Appropriate and Inappropriate ICD Shocks in Patients with LVADS: Prevalence, Associated Factors, and Etiologies.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) shocks are a common complication following Left Ventricular Assist Device (LVAD) implantation; however, there is limited data on their frequency and causes. OBJECTIVE: To define the incidence, programming, patient characteristics, and factors associated with appropriate and inappropriate ICD shocks in persons with LVADs. METHODS: We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted between January 1, 2013 to June 30, 2019 with a pre-existing ICD. ICD shocks were adjudicated by the treating physician and a 2nd reviewer for the purpose of this study. RESULTS: Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) patients had at least one shock following LVAD implantation. Among 134 patients with complete device history, there were a total of 330 shock episodes: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included SVT (n=66, 20.0%), physiologic oversensing (n=1, 0.3%), and non-physiologic oversensing (n=8, 2.4%) including LVAD electromagnetic interference (n=1, 0.3%). ICD programming with shorter detection delay (p < 0.001) and absence of anti-tachycardia pacing programming (p = 0.001) in high-rate zones was seen more commonly in inappropriate shock than appropriate shock. CONCLUSIONS: The rate of inappropriate shocks in LVAD recipients is very high and is most often due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus AHA recommendations for LVAD programming with long detection delays and high rate cutoffs may help avoid inappropriate ICD shocks.

Procedural volume and outcomes with atrial fibrillation ablation: A report from the NCDR AFib Ablation Registry.

BACKGROUND: The association of hospital and physician procedure volume with outcome has not been well evaluated for atrial fibrillation (AF) ablation in contemporary practice. OBJECTIVE: This study aimed to determine the association between hospital and physician AF ablation volume and procedural success (isolation of all pulmonary veins) and major adverse events (MAEs). METHODS: Procedures reported to the National Cardiovascular Data Registry AFib Ablation Registry between July 2019 and June 2022 were included. Hospital and physician procedural volumes were annualized and stratified into quartiles to compare outcomes. Three-level hierarchical (patient, hospital, and physician) models were used to assess the procedural volume-outcome relationship. RESULTS: A total of 70,296 first-time AF ablations at 186 US hospitals were included. Overall, procedural success and MAE rates were 98.5% and 1.0%, respectively. With hospital volume (Q4) as a reference, the likelihood of procedural success was lower for Q1 (odds ratio [OR], 0.44; 95% CI, 0.29-0.68), Q2 (OR, 0.50; 95% CI, 0.33-0.75), and Q3 (OR, 0.60; 95% CI, 0.40-0.89); the results were similarly significant for physician volume. With MAE for hospitals, there was an inverse procedural volume relationship for Q1 (OR, 1.78; 95% CI, 1.26-2.52) but not for Q2 (OR, 1.06; 95% CI, 0.77-1.46) or Q3 (OR, 1.19; 95% CI, 0.89-1.58) and similarly for physicians in Q1 and Q2 but not in Q3. An adjusted MAE ≤1% was predicted by an annual volume of approximately 190 for hospitals and 60 for physicians. CONCLUSION: In this national cohort, hospital and physician AF ablation procedural volumes were directly related to acute procedural success and inversely related to rates of MAE.

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.

Procedure Volume and Outcomes With WATCHMAN Left Atrial Appendage Occlusion.

