Benefit Of Cardiac Resynchronization Therapy Research Articles

Outcomes of cardiac resynchronization therapy (CRT) in cardiac sarcoidosis patients with a range of ejection fractions.

In cardiac sarcoidosis (CS) patients, the benefit of cardiac resynchronization therapy (CRT) remains unclear. We sought to assess the short-term and long-term effects of CRT in CS patients with a range of left ventricular (LV) ejection fractions (LVEFs). Consecutive CS patients with heart failure with reduced ejection fraction (HFrEF; LVEF≤40%), mildly reduced ejection fraction (HFmrEF; LVEF 41%-49%) and preserved ejection fraction (HFpEF; LVEF≥50) treated with CRT under the care of a tertiary UK centre between 2008 and 2023 were reviewed. CRT response was defined by >5% improvement in serial LVEF. The primary endpoint was a composite of all-cause mortality, cardiac transplantation or unplanned hospitalization for decompensated heart failure. The secondary endpoint included ventricular arrhythmic events. Of the 100 patients enrolled (age 58±10years; 71% male), 63 had HFrEF, 17 had HFmrEF and 20 had HFpEF. After short-term follow-up (9.8±5.4months), HFrEF patients demonstrated significant LVEF response (P<0.01). On Kaplan-Meier analysis (follow-up 38±32months), HFrEF non-responders had significantly worse event-free survival compared with HFrEF responders for the primary (P<0.001) and secondary (P=0.001) endpoints. Despite short-term LV function improvement, CRT responders still had worse event-free survival compared with HFmrEF/HFpEF patients for the primary endpoint (P<0.001). On multivariable Cox analysis, age [hazard ratio (HR) 1.05, 95% confidence interval (CI) 1.01-1.10, P=0.008] and HFrEF CRT non-response (HR 12.33, 95% CI 2.45-61.87, P=0.002) were associated with the primary endpoint. In CS patients with HFrEF, CRT response is associated with a better long-term prognosis than non-response. However, HFrEF CRT responders still have worse long-term prognosis than HFmrEF/HFpEF patients.

Outcomes of Cardiac Resynchronization Therapy by New York Heart Association Class: A Patient-Level Meta-Analysis.

Data on the benefits of cardiac resynchronization therapy (CRT) in patients with severe heart failure symptoms are limited. We investigated the relative effects of CRT in patients with ambulatory New York Heart Association (NYHA) IV versus III functional class at the time of device implantation. In this meta-analysis, we pooled patient-level data from the MIRACLE (Multicenter InSync Randomized Clinical Evaluation), MIRACLE-ICD (Multicenter InSync Implantable Cardioversion Defibrillation Randomized Clinical Evaluation), and COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) trials. Outcomes evaluated were time to the composite end point of the first heart failure hospitalization or all-cause mortality, and time to all-cause mortality alone. The association between CRT and outcomes was evaluated using a Bayesian hierarchical Weibull survival regression model. We assessed if this association differed between NYHA III and IV groups by adding an interaction term between CRT and NYHA class as a random effect. A sensitivity analysis was performed by including data from RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure). Our pooled analysis included 2309 patients. Overall, CRT was associated with a longer time to heart failure hospitalization or all-cause mortality (adjusted hazard ratio [aHR], 0.79 [95% credible interval [CI], 0.64-0.99]; posterior probability or P=0.044), with a similar association with time to all-cause mortality (aHR, 0.78 [95% CI, 0.59-1.03]; P=0.083). Associations of CRT with outcomes were not significantly different for those in NYHA III and IV classes (ratio of aHR, 0.72 [95% CI, 0.30-1.27]; P=0.23 for heart failure hospitalization/mortality; ratio of aHR, 0.70 [95% CI, 0.35-1.34]; P=0.27 for all-cause mortality alone). The sensitivity analysis, including RAFT data, did not show a significant relative CRT benefit between NYHA III and IV classes. Overall, there was no significant difference in the association of CRT with either outcome for patients in NYHA functional class III compared with functional class IV.

Mortality after cardiac resynchronization therapy or right ventricular pacing in transcatheter aortic valve replacement recipients.

