Cardiac Resynchronization Therapy in Ischemic Versus Nonischemic Cardiomyopathy: Patient-Level Meta-Analysis of 7 Randomized Clinical Trials.

BACKGROUND: Data on whether cardiac resynchronization therapy (CRT) results in better clinical and echocardiographic outcomes in patients with nonischemic cardiomyopathy (NICM) vs ischemic cardiomyopathy (ICM) are conflicting. OBJECTIVES: The authors conducted this meta-analysis of 7 clinical trials of CRT to determine the association between etiology of cardiomyopathy and clinical and echocardiographic outcomes. METHODS: The authors analyzed patient-level data using Bayesian Hierarchical Weibull survival regression modeling to determine the association between etiology of cardiomyopathy and time to all-cause death or heart failure hospitalization (HFH). Linear regression was used to assess the association between etiology of cardiomyopathy and echocardiographic measurements. RESULTS: Of 6,252 patients included, 4,717 (75%) were men, median age was 66 years (IQR: 58-73 years), 3,704 (59%) had ICM, and 3,778 (60%) received CRT. CRT increased the time to HFH or all-cause death (HR: 0.67; 95% credible interval [CrI]: 0.56-0.82; P < 0.001) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.87-1.29]; P = 0.57). Likewise, CRT increased the time to all-cause death (HR: 0.71 [95% CrI: 0.55-0.93]; P = 0.019) with no difference by etiology of cardiomyopathy (HR ratio: 1.06 [95% CrI: 0.80-1.43]; P = 0.70). Echocardiographic data that were available for 2,430 (39%) patients showed that CRT improvements in left ventricular ejection fraction, left ventricular end-diastolic diameter, and left ventricular end-systolic diameter were larger for patients with NICM. CONCLUSIONS: Although CRT led to greater increases in left ventricular ejection fraction and reductions in ventricular dimensions for patients with NICM compared with those with ICM, CRT significantly increased the time to HFH or all-cause death independently of the etiology of cardiomyopathy. Further studies on improving patient selection for CRT are needed.

Risk of Stroke or Systemic Embolism According to Baseline Frequency and Duration of Subclinical Atrial Fibrillation: Insights From the ARTESiA Trial.

BACKGROUND: In the ARTESiA trial (Apixaban for the Reduction of Thromboembolism in Patients With Device-Detected Subclinical Atrial Fibrillation), apixaban, compared with aspirin, reduced stroke or systemic embolism in patients with device-detected subclinical atrial fibrillation (SCAF). Clinical guidelines recommend considering SCAF episode duration when deciding whether to prescribe oral anticoagulation for this population. METHODS: We performed a retrospective cohort study in ARTESiA. Using Cox regression adjusted for CHA2DS2-VASc score and treatment allocation (apixaban or aspirin), we assessed frequency of SCAF episodes and duration of the longest SCAF episode in the 6 months before randomization as predictors of stroke risk and of apixaban treatment effect. RESULTS: Among 3986 patients with complete baseline SCAF data, 703 (17.6%) had no SCAF episode ≥6 minutes in the 6 months before enrollment. Among 3283 patients (82.4%) with ≥1 episode of SCAF ≥6 minutes in the 6 months before enrollment, 2542 (77.4%) had up to 5 episodes, and 741 (22.6%) had ≥6 episodes. The longest episode lasted <1 hour in 1030 patients (31.4%), 1 to <6 hours in 1421 patients (43.3%), and >6 hours in 832 patients (25.3%). Higher baseline SCAF frequency was not associated with increased risk of stroke or systemic embolism: 1.1% for 1 to 5 episodes versus 1.2%/patient-year for ≥6 episodes (adjusted hazard ratio, 0.89 [95% CI, 0.59-1.34]). In an exploratory analysis, patients with previous SCAF but no episode ≥6 minutes in the 6 months before enrollment had a lower risk of stroke or systemic embolism than patients with at least one episode during that period (0.5% versus 1.1%/patient-year; adjusted hazard ratio, 0.48 [95% CI, 0.27-0.85]). The frequency of SCAF did not modify the reduction in stroke or systemic embolism with apixaban (Pinteraction=0.1). The duration of the longest SCAF episode in the 6 months before enrollment was not associated with the risk of stroke or systemic embolism during follow-up (<1 hour: 1.0%/patient-year [reference]; 1-6 hours: 1.2%/patient-year [adjusted hazard ratio, 1.27 (95% CI, 0.85-1.90)]; >6 hours: 1.0%/patient-year [adjusted hazard ratio, 1.02 (95% CI, 0.63-1.66)]). SCAF duration did not modify the reduction in stroke or systemic embolism with apixaban (Ptrend=0.1). CONCLUSIONS: In ARTESiA, baseline SCAF frequency and longest episode duration were not associated with risk of stroke or systemic embolism and did not modify the effect of apixaban on reduction of stroke or systemic embolism. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01938248.

