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Bradyarrhythmias leading to permanent pacemaker (PPM) implantation continue to be a complication after transcatheter aortic valve replacement (TAVR).The purpose of this study was to assess the prevalence of bradyarrhythmias using an electrocardiographic (ECG) extended rhythm recording in patients pre- and post-TAVR and whether they can predict the need for PPM.This was a prospective single-center study in patients undergoing TAVR. Patients received an ECG patch for 2 weeks pre-, immediately post-, and 2-3 months post-TAVR. Caring physicians were blinded to the results of the patch except when predefined urgent arrhythmias were detected. The main outcome was the need for PPM implantation after TAVR.We enrolled 110 patients, of whom 96 underwent TAVR and were included in the final analysis. Bradyarrhythmias, defined as a pause of 3 seconds or more, occurred in 5.2%, 12.7%, and 7% of patients pre-, immediately post-, and 2-3 months post-TAVR, respectively. PPM implantation occurred in 12 patients (12.5%), of whom 9 (9.4%) underwent implantation during their index hospitalization while 3 (3.1%) required implantation postdischarge for indications other than heart block. No patients required PPM after receiving an ECG patch 2-3 months post-TAVR. Significant baseline predictors for the need for PPM included the presence of right bundle branch block and increased QRS duration. Bradyarrhythmias detected by the ECG patch did not predict the need for PPM at either the index hospitalization or the follow-up period.Bradyarrhythmias are common and can be detected with extended ECG monitoring before and after TAVR; however, in our study they did not predict the need for PPM after TAVR (ClinicalTrials.gov identifier: NCT03180073).

This study aimed to identify risk factors for infection after secondary cardiac implantable electronic device (CIED) procedures.Risk factors for CIED infection are not well defined and techniques to minimize infection lack supportive evidence. WRAP-IT (World-wide Randomized Antibiotic Envelope Infection Prevention trial), a large study that assessed the safety and efficacy of an antibacterial envelope for CIED infection reduction, offers insight into procedural details and infection prevention strategies.This analysis included 2,803 control patients from the WRAP-IT trial who received standard preoperative antibiotics but not the envelope (44 patients with major infections through all follow-up). A multivariate least absolute shrinkage and selection operator machine learning model, controlling for patient characteristics and procedural variables, was used for risk factor selection and identification. Risk factors consistently retaining predictive value in the model (appeared10 times) across 100 iterations of imputed data were deemed significant.Of the 81 variables screened, 17 were identified as risk factors with 6 being patient/device-related (nonmodifiable) and 11 begin procedure-related (potentially modifiable). Patient/device-related factors included higher number of previous CIED procedures, history of atrial arrhythmia, geography (outside North America and Europe), device type, and lower body mass index. Procedural factors associated with increased risk included longer procedure time, implant location (non-left pectoral subcutaneous), perioperative glycopeptide antibiotic versus nonglycopeptide, anticoagulant, and/or antiplatelet use, and capsulectomy. Factors associated with decreased risk of infection included chlorhexidine skin preparation and antibiotic pocket wash.In WRAP-IT patients, we observed that several procedural risk factors correlated with infection risk. These results can help guide infection prevention strategies to minimize infections associated with secondary CIED procedures.

Background: Cardiac resynchronization therapy (CRT) represents a major medical advance in patients with heart failure with electrical dyssynchrony to improve symptoms, reduce hospitalization, and increase survival both in the presence and absence of implantable cardioverter-defibrillator therapy. However, among CRT-eligible patients with nonischemic cardiomyopathy (NICM), the benefit of defibrillator therapy in addition to CRT remains unclear. A systematic review and meta-analysis comparing outcomes of patients with NICM and heart failure who underwent CRT with implantable cardioverter-defibrillator (CRT-D) versus CRT-pacemaker only (CRT-P) was, therefore, performed. Methods: A literature search from inception through February 2020 was conducted in PubMed and Cochrane Review Databases for all studies reporting outcomes of CRT-D versus CRT-P in CRT-eligible patients with NICM. Studies reporting nonstratified outcomes, including patients with ischemic cardiomyopathy, were excluded. The primary end point of interest was all-cause mortality. A random-effects model using hazards ratio (HR) was used to calculate a cumulative HR for all-cause mortality. The Grading of Recommendations Assessment, Development, and Evaluation approach assessed the certainty of evidence across outcomes. Results: Of a total of 1478 potential citations, the search yielded 8 citations that met inclusion and exclusion criteria. There was one randomized controlled trial which included a subgroup of 645 CRT-eligible patients with NICM (322 with CRT-D and 323 with CRT-P). Seven observational studies representing 9944 CRT-eligible patients with NICM (6865 CRT-D implantation and 3079 with CRT-P) were included in a pooled meta-analysis. The cumulative adjusted HR for all-cause mortality for CRT-D versus CRT-P was 0.92 (95% CI, 0.83–1.03); I 2 =0 though with low certainty of evidence. There may be little difference in infection and cardiac mortality between CRT-D versus CRT-P devices (HR, 0.82 [95% CI, 0.29–2.20] moderate certainty of evidence and HR, 0.68 [95% CI, 0.37–1.25], low certainty of evidence, respectively). Conclusions: In this meta-analysis, the addition of defibrillator therapy was not significantly associated with a reduction in all-cause mortality in CRT-eligible patients with NICM.

Introduction In patients with chronic systolic heart failure and frequent right ventricular pacing (RVP), upgrade to cardiac resynchronization therapy (CRT) has become common practice despite a lack of randomized clinical trials. We aimed to evaluate long term outcomes in patients upgraded to CRT from chronic RVP compared with de novo CRT implants. Methods and results We reviewed medical charts on consecutive patients with a left ventricular ejection fraction (LVEF) ≤ 35% and a QRSd ≥ 120 ms undergoing CRT. Survival free of left ventricular assist device (LVAD) and a heart transplant was compared amongst patients on the basis of pre-CRT QRS morphology. Improvement in LVEF was also compared across groups. A total of 1260 patients met inclusion criteria of whom 233 were upgraded from chronic RVP. Over a mean follow up 6.5 ± 4.0 years there were 821 endpoints (27 LVAD, 30 heart transplants, and 764 deaths). In a multivariate Cox regression model, upgraded patients had worse outcomes (HR 1.3(1.1-1.7) P = .007) compared with those with native LBBB and similar outcomes to patients with non-LBBB(HR 0.96(0.76-1.21) P = .7). The survival curve for chronic RVP parallels native LBBB for approximately 2.5 years before dropping sharply. Patients with chronic RVP derive similar improvements in LVEF compared with those with LBBB and superior improvements compared with those with non-LBBB. Conclusions Despite achieving similar levels of LVEF improvement, patients with systolic heart failure with chronic RVP undergoing upgrade to CRT have inferior long term outcomes compared with patients with native LBBB. Long term outcomes with CRT in patients with chronic RVP, RBBB, and IVCD are similar.