BACKGROUND: Procedure volumes are associated with outcomes for many cardiovascular procedures, leading to guidelines on minimum volume thresholds for certain procedures; however, the volume-outcome relationship with left atrial appendage occlusion is poorly understood. As such, we sought to determine the relationship between hospital and physician volume and WATCHMAN left atrial appendage occlusion procedural success overall and with the new generation WATCHMAN FLX device. METHODS: We performed an analysis of WATCHMAN procedures (January 2019 to October 2021) from the National Cardiovascular Data Registry LAAO Registry. Three-level hierarchical generalized linear models were used to assess the adjusted relationship between procedure volume and procedural success (device released with peridevice leak <5 mm, no in-hospital major adverse events). RESULTS: Among 87 480 patients (76.2±8.0 years; 58.8% men; mean CHA2DS2-VASc score, 4.8±1.5) from 693 hospitals, the procedural success rate was 94.2%. With hospital volume Q4 (greatest volume) as the reference, the likelihood of procedural success was significantly less among Q1 (odds ratio [OR], 0.66 [CI, 0.57-0.77]) and Q2 (OR, 0.78 [CI, 0.69-0.90]) but not Q3 (OR, 0.95 [CI, 0.84-1.07]). With physician volume Q4 (greatest volume) as the reference, the likelihood of procedural success was significantly less among Q1 (OR, 0.72 [CI, 0.63-0.82]), Q2 (OR, 0.79 [CI, 0.71-0.89]), and Q3 (OR, 0.88 [CI, 0.79-0.97]). Among WATCHMAN FLX procedures, there was attenuation of the volume-outcome relationships, with statistically significant but modest absolute differences of only ≈1% across volume quartiles. CONCLUSIONS: In this contemporary national analysis, greater hospital and physician WATCHMAN volumes were associated with increased procedure success. The WATCHMAN FLX transition was associated with increased procedural success and less heterogeneity in outcomes across volume quartiles. These findings indicate the importance of understanding the volume-outcome relationship for individual left atrial appendage occlusion devices.

Meta-Analysis of Genome-Wide Association Studies Reveals Genetic Mechanisms of Supraventricular Arrhythmias.

BACKGROUND: Substantial data support a heritable basis for supraventricular tachycardias, but the genetic determinants and molecular mechanisms of these arrhythmias are poorly understood. We sought to identify genetic loci associated with atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular accessory pathways or atrioventricular reciprocating tachycardia (AVAPs/AVRT). METHODS: We performed multiancestry meta-analyses of genome-wide association studies to identify genetic loci for AVNRT (4 studies) and AVAP/AVRT (7 studies). We assessed evidence supporting the potential causal effects of candidate genes by analyzing relations between associated variants and cardiac gene expression, performing transcriptome-wide analyses, and examining prior genome-wide association studies. RESULTS: Analyses comprised 2384 AVNRT cases and 106 489 referents, and 2811 AVAP/AVRT cases and 1,483 093 referents. We identified 2 significant loci for AVNRT, which implicate NKX2-5 and TTN as disease susceptibility genes. A transcriptome-wide association analysis supported an association between reduced predicted cardiac expression of NKX2-5 and AVNRT. We identified 3 significant loci for AVAP/AVRT, which implicate SCN5A, SCN10A, and TTN/CCDC141. Variant associations at several loci have been previously reported for cardiac phenotypes, including atrial fibrillation, stroke, Brugada syndrome, and electrocardiographic intervals. CONCLUSIONS: Our findings highlight gene regions associated with ion channel function (AVAP/AVRT), as well as cardiac development and the sarcomere (AVAP/AVRT and AVNRT) as important potential effectors of supraventricular tachycardia susceptibility.

Peak frequency mapping of atypical atrial flutter.