Leadless Ultrasound-Based Cardiac Resynchronization System in Heart Failure.

Importance: Approximately 40% of patients with heart failure (HF) who are eligible for cardiac resynchronization therapy (CRT) either fail to respond or are untreatable due to anatomical constraints. Objective: To assess the safety and efficacy of a novel, leadless, left ventricular (LV) endocardial pacing system for patients at high risk for a CRT upgrade or whose coronary sinus (CS) lead placement/pacing with a conventional CRT system failed. Design, Setting, and Participants: The SOLVE-CRT study was a prospective multicenter trial enrolling January 2018 through July 2022, with follow-up at 6 months. Data were analyzed from January 17, 2018, through February 15, 2023. The trial combined data from an initial randomized, double-blind study (n = 108) and a subsequent single-arm part (n = 75). It took place at 36 centers across Australia, Europe, and the US. Participants were nonresponders, previously untreatable (PU), or high-risk upgrades (HRU). All participants contributed to the safety analysis. The primary efficacy analysis (n = 100) included 75 PU-HRU patients from the single-arm part and 25 PU-HRU patients from the randomized treatment arm. Interventions: Patients were implanted with the WiSE CRT System (EBR Systems) consisting of a leadless LV endocardial pacing electrode stimulated with ultrasound energy delivered by a subcutaneously implanted transmitter and battery. Main Outcomes and Measures: The primary safety end point was freedom from type I complications. The primary efficacy end point was a reduction in mean LV end systolic volume (LVESV). Results: The study included 183 participants; mean age was 68.1 (SD, 10.3) years and 141 were male (77%). The trial was terminated at an interim analysis for meeting prespecified stopping criteria. In the safety population, patients were either New York Heart Association Class II (34.6%) or III (65.4%). The primary efficacy end point was met with a 16.4% (95% CI, -21.0% to -11.7%) reduction in mean LVESV (P = .003). The primary safety end point was met with an 80.9% rate of freedom from type I complications (P < .001), which included 12 study device system events (6.6%), 5 vascular events (2.7%), 3 strokes (1.6%), and 7 cardiac perforations which mostly occurred early in the study (3.8%). Conclusions and Relevance: The SOLVE-CRT study has demonstrated that leadless LV endocardial pacing with the WiSE CRT system is associated with a reduction in LVESV in patients with HF. This novel system may represent an alternative to conventional CRT implants in some HF patient populations. Trial Registration: ClinicalTrials.gov Identifier: NCT0292203.

Apixaban vs Aspirin According to CHA2DS2-VASc Score in Subclinical Atrial Fibrillation: Insights From ARTESiA.

BACKGROUND: ARTESiA (Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation) demonstrated that apixaban, compared with aspirin, significantly reduced stroke and systemic embolism (SE) but increased major bleeding in patients with subclinical atrial fibrillation. OBJECTIVES: To help inform decision making, the authors evaluated the efficacy and safety of apixaban according to baseline CHA2DS2-VASc score. METHODS: We performed a subgroup analysis according to baseline CHA2DS2-VASc score and assessed both the relative and absolute differences in stroke/SE and major bleeding. RESULTS: Baseline CHA2DS2-VASc scores were <4 in 1,578 (39.4%) patients, 4 in 1,349 (33.6%), and >4 in 1,085 (27.0%). For patients with CHA2DS2-VASc >4, the rate of stroke was 0.98%/year with apixaban and 2.25%/year with aspirin; compared with aspirin, apixaban prevented 1.28 (95% CI: 0.43-2.12) strokes/SE per 100 patient-years and caused 0.68 (95% CI: -0.23 to 1.57) major bleeds. For CHA2DS2-VASc <4, the stroke/SE rate was 0.85%/year with apixaban and 0.97%/year with aspirin. Apixaban prevented 0.12 (95% CI: -0.38 to 0.62) strokes/SE per 100 patient-years and caused 0.33 (95% CI: -0.27 to 0.92) major bleeds. For patients with CHA2DS2-VASc =4, apixaban prevented 0.32 (95% CI: -0.16 to 0.79) strokes/SE per 100 patient-years and caused 0.28 (95% CI: -0.30 to 0.86) major bleeds. CONCLUSIONS: One in 4 patients in ARTESiA with subclinical atrial fibrillation had a CHA2DS2-VASc score >4 and a stroke/SE risk of 2.2% per year. For these patients, the benefits of treatment with apixaban in preventing stroke/SE are greater than the risks. The opposite is true for patients with CHA2DS2-VASc score <4. A substantial intermediate group (CHA2DS2-VASc =4) exists in which patient preferences will inform treatment decisions. (Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation; NCT01938248).