Objectives This study aimed to evaluate the effectiveness and safety of transvenous lead extraction (TLE) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Background ARVC is an increasingly diagnosed cardiomyopathy that often requires device implantation to prevent sudden death. Little is known about TLE in this setting, which has potential challenges and risks, primarily due to right ventricular (RV) wall thinning and fragility. Methods All consecutive patients with ARVC who underwent TLE at our institution between 1996 and 2016 were included. When extraction tools were used, sheaths were advanced to the RV with countertraction at the lead tip. Success and complications were defined in concordance with Heart Rhythm Society guidelines. Results Twenty-two TLE procedures in patients with ARVC involved extraction of 27 leads (22 defibrillators and 5 pacemakers). TLEs were performed due to evidence of lead malfunction (n = 17; 77%) or device infection (n = 5; 23%). Twenty-four leads (89%) were RV, and 3 leads (11%) were right atrial. The median age of the oldest extracted lead was 1,691 days (interquartile range [IQR]: 1,168 to 2,726 days). Specialized extraction tools were required in 20 procedures (91%). None required the use of a snare or a femoral workstation. The median procedural and fluoroscopic times were 152 min (IQR: 129 to 185 min) and 11 min (IQR: 6 to 18 min), respectively. Complete procedural success with removal of all leads was achieved in all cases. There were no major complications. Conclusions In a high-volume center, TLE in patients with ARVC was associated with a high success rate and a low rate of complications when guideline-established techniques and tools were used.

The population of patients with heart failure continues to grow, which introduced significant challenges in clinical practice related to the management of cardiac arrhythmia and advanced heart failure syndromes. Device therapy has increasingly become essential in the management of life-threatening arrhythmia and clinical heart failure in this population. This review will discuss the use of cardiac implantable electronic devices in heart failure with primary focus on sudden cardiac death prevention and cardiac resynchronization, including published evidence and evolving technologies.

BACKGROUND Athletes with an implantable cardioverter-defibrillator (ICD) may require unique optimal device-based tachycardia programming. OBJECTIVE The purpose of this study was to assess the association of tachycardia programming characteristics of ICDs with occurrence of shocks, transient loss-of-consciousness, and death among athletes. METHODS A subanalysis of a prospective, observational, international registry of 440 athletes with ICDs followed for a median of 44 months was performed. Programming characteristics were divided into groups for rate cutoff (very high, high, or low) and detection (long-detection interval [> nominal] or nominal). Endpoints included total, appropriate, and inappropriate shocks, transient loss-of-consciousness, and mortality. RESULTS In this cohort, 62% were programmed with high-rate cutoff and 30% with long detection. No athlete died of an arrhythmia (related or unrelated) to ICD shocks. Three patients had sustained ventricular tachycardia below programmed detection rate, presenting as palpations and/or dizziness. ICD shocks were received by 98 athletes (64 appropriate, 32 inappropriate); 2 patients received both. Programming a high-rate cutoff was associated with decreased risk of total (P = .01) and inappropriate (P = .04) shocks overall and during competition or practice. Programming long-detection intervals was associated with fewer total shocks. Single-vs dual-chamber devices and the number of zones were unrelated to risk of shock. Transient loss-of-consciousness, associated with 27 appropriate shocks, was not related to programming characteristics. CONCLUSION High-rate cutoff and long- detection duration programming of ICDs in athletes at risk for sudden death can reduce total and inappropriate ICD shocks without affecting survival or the incidence of transient loss-of-consciousness.

Background Traditionally, insertable cardiac monitor (ICM) procedures have been performed in the cardiac catheterization (CATH) or electrophysiology (EP) laboratory. The introduction of the miniaturized Reveal LINQ ICM has led to simplified and less invasive procedures, affording hospitals flexibility in planning where these procedures occur without compromising patient safety or outcomes. Methods The present analysis of the ongoing, prospective, observational, multicenter Reveal LINQ Registry sought to provide real-world feasibility and safety data regarding the ICM procedure performed in the CATH/EP lab or operating room and to compare it with insertions performed outside of these traditional hospital settings. Patients included had at least a 30-day period after the procedure to account for any adverse events. Results We analyzed 1222 patients (58.1% male, age 61.0 ± 17.1 years) enrolled at 18 centers in the US, 17 centers in Middle East/Asia, and 15 centers in Europe. Patients were categorized into 2 cohorts according to the location of the procedure: in-lab (CATH lab, EP lab, or operating room) (n = 820, 67.1%) and out-of-lab (n = 402, 32.9%). Several differences were observed regarding baseline and procedure characteristics. However, no significant differences in the occurrence of procedure-related adverse events (AEs) were found; of 19 ICM/procedure-related AEs reported in 17 patients (1.4%), 11 occurred in the in-lab group (1.3%) and 6 in the out-of-lab group (1.5%) (P = .80). Conclusions This real-world analysis demonstrates the feasibility of performing Reveal LINQ ICM insertion procedures outside of the traditional hospital settings without increasing the risk of infection or other adverse events.

Cardiac resynchronization therapy (CRT) has been shown to be beneficial in patients with medically refractory heart failure. Although it has been found to be effective in a wide range of etiologies for nonischemic cardiomyopathy, its role in improving remodeling and survival of patients with cardiac sarcoidosis (CS) remains undefined. We performed a retrospective review of all patients at our institution with CS who underwent implantation of a CRT device from 2007 to 2017. The outcomes of this population were compared with the outcomes of a cohort of patients with nonischemic cardiomyopathy with an etiology other than sarcoidosis. Nineteen patients in our institution with CS underwent CRT implantation during the time period. This group was compared with 311 consecutive patients with other etiologies of nonischemic cardiomyopathy who underwent CRT implantation. CRT improved left ventricular ejection fraction (LVEF) from 28.8% to 35.9% (p

Quality has a foundation that consists of the nomenclature, definitions, and metrics of success, failure, and complications. There is now a firm foundation for reporting outcomes and for making clinical decisions with patients and their families. This has developed from an international consensus, ratified by the four continental heart rhythm societies and by the overlapping cardiovascular, surgical, anesthesiology, and infectious disease societies. Reporting of outcomes, using these metrics and definitions, is now mandated to promote transparency and facilitate clinical decision making with patients. The best path to accomplishing this goal is to participate in a center-specific or multicenter registry.