Permanent pacemaker implantation (PMI) is associated with increased morbidity after transcatheter aortic valve replacement (TAVR). Cardiac resynchronization-therapy (CRT) is recommended for patients if left ventricular ejection fraction (LVEF) is ≤ 40% and ventricular pacing is expected in favor to sole right ventricular (RV) pacing. Meanwhile, LVEF may recover after TAVR in patients with aortic valve disease and the benefit of CRT is unknown. To analyze the impact of CRT implantation as compared to RV pacing after TAVR. Between 2012 and 2022, 4385 patients (53.1% female, mean age 81 ± 6years) without prior PMI undergoing TAVR were retrospectively identified in our institutional registry. After stratification of patients in LVEF ≤ 40%, 41-49% and ≥ 50%, Kaplan-Meier analysis revealed significantly different survival rates in each subgroup at 5years (37.0% vs. 43.5% vs. 55.1%; P ≤ 0.021). At multivariate regression, LVEF and new PMI after TAVR were not relevant for survival. A total of 105 patients with LVEF ≤ 40% received PMI after TAVR (86 patients with RV pacing and 19 with CRT). At 5years, all-cause mortality was significantly lower in patients with CRT-device as compared to patients without CRT-device (Kaplan Meier estimate of 21.1% vs. 48.8%; HR 0.48, CI 0.204 - 1.128; log rank p = 0.045). In multivariate analysis CRT remained a significant factor for 5-year survival in these patients (HR 0.3, CI 0.095-0.951, p = 0.041). In patients undergoing TAVR, PMI did not influence 5-year survival. In patients with LVEF ≤ 40%, CRT-device implantation was associated with improved survival compared to non-CRT-device implantation.

Cardiac resynchronization therapy for patients with mild to moderately reduced ejection fraction and left bundle branch block

BackgroundIt is unknown whether cardiac resynchronization therapy (CRT) would improve or halt the progression of heart failure (HF) in patients with mild to moderately reduced ejection fraction (HFmmrEF) and left bundle branch block (LBBB). ObjectiveThis study aimed to investigate the outcomes of CRT in patients with HFmmrEF and left ventricular conduction delay. MethodsA prospective, randomized clinical trial sponsored by the National Heart, Lung, and Blood Institute included 76 patients who met the study inclusion criteria (left ventricular ejection fraction [LVEF] of 36%–50% and LBBB). Patients received CRT-pacemaker and were randomized to CRT-OFF (right ventricular pacing 40 beats/min) or CRT-ON (biventricular pacing 60–150 beats/min). At a 6-month follow-up, pacing programming was changed to the opposite settings. New York Heart Association class, N-terminal pro–brain natriuretic peptide levels, and echocardiographic variables were collected at baseline, 6 months, and 12 months. The primary study end point was the left ventricular end-systolic volume (LVESV) change from baseline, and the primary randomized comparison was the comparison of 6-month to 12-month changes between randomized groups. ResultsThe mean age of the patients was 68.4 ± 9.8 years (male, 71%). Baseline characteristics were similar between the 2 randomized groups (all P > .05). In patients randomized to CRT-OFF first, then CRT-ON, LVESV was reduced from baseline only after CRT-ON (baseline, 116.1 ± 36.5 mL; CRT-ON, 87.6 ± 26.0 mL; P < .0001). The randomized analysis of LVEF showed a significantly better change from 6 to 12 months in the OFF-ON group (P = .003). LVEF was improved by CRT (baseline, 41.3% ±.7%; CRT-ON, 46.0% ± 8.0%; P = .002). In patients randomized to CRT-ON first, then CRT-OFF, LVESV was reduced after both CRT-ON and CRT-OFF (baseline, 109.8 ± 23.5 mL; CRT-ON, 91.7 ± 30.5 mL [P < .0001]; CRT-OFF, 99.3 ± 28.9 mL [P = .012]). However, the LVESV reduction effect became smaller between CRT-ON and CRT-OFF (P = .027). LVEF improved after both CRT-ON and CRT-OFF (baseline, 42.7% ± 4.3%; CRT-ON, 48.5% ± 8.6% [P < .001]; CRT-OFF, 45.9% ± 7.7% [P = .025]). ConclusionCRT for patients with HFmmrEF significantly improves LVEF and ventricular remodeling after 6 months of CRT. The study provides novel evidence that early CRT benefits patients with HFmmrEF with LBBB.

