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BackgroundInformation regarding the prevalence and etiologies of complete atrioventricular block (CAVB) in younger patients is scarce. We aimed to investigate the potential causes for non-iatrogenic CAVB, the prevalence of CAVB without an identified etiology, the utilization of guidelines-recommended advanced imaging modalities in adults presenting with an early-onset CAVB of unidentified etiology, as well as to identify the predictors for cardiac implantable electronic device (CIED) insertion.MethodsUsing the National Inpatient Sample (NIS) database, we identified patients aged 18-60 hospitalized with non-iatrogenic CAVB in the US between 2015 (last quarter)-2019. Baseline demographics, clinical characteristics, potential etiologies for CAVB, advanced imaging utilization as well as outcomes including the need for temporary cardiac pacing (TCP) and CIED implantation were analyzed. Multivariable logistic regression models were used to identify predictors of CIED implantation.ResultsAn estimated total of 14,495 patients aged 18-60 with non-iatrogenic CAVB were identified. The mean age was 51 years, 60% were males and 3,050 (21%) had documentation of a prior conduction disorder. Eleven percent of the patients had a diagnosis of syncope and 6% suffered from a cardiac arrest. Two third of the patients (9,735, 67%) had no identified etiology for CAVB, of whom 8,205 (84%) were implanted with a permanent pacemaker (PPM), 180 patients (2%) with an implantable cardioverter-defibrillator (ICD), and 295 patients (3%) with a cardiac resynchronization therapy device. Only 40 patients (0.3%) underwent advanced imaging during their hospitalization. In multivariate analyses, older age [adjusted OR 1.046 (1.04-1.05), pConclusionThe majority of patients, hospitalized in the US for non-iatrogenic early-onset CAVB, had no identified etiology for their conduction disease. Despite the current US and European guidelines recommendation, advanced imaging prior to CIED implantation was under-utilized in this patient population.

This case describes a 74-year-old male who presented with rapid atrial flutter in association with large atrial lipoma along the interatrial septum. Conversion to sinus rhythm revealed the electrocardiographic criteria for advanced interatrial block. Interatrial block results from disruption of conduction through Bachmann's bundle, most commonly due to progressive atrial fibrosis. Bayés syndrome is recognized as the association of atrial arrhythmias with underlying interatrial block. This case supports the concept that localized disruption of atrial conduction via Bachmann's bundle from an atrial lipoma can produce the electrophysiologic substrate for atrial arrhythmias and the Bayés syndrome.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disorder affecting 1 in 500 people in the general population. Characterized by asymmetric left ventricular hypertrophy, cardiomyocyte disarray, cardiac fibrosis and increased risk of sudden cardiac death, HCM is in fact a highly complex disease with heterogenous clinical presentation, onset and complication. While mutations in the sarcomere gene can account for a substantial proportion of familial cases of HCM, up to 70% of HCM patients do not carry such sarcomere variants and the causal mutations for their diseases remain elusive. Recently, we identified a novel variant of the alpha-crystallin B chain (CRYAB R123W ) in a pair of monozygotic twins who developed concordant HCM phenotypes that manifested over a nearly identical time course. Yet, how CRYAB R123W promotes HCM phenotype remains unclear. Here, we generated mice carrying the Cryab R123W -knockin allele and demonstrated that hearts from these animals exhibit increased elastance, reduced end diastolic volume and increased E/E’ consistent with increased systolic and reduced diastolic function. Upon transverse aortic constriction, mice carrying the Cryab R123W allele developed pathological left ventricular hypertrophy with substantial cardiac fibrosis and progressively reduced ejection fraction. In contrast to another well-characterized CRYAB variant (R120G) which induced Desmin aggregation, no evidence of protein aggregation was observed in hearts expressing CRYAB R123W despite its potent effect on driving cellular hypertrophy. Unexpectedly, CRYAB R123W appears to enhance calcium signaling by promoting nuclear localization of NFAT through direct interaction with calcineurin. Mice also were more susceptible to ventricular tachycardia with programmed stimulation. Single nuclei RNA-sequencing of mouse hearts is underway and preliminarily reveals reduction in oxidative phosphorylation, consistent with known effects of Cryab on mitochondrial function. Thus, our data establishes the Cryab R123W allele as a novel genetic model of HCM and unveiled additional sarcomere-independent mechanisms of cardiomyocyte hypertrophy.