No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds).The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated.All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried. Baseline HrSc was defined as the percentage of all atrial sensed and paced beats in the tallest 10-beat histogram bin postimplant. LRL was assessed during repeated RPM uploads. Using a Cox model multivariable analysis, relationships between LRL, survival, HrSc, and other variables were evaluated. Survival was determined by query of death indices.Data analyzed included 61,881 subjects (mean follow-up 2.9 years). LRL ranged from 40 to 85 bpm. Baseline lower LRL was associated with younger age, less atrial fibrillation, female sex, and lower HrSc (P.001 for all covariates). Lower LRL was associated with improved survival, with LRL 40 associated with the largest survival benefit. This was significant for all 3 HrSc subgroups (P .001). An interaction between HrSc and LRL was observed, with the largest survival difference between HrSc groups observed at LRL-40 (P.001).LRL programming and HrSc were associated, and lower values of both were associated with improved survival in a large database of CRT-D subjects. Relationships between survival, LRL programming, and HrSc merit further study.

Development of a cardiac lead fracture model has the potential to differentiate well-performing lead designs from poor performing ones and could aid in future lead development.The purpose of this study was to demonstrate a predictive model for lead fracture and validate the results generated by the model by comparing them to observed 10-year implantable cardioverter-defibrillator lead fracture-free survival.The model presented here uses a combination of in vivo patient data, in vitro conductor fatigue test data, and statistical simulation to predict the fracture-free survival of cardiac leads. The model was validated by comparing the results to human clinical performance data from the Medtronic Sprint Fidelis (Minneapolis, MN) models 6931 (single coil, active fixation) and 6949 (dual coil, active fixation), as well as the Quattro model 6947 (dual coil, active fixation).Median patient age in the single coil Fidelis 6931 population (64 years) was less than in the dual coil Fidelis 6949 and Quattro populations (68 years). Modeled and observed fracture-free survival for Quattro (97%) was superior to that for Fidelis (94%). The modeled survival agreed with the observed fracture-free survival data. The average model error was 0.3% (SD 1.2%).This model for cardiac lead fracture-free survival using in vivo lead bending measurements and in vitro bench testing can be used to predict lead performance as observed by alignment with field survival data.

Background: In heart failure (HF) with sinus rhythm, resting and exercise heart rates correlate with exercise capacity and mortality. However, in HF with atrial fibrillation (AF), this correlation is unknown. Our aim is to investigate the association of resting and exercise ventricular rates (VRs) with exercise capacity and mortality in HF with AF. Methods: We identified 903 patients with HF and AF referred for cardiopulmonary stress testing. AF was defined as history of AF and AF during cardiopulmonary stress testing. We constructed multivariable models to evaluate the association of resting VR, peak exercise VR, VR reserve (peak VR−resting VR), and chronotropic index with (1) peak oxygen consumption (PVO 2 ) ≤18 mL/kg per minute, (2) continuous PVO 2 , and (3) 10-year all-cause mortality. Results: Median (25th–75th percentile) age was 60 (52–67) years, left ventricular ejection fraction was 25 (15–50)%, and 76.1% were males. Patients with lower (quartile 1) compared with higher (quartile 4) peak VR, VR reserve, and chronotropic index were more likely to have PVO 2 ≤18 mL/kg per min (adjusted odds ratio [95% CI]: 14.92 [8.07–27.58], 24.60 [12.36–48.98], and 22.31 [11.24–44.27], respectively), and higher all-cause mortality (adjusted hazard ratio [95% CI]: 2.56 [1.62–4.04], 2.29 [1.47–3.59], and 2.30 [1.51–3.49], respectively). For every 10 beats per minute increase in VR reserve, PVO 2 increased by 1.05 mL/kg per minute (B-coefficient [95% CI]: 1.05 [0.94–1.15]) and mortality decreased by 12% (adjusted hazard ratio [95% CI]: 0.88 [0.83–0.94]). Resting VR was associated with PVO 2 (B-coefficient [95% CI]: −0.46 [−0.70 to −0.23]) but not mortality (adjusted hazard ratio [95% CI]: 0.97 [0.88–1.06]). Conclusions: In patients with HF and AF, higher resting VR and lower peak exercise VR, VR reserve, and chronotropic index were all associated with worse peak exercise capacity, but only lower exercise VR parameters were associated with higher mortality. Dedicated studies are needed to gauge whether modulating exercise VR enhances exercise performance and outcomes.

Background Cardiac device procedures require tissue dissection to free existing device lead(s). Common techniques include blunt dissection, standard electrocautery, and low-temperature electrocautery (PlasmaBlade, Medtronic); however, data on the type of electrosurgical tool used and the development of procedure- or lead-related adverse events are limited. Objective The purpose of this study was to determine whether standard or low-temperature electrocautery impacts the development of an adverse event. Methods We evaluated patients enrolled in WRAP-IT (Worldwide Randomized Antibiotic EnveloPe Infection PrevenTion Trial) undergoing cardiac implantable electronic device (CIED) revision, upgrade, or replacement. All adverse events were adjudicated by an independent physician committee. Data were analyzed using Cox proportional hazard regression modeling. Results In total, 5641 patients underwent device revision/upgrade/replacement. Electrocautery was used in 5205 patients (92.3%) (mean age 70.6 ± 12.7 years; 28.8% female), and low-temperature electrocautery was used in 1866 patients (35.9%). Compared to standard electrocautery, low-temperature electrocautery was associated with a 23% reduction in the incidence of a procedure- or lead-related adverse event through 3 years of follow up (hazard ratio [HR] 0.77; 95% confidence interval [CI] 0.65–0.91; P = .002). After controlling for the number of active leads, degree of capsulectomy, degree of lead dissection, and renal dysfunction, low-temperature electrocautery was associated with a 32% lower risk of lead-related adverse events (HR 0.68; 95% CI 0.52–0.89; P = .004). These effects were consistent across a spectrum of lead-related adverse event types. Conclusion This study represents one of the largest assessments of electrocautery use in patients undergoing CIED revision, upgrade, or replacement procedures. Compared to standard electrocautery, low-temperature electrocautery significantly reduces adverse effects from these procedures.