Concepts of Cardiac Dyssynchrony and Dynamic Approach.

Cardiac conduction involves electrical activity from one myocyte to another, creating coordinated contractions in each. Disruptions in the conducting system, such as left bundle branch block (LBBB), can result in premature activation of specific regions of the heart, leading to heart failure and increased morbidity and mortality. Structural alterations in T-tubules and the sarcoplasmic reticulum can lead to dyssynchrony, a condition that can be treated by cardiac resynchronization therapy (CRT), which stands as a cornerstone in this pathology. The heterogeneity in patient responses underscored the necessity of improving the diagnostic approach. Vectocardiography, ultra-high-frequency ECG, 3D echocardiography, and electrocardiographic imaging seem to offer advanced precision in identifying optimal candidates for CRT in addition to the classic diagnostic methods. The advent of His bundle pacing and left bundle branch pacing further refined the approach in the treatment of dyssynchrony, offering more physiological pacing modalities that promise enhanced outcomes by maintaining or restoring the natural sequence of ventricular activation. HOT-CRT emerges as a pivotal innovation combining the benefits of CRT with the precision of His bundle or left bundle branch area pacing to optimize cardiac function in a subset of patients where traditional CRT might fall short.

Relationship between sex, body size, and cardiac resynchronization therapy benefit: A patient-level meta-analysis of randomized controlled trials

BackgroundWomen might benefit more than men from cardiac resynchronization therapy (CRT) and do so at shorter QRS durations. ObjectiveThis meta-analysis was performed to determine whether sex-based differences in CRT effects are better accounted for by height, body surface area (BSA), or left ventricular end-diastolic dimension (LVEDD). MethodsWe analyzed patient-level data from CRT trials (MIRACLE, MIRACLE ICD, MIRACLE ICD II, REVERSE, RAFT, COMPANION, and MADIT-CRT) using bayesian hierarchical Weibull regression models. Relationships between QRS duration and CRT effects were examined overall and in sex-stratified cohorts; additional analyses indexed QRS duration by height, BSA, or LVEDD. End points were heart failure hospitalization (HFH) or death and all-cause mortality. ResultsCompared with men (n = 5628), women (n = 1439) were shorter (1.62 [interquartile range, 1.57–1.65] m vs 1.75 [1.70–1.80] m; P < .001), with smaller BSAs (1.76 [1.62–1.90] m2 vs 2.02 [1.89–2.16] m2; P < .001). In adjusted sex-stratified analyses, the reduction in HFH or death was greater for women (hazard ratio, 0.54; credible interval, 0.42–0.70) than for men (hazard ratio, 0.77; credible interval, 0.66–0.89; Pinteraction = .009); results were similar for all-cause mortality even after adjustment for height, BSA, and LVEDD. Sex-specific differences were observed only in nonischemic cardiomyopathy. The effect of CRT on HFH or death was observed at a shorter QRS duration for women (126 ms) than for men (145 ms). Indexing QRS duration by height, BSA, or LVEDD attenuated sex-specific QRS duration thresholds for the effects of CRT on HFH or death but not on mortality. ConclusionAlthough body size partially explains sex-specific QRS duration thresholds for CRT benefit, it is not associated with the magnitude of CRT benefit. Indexing QRS duration for body size might improve selection of patients for CRT, particularly with a “borderline” QRS duration.