INTRODUCTION: Peak frequency (PF) mapping is a novel method that may identify critical portions of myocardial substrate supporting reentry. The aim of this study was to describe and evaluate PF mapping combined with omnipolar voltage mapping in the identification of critical isthmuses of left atrial (LA) atypical flutters. METHODS AND RESULTS: LA omnipolar voltage and PF maps were generated in flutter using the Advisor HD-Grid catheter (Abbott) and EnSite Precision Mapping System (Abbott) in 12 patients. Normal voltage was defined as ≥0.5 mV, low-voltage as 0.1-0.5 mV, and scar as <0.1 mV. PF distributions were compared with ANOVA and post hoc Tukey analyses. The 1 cm radius from arrhythmia termination was compared to global myocardium with unpaired t-testing. The mean age was 65.8 ± 9.7 years and 50% of patients were female. Overall, 34 312 points were analyzed. Atypical flutters most frequently involved the mitral isthmus (58%) or anterior wall (25%). Mean PF varied significantly by myocardial voltage: normal (335.5 ± 115.0 Hz), low (274.6 ± 144.0 Hz), and scar (71.6 ± 140.5 Hz) (p < .0001 for all pairwise comparisons). All termination sites resided in low-voltage regions containing intermediate or high PF. Overall, mean voltage in the 1 cm radius from termination was significantly lower than the remaining myocardium (0.58 vs. 0.95 mV, p < .0001) and PF was significantly higher (326.4 vs. 245.1 Hz, p < .0001). CONCLUSION: Low-voltage, high-PF areas may be critical targets during catheter ablation of atypical atrial flutter.

Severe mental illness: cardiovascular risk assessment and management.

Patients with severe mental illness (SMI) including schizophrenia and bipolar disorder die on average 15-20 years earlier than the general population often due to sudden death that, in most cases, is caused by cardiovascular disease. This state-of-the-art review aims to address the complex association between SMI and cardiovascular risk, explore disparities in cardiovascular care pathways, describe how to adequately predict cardiovascular outcomes, and propose targeted interventions to improve cardiovascular health in patients with SMI. These patients have an adverse cardiovascular risk factor profile due to an interplay between biological factors such as chronic inflammation, patient factors such as excessive smoking, and healthcare system factors such as stigma and discrimination. Several disparities in cardiovascular care pathways have been demonstrated in patients with SMI, resulting in a 47% lower likelihood of undergoing invasive coronary procedures and substantially lower rates of prescribed standard secondary prevention medications compared with the general population. Although early cardiovascular risk prediction is important, conventional risk prediction models do not accurately predict long-term cardiovascular outcomes as cardiovascular disease and mortality are only partly driven by traditional risk factors in this patient group. As such, SMI-specific risk prediction models and clinical tools such as the electrocardiogram and echocardiogram are necessary when assessing and managing cardiovascular risk associated with SMI. In conclusion, there is a necessity for differentiated cardiovascular care in patients with SMI. By addressing factors involved in the excess cardiovascular risk, reconsidering risk stratification approaches, and implementing multidisciplinary care models, clinicians can take steps towards improving cardiovascular health and long-term outcomes in patients with SMI.

Predicting Major Adverse Events in Patients Undergoing Transcatheter Left Atrial Appendage Occlusion.

BACKGROUND: The National Cardiovascular Data Registry Left Atrial Appendage Occlusion Registry (LAAO) includes the vast majority of transcatheter LAAO procedures performed in the United States. The objective of this study was to develop a model predicting adverse events among patients undergoing LAAO with Watchman FLX. METHODS: Data from 41 001 LAAO procedures with Watchman FLX from July 2020 to September 2021 were used to develop and validate a model predicting in-hospital major adverse events. Randomly selected development (70%, n=28 530) and validation (30%, n=12 471) cohorts were analyzed with 1000 bootstrapped samples, using forward stepwise logistic regression to create the final model. A simplified bedside risk score was also developed using this model. RESULTS: Increased age, female sex, low preprocedure hemoglobin, no prior attempt at atrial fibrillation termination, and increased fall risk most strongly predicted in-hospital major adverse events and were included in the final model along with other clinically relevant variables. The median in-hospital risk-standardized adverse event rate was 1.50% (range, 1.03%-2.84%; interquartile range, 1.42%-1.64%). The model demonstrated moderate discrimination (development C-index, 0.67 [95% CI, 0.65-0.70] and validation C-index, 0.66 [95% CI, 0.62-0.70]) with good calibration. The simplified risk score was well calibrated with risk of in-hospital major adverse events ranging from 0.26% to 3.90% for a score of 0 to 8, respectively. CONCLUSIONS: A transcatheter LAAO risk model using National Cardiovascular Data Registry and LAAO Registry data can predict in-hospital major adverse events, demonstrated consistency across hospitals and can be used for quality improvement efforts. A simple bedside risk score was similarly predictive and may inform shared decision-making.