Reports in 2016 that St. Jude implantable defibrillators might be vulnerable to hacking brought to light how unprepared the medical community was to evaluate and manage a potential cybersecurity crisis. In this chapter, we provide an overview of the present cybersecurity landscape, including the existing infrastructure in place to minimize cybersecurity vulnerabilities and the important role that healthcare providers serve both in reducing the risks and advising patients.

Supplemental Digital Content is available in the text., Background: In the WRAP-IT trial (Worldwide Randomized Antibiotic Envelope Infection Prevention), adjunctive use of an absorbable antibacterial envelope resulted in a 40% reduction of major cardiac implantable electronic device infection without increased risk of complication in 6983 patients undergoing cardiac implantable electronic device revision, replacement, upgrade, or initial cardiac resynchronization therapy defibrillator implant. There is limited information on the cost-effectiveness of this strategy. As a prespecified objective, we evaluated antibacterial envelope cost-effectiveness compared with standard-of-care infection prevention strategies in the US healthcare system. Methods: A decision tree model was used to compare costs and outcomes of antibacterial envelope (TYRX) use adjunctive to standard-of-care infection prevention versus standard-of-care alone over a lifelong time horizon. The analysis was performed from an integrated payer-provider network perspective. Infection rates, antibacterial envelope effectiveness, infection treatment costs and patterns, infection-related mortality, and utility estimates were obtained from the WRAP-IT trial. Life expectancy and long-term costs associated with device replacement, follow-up, and healthcare utilization were sourced from the literature. Costs and quality-adjusted life years were discounted at 3%. An upper willingness-to-pay threshold of $150 000 per quality-adjusted life year was used to determine cost-effectiveness, in alignment with the American College of Cardiology/American Heart Association practice guidelines and as supported by the World Health Organization and contemporary literature. Results: The base case incremental cost-effectiveness ratio of the antibacterial envelope compared with standard-of-care was $112 603/quality-adjusted life year. The incremental cost-effectiveness ratio remained lower than the willingness-to-pay threshold in 74% of iterations in the probabilistic sensitivity analysis and was most sensitive to the following model inputs: infection-related mortality, life expectancy, and infection cost. Conclusions: The absorbable antibacterial envelope was associated with a cost-effectiveness ratio below contemporary benchmarks in the WRAP-IT patient population, suggesting that the envelope provides value for the US healthcare system by reducing the incidence of cardiac implantable electronic device infection. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02277990.

Background: Dofetilide is one of the only anti-arrhythmic agents approved for atrial fibrillation (AF) in patients with reduced left ventricular ejection fraction (LVEF). However, postapproval data and safety outcomes are limited. In this study, we assessed the incidence and predictors of LVEF improvement, safety, and outcomes in patients with AF with LVEF ≤35% without prior implantable cardioverter defibrillator, cardiac resynchronization therapy, or AF ablation. Methods: An analysis of 168 consecutive patients from 2007 to 2016 was performed. Incidences of adverse events, drug continuation, implantable cardioverter defibrillator and cardiac resynchronization therapy implantation, LVEF improvement (>35%) and recovery (≥50%), AF recurrence, and AF ablation were determined. Multivariable regression analysis to identify predictors of LVEF improvement/recovery was performed. Results: The mean age was 64±12 years. Dofetilide was discontinued before hospital discharge in 46 (27%) because of QT prolongation (14%), torsades de pointe or polymorphic ventricular tachycardia/fibrillation (6% [sustained 3%, nonsustained 3%]), ineffectiveness (5%), or other causes (3%). At 1 year, 43% remained on dofetilide. Freedom from AF was 42% at 1 year, and 40% underwent future AF ablation. LVEF recovered (≥50%) in 45% and improved to >35% in 73%. Predictors of LVEF improvement included presence of AF during echocardiogram (odds ratio, 4.22 [95% CI, 1.71–10.4], P =0.002), coronary artery disease (odds ratio, 0.35 [95% CI, 0.16–0.79], P =0.01), left atrial diameter (odds ratio, 0.52 per 1 cm increase [95% CI, 0.30–0.90], P =0.01), and LVEF (odds ratio, per 1% increase, 1.09 [95% CI, 1.02–1.16], P =0.006). The C statistic was 0.78. Conclusions: In patients with LVEF ≤35%, who are potential implantable cardioverter defibrillator candidates, treated with dofetilide as an initial anti-arrhythmic strategy for AF, drug discontinuation rates were high, and many underwent future AF ablation. However, most patients had improvement in LVEF, obviating the need for primary prevention implantable cardioverter defibrillator.

This study characterized the microbiology of major cardiac implantable electronic device (CIED) infections that occurred during the WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) study.The WRAP-IT study offers a unique opportunity for further understanding of the pathogens involved in major CIED infections in a prospective dataset, with implications for clinical practice and infection management.A total of 6,800 patients randomized 1:1 to receive an antibacterial envelope or not (control subjects) were included in this analysis. Patient characteristics, infection manifestation (pocket vs. systemic), and infection microbiology were evaluated through all follow-up (36 months). Data were analyzed using Cox proportional hazards regression.A total of 3,371 patients received an envelope, and 3,429 patients were control subjects. Major CIED infection occurred in 32 patients who received an envelope and 51 control subjects (36-month Kaplan-Meier estimated event rate, 1.3% and 1.9%, respectively; p = 0.046). A 61% reduction in major pocket infection was observed within 12 months of the procedure in the envelope group (hazard ratio: 0.39, 95% confidence interval: 0.21 to 0.73; p = 0.003). Among 76 patients with major infections who had a sample taken, causative pathogens were identified in 47 patients. Staphylococcus species were the predominate pathogen (n = 31) and envelope use resulted in a 76% reduction in Staphylococcus-related pocket infections (n = 4 vs. 17; p = 0.010). Envelope use was not associated with delayed onset of pocket infections and did not affect the presentation of infections.Antibacterial envelope use resulted in a significant reduction of major CIED pocket infections and was particularly effective against Staphylococcus species, the predominant cause of pocket infections. (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial [WRAP-IT]; NCT02277990).