1724 Age is just a number: Cardiac resynchronisation therapy in older patients has comparable outcomes to those that are younger

Abstract Introduction Older people may be less likely to receive cardiac resynchronisation therapy (CRT) for the management of chronic heart failure. We aimed to describe differences in clinical response, complications, and subsequent outcomes following CRT implantation in older patients when compared to those that were younger. Methods We conducted a retrospective cohort study of consecutive patients implanted with CRT between March 2008 and July 2017. We recorded complications, symptomatic and echocardiographic response, hospitalisations for heart failure, and all-cause mortality comparing patients aged &amp;lt;70, 70-79, and ≥80 years. Results During the study period, 574 patients (median age 76 years [IQR 68-81], 73.3% male) received CRT. Patients aged ≥80 years had worse symptoms at baseline and were more likely to have co-morbidities. Although the provision of guideline-directed medical therapy for heart failure was less optimal in those ≥80 years old, left ventricular function was similar at baseline. Older patients were less likely to receive CRT-defibrillators (which were twice as likely to require generator replacement) compared to CRT-pacemakers. Complications were infrequent and not more common in older patients. Age was not a predictor of symptomatic or echocardiographic response to CRT (67.2%, 71.2%, and 62.6% responders in patients aged &amp;lt;70, 70-79, and ≥80 years, respectively; p=0.43) and time to first heart failure hospitalisation was similar across all groups (p=0.28). Finally, estimated 10-year survival was lower for older patients (49.9%, 23.9%, and 6.8% for patients aged &amp;lt;70, 70-79, and ≥80 years, respectively; p&amp;lt;0.001). Conclusions The benefits of CRT were consistent in selected older patients (≥80 years) despite a greater burden of co-morbidities and less optimal provision of guideline-directed medical therapy. These findings support the use of CRT in an aging population.

Exploring QRS Area beyond Patient Selection in CRT-Can It Guide Left Ventricular Lead Placement?

Vectorcardiographic QRS area is a promising tool for patient selection and implantation guidance in cardiac resynchronization therapy (CRT). Research has mainly focused on the role of QRS area in patient selection for CRT. Recently, QRS area has been proposed as a tool to guide left ventricular lead placement in CRT. Theoretically, vector-based electrical information of ventricular fusion pacing, calculated from the basic 12-lead ECG, can give real-time insight into the extent of resynchronization at any LV lead position, as well as any selected electrode on the LV lead. The objective of this review is to provide an overview of the background of vectorcardiographic QRS area and its potential in optimizing LV lead location in order to optimize the benefits of CRT.

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.

Optimizing Cardiac Resynchronization Therapy in Heart Failure Patients With Prolonged QRS Duration: Insights Into Electrical and Mechanical Dyssynchrony

Heart failure (HF) represents a critical stage of cardiac disease, associated with high morbidity and mortality. Cardiac resynchronization therapy (CRT) has become a pivotal treatment for HF patients with prolonged QRS duration. This therapy employs a biventricular pacing system to correct cardiac electromechanical dyssynchrony, thereby improving cardiac function, symptoms, and prognosis. Numerous clinical trials have consistently highlighted the benefits of CRT in this subgroup, leading to its unanimous recommendation in clinical practice guidelines. However, a significant proportion of patients do not achieve an adequate therapeutic response, despite adherence to these guidelines. As CRT treats patients by correcting cardiac electromechanical dyssynchrony, assessing electrical and mechanical dyssynchrony is crucial in candidate selection. This review explores the evidence, recent clinical practice guidelines, and insight into electrical and mechanical dyssynchrony to optimize CRT candidate selection in HF patients with prolonged QRS duration.

Benefit of cardiac resynchronization therapy among older patients: A patient-level meta-analysis

Cardiac resynchronization therapy (CRT) reduces heart failure hospitalizations (HFH) and mortality for guideline-indicated patients with heart failure (HF). Most patients with HF are aged ≥70 years but such patients are often under-represented in randomized trials. Patient-level data were combined from 8 randomized trials published 2002-2013 comparing CRT to no CRT (n=6,369). The effect of CRT was estimated using an adjusted Bayesian survival model. Using age as a categorical (<70 vs ≥70 years) or continuous variable, the interaction between age and CRT on the composite end point of HFH or all-cause mortality or all-cause mortality alone was assessed. The median age was 67 years with 2436 (38%) being 70+; 1,554 (24%) were women; 2,586 (41%) had nonischemic cardiomyopathy and median QRS duration was 160 ms. Overall, CRT was associated with a delay in time to the composite end point (adjusted hazard ratio [aHR] 0.75, 95% credible interval [CI] 0.66-0.85, P=.002) and all-cause mortality alone (aHR of 0.80, 95% CI 0.69-0.96, P=.017). When age was treated as a categorical variable, there was no interaction between age and the effect of CRT for either end point (P > .1). When age was treated as a continuous variable, older patients appeared to obtain greater benefit with CRT for the composite end point (P for interaction=.027) with a similar but nonsignificant trend for mortality (P for interaction=.35). Reductions in HFH and mortality with CRT are as great or greater in appropriately indicated older patients. Age should not be a limiting factor for the provision of CRT.