Association Between the Use of an Adaptive Cardiac Resynchronization Therapy Algorithm and Health Care Use and Cost.

OBJECTIVES: To assess the association between the use of adaptive pacing on clinical and economic outcomes of cardiac resynchronization therapy (CRT) recipients in a real-world analysis. BACKGROUND: The adaptivCRT (aCRT) algorithm was shown in prior subgroup analyses of prospective trials to achieve clinical benefits, but a large prospective trial showed nonsignificant changes in the endpoint of mortality or hospitalizations due to heart failure. METHODS: CRT-implanted patients from the Optum Clinformatics database with ≥ 90 days of follow-up were included. Remote monitoring data were used to classify patients based on CRT setting-adaptive biventricular and left ventricular pacing (aCRT) vs standard biventricular pacing (Standard CRT). Inverse probability of treatment weighting was used to adjust for baseline differences between groups. Mortality, 30-day readmissions, health care use, and payer and patients' costs were evaluated post-implantation. RESULTS: This study included 2412 aCRT and 1638 Standard CRT patients (mean follow-up: 2.4 ± 1.4 years), with balanced baseline characteristics after adjustment. The aCRT group was associated with lower all-cause mortality rates (adjusted hazard ratio = 0.88 [95% confidence interval (CI):0.80, 0.96]), fewer all-cause 30-day readmissions (adjusted incidence rate ratio = 0.87 [CI:0.81, 0.94]), and fewer all-cause and HF-related inpatient, outpatient and emergency department visits. The aCRT cohort was also associated with lower all-cause outpatient payer-paid amounts and lower all-cause and HF-related inpatient and emergency department patient-paid amounts. CONCLUSIONS: In this retrospective analysis of a large real-world cohort, the use of an adaptive CRT algorithm was associated with lower mortality rates, reduced health care resource use and lower payer and patient costs.

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

BACKGROUND: 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. METHODS AND RESULTS: 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. CONCLUSIONS: 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.

A Comparison of the Association of Septal Scar Burden on Responses to LBBAP-CRT and BVP-CRT.

BACKGROUND: Left bundle branch area pacing (LBBAP) is an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). However, despite the presence of left bundle branch block, whether cardiac substrate may influence the effect between the 2 strategies is unclear. OBJECTIVES: This study aims to assess the association of septal scar on reverse remodeling and clinical outcomes of LBBAP compared with BVP. METHODS: We analyzed patients with nonischemic cardiomyopathy who had CRT indications undergoing preprocedure cardiac magnetic resonance examination. Changes in left ventricular ejection fraction (LVEF) and echocardiographic response (ER) (≥5% absolute LVEF increase) were assessed at 6 months. The clinical outcome was the composite of all-cause mortality, heart failure hospitalization, or major ventricular arrhythmia. RESULTS: There were 147 patients included (51 LBBAP and 96 BVP). Among patients with low septal scar burden (below median 5.7%, range: 0% to 5.3%), LVEF improvement was higher in the LBBAP than the BVP group (17.5% ± 10.9% vs 12.3% ± 11.8%; P = 0.037), with more than 3-fold increased odds of ER (OR: 4.35; P = 0.033). In high sepal scar subgroups (≥5.7%, range: 5.7%-65.9%), BVP trended towards higher LVEF improvement (9.2% ± 9.4% vs 6.4% ± 12.4%; P = 0.085). Interaction between septal scar burden and pacing strategy was significant for ER (P = 0.002) and LVEF improvement (P = 0.011) after propensity score adjustment. During median follow-up of 33.7 (Q1-Q3: 19.8-42.1) months, the composite clinical outcome occurred in 34.7% (n = 51) of patients. The high-burden subgroups had worse clinical outcomes independent of CRT method. CONCLUSIONS: Remodeling response to LBBAP and BVP among nonischemic cardiomyopathy patients is modified by septal scar burden. High septal scar burden was associated with poor clinical prognosis independent of CRT methods.

