pacing; triventricular pacing from distal dipoles of 2 LV leads; and maximum MSP (MSP-Max) from 4 dipoles of 2 LV leads. Compared with right atrial pacing, any BVP configuration produced a significant increase in the maximal LV diastolic pressure rise (LVdP/dTMax) (amedian relative increase of 28% [IQR: 8%-45%], 25% [IQR: 18%-46%], 36% [IQR: 18%-54%], and 38% [IQR: 28%-58%], respectively; all, P< 0.001). MSP-Max but no other multisite BVP generated a significant increase of the maximal LVdP/dTMax than conventional BVP (P=0.041). Increased LVdP/dTMax during MSP-Max was associated with greater LV diameter and lower LV ejection fraction, independently of the QRS width. The study shows the hemodynamic advantage of a novel dual-vein MSP-Max configuration that could be useful for CRT in patients with advanced LV remodeling.

Progress in Cardiac Resynchronisation Therapy and Optimisation.

Cardiac resynchronisation therapy (CRT) has become the cornerstone of heart failure (HF) treatment. Despite the obvious benefit from this therapy, an estimated 30% of CRT patients do not respond ("non-responders"). The cause of "non-response" is multi-factorial and includes suboptimal device settings. To optimise CRT settings, echocardiography has been considered the gold standard but has limitations: it is user dependent and consumes time and resources. CRT proprietary algorithms have been developed to perform device optimisation efficiently and with limited resources. In this review, we discuss CRT optimisation including the various adopted proprietary algorithms and conduction system pacing.