The convergent procedure is a hybrid ablation treatment for atrial fibrillation. It is increasingly considered as a management option for patients with persistent and long-standing atrial fibrillation. It consists of surgical ablation of the posterior left atrium through a minimally invasive closed-chest approach followed by endocardial catheter ablation. It is increasingly performed with concurrent epicardial occlusion of the left atrial appendage with a video-assisted thoracoscopic technique to physically and electrically isolate the left atrial appendage. This article provides an overview of a multidisciplinary approach to the convergent procedure, with concurrent thoracoscopic closure of the left atrial appendage, with an emphasis on perioperative management at a single institution. It provides a literature review of procedural outcomes, current data limitations, and future considerations.

In March 2010, the Patient Protection and Affordable Care Act (ACA) was passed in the United States. Among other reforms, Medicaid expansion for low-income adults earning up to 138% of the federal poverty level contributed to broadening health insurance access to >17 million Americans ([1][1]).

Introduction: LBBB results in impaired transseptal conduction and delayed posterolateral LV activation. Criteria for left bundle branch block (LBBB) vary across scientific organizations. Septal myectomy for hypertrophic cardiomyopathy (HCM) could serve as an iatrogenic anatomic model to characterize LBBB. Objective: To describe ECG features of LBBB after septal myectomy for HCM. Methods: ECG data were analyzed for 377 HCM patients (204 male) who developed post-operative LBBB after extended septal myectomy between 2004-2018. Results: Average age of the cohort at myectomy was 53 ± 14 years. Baseline QRS duration (QRSd) was 94 ± 10ms. The post myectomy QRSd was 152 ± 15ms, consistent with an average ΔQRSd of 58 ± 13ms. There was positive correlation between pre and post myectomy QRSd (r = 0.485; p < 0.0001). The average LV end-diastolic diameter (LVEDd) pre and 2 months post myectomy was 40 ± 5.6mm and 46.2 ± 6.5mm, respectively. Positive correlation between post myectomy QRSd and post myectomy LVEDd was also observed (r = 0.340; p < 0.0001). Females and males had pre myectomy QRSd of 93 ± 10ms and 95 ± 10ms respectively (p = 0.007) and post myectomy QRSd of 147 ± 13ms (120-184ms) and 157 ± 14ms (126-209ms) respectively (p < 0.0001). ΔQRSd was less in females than males (54 ± 13ms vs. 62 ± 11ms; p Conclusions: Surgical myectomy serves as a model to characterize LBBB. Following myectomy, QRSd correlated with LVEDd as well as pre-myectomy QRSd, and was longer in males due to delayed depolarization of larger hearts in men. Notably only 3 males and a minority of females had QRSd < 130ms. These data provide important insights for the validation of electrocardiographic LBBB criteria.

Introduction: Defibrillation threshold testing (DFT) is generally reserved for populations with perceived concern for defibrillation failure, including in hypertrophic cardiomyopathy (HCM). Higher shock impedance has been associated with risk of DFT failure with subcutaneous defibrillators (SICD). The PRAETORIAN score is a chest radiograph based tool that evaluates device positioning to predict risk of DFT failure. Objective: We assessed predictors of impedance during DFT in a single center HCM SICD cohort. Methods: Data was collected from HCM patients who underwent SICD implantation from 2013 to 2021. Predictors of impedance were evaluated with linear and logistic regression. Results: Impedance was reported in 75 HCM SICD patients during DFT with 65J. DFT was successful in 74 patients with mean impedance of 72.7 ohm and septal thickness of 20.6 mm. Ten patients had massive HCM (> 30 mm) with mean impedance of 66.4 ohm. Septal thickness was not predictive of impedance (β 0.37, 95% CI 1.24-0.50; P = .40). Independent predictors of impedance were BMI (β 1.41, 95% CI 0.61-2.21; P = .0008) and PRAETORIAN score (β 0.14, 95% CI 0.05-0.22; P = .0015). Multivariable regression revealed BMI no longer significant and PRAETORIAN score remaining significant (β 0.10, 95% CI 0.01-1.66; P = .038). Conclusion: In this HCM SICD cohort BMI and PRAETORIAN score were predictive of impedance. However, in a multivariable model, BMI was no longer predictive, highlighting importance of implant technique to improve impedance and DFT. Additionally, patients with massive hypertrophy all had successful DFT and septal thickness was not predictive of impedance. HCM has historically been portrayed as a high DFT population. Further prospective trials are necessary to establish whether standard DFT practice can be applied in HCM.