Objectives This study aimed to determine the long-term outcomes and predictors of left ventricular (LV) ejection fraction (LVEF) improvement in patients with severe cardiomyopathies undergoing cardiac resynchronization therapy (CRT). Background Whether patients with severe LV dysfunction benefit from CRT or have reached a point in disease severity past the point at which CRT is beneficial is unknown. Methods We collected clinical and echocardiographic data on 420 patients with an LVEF of ≤15% and a QRS duration of ≥120 ms undergoing CRT at the Cleveland Clinic and 2 hospitals in the Johns Hopkins Health System between April 2003 and May 2014. Multivariate models were created to determine factors associated with response to CRT, defined as an absolute improvement in LVEF of >5% and survival free of LVAD and heart transplant. Procedure-related deaths were also collected. Results A total of 298 patients had pre- and appropriately timed post-CRT echocardiograms, of whom 145 (48.7%) met the criteria for response. In multivariate analysis, LV size and left bundle branch block (LBBB) were associated with response. Among the most dilated quintile (LV end-diastolic diameter [LVEDD] of >7.8 cm), 30.4% met the criteria for response. In multivariate analysis, smaller LV end-diastolic dysfunction and presence of LBBB were associated with improved survival free of heart failure and LVAD over a mean follow-up period of 5.2 years. There were no procedure-related deaths. Conclusions Patients with severe LV dysfunction respond to CRT, although at a lower rate compared to traditional CRT candidates. Smaller LV size and LBBB are important predictors of positive outcomes in this population. Even among the most dilated patients, 30.4% realized a meaningful improvement in LVEF with CRT. The CRT implant procedure itself appears well tolerated.

This chapter discusses implantation of pacemakers and implantable cardioverter-defibrillators (ICDs). Patients must have an indication for pacemaker or implantable cardioverter-defibrillator (ICD) according to ACC/AHA guidelines. Once patients are in the EP lab, there should be meticulous attention paid to sterility. The implantation site should be clear of any superficial wounds, be clipped and not shaven, and be prepped with either betadine or chlorohexidine and a head-to-toe drape. Most devices are placed in a left prepectoral pocket since most patients are right-handed and implantation of the leads is easier from the left versus the right side. For ICDs, defibrillation efficacy testing can be performed to assure that the ICD can detect and terminate ventricular fibrillation with an adequate safety margin for defibrillation. After implantation, the device is usually interrogated through the device, for atrial and ventricular sensing, capture thresholds, and impedance. This helps identify problems such as early lead dislodgement or a loose set-screw prior to the patient leaving the lab.

Background Programmed long AV delays and intrinsic long first degree AV block may increase risk for competitive atrial pacing (CAP) in devices without CAP avoidance algorithms. Methods Patients identified with CAP-induced mode switch episodes were followed clinically from September 2013 to August 2019. Attempts to avoid CAP included shortening of postventricular atrial refractory period (PVARP) or postventricular atrial blanking period (PVAB), or change to AAI or DDI modes. After observing associations with sensor-driven pacing, rate response was inactivated in a subset. Results Among 23 patients identified with CAP (22 St Jude Medical [Abbott]; one Boston Scientific Corporation devices), atrial fibrillation (AF) was induced in 12 (52%), lasting 10 seconds to 28 hours and 32 minutes. In one patient with an ICD CAP-induced AF with rapid ventricular rates that triggered a shock, inducing ventricular fibrillation, syncope, and another shock. Changing AV delays and shortening of PVARP failed to resolve CAP. After noting that all had CAP during sensor-driven pacing, rate response was inactivated in seven, resolving further device-induced AF in the three of seven that had prior CAP-induced AF. In two patients with intact AV conduction, AAI(R) pacing resolved further documentation of CAP. Conclusions CAP predominantly occurs during sensor-driven atrial pacing that competes with intrinsic atrial events falling in PVARP. Inactivation of the activity sensor or change to atrial-based pacing modes (AAI/R) appears to effectively prevent induction of device-induced atrial proarrhythmia. Ultimately, a corrective algorithm is needed to avoid CAP-induced proarrhythmia.

Aims Response to cardiac resynchronization therapy (CRT) is known to be associated with a number of clinical characteristics, including QRS duration and morphology, gender, height, and the aetiology of heart failure (HF). We assessed the relation of gender and baseline characteristics with QRS duration and Kansas City Cardiomyopathy Questionnaire. Methods and results AdaptResponse is a global randomized trial. The trial enrolled CRT‐indicated patients with New York Heart Association classes II–IV HF, left bundle branch block (QRS ≥ 140 ms in men, ≥130 ms in women), and baseline PR interval ≤200 ms. In total, 3620 patients were randomized, including 1569 women (43.3%) approaching the actual proportion of women in the HF population. Women were older and more often New York Heart Association class III or IV than men (55.6% vs. 48.7%), had less frequent ischaemic cardiomyopathy (21.2% vs. 39.5%), and had a 5.1 ms shorter QRS duration than men. Women were more often depressed (18.5% vs. 9.7%), had a significantly lower Kansas City Cardiomyopathy Questionnaire score, and had differences in medication prescriptions. Conclusions AdaptResponse is the largest randomized CRT trial and enrolled more women than any other landmark CRT trial. Women differed from men with regard to baseline characteristics and quality of life. Whether these differences translate into clinical outcome differences will be examined further in the AdaptResponse trial.

International audience; Aims Although cardiac resynchronization therapy (CRT) has proven beneficial in several randomized trials, a subset of patients have limited clinical improvement. The AdaptivCRT algorithm provides automated selection between synchronized left ventricular or biventricular pacing with optimization of atrioventricular delays. The rationale and design of the economic analysis of the AdaptResponse clinical trial are described. Rationale The costs associated with HF hospitalization are substantial and are compounded by a high rate of readmission. HF hospitalization payments range from $1,001 for Greece to $12,235 for US private insurance. When examining the breakdown of HF-related costs, it is clear that approximately 55% of the hospitalization costs are directly attributable to length of stay. Notably, the mean costs of a CRT patient in need of a HF-related hospitalization are currently estimated to be an average of $10,679. Methods The economic analysis of the AdaptResponse trial has two main objectives. The hospital provider objective seeks to test the hypothesis that AdaptivCRT reduces the incidence of all-cause re-admissions after a heart failure admission within 30 days of the index event. A negative binomial regression model will be used to estimate and compare the number of readmissions after an index HF hospitalization. The payer economic objective will assess cost-effectiveness of CRT devices with the AdaptivCRT algorithm relative to traditional CRT programming. This analysis will be conducted from a U.S. payer perspective. A decision analytic model comprised of a 6-month decision tree and a Markov model for long term extrapolation will be used to evaluate lifetime costs and benefits. Conclusion AdaptivCRT may offer improvements over traditional device programming in patient outcomes. How the data from AdaptResponse will be used to demonstrate if these clinical benefits translate into substantial economic gains is herein described.