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.

Repeat catheter ablation for atrial fibrillation.

Catheter ablation of atrial fibrillation (AF) is an established therapy that reduces AF burden, improves quality of life, and reduces the risks of cardiovascular outcomes. Although there are clear guidelines for the application of de novo catheter ablation, there is less evidence to guide recommendations for repeat catheter ablation in patients who experience recurrent AF. In this review, we examine the rationale for repeat ablation, mechanisms of recurrence, patient selection, optimal timing, and procedural strategies. We discuss additional important considerations, including treatment of comorbidities and risk factors, risk of complications, and effectiveness. Mechanisms of recurrent AF are often due to non-pulmonary vein (non-PV) triggers; however, there is insufficient evidence supporting the routine use of empiric lesion sets during repeat ablation. The emergence of pulsed field ablation may alter the safety and effectiveness of de novo and repeat ablation. Extrapolation of data from randomized trials of de novo ablation does not optimally inform efficacy in cases of redo ablation. Additional large, randomized controlled trials are needed to address important clinical questions regarding procedural strategies and timing of repeat ablation.

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.

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.

Utilization and Outcomes of Primary Prevention Implantable Cardioverter-Defibrillators in Patients With Hypertrophic Cardiomyopathy.

Background There is uncertainty about the appropriate use of primary prevention implantable cardioverter-defibrillators (ICDs) among older patients with hypertrophic cardiomyopathy. Methods and Results Patients with hypertrophic cardiomyopathy who received a primary prevention ICD between 2010 and 2016 were identified using the National Cardiovascular Data Registry ICD Registry. Trends in ICD utilization and patient characteristics were assessed over time. Using linked Centers for Medicare and Medicaid Service claims data, Cox proportional hazard models assessed factors associated with mortality and postdischarge hospitalization for cardiac arrest/ventricular arrhythmia. Of 5571 patients with hypertrophic cardiomyopathy, 1511 (27.1%) were ≥65 years old. ICD utilization increased over time in all age groups. There were no changes in the prevalence of risk factors for sudden cardiac death over time. The variables most strongly associated with postdischarge mortality were older age (adjusted hazard ratio (aHR) 1.80 [95% CI, 1.47-2.21]), New York Heart Association class (III/IV versus I/II aHR 2.17 [95% CI, 1.57-2.98]), and left ventricular ejection fraction (left ventricular ejection fraction ≤35% versus >50% aHR 2.34 [95% CI, 1.58-3.48]; left ventricular ejection fraction 36%-50% versus >50% aHR 2.98 [95% CI, 2.02-4.40]), while history of nonsustained ventricular tachycardia (aHR 2.38 [95% CI, 1.62-3.51]) and New York Heart Association class (III/IV versus I/II aHR 1.84 [95% CI, 1.22-2.78]) were strongly associated with hospitalization for ventricular arrhythmia/cardiac arrest. Conclusions Primary prevention ICD utilization in patients with hypertrophic cardiomyopathy increased over time, including among those ≥65 years old. Among older patients, the strongest risk factors for hospitalization for ventricular arrhythmia/cardiac arrest following ICD implantation were history of nonsustained ventricular tachycardia and New York Heart Association class.

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 (HF) symptoms are limited. We investigated the relative effects of CRT in patients with ambulatory NYHA IV vs. III functional class at the time of device implantation. In this meta-analysis, we pooled patient-level data from the MIRACLE, MIRACLE-ICD, and COMPANION trials. Outcomes evaluated were time to the composite endpoint of first HF hospitalization (HFH) 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 differs 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 the RAFT trial. Our pooled analysis included 2309 patients. Overall, CRT was associated with a longer time to HFH or all-cause mortality (adjusted hazard ratio [aHR] 0.79, 95%CI 0.64 - 0.99, 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 HFH/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.