Introduction: Subcutaneous implantable cardioverter defibrillators (SICD) are an attractive option for sudden death (SCD) prevention in younger hypertrophic cardiomyopathy (HCM) patients. Conversely, SICDs have higher rate of inappropriate shock (IAS) when compared to transvenous devices. Objective: We characterize incidence of appropriate shock (AS) and IAS and analyze predictors of IAS in HCM SICD patients. Methods: Data was collected from HCM SICD patients from 2013 to 2021. We used multivariable logistic regression to assess for predictors of IAS in patients with > 6 mo follow up. Results: 94 HCM patients (age 47 ± 15 years) underwent SICD implant with mean follow up of 3.7 ± 2.0 year. Maximal LV thickness 20.5 ± 5.8 mm with massive hypertrophy (> 30 mm) in 10 patients (11.8%). Initial DFT with 65J was successful in 88 patients, with 5 more successful after device adjustment. 5 patients (5.9%) had 10 AS (3.2 AS per 100 pt-years). 10 patients (11.8%) had 19 IAS (6.0 IAS per 100 pt-years) due to T wave oversensing (n = 13), P wave oversensing (n = 2), atrial arrhythmia (n=2), and external noise (n = 1). IAS rate decreased over time, with IAS occurring in 8 patients of the initial half of the cohort and in only 2 of the second half. Time to IAS from implant was 11 ± 10.8 mo. QRS duration (OR 1.025, 95% CI 0.997-1.053; P = 0.084) showed trend to prediction of IAS, but no characteristic proved independently significant. Conclusions: This data adds to increasing evidence that in high-risk HCM patients, SICD represents a reliable treatment option for SCD prevention. IAS mainly due to cardiac oversensing, was seen in 11.8% of patients within this HCM cohort. IAS decreased over time, possibly due to improved patient selection, implant technique and device programming (SMART pass filter). A larger dataset is likely necessary to better understand this trend.

Introduction: Subcutaneous implantable cardioverter-defibrillators (SICD) are effective for sudden death (SCD) prevention in patients (pts) with hypertrophic cardiomyopathy (HCM). Pre-implant ECG screening to evaluate R and T wave sensing is done to decrease the risk of inappropriate shocks (IAS). Pts who undergo septal myectomy are at high risk of developing left bundle branch block (LBBB) that could potentially result in SICD T wave oversensing (TWOS). Objective: We describe 6 cases of pts with SICD and septal myectomy to understand the risks and benefits of maintaining SICD therapy in this cohort. Methods: We performed a retrospective cohort study of all pts with HCM who underwent SICD implantation and septal myectomy from 2013 to 2021. Results: Six pts with HCM underwent both SICD implantation and myectomy. Post myectomy ECGs for all pts show LBBB with QRS between 137 to 166 ms. Four of these pts were implanted prior to myectomy. The average time to myectomy after SICD was 1.3 years. Three out of the four pts have had no IAS or TWOS since myectomy. One patient experienced TWOS with 2 IAS 4 months after myectomy. The sensing vector was changed from primary to alternate with no further TWOS for the last 6 years. The remaining two pts underwent SICD implantation after myectomy, both of whom screened “OK” using the manual screening tool prior to implant. Neither patient has experienced IAS. One patient displayed episodes of TWOS and underwent vector change with no TWOS for the last 5 years. At the time of recent SICD generator replacement, he was screened using the automated programmer software and failed screening in all 3 vectors (Figure 1). Conclusions: This series demonstrates that maintenance of SICD is a viable option for SCD prevention in young pts who develop LBBB after septal myectomy. With close monitoring and vector adjustment, IAS and TWOS can be avoided. Further larger studies are necessary to assess the long-term risk of TWOS and IAS in this unique population.