Abstract 16146: A Scoping Review of Adverse Outcomes Associated With Cardiac Resynchronization Therapy Device Implantation: Implications for Informed Consent

Background/Objectives: Cardiac Resynchronization Therapy (CRT) is a treatment option for many adults with heart failure with reduced ejection fraction (HFrEF). While the benefits of CRT are well-established, the downstream implications of adverse events are not well-characterized. We sought to better understand the ramifications of CRT-related adverse events on length of hospital stay (LOS) and mortality—information relevant for patients and clinicians to make informed decisions about pursuing CRT. Design: Scoping Review Methods: We conducted an initial PubMed search using terms including “Congestive Heart Failure” or “Heart Failure” and "Cardiac resynchronization" or "Cardiac re-synchronization" or "Biventricular pacing.” We reviewed resulting articles that were written in English, studied CRT devices, and outlined adverse events related to CRT device placement. We separately searched PubMed for additional articles outlining individual adverse events identified using search terms “event name,” “mortality,” and “hospital stay.” We read articles and summarized data regarding the impact of reported adverse events on hospital LOS and mortality. Results: Our search identified 18 full length articles with relevant data. The most common adverse events included device implant failure/non-response, lead dislodgment, coronary sinus dissection, and pocket hematoma. The LOS and mortality rates of each event are shown in Table 1. Of note, LOS for implantation in the ambulatory setting is up to 1 day; LOS for uncomplicated implantation during hospitalization is 4.6 days. Implantation during hospitalization with complication is mean 13.6 days. Conclusion: While absolute risks for adverse events associated with CRT implantation are low, several have important implications on hospital LOS and mortality. These findings warrant inclusion in discussion regarding the risks of CRT when clinicians and patients engage in informed decision making related to CRT.

Outcomes following cardiac resynchronisation therapy in older people.

Older patients may be less likely to receive cardiac resynchronisation therapy (CRT) for the management of heart failure. We aimed to describe the differences in clinical response, complications, and subsequent outcomes following CRT implantation compared to younger patients. We conducted a retrospective cohort study of unselected, consecutive patients implanted with CRT devices between March 2008 and July 2017. We recorded complications, symptomatic and echocardiographic response, hospitalisation for heart failure, and all-cause mortality comparing patients aged <70, 70-79 and ≥ 80years. Five hundred and seventy-four patients (median age 76years [interquartile range 68-81], 73.3% male) received CRT. At baseline, patients aged ≥80years had worse symptoms, were more likely to have co-morbidities, and less likely to be receiving comprehensive medical therapy, although left ventricular function was similar. Older patients were less likely to receive CRT-defibrillators compared to CRT-pacemakers. Complications were infrequent and not more common in older patients. Age was not a predictor of symptomatic or echocardiographic response to CRT (67.2%, 71.2% and 62.6% responders in patients aged <70, 70-79 and ≥ 80years, respectively; P = 0.43), and time to first heart failure hospitalisation was similar across age groups (P = 0.28). Ten-year survival was lower for older patients (49.9%, 23.9% and 6.8% in patients aged <70, 70-79 and ≥ 80years, respectively; P < 0.001). The benefits of CRT on symptoms and left ventricular function were not different in older patients despite a greater burden of co-morbidities and less optimal medical therapy. These findings support the use of CRT in an ageing population.

CRT non-responder to responder conversion rate in the MORE-CRT MPP Trial.