Atrioventricular optimization improves cardiac resynchronization response in patients with long interventricular electrical delays: A pooled analysis of the SMART-AV and SMART-CRT trials.

BACKGROUND: The utility of atrioventricular (AV) optimization (AVO) algorithms remains in question. A substudy of the SMART-AV trial found that patients with prolonged interventricular delays ≥70 ms were more likely to benefit from cardiac resynchronization therapy (CRT) with AVO. The SMART-CRT trial evaluated AVO on the basis of these results, but the study was underpowered. OBJECTIVE: To increase statistical power, data from SMART-AV patients meeting the inclusion criterion of interventricular delay ≥70 ms were pooled with data from SMART-CRT to reassess AVO. METHODS: SMART-CRT and SMART-AV were prospective, randomized, multicenter clinical trials. Patients in both studies were randomized to be programmed with an AVO algorithm (SmartDelay) or fixed AV delay (120 ms). Paired echocardiograms obtained at baseline and 6 months were compared, with CRT response defined as ≥15% reduction in left ventricular end-systolic volume. RESULTS: A total of 451 complete patient data sets were pooled and analyzed. The baseline demographics between studies did not differ statistically in terms of age, sex, left ventricular ejection fraction, or left ventricular end-systolic volume. The AVO group had a greater proportion of CRT responders (SmartDelay, 73.9%; fixed, 63.1%; P = .014) and greater changes in measures of reverse remodeling. SmartDelay patients with a recommended sensed AV delay outside the nominal range (100-120 ms) had 2.3 greater odds of CRT response than fixed AV delay patients. CONCLUSION: Greater CRT response and measures of reverse remodeling were observed in patients with SmartDelay enabled vs a fixed AV delay. This study supports the use of SmartDelay in patients with a CRT indication and interventricular delay ≥70 ms.

Comparisons of long-term clinical outcomes with left bundle branch pacing, left ventricular septal pacing, and biventricular pacing for cardiac resynchronization therapy.

BACKGROUND: Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are referred to as left bundle branch area pacing. OBJECTIVE: This study investigated whether long-term clinical outcomes differ in patients undergoing LBBP, LVSP, and biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). METHODS: Consecutive patients with reduced left ventricular ejection fraction (LVEF <50%) undergoing CRT were prospectively enrolled if they underwent successful LBBP, LVSP, or BiVP. The primary composite end point was all-cause mortality or heart failure hospitalization. Secondary end points included all-cause mortality, heart failure hospitalization, and echocardiographic measures of reverse remodeling. RESULTS: A total of 259 patients (68 LBBP, 38 LVSP, and 153 BiVP) were observed for a mean duration of 28.8 ± 15.8 months. LBBP was associated with a significantly reduced risk of the primary end point by 78% compared with both BiVP (7.4% vs 41.2%; adjusted hazard ratio [aHR], 0.22 [0.08-0.57]; P = .002) and LVSP (7.4% vs 47.4%; aHR, 0.22 [0.08-0.63]; P = .004]. The adjusted risk of all-cause mortality was significantly higher in LVSP than in BiVP (31.6% vs 7.2%; aHR, 3.19 [1.38-7.39]; P = .007) but comparable between LBBP and BiVP (2.9% vs 7.2%; aHR, 0.33 [0.07-1.52], P = .155). Propensity score adjustment also obtained similar results. LBBP showed a higher rate of echocardiographic response (ΔLVEF ≥10%: 60.0% vs 36.2% vs 16.1%; P < .001) than BiVP or LVSP. CONCLUSION: LBBP yielded long-term clinical outcomes superior to those of BiVP and LVSP. The role of LVSP for CRT needs to be reevaluated because of its high mortality risk.

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

BACKGROUND: Women might benefit more than men from cardiac resynchronization therapy (CRT) and do so at shorter QRS durations. OBJECTIVE: This 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). METHODS: We 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. RESULTS: Compared 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. CONCLUSION: Although 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.