BACKGROUND The impact of comorbid disease states on the development of atrial and ventricular arrhythmias in patients with hypertrophic cardiomyopathy (HCM) remains unresolved. OBJECTIVE Evaluate the association of comorbidities linked to arrhythmias in other cardiovascular diseases (e.g., obesity, systemic hypertension, diabetes, obstructive sleep apnea, renal disorders, tobacco and alcohol use) to atrial fibrillation (AF) and sudden cardiac death (SCD) events in a large cohort of HCM patients. METHODS 2269 patients, 54 ± 15 years of age, 1392 males, were evaluated at the Tufts HCM Institute between 2004 to 2018 and followed for an average of 4 ± 3 years for new-onset clinical AF and SCD events (appropriate defibrillation for ventricular tachyarrhythmias, resuscitated cardiac arrest, or SCD). RESULTS One or more comorbidity was present in 75% of HCM patients, including 50% with ≥ 2 comorbidities, most commonly obesity (BMI ≥30 kg/m2 ) in 43%. New-onset atrial fibrillation developed in 11% of our cohort (2.6%/year). On univariate analysis, obesity was associated with a 1.7-fold increased risk for AF (p=0.03) with 12% of obese patients developing AF (3.3%/year) as compared to 7% of patients with BMI 0.10 for each). SCD events occurred in 3.3% of patients (0.8%/year) and neither obesity nor other comorbidities were associated with increased risk for SCD (p > 0.10 for each). CONCLUSIONS In adult HCM patients comorbidities do not appear to impact AF or SCD risk. Therefore, for most patients with HCM adverse disease related events of AF and SCD appear to be primarily driven by underlying left ventricular and atrial myopathy as opposed to comorbidities. This article is protected by copyright. All rights reserved.

A man with a presumed diagnosis of hypertrophic cardiomyopathy presented after a ventricular fibrillation arrest. Review of prior cardiac magnetic resonance imaging revealed a pattern of late gadolinium enhancement that was atypical for hypertrophic cardiomyopathy and most consistent with cardiac sarcoidosis, with diagnosis confirmed by endomyocardial biopsy. (Level of Difficulty: Beginner.), Graphical abstract

Moderate-intensity exercise improves cardiovascular outcomes. However, mounting clinical evidence demonstrates that long-term, high-intensity endurance training predisposes male and veteran athletes to an increased risk of atrial fibrillation (AF), a risk that is not observed across both genders. Although increased mortality associated with AF in the general population is not shared by athletes, clinically significant morbidities exist (eg, reduced exercise capacity, athletic performance, and quality of life). Additional research is needed to fill current gaps in knowledge pertaining to the natural history, pathophysiologic mechanisms, and management strategies of AF in the athlete.

Background: The implantable cardioverter-defibrillator (ICD) is effective for preventing sudden death in patients with hypertrophic cardiomyopathy. However, data on performance and complications of implanted ICDs over particularly long time periods to inform clinical practice is presently incomplete. Methods: The study cohort comprises 217 consecutive hypertrophic cardiomyopathy patients with primary prevention ICDs implanted before 2008 and followed for ≥10 years (mean 12±4; range to 31). Results: Patients were 38±17 years at implant and 45 (21%) experienced appropriate interventions terminating ventricular tachycardia/ventricular fibrillation. The majority of ICD discharges occurred ≥5 years after implant (29 patients; 64%), including ≥10 years in 16 patients (36%). Initial device therapy increased in frequency from 2.3% of patients at P =0.005). Inappropriate ICD shocks in 39 patients occurred most commonly P =0.02). Other major device complications including infection and lead fractures and dislodgement occurred in 27 patients (12%) but did not increase in frequency over follow-up after implant ( P =0.47). There were no arrhythmic sudden death events among the 217 patients with ICD. Conclusions: In hypertrophic cardiomyopathy, after a primary prevention implant, ICD therapy often followed prolonged periods of device dormancy and increased progressively in frequency over time, including one-third of patients with initial therapy after 5 to 9 years, and an additional one-third of patients at ≥10 years. Frequency of inappropriate shocks decreased over follow-up, likely reflecting standard changes in device programming, while occurrence of device complications, such as lead fractures/infection, did not increase during follow-up.

PURPOSE Commotio cordis is sudden cardiac death caused by a relatively innocent blow to the left chest wall. Adolescents account for the majority of the cases; whether this is due to the higher frequency of adolescents playing ball sports or whether there is some maturational reduction of risk is not known. METHODS In a swine model of commotio cordis, the effect of body weight/size (directly related to age) to the susceptibility of chest impact-induced ventricular fibrillation (VF) is examined. METHODS Ball impacts were delivered at escalating velocities from 48.3 to 96.9 km·h (30-60 mph) to 128 swine ranging in weight from 5 to 54 kg. RESULTS VF occurred in 29% of impacts to the smallest animals compared with 34% in the 14- to 239-kg group, 27% in the 24- to 33.9-kg group, 30% in 34- to 43-kg group, and 15% in the 44- to 54-kg animals. The highest-weight group was associated with a significantly lower incidence of VF compared with other weights (P = 0.002). In a multivariate logistic regression analysis, controlling for repeated measures, four variables predicted VF: body weight (P = 0.0008), velocity (P < 0.0001), distance from the center of the heart, (P < 0.0001), and peak left ventricular pressure induced by the blow (P = 0.0007). CONCLUSIONS In this experimental model, animals weighing