Cardiac resynchronization therapy in patients with a prior history of atrial fibrillation: Insights from four major clinical trials.

AIMS: To investigate the association of cardiac resynchronization therapy (CRT) on outcomes among participants with and without a history of atrial fibrillation (AF). METHODS: Individual-patient-data from four randomized trials investigating CRT-Defibrillators (COMPANION, MADIT-CRT, REVERSE) or CRT-Pacemakers (COMPANION, MIRACLE) were analyzed. Outcomes were time to a composite of heart failure hospitalization or all-cause mortality or to all-cause mortality alone. The association of CRT on outcomes for patients with and without a history of AF was assessed using a Bayesian-Weibull survival regression model adjusting for baseline characteristics. RESULTS: Of 3964 patients included, 586 (14.8%) had a history of AF; 2245 (66%) were randomized to CRT. Overall, CRT reduced the risk of the primary composite endpoint (hazard ratio [HR]: 0.69, 95% credible interval [CI]: 0.56-0.81). The effect was similar (posterior probability of no interaction = 0.26) in patients with (HR: 0.78, 95% CI: 0.55-1.10) and without a history of AF (HR: 0.67, 95% CI: 0.55-0.80). In these four trials, CRT did not reduce mortality overall (HR: 0.82, 95% CI: 0.66-1.01) without evidence of interaction (posterior probability of no interaction = 0.14) for patients with (HR: 1.09, 95% CI: 0.70-1.74) or without a history of AF (HR: 0.70, 95% CI: 0.60-0.97). CONCLUSION: The association of CRT on the composite endpoint or mortality was not statistically different for patients with or without a history of AF, but this could reflect inadequate power. Our results call for trials to confirm the benefit of CRT recipients with a history of AF.

Left ventricular lead implantation failure in an unselected nationwide cohort.

BACKGROUND: Left ventricular (LV) lead implantation is often the most challenging aspect of cardiac resynchronization therapy (CRT) procedures; early studies reported implant failure rates in ∼10% of cases. OBJECTIVE: The purpose of this study was to define rates, reasons for, and factors independently associated with LV lead implant failure. METHODS: We studied patients with left bundle branch block and ejection fraction ≤ 35% who underwent planned de novo transvenous CRT implantation (2010-2016) and were reported to the National Cardiovascular Data Registry ICD Registry. Independent predictors of LV lead implant failure were determined using logistic regression; age, sex, and variables with a univariable P value of <.15 were considered for inclusion in the model. RESULTS: Of the 111,802 patients who underwent a planned CRT procedure, 3.6% of patients (n = 3979) had LV lead implant failure. Reasons for implant failure included venous access (7.5%), coronary sinus access (64.3%), tributary vein access (13.5%), coronary sinus dissection (7.6%), unacceptable threshold (4.4%), and diaphragmatic stimulation (1.7%). Significant independent predictors of LV lead implant failure included younger age (odds ratio [OR] 1.01; 95% confidence interval [CI] 0.1.01-1.02), female sex (OR 1.38; 95% CI 1.29-1.47), black race (vs white, OR 1.44; 95% CI 1.32-1.57), Hispanic ethnicity (OR 1.23; 95% CI 1.08-1.40), QRS duration (OR 1.055 per 10 ms; 95% CI 1.038-1.072 per 10 ms), obstructive sleep apnea (OR 1.14; 95% CI 1.04-1.24), and implantation by a physician without specialized training (vs electrophysiology trained, OR 1.53; 95% CI 1.34-1.76). CONCLUSION: LV lead implant failure is uncommon in the current era and is most commonly due to coronary sinus access failure. Predictors of LV lead implant failure included younger age, female sex, black race, Hispanic ethnicity, increased QRS duration, sleep apnea, and absence of electrophysiology training.