Need for cardiac implantable electronic devices and long-term follow-up in recipients of orthotopic heart transplants.

BACKGROUND: Cardiac pacemaker implantation after orthotopic heart transplantation declined dramatically after development of the bicaval anastomosis technique. However, much less is known about the rate, indications, and predictors of device implantation procedures with the current surgical technique. OBJECTIVE: The purpose of this study was to evaluate the indications, patient characteristics, incidence, and survival related to cardiac implantable electronic device (CIED) implantation after heart transplantation. METHODS: This was a single-center study of 399 consecutive adult recipients of orthotopic heart transplants with bicaval anastomosis from 1991 to 2017. The primary end point was freedom from pacemaker or implantable cardioverter-defibrillator (ICD) implantation, and the secondary end point was all-cause mortality. RESULTS: At the time of transplantation, the mean age of recipients was 50 ± 12 years and that of donors 31 ± 12 years. CIEDs were implanted in 8% of recipients (n = 31): 11 pacemakers (35%) for sinus node dysfunction, 17 (55%) for high-grade heart block, and 3 ICDs (10%) for the primary prevention of sudden cardiac death. Early CIED implantation (<30 days) was rare and absent for sinus node dysfunction. The risk for CIED implantation increased progressively during follow-up (0-30 years; median 11 years), with low-, moderate-, and high-risk periods between 0 and 10, between 10 and 20, and between 20 and 30 years, respectively. Recipients receiving CIEDs survived longer after transplantation (21 years vs 13 years; P < .01). Recipients receiving pacemakers for heart block were more likely to receive older donor hearts at the time of transplantation. CONCLUSION: The risk of pacemaker implantation increases progressively, while ICD implantation is rare. Donor age is the predominant risk factor for subsequent heart block. Early sinus node dysfunction requiring permanent pacing is rare.

Apixaban for Stroke Prevention in Subclinical Atrial Fibrillation.

BACKGROUND: Subclinical atrial fibrillation is short-lasting and asymptomatic and can usually be detected only by long-term continuous monitoring with pacemakers or defibrillators. Subclinical atrial fibrillation is associated with an increased risk of stroke by a factor of 2.5; however, treatment with oral anticoagulation is of uncertain benefit. METHODS: We conducted a trial involving patients with subclinical atrial fibrillation lasting 6 minutes to 24 hours. Patients were randomly assigned in a double-blind, double-dummy design to receive apixaban at a dose of 5 mg twice daily (2.5 mg twice daily when indicated) or aspirin at a dose of 81 mg daily. The trial medication was discontinued and anticoagulation started if subclinical atrial fibrillation lasting more than 24 hours or clinical atrial fibrillation developed. The primary efficacy outcome, stroke or systemic embolism, was assessed in the intention-to-treat population (all the patients who had undergone randomization); the primary safety outcome, major bleeding, was assessed in the on-treatment population (all the patients who had undergone randomization and received at least one dose of the assigned trial drug, with follow-up censored 5 days after permanent discontinuation of trial medication for any reason). RESULTS: We included 4012 patients with a mean (±SD) age of 76.8±7.6 years and a mean CHA2DS2-VASc score of 3.9±1.1 (scores range from 0 to 9, with higher scores indicating a higher risk of stroke); 36.1% of the patients were women. After a mean follow-up of 3.5±1.8 years, stroke or systemic embolism occurred in 55 patients in the apixaban group (0.78% per patient-year) and in 86 patients in the aspirin group (1.24% per patient-year) (hazard ratio, 0.63; 95% confidence interval [CI], 0.45 to 0.88; P = 0.007). In the on-treatment population, the rate of major bleeding was 1.71% per patient-year in the apixaban group and 0.94% per patient-year in the aspirin group (hazard ratio, 1.80; 95% CI, 1.26 to 2.57; P = 0.001). Fatal bleeding occurred in 5 patients in the apixaban group and 8 patients in the aspirin group. CONCLUSIONS: Among patients with subclinical atrial fibrillation, apixaban resulted in a lower risk of stroke or systemic embolism than aspirin but a higher risk of major bleeding. (Funded by the Canadian Institutes of Health Research and others; ARTESIA ClinicalTrials.gov number, NCT01938248.).

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

WAVE2 Regulates Actin-Dependent Processes Induced by the B Cell Antigen Receptor and Integrins.