To assess the impact of MultiPoint™ Pacing (MPP) in cardiac resynchronization therapy (CRT) non-responders after six months of standard biventricular pacing (BiVP). The trial enrolled 5,850 patients who planned to receive a CRT device. The echocardiography core laboratory assessed CRT response before implant and after six months of BiVP; non-response to BiVP was defined as < 15% relative reduction in left ventricular end-systolic volume (LVESV). Echocardiographic non-responders were randomized in a 1:1 ratio to receive MPP (541 patients) or continued BiVP (570 patients) for an additional six months and evaluated the conversion rate to the echocardiographic response. The characteristics of both groups at randomization were comparable. The percentage of non-responder patients who became responders to CRT therapy was 29.4% in the MPP arm and 30.4% in the BIVP arm (p=0.743). In patients with > 30 mm spacing between the two left ventricular pacing sites (MPP-AS), identified during the first phase as a potential beneficial subgroup, no significant difference in the conversion rate was observed. Our trial shows that approximately 30% of patients, who do not respond to CRT in the first six months, experience significant reverse remodeling in the following six months. This finding suggests that CRT benefit may be delayed or slowly incremental in a relevant proportion of patients and that the percentage of CRT responders may be higher than what has been described in short/middle-term studies. MPP does not improve CRT response in non-responders to BiVP, even with MPP-AS.

The evolution of hemodynamic force parameters after cardiac resynchronization

Abstract Funding Acknowledgements Type of funding sources: None. Background A new mathematical model allows calculation of hemodynamic forces (HDF) from routine transthoracic echocardiographic images. In large cohorts, the evolution of HDF parameters in patients after onset of cardiac resynchronization therapy (CRT) has not been investigated. Purpose To compare HDF parameters at baseline versus six months follow-up after CRT implantation in patients with non-ischemic cardiomyopathy. Methods Patients with LV ejection fraction (LVEF) ≤35%, QRS duration ≥130 ms and left bundle branch block were included. In the complete heart cycle, the following HDF parameters were calculated: apical-basal strength (AB strength), lateral-septal strength (LS strength), the ratio of LS strength to AB strength (LS-AB ratio) and the dominant angle of HDF (angle) (Figure 1). In the systolic thrust, apical-basal impulse (AB impulse) and the angle were measured (Figure 1). The measurements are presented as percentages, normalized for left ventricular volume and adjusted for fluid density and gravity acceleration. The measurements were acquired at baseline and six months after CRT implantation. Results 196 patients were included (mean age 64 ± 11 years, 62% male). Clinical and echocardiographic characteristics were acquired, as well as HDF parameters at baseline and after six months (Table 1). After six months a significant improvement occurred in clinical parameters (New York Heart Association class, Quality of Life and 6-minute walking distance) with significant reverse LV remodeling (reduction in left ventricular and left atrial volumes with increased LVEF and global longitudinal strain). Moreover, a significant change in the magnitude of apical-basal force, represented in the AB strength and AB impulse and in the orientation of force, represented as the ratio and the angle of HDF were observed. Conclusion The evaluation of HDF parameters after CRT implantation shows an increase in magnitude of force and a change in orientation of force. This new tool provides insight in changes of fluid dynamics after CRT implantation and may contribute to better understand the benefit of CRT.

Defibrillator capability and all-cause mortality in patients receiving cardiac resynchronization therapy for non-ischemic cardiomyopathy: a Korean nationwide cohort study

Abstract Funding Acknowledgements Type of funding sources: None. Background Concerns exist about the benefit of cardiac resynchronization therapy with a defibrillator (CRT-D) compared to those without a defibrillator (CRT-P), especially in patients with non-ischemic cardiomyopathy. We evaluated the association between defibrillator capability and all-cause mortality in patients receiving cardiac resynchronization therapy (CRT) for non-ischemic cardiomyopathy. Methods From patients with nationally registered cardiomyopathy in the Korea National Health Insurance Service (KNHIS) database, after the exclusion of those with ischemic heart disease, 1,478 patients with newly-implanted CRT-P (n=258) or CRT-D (n=1220) were identified from 2008 to 2020. The association between defibrillator capability and all-cause mortality was assessed with propensity score (PS) weighting to correct for differences between the groups. Results Compared with patients receiving CRT-D, those receiving CRT-P included more subjects older than 75. After PS weighting, over a mean follow-up period of 52.9 months (interquartile interval: 23.5-75.8), CRT-D was associated with a lower rate of mortality (6.5 vs 9.2 per 100 person-years) compared with CRT-P. The weighted risk of all-cause death in patients with CRT-D was lower than those with CRT-P within 1 year (hazard ratio [HR]: 0.70 [95% CI, 0.53–0.91]; p = 0.009) and 5 years (HR: 0.71 [95% CI, 0.61–0.83]; p &amp;lt; 0.001). Results were consistent regardless of subgroups, such as age, sex, year of registration, and comorbidities. Conclusions In Korean patients with non-ischemic cardiomyopathy, the defibrillator capability of CRT was associated with reduced 1-year and 5-year all-cause mortality. This association was consistent across all the investigated subgroups.