Supplemental Digital Content is available in the text., Background: Current understanding of the impact of cardiac implantable electronic device (CIED) infection is based on retrospective analyses from medical records or administrative claims data. The WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) offers an opportunity to evaluate the clinical and economic impacts of CIED infection from the hospital, payer, and patient perspectives in the US healthcare system. Methods: This was a prespecified, as-treated analysis evaluating outcomes related to major CIED infections: mortality, quality of life, disruption of CIED therapy, healthcare utilization, and costs. Payer costs were assigned using medicare fee for service national payments, while medicare advantage, hospital, and patient costs were derived from similar hospital admissions in administrative datasets. Results: Major CIED infection was associated with increased all-cause mortality (12-month risk-adjusted hazard ratio, 3.41 [95% CI, 1.81–6.41]; P

Heart rate score (HRSc) ≥70%, a novel parameter, predicts risk of mortality in patients with implantable cardioverter-defibrillators and identifies patients who have survival benefit with DDDR vs DDD pacing.The purpose of this study was to determine if DDDR pacing lowers HRSc, and a blended sensor with minute ventilation (MV) and accelerometer (XL) improves HRSc more than accelerometer (XL) alone in patients requiring pacemakers (PMs).HRSc, the percentage of all beats in the tallest 10-beat/min device histogram bin, was calculated. Data from the Limiting Chronotropic Incompetence for Pacemaker Recipients Study, a prospective randomized trial of PM patients, comparing XL to blended-sensor (XL + MV) rate-responsive pacing, were analyzed retrospectively for HRSc changes from baseline. The relationship of patient activity (sensor-detected from device memory) to HRSc was examined.Of the 501 randomized patients, 215 (43%) patients had HRSc ≥70% during DDD pacing at baseline. In these patients, HRSc decreased after DDDR programming by 14.2%, while it increased by 0.4% in those with baseline HRSc70% (n = 286) (HRSc ≥70% vs HRSc70%; P.01). No differences were detected between the 2 randomized sensor-based groups at baseline. Blended-sensor (MV + XL) programming reduced HRSc more than the XL sensor alone (MV + XL: 18% vs XL: 10%; P.001). No correlation was observed between patient activity and HRSc (correlation = -0.14; P = .07).HRSc improved (reduced) with rate-response (DDDR) programming in PM patients with high HRSc during DDD pacing. Blended sensors (MV + XL) improved HRSc more than XL alone. HRSc does not correlate with patient activity levels, suggesting that other patient factors determine this parameter. This programming approach needs to be investigated prospectively in a PM outcomes trial.

Cardiac implantable electronic devices (CIEDs) including pacemakers, implantable cardioverter defibrillators and loop recorders have become widespread adjuncts in the care of patients with cardiovascular disease. CIEDs provide increased diagnostic yield, better quality of life and improved longevity. While there are obvious benefits with these devices, the mere fact that these therapies involve implantation of a foreign device within the body leads to certain risks. The most feared complication associated with CIED use is infection. While the incidence of CIED infection is relatively low for first-time implants, the consequences are serious and involve increased morbidity and mortality despite optimal management. In this review, we discuss preventive practices including a new antimicrobial envelope aimed at reducing the risk of CIED infections.

Background: The World-wide Randomized Antibiotic Envelope Infection Prevention trial reported a 40% reduction in major cardiac implantable electronic device (CIED) infections within 12 months of the procedure with the use of an antibacterial-eluting envelope (TYRX Absorbable Antibacterial Envelope, Medtronic, Mounds View, MN). Objective: The purpose of this report was to describe the longer-term (>12 months) envelope effects on infection reduction and complications. Methods: All trial patients who underwent CIED replacement, upgrade, revision, or initial cardiac resynchronization therapy – defibrillator implantation received standard-of-care infection prophylaxis and were randomized in a 1:1 ratio to receive the envelope or not. CIED infection incidence and procedure and system-related complications were characterized through all follow-up (36 months) by using Cox proportional hazards regression modeling. Results: In total, 6800 patients received their intended randomized treatment (3371 envelope; 3429 control; mean follow-up period 21.0 ± 8.3 months). Major CIED-related infections occurred in 32 envelope patients and 51 control patients (Kaplan-Meier [KM] estimate 1.3% vs 1.9%; hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.41–0.99; P = .046). Any CIED-related infection occurred in 57 envelope patients and 84 control patients (KM estimate 2.1% vs 2.8%; HR 0.69; 95% CI 0.49–0.97; P = .030). System- or procedure-related complications occurred in 235 envelope patients and 252 control patients (KM estimate 8.0% vs 8.2%; HR 0.95; 95% CI 0.79–1.13; P < .001 for noninferiority); the most common were lead dislodgment (1.1%), device lead damage (0.5%), and implant site hematoma (0.4%). Implant site pain occurred less frequently in the envelope group (0.1% vs 0.4%; P = .067). There were no (0.0%) reports of allergic reactions to the components of the envelope (mesh, polymer, or antibiotics). Conclusion: The effects of the TYRX envelope on the reduction of the risk of CIED infection are sustained beyond the first year postprocedure, without an increased risk of complications.

Aims Implantable cardioverter-defibrillators (ICDs) are key in the prevention of sudden cardiac death, but outcomes may vary by type of device or programming [single chamber (SC) vs. dual chamber (DC)] in patients without a bradycardia pacing indication. We sought to meta-analyse patient outcomes of randomized trials of SC vs. DC devices or programming. Methods and results We searched PubMed, Embase, Scopus, Web of Science, and Cochrane trials databases for relevant studies excluding those published before 2000, involving children, or not available in English. Endpoints included mortality, inappropriate ICD therapies, and implant complications. Endpoints with at least three reporting studies were meta-analysed. We identified eight studies meeting inclusion criteria representing 2087 patients with 16.1 months mean follow-up. Mean age was 62.7 years (SD 1.92); in six studies reporting sex, most patients were male (85%). Comparing patients with a SC or DC ICD or programming, we found similar rates of mortality [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.54-1.68; P = 0.86] and inappropriate therapies (OR 1.46, 95% CI 0.97-2.19; P = 0.07) in five and six studies, respectively. In three studies of SC vs. DC ICDs (but not programming) rates of pneumothorax and lead dislodgement were not different (OR 2.12, 95% CI 0.18-24.72; P = 0.55 and OR 0.87, 95% CI 0.32-2.47; P = 0.83, respectively). Conclusion In this meta-analysis of randomized controlled trials comparing SC vs. DC ICD device or programming, there was no significant difference in inappropriate therapies, mortality, pneumothorax, or lead dislodgement. Future studies should compare these devices over longer follow-up and in specific patient populations.