B cell antigen receptor (BCR) signaling induces actin cytoskeleton remodeling by stimulating actin severing, actin polymerization, and the nucleation of branched actin networks via the Arp2/3 complex. This enables B cells to spread on antigen-bearing surfaces in order to increase antigen encounters and to form an immune synapse (IS) when interacting with antigen-presenting cells (APCs). Although the WASp, N-WASp, and WAVE nucleation-promoting factors activate the Arp2/3 complex, the role of WAVE2 in B cells has not been directly assessed. We now show that both WAVE2 and the Arp2/3 complex localize to the peripheral ring of branched F-actin when B cells spread on immobilized anti-Ig antibodies. The siRNA-mediated depletion of WAVE2 reduced and delayed B cell spreading on immobilized anti-Ig, and this was associated with a thinner peripheral F-actin ring and reduced actin retrograde flow compared to control cells. Depleting WAVE2 also impaired integrin-mediated B cell spreading on fibronectin and the LFA-1-induced formation of actomyosin arcs. Actin retrograde flow amplifies BCR signaling at the IS, and we found that depleting WAVE2 reduced microcluster-based BCR signaling and signal amplification at the IS, as well as B cell activation in response to antigen-bearing cells. Hence, WAVE2 contributes to multiple actin-dependent processes in B lymphocytes.

Conventional biventricular pacing is still preferred to conduction system pacing for atrioventricular block in patients with reduced ejection fraction and narrow QRS.

It is well established that right ventricular pacing is detrimental in patients with reduced cardiac function who require ventricular pacing (VP), and alternatives nowadays are comprised of biventricular pacing (BiVP) and conduction system pacing (CSP). The latter modality is of particular interest in patients with a narrow baseline QRS as it completely avoids, or minimizes, ventricular desynchronization associated with VP. In this article, experts debate whether BiVP or CSP should be used to treat these patients.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

AIMS: Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP. METHODS AND RESULTS: Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05). CONCLUSION: Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure.

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Comorbidities and clinical response to cardiac resynchronization therapy: patient-level meta-analysis from eight clinical trials.

AIMS: Patients with heart failure usually have several other medical conditions that might alter the effects of interventions. We investigated whether the burden of comorbidity modified the clinical response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Original patient-level data from eight randomized trials exploring the effects of CRT versus no CRT were pooled (BLOCK-HF, MIRACLE, MIRACLE-ICD, MIRACLE-ICD II, RAFT, COMPANION, MADIT-CRT and REVERSE). A prior history of the following comorbidities was considered: episodic or persistent atrial fibrillation (n = 920), coronary artery disease (n = 3732), diabetes (n = 2171), and hypertension (n = 3353). Patients were classified into three groups based on the number of comorbidities: 0, 1-2, or ≥3. The outcomes of interest were time to all-cause mortality and time to the composite outcome of heart failure hospitalization (HFH) or all-cause mortality. Outcomes were evaluated within each comorbidity group using a Bayesian hierarchical Weibull survival regression model. Of 6324 patients, 970 (15%) had no comorbidities, 4052 (64%) had 1-2 and 1302 (21%) had ≥3 comorbidities. The adjusted hazard ratio (aHR) for CRT versus no CRT for all-cause mortality in the overall cohort was 0.79 (95% credible interval [CI] 0.68-0.93) (p = 0.010); for no comorbidities the aHR was 0.54 (95% CI 0.34-0.86), for 1-2 comorbidities was 0.81 (95% CI 0.67-0.97) and for ≥3 comorbidities was 0.83 (95% CI 0.64-1.07) (no significant interaction between CRT and comorbidity burden: p = 0.13). For the endpoint of HFH or all-cause mortality, the aHR for the overall cohort was 0.74 (95% CI 0.65-0.84) (p = 0.001), for no comorbidities was 0.69 (95% CI 0.50-0.94), for 1-2 comorbidities was 0.77 (95% CI 0.66-0.90) and for ≥3 comorbidities was 0.68 (95% CI 0.55-0.82) (no significant interaction between CRT and comorbidity burden: p = 0.081). CONCLUSION: In a meta-analysis of patient-level data from eight major trials, the totality of evidence suggests that CRT reduces HFH and/or all-cause mortality even when several comorbid diseases are present. CLINICAL TRIAL REGISTRATION: NCT00271154, NCT00251251, NCT00267098, NCT00180271.