His bundle pacing (HBP) has recently emerged as a technique to avoid the negative effects of long-term right ventricular apical pacing. In addition to providing physiologic ventricular activation, HBP has been shown to correct underlying conduction abnormalities in certain patients. Although large prospective, randomized clinical trials have not yet been completed, the available observational clinical data support the safety and efficacy of this technique. Here, we review the physiology of the his bundle (HB) as it relates to HBP, describe the current clinical experience, and discuss future directions of this emerging therapy.

Although the cardiovascular benefits of moderate exercise are well established, there is growing epidemiological support for the notion that high-intensity endurance athletics increases the risk of atrial fibrillation (AF). There are many gaps in evidence related to epidemiology and mechanisms of AF in endurance athletes. The proposed pathophysiological mechanisms include alterations of autonomic tone, electrical remodeling, anatomical remodeling, fibrosis, and inflammation. Clinical management of the athlete with AF often includes a period of decreased frequency, intensity, and duration of exercise with assessment for improvement in AF recurrence. Based on symptoms, a strategy of rate or rhythm control should be selected; however, due to side effects and intolerance of medications, ablation may be a preferred approach. The risks and benefits of anticoagulation for stroke prevention must be carefully assessed in the athlete with AF. All patients should be encouraged to be physically active with moderation; however, men should be advised of the higher risk of AF with long-term, high-intensity endurance training.

End-stage nonobstructive hypertrophic cardiomyopathy (HCM), with systolic dysfunction and adverse left ventricular (LV) remodeling due to extensive myocardial scarring, is associated with high risk for progressive heart failure and mortality [(1–5)][1]. Currently, heart transplantation is the only

Highly reliable identification of adults with hypertrophic cardiomyopathy (HC) at risk for sudden death (SD) has been reported. A significant controversy remains, however, regarding the most reliable risk stratification methodology for children and adolescents with HC. The present study assesses the accuracy of SD prediction and prevention with prophylactic implantable cardioverter-defibrillators (ICDs) in young HC patients. The study group is comprised of 146 HC patients

The transvenous implantable cardioverter-defibrillator (ICD) experience in hypertrophic cardiomyopathy (HCM) now spans 20 years of reliably terminating potentially lethal ventricular tachyarrhythmia ([1][1]), and along with a matured sudden death risk stratification strategy, has resulted in

Patients with hypertrophic cardiomyopathy (HC) may require higher energies to terminate ventricular fibrillation (VF); thus, dual coil defibrillation leads are often implanted. However, single coil leads may be preferred in young patients. All patients with HCM implanted with a transvenous ICD from years 2000 to 2014 were included. Of 249 patients, 223 underwent VF testing including 150 with a dual coil lead and 73 a single coil. Patients tested with dual coil compared with single coil had lower successful VF energies (15.7 ± 6.1 joule to 20.2 ± 7.9 joule (p

Pulmonary vein isolation is the cornerstone for atrial fibrillation ablation. Effectiveness of pulmonary vein isolation during cryoablation is demonstrated by confirming entrance and exit block. Loss of pulmonary vein potentials during cryoablation demonstrates presence of entrance block. Exit block is confirmed by pacing from within the pulmonary veins and demonstrating lack of capture of the left atrium. Administration of adenosine can unmask dormant conduction in the pulmonary veins.

There has been a recent proliferation of consumer health devices (CHDs) that enable user-initiated screening for a variety of diseases. These devices represent a paradigm shift in the deployment of disease screening, a process that has historically been led by clinicians following the guidance of professional bodies. The detection of AF via CHDs is a contemporary example of this phenomenon and highlights several important implications of the shift of disease screening from clinicians to CHD users. These include responsibility for patient data and outcomes, healthcare costs and access, and an evolution of the patient-provider relationship. However, as CHD technologies mature and become more affordable, they have the potential to detect actionable subclinical disease and improve health. Rather than allow CHDs to enter the marketplace organically with the potential for unintended negative consequences, it is critical that clinical, research, and industry communities proactively collaborate and establish best practices for their use.