Cardiac resynchronization therapy guided by activation mapping in non-left bundle branch block patients

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Various studies have questioned the magnitude of the benefit of cardiac resynchronization therapy (CRT) in patients without left bundle branch block (LBBB). This worse response could be due to the suboptimal location of the electrodes. Purpose We hypothesize that in non-LBBB patients, an implant guided by ventricular electroanatomic mapping by locating the areas with the greatest activation delay will improve the outcome of CRT. Material and methods We included 7 patients non-LBBB. To locate the most delayed activation zones, an electromagnetic activation map was created using the Ensite Precision navigator connected to the right ventricular catheter and to a guidewire with electrical recording capacity at its distal end. ECG, clinical, and echocardiographic data were recorded at baseline and post-implantation, compared with 7 patients LBBB (control group). Results In non-LBBB patients, several activation patterns could be defined according to the conduction disorder, including right bundle branch block (RBBB)+left anterior hemiblock (figure 1A) or RBBB alone (figure 1B). All patients with non-LBBB improved at follow-up in the NYHA functional class (p=0,011) and in the Minnesota test (7,85±4,63; p=0.004). The mean reduction in QRS duration was 14,57±9,86 ms (p=0.008), LVEF increased 8.22±4.62 ms (p=0.003), LVOTS decreased by 15,71±12,23 ml (p=0.015) and the LVEDV in 10,42±5,15 ml (p=0.002). There were no significant differences between the response to CTR in non-LBBB patients and LBBB patients (table 1), including LVEF (8.22±4.62 vs 11.54±5.54, p=0.248) and difference in Minnesota test (7.85±4.63 vs 9.71±5.87, p=0.524). Conclusions CRT guided by electroanatomical mapping produced significant clinical and structural improvement in non-LBBB patients. This improvement was of a similar magnitude to LBBB patients. Various patterns of ventricular activation according to the conduction disorder were observed.

PO-02-026 LONG-TERM MORTALITY IN PATIENTS WITH ISCHEMIC VERSUS NONISCHEMIC CARDIOMYOPATHY FOLLOWING CARDIAC RESYNCHRONIZATION THERAPY

Studies have shown comparable benefits in all-cause mortality in patients with ischemic (ICM) vs. nonischemic cardiomyopathy (NICM) following cardiac resynchronization therapy (CRT). Data on long-term outcomes of CRT between these etiologies is limited. We aim to evaluate long-term all-cause mortality in patients with ICM and NICM that have undergone CRT. We conducted a retrospective analysis of patients with ICM and NICM that have undergone CRT within the Mayo Clinic Health System since 2002. Patients with LVEF ≤ 35% pre-implant were included in the study. All-cause mortality data were compared between the two groups. Data from 872 (59%) patients with ICM and 614 (41%) patients with NICM that underwent CRT implantation between 11/2002 and 7/2022 were analyzed. 85% of patients with ICM were males compared to 64% of patients with NICM (p<0.001). The average age at implant was significantly lower among patients with NICM compared to ICM (68 vs. 73 years, p<0.001). The median age at implant among patients with NICM was 69 (IQR 59-77.5), and among patients with ICM was 74 (interquartile range [IQR] 68-79). Mean pre-implant LVEFs were 22% in both groups (p = NS). Survival distributions for patients with ICM and NICM that had undergone CRT were significantly different (log-rank p<0.001), with lower all-cause mortality for patients with NICM than with ICM. Following CRT, patients with NICM have lower all-cause mortality as compared to patients with ICM. However, randomized trials with control group data are needed to comment on the relative mortality benefit of CRT in these two modalities over the long term.