Racial/ethnic and sex differences in safety outcomes and atrial fibrillation/atrial flutter-related acute healthcare utilization after catheter ablation of atrial fibrillation.

Background: Catheter ablation is recommended for the treatment of symptomatic atrial fibrillation (AF) refractory to medical therapy. Objective: The study sought to examine racial/ethnic and sex differences in complications and AF/atrial flutter (AFL)-related acute healthcare utilization following catheter ablation for AF. Methods: We performed a retrospective analysis using data from the Centers for Medicare and Medicaid Services Medicare Standard Analytical Files (October 1, 2014, to September 30, 2019) among patients ≥65 years of age with AF who underwent catheter ablation for rhythm control. The risk of any complication within 30 days and AF/AFL-related acute healthcare utilization within 1 year of ablation by race, ethnicity, and sex were assessed using multivariable Cox regression modeling. Results: We identified 95,394 patients for analysis of postablation complications and 68,408 patients for analysis of AF/AFL-related acute healthcare utilization. Both cohorts were ∼95% White and 52% male. Female patients had a slightly elevated risk of complications compared with male patients (adjusted hazard ratio [aHR] 1.07, 95% confidence interval [CI] 1.03-1.12). Black (aHR 0.78, 95% CI 0.77-1.00) and Asian (aHR 0.67, 95% CI 0.50-0.89) patients had lower utilization compared with White patients. Specifically, Asian men (aHR 0.58, 95% CI 0.38-0.91) had lower utilization compared with White men. Conclusion: Differences in safety and healthcare utilization after catheter ablation for AF were observed by race/ethnicity and sex groups. Underrepresented racial and ethnic groups with AF had a lower risk of AF/AFL-related acute healthcare utilization postablation.

Impact of Preprocedure Imaging for Left Atrial Appendage Occlusion: Insights From the NCDR LAAO Registry.

BACKGROUND: The impact of preprocedure imaging on the safety and effectiveness of left atrial appendage occlusion (LAAO) remains unclear. OBJECTIVES: This study sought to determine the rates of use of preprocedure computed tomography (CT)/cardiac magnetic resonance (CMR) and its association with safety and effectiveness of LAAO procedures. METHODS: The National Cardiovascular Data Registry LAAO Registry was used to evaluate patients who underwent attempted LAAO with the WATCHMAN and WATCHMAN FLX devices between January 1, 2016, and June 30, 2021. Safety and effectiveness of LAAO procedures was compared by use vs nonuse of preprocedural CT/CMR. Outcomes of interest included implantation success (deployment and release of device), device success (device released with peridevice leak <5 mm), and procedure success (device released with peridevice leak <5 mm and no in-hospital major adverse events [MAE]). Multivariable logistic regression was used to assess the relationship between preprocedure imaging and outcomes. RESULTS: Preprocedure CT/CMR was used for 18.2% (n = 20,851) of the 114,384 procedures in this study. CT/CMR use was more common among government and university hospitals and hospitals in the Midwest and South; it was less common among patients with uncontrolled hypertension, with abnormal renal function, and without prior thromboembolism. Overall rates of implantation success, device success, and procedure success were 93.4%, 91.2%, and 89.4%, respectively. Preprocedure CT/CMR was independently associated with an increased likelihood of implantation success (OR: 1.08; 95% CI: 1.00-1.17), device success (OR: 1.10; 95% CI: 1.04-1.16), and procedural success (OR: 1.07; 95% CI: 1.02-1.13). MAE were uncommon (2.3%) and not associated with use of preprocedure CT/CMR (OR: 1.02; 95% CI: 0.92-1.12). CONCLUSIONS: Preprocedure CT/CMR was associated with an increased likelihood of successful LAAO implantation; however, the magnitude of benefit appears small and it was not associated with MAE.