As the most common sustained arrhythmia in adults, atrial fibrillation (AF) is an established and growing epidemic. To provide optimal patient care, it is important for clinicians to be aware of AF's epidemiological trends, methods of risk reduction, and the various available treatment modalities. Our understanding of AF's pathophysiology has advanced, and with this new understanding has come advancements in prevention strategies as well as pharmacological and nonpharmacological treatment options. Following PubMed and MEDLINE searches for AF risk factors, epidemiology, and therapies, we reviewed relevant articles (and bibliographies of those articles) published from 2000 to 2016. This “state-of-the-art” review provides a comprehensive update on the understanding of AF in the world today, contemporary therapeutic options, and directions of ongoing and future study.

A 34-year-old man with Brugada syndrome (BrS) presented with electrical storm, manifested as multiple appropriate shocks from his implantable cardioverter-defibrillator over a period of 7 hours. He had not tolerated prior treatment with quinidine, and had self-discontinued cilostazol citing persistent palpitations. After stabilization with intravenous isoproterenol, an electrophysiology study was performed but no spontaneous or induced ventricular ectopic beats were identified. A three-dimensional (3D) endocardial electro-anatomic map of the right ventricular outflow tract (RVOT), pulmonic valve, and pulmonary artery, as well as a 3D epicardial map of the RVOT, were created. Low voltage, complex, fractionated electrograms and late potentials were targeted for irrigated radiofrequency ablation both endocardially and epicardially. Post-procedure, he was maintained on cilostazol (referring clinician preference), and has had no further ventricular tachyarrhythmia episodes over the past forty-one months. We propose that this novel ablation strategy may be useful for acute management of selected patients with BrS.

Objectives To reevaluate risk factors for high defibrillation threshold (DFT) and propose a risk assessment tool. Background Controversy exists over routine DFT testing during implantable cardioverter defibrillator (ICD) placement. Methods We retrospectively analyzed 1,642 consecutive patients who received an ICD and underwent DFT testing. Results The incidence of high DFT requiring addition of a subcutaneous array was 2.3%. Five significant independent variables predictive of high DFT were identified, including younger age, male gender (hazard ratio 1.99), left ventricular (LV) dysfunction, secondary prevention (hazard ratio 2.33), and amiodarone use (hazard ratio 2.39). Each 10-year increase in age was indicative of a 0.35-times lower chance of high DFT. Each 10% increase of LV ejection fraction (EF) was indicative of a 0.52-times lower chance of high DFT. These five variables form the EF-SAGA risk score (LVEF 20% had a negative predictive value for high DFT of 99.3%. Conclusion We identified five independent predictors of high DFT. We propose the EF-SAGA risk score to help decision making. Primary prevention patients with an LVEF > 20% had an exceedingly low incidence of high DFT suggesting that testing could be avoided in these patients. Careful assessment of the risk-benefit ratio of testing is important in high-risk patients.

The introduction of quadripolar (QP) cardiac resynchronization therapy (CRT) leads aimed to improve procedural and clinical outcomes.The National Cardiovascular Data Registry was analyzed to characterize the use as well as the procedural and clinical outcomes of QP leads in comparison with unipolar and bipolar (BP) leads.We evaluated data on 175,684 procedures reported between September 1, 2010, and December 31, 2015. Clinical outcomes were analyzed using Centers for MedicareMedicaid Services claims data.Among all CRT device implants, there was a drop in reported lead placement failure from 6.04% to 5.21% (P.0001 for trend) and a drop in the reported diaphragmatic stimulation rates from 0.07% to 0.01% (P.007 for trend) between the last quarters of 2010 and 2015. No significant difference in procedural complication rates between QP and BP leads occurred (1.34% and 1.39%, respectively; P = .50). Among patients linked to Centers for MedicareMedicaid Services claims data, no statistically significant difference in the combined primary outcome of death, congestive heart failure admission, device malfunction, and reoperation between BP and QP leads was observed (34.15 and 34.19 events per 100 patient-years, respectively; P = .89).Since the introduction of QP leads, there was a reduction in CRT lead placement failure rates and a reduction in diaphragmatic stimulation rates. However, no statistically significant difference in long-term clinical outcomes between BP and QP leads was observed in elderly patients undergoing CRT implantation.