Purpose: To discover oculofacial plastic surgeon practice patterns for cautery selection in the setting of implantable electronic devices and present guidelines based on a review of current literature. Methods: A 10-Question web-based survey was sent to the email list serve of the American Society of Ophthalmic Plastic and Reconstructive Surgery to determine surgeon cautery preference in the setting of various implantable electronic devices and comfort level with the guidelines for cautery selection in their practice or institution. The relationship between survey questions was assessed for statistical significance using Pearson’s Chi-square tests. Results: Two hundred ninety-three (41% response rate) surveys were completed and included for analysis. Greater than half of respondents either had no policy (36%) or were unaware of a policy (19%) in their practice or institution regarding cautery selection in patients with a cardiac implantable electronic device. Bipolar cautery was favored for use in patients with a cardiac implantable electronic device (79%–80%) and this number dropped in patients with implantable neurostimulators (30%). Overall, one-third of respondents did not feel comfortable with their practice/institution policy. Conclusion: Choices and comfort level among oculofacial plastic surgeons for cautery selection in patients with implantable electronic devices vary considerably, and some choices may increase the risk for interference-related complications. Practice patterns vary significantly in the setting of a neurostimulator or cochlear implant, where interference can cause thermal injury to the brain and implant damage, respectively. Guidelines are proposed for cautery selection in patients with implantable electronic devices undergoing oculofacial plastic surgery.

With increasing use of cardiovascular implantable electronic devices, the need for lead extractions has increased to an annual volume of more than 10,000 extractions worldwide. This article provides a focused clinical commentary on the perioperative management, identification, and treatment of life-threatening complications associated with lead extractions. In addition, a summary of indications, techniques, and lead extraction complications is provided. Although uncommon, lead extractions are associated with a consistent rate of major procedure-related complications and mortality. Major life-threatening complications include vascular laceration, cardiac avulsion, hemothorax, pericardial effusion, and cardiac arrest. Comprehensive preoperative risk assessment and adequate planning and preparedness are crucial to decreasing all procedure-related adverse events. The location of the procedure (electrophysiology suite v hybrid operating room) and the nature of cardiac surgical backup are determined after meticulous risk stratification. In addition to decisions on vascular access, invasive monitoring, and modality of rhythm support, transesophageal echocardiography plays a crucial role in early diagnosis, timely management, and potential prevention of these complications.

Background Limited medical options are available for rhythm control in patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM). There are no published reports of dofetilide use in this population. Methods A retrospective chart review was conducted on 1,404 patients loaded on dofetilide for AF suppression at the Cleveland Clinic from 2008 to 2012, 25 of whom were found to have HCM. Results The HCM cohort was 32% female, 76% with persistent AF, mean age of 59 ± 10 years, and mean ejection fraction of 54 ± 9 %. Of the 25 patients, 21 were discharged on dofetilide, three discontinued during loading due to QTc prolongation, and one due to inefficacy. There were no adverse events during loading. Of those discharged on dofetilide, 11/21 (52%) were still on it at a median follow-up of 396 (198, 699) days at the time of the chart review. For those in whom it was discontinued, the median time on the drug was 301 (111, 738) days. Of the 10 patients who discontinued dofetilide during follow-up, six were due to inefficacy, one postablation, one postheart transplant, one due to death secondary to lung cancer, and one due to worsening edema. Conclusions Dofetilide was well tolerated in this group of patients with AF and HCM and it facilitated management of AF in 21/25 (84%) patients. Further research is needed to assess the safety and efficacy of dofetilide in order to develop evidence-based guidelines for the pharmacological management of AF in this population.

Background The major complication rate of transvenous lead extraction (TLE) is estimated to be 1%–2%. Laceration of the central veins can be fatal. Objectives To define the incidence and extent of venous injuries on a microscopic level after TLE and compare these data with those of clinically documented events of venous laceration. Methods We studied all patients who underwent TLE at our tertiary center within 30 months via a variety of techniques. Extracted leads and tissue around them were fixed in formalin. Pathologic examination was standardized to examine the leads identifying the areas covered by tissue cuffs along the length of the lead. The cuffs were removed and sectioned transversely to their longitudinal axis. Microscopic examination was performed using hematoxylin and eosin stains and Movat stains to identify the presence of vein tissue. Results In all, 861 leads (585 pacemaker and 272 defibrillator leads) were extracted from 461 patients (median age 63 years, standard deviation 15 years), with an average of 1.9 leads per patient and a median lead age of 2546 days. On microscopic review, 80 leads (9.3%) in 72 of 461 patients (15.6%) showed segments of vein, most of which were transmural (venous tissue including adventitia). Despite this finding, only 5 catastrophic complications (1.1%) occurred that required emergent surgical intervention. Risk factors for venous injury included implantable cardioverter defibrillator lead, age of lead, and the use of laser sheath. Conclusions Microscopic venous injuries during lead extraction are common but often not recognized clinically.

Superior vena cava (SVC) syndrome is a rare complication of transvenous pacemaker implantation. Treatment strategies include endovascular stenting and open SVC reconstruction. In either case, the need for implantation of new pacing leads can present clinical challenges. Here we present the first reported use of a surgically placed leadless pacemaker for the treatment of pacemaker-induced SVC syndrome.

International audience

New-onset complete heart block (CHB) commonly complicates cardiac surgery, for which some patients require a permanent pacemaker (PPM). Little is known regarding late atrioventricular (AV) conduction recovery.The purpose of this study was to characterize the incidence and predictors of late AV conduction recovery among patients requiring PPM after cardiac surgery.Consecutive patients receiving PPM for CHB after cardiac surgery at a high-volume U.S. center from 2000 to 2014 were evaluated. The primary outcome was late AV conduction recovery, defined as a reduction in ventricular pacing requirement to10% beyond 1 month postimplant. Regression analysis was performed to evaluate predictors of AV recovery.Among 301 patients evaluated over 4 ± 4 years of follow-up, the incidence of late AV conduction recovery was 12% (n = 37), for whom the median ventricular pacing requirement decreased from 96% at implant to1% at 6 months and persisted throughout study follow-up. AV recovery was less common when preoperative conduction abnormalities were present, including no recovery among patients with preoperative PR200 ms and QRS120 ms (n = 42). Multivariable analysis identified only female sex and transient AV conduction postoperatively as independent predictors of recovery (odds ratio 3.5; P.01 for each). Neither cardiac surgery subtype nor PPM implant timing postoperatively was significantly associated with recovery.Late AV conduction recovery is not uncommon after cardiac surgery, occurring in 1 of 8 patients within 6 months postoperatively. Preoperative AV conduction abnormalities were associated with decreased recovery, whereas female sex and transient postoperative AV conduction were associated with increased recovery.