Conduction system versus biventricular pacing in heart failure with non-left bundle branch block.

The benefits of cardiac resynchronization therapy (CRT) with biventricular pacing (BiV) is significantly lower when applied to heart failure (HF) patients with non-left bundle branch block (LBBB) conduction delay. We investigated clinical outcomes of conduction system pacing (CSP) for CRT in non-LBBB HF. Consecutive HF patients with non-LBBB conduction delay undergoing CSP were propensity matched for age, sex, HF-etiology, and atrial fibrillation (AF) in a 1:1 ratio to BiV from a prospective registry of CRT recipients. Echocardiographic response was defined as an increase in left ventricular ejection fraction (LVEF) by ≥10%. The primary outcome was the composite of HF-hospitalizations or all-cause mortality. A total of 96 patients were recruited (mean age 70 ± 11years, 22% female, 68% ischemic HF and 49% AF). Significant reductions in QRS duration and LV dimensions were seen only after CSP, while LVEF improved significantly in both groups (p < 0.05). Echocardiographic response occurred more frequently in CSP than BiV (51% vs. 21%, p < 0.01), with CSP independently associated with four-fold increased odds (adjusted odds ratio 4.08, 95% confidence interval [CI] 1.34-12.41). The primary outcome occurred more frequently in BiV than CSP (69% vs. 27%, p < 0.001), with CSP independently associated with 58% risk reduction (adjusted hazard ratio [AHR] 0.42, 95% CI 0.21-0.84, p = 0.01), driven by reduced all-cause mortality (AHR 0.22, 95% CI 0.07-0.68, p < 0.01), and a trend toward reduced HF-hospitalization (AHR 0.51, 95% CI 0.21-1.21, p = 0.12). CSP provided greater electrical synchrony, reverse remodeling, improved cardiac function and survival compared to BiV in non-LBBB, and may be the preferred CRT strategy for non-LBBB HF.

Predicting the survival benefit of cardiac resynchronization therapy with defibrillator function for non-ischemic heart failure-Role of the Goldenberg risk score.

Primary prevention of sudden cardiac death (SCD) in non-ischemic heart failure (HF) patients remains a topic of debate at cardiac resynchronization therapy (CRT) implantation requiring individual risk assessment. Using the Goldenberg SCD risk score, we aimed to predict, which non-ischemic HF patients will benefit from the addition of an implantable cardioverter defibrillator (ICD) to CRT at long-term. Between 2000 and 2018 non-ischemic HF patients undergoing CRT implantation were collected into our retrospective registry. The Goldenberg risk score (GRS) was calculated by the presence of atrial fibrillation, New York Heat Association (NYHA) class > 2, age > 70 years, blood urea nitrogen > 26 mg/dl and QRS > 120 ms. The primary endpoint was all-cause mortality, heart transplantation or left ventricular assist device implantation. From 667 patients, 347 (52%) underwent cardiac resynchronization therapy-pacemaker (CRT-P), 320 (48%) cardiac resynchronization therapy-defibrillator (CRT-D) implantations. During the median follow up time of 4.3 years, 306 (46%) patients reached the primary endpoint (CRT-D 37% vs. CRT-P 63%; p < 0.001). CRT-D patients were younger (64 vs. 69 years; p < 0.001), infrequently females (26 vs. 39%; p < 0.001), and had a lower ejection fraction (27 vs. 29%; p < 0.01) compared to CRT-P patients. After GRS calculation, patients were dichotomized by low (< 3) and high (≥ 3) scores. CRT-D patients with low GRS showed a mortality benefit compared to CRT-P (HR 0.68; 95% CI 0.48-0.96; p = 0.03), high-risk patients did not (HR 0.84; 95% CI 0.62-1.13; p = 0.26). In our non-ischemic cohort, patients with low GRS showed a clear long-term mortality benefit by adding ICD to CRT, however, in high-risk patients no further benefit could be observed.