Although the influence of QRS duration (QRSd) and/or bundle branch block morphology on outcomes of cardiac resynchronization therapy (CRT) have been well studied, the effect of PR interval remains uncertain.The purpose of this study was to evaluate the impact of PR prolongation (PRp) before CRT on long-term outcomes, specifically taking into account bundle branch block morphology and QRSd.We extracted clinical data on consecutive patients undergoing CRT. Multivariate models were constructed to analyze the effect of PRp (≥200 ms) on the combined endpoint of death, heart transplant, or left ventricular assist device. Kaplan-Meier curves were constructed stratifying patients based on bundle branch block and QRSd (dichotomized by 150 ms).Of the 472 patients who met inclusion criteria, 197 (41.7%) had PR interval ≥200 ms. During follow-up (mean 5.1 ± 2.6 years) there were 214 endpoints, of which 109 (23.1%) occurred in patients with PRp. In multivariate analysis, PRp was independently associated with worsened outcomes (hazard ratio 1.34, 95% confidence interval 1.01-1.77, P = .04). When stratified by bundle branch block morphology, PRp was significantly associated with worsened outcomes (log-rank P.001) in patients with LBBB but not in those with non-LBBB (log-rank P = .55). Among patients with LBBB, stratified by QRSd, patients without PRp had improved outcomes compared to those with PRp independent of QRSd (log-rank P.001).PRp is an independent predictor of impaired long-term outcome after CRT among patients with LBBB but not in non-LBBB patients. Notably, among LBBB patients, PRp is a more important predictor than QRSd in assessing long-term outcomes.

The AdaptResponse trial is designed to test the hypothesis that preferential adaptive left ventricular-only pacing with the AdaptivCRT® algorithm reduces the incidence of the combined endpoint of all-cause mortality and intervention for heart failure (HF) decompensation, compared with conventional cardiac resynchronization therapy (CRT), among patients with a CRT indication, left bundle branch block (LBBB) and normal atrioventricular (AV) conduction. The AdaptResponse study is a prospective, randomized, controlled, single-blinded, multicentre, clinical trial (ClinicalTrials.gov Identifier: NCT02205359), conducted at up to 200 centres worldwide. Following enrolment and baseline assessment, eligible subjects will be implanted with a CRT system containing the AdaptivCRT algorithm, and randomized in a 1:1 fashion to either a treatment ('AdaptivCRT') or control ('Conventional CRT') group. The study is designed to observe a primary endpoint in 1100 patients ('event-driven') and approximately 3000 patients will be randomized. The primary endpoint is the composite of all-cause mortality and intervention for HF decompensation; secondary endpoints include all-cause mortality, intervention for HF decompensation, clinical composite score (CCS) at 6 months, atrial fibrillation, quality of life measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), health outcome measured by the EQ-5D instrument, all-cause readmission after a HF admission, and cost-effectiveness. The AdaptResponse clinical trial is powered to assess clinical endpoints and is expected to provide definitive evidence on the incremental utility of AdaptivCRT-enhanced CRT systems.

BACKGROUND QRS duration (QRSd) may be impacted by both left ventricular (LV) dilatation and conduction delay. It is possible therefore that the same QRSd may portend significantly different amounts of LV activation delay in patients with small versus large left ventricles. We hypothesized that LV size modifies the effect of QRSd on predicting outcomes in patients undergoing CRT implant. METHODS We extracted data on consecutive patients presenting for initial CRT implant. In patients with a follow-up echocardiogram, response was defined as an absolute improvement in LV ejection fraction ≥5%. Multivariate models were created to determine if left ventricular end-diastolic diameter (LVEDD) modified the effect of QRSd on its association with both long-term survival free of left ventricular assist device (LVAD) and heart transplant and echocardiographic response. RESULTS 464 patients met inclusion criteria. At a mean follow-up of 4.9 ± 2.6 years, there were 210 deaths, 13 heart transplants, and 12 LVAD placements. There was a weak but significant correlation between baseline QRSd and LVEDD (Spearman's Rho 0.106, P < 0.001). In a multivariate analysis, there was no evidence of effect modification of LVEDD on QRSd (LVEDDi*QRS interaction term HR 1.0 [0.995-1.006], P = 0.94). Note that 305 patients had a follow-up echocardiogram, of whom 193 met the criteria for response. In a multivariate analysis, there was no evidence of effect modification of LVEDD on QRSd (LVEDDi*QRS interaction term odds ratio 0.998 (0.988-1.008), P = 0.65). CONCLUSION LV size does not modify the effect of QRSd and its association with outcomes following CRT. The correlation between LV size and QRSd in patients with a QRSd ≥ 120 ms is weak.

Reverse Remodeling Survival CRTBackground Multiple definitions of reverse ventricular remodeling (RVR) employing various changes in left ventricular end-systolic (LVESV) or diastolic volumes (LVEDVs) or left ventricular ejection fraction (LVEF) have been used in determining cardiac resynchronization therapy (CRT) response, making comparability across studies difficult. We compared different metrics to each other, and in combination, in terms of association with long-term outcomes. Methods We collected clinical and echocardiographic data on 436 patients undergoing CRT. LVEF was assessed via a combined volumetric and visual assessment. Volumes were manually traced. Using a nested multivariate model of a priori determined predictors of long-term survival free of left ventricular assist device (LVAD) or heart transplant, multiple definitions of RVR were added to the model individually to determine which provided the best model fit. Results Over a mean follow-up of 5.4 ± 2.3 years, there were 198 endpoints (10 LVADs, 15 heart transplants, and 173 deaths). When added to a nested model controlling for multiple potential confounders, all definitions of RVR were significantly associated with improved survival. Changes in LVEF and LVESV were superior to changes in LVEDV. A combination metric of an LVEF improvement ≥ 5% and LVESV reduction ≥ 10% was the best overall metric for model fit. Conclusions Changes in LVESV and LVEF are better predictors of long-term outcome following CRT compared to changes in LVEDV. Adding an assessment of LVEF to reduction in LVESV ≥ 10% provided the best overall definition for RVR in predicting CRT outcomes.