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Background Ventricular tachyarrhythmias (VTA) with low and varying signal amplitudes and morphologies may not be successfully identified utilizing traditional implantable cardioverter defibrillator algorithms. Objective Develop and validate a novel algorithm (VF Therapy Assurance, VFTA) to improve detection and timely delivery of high voltage therapy (HVT) for these arrhythmias. Method Arrhythmia detection was simulated on recorded VTA electrograms (EGMs) utilizing Abbott's Merlin.net database. EGMs where an HVT occurred only when VFTA was enabled, or where VFTA provided an HVT >30 seconds earlier than without VFTA were re-adjudicated with physician review. As VFTA never prevents detection or therapy, EGMs where VFTA didn't activate or alter HVT were not adjudicated. Results Among 564,353 recorded VTA EGMs from 20,000 devices, VFTA altered HVT in 105 EGMs from 67 devices. Physician adjudication determined that 81.9% (86/105) of these EGMs were true undertreated VTA episodes and would have received appropriate HVT with VFTA enabled. Furthermore, 65% (56/86) of the episodes were ventricular fibrillation, polymorphic, did not self-terminate during the recording window, or not amenable anti-tachycardia pacing. 87.5% (49/56) would not have elicited HVT without VFTA. Overall, VFTA provided new or earlier appropriate HVT in 0.27% (53/20,000) of devices with an increase in inappropriate HVT in 0.07% (14/20,000) devices. Conclusion The VFTA algorithm successfully identifies VTA missed by traditional detection algorithms, due to undersensed ventricular signals resulting in rate falling below the programmed detection rate. The use of VFTA increases the likelihood of delivering life-saving HVT.

IntroductionChemotherapy-induced cardiomyopathy has been increasingly recognised as patients are living longer with more effective treatments for their malignancies. Anthracyclines are known to cause left ventricular (LV) dysfunction. While heart failure medications are frequently used, some patients may need consideration for device-based therapies such as cardiac resynchronisation therapy (CRT). However, the role of CRT in anthracycline-induced cardiomyopathy (AIC) is not well understood.MethodsWe performed a retrospective review of all patients undergoing CRT implantation at our centre from 2003 to 2019 with a diagnosis of AIC. The LV remodelling and survival outcomes of this population were obtained and then compared with consecutive patients with other aetiologies of non-ischaemic cardiomyopathy (NICM).ResultsA total of 34 patients underwent CRT implantation with a diagnosis of AIC with a mean age of 60.5±12.7 years, left ventricular ejection fraction (LVEF) of 21.7%±7.4%, and 11.3±7.5 years and 10.2±7.4 years from cancer diagnosis and last anthracycline exposure, respectively. At 9.6±8.1 months after CRT implantation, there was an increase of LVEF from 21.8%±7.6% to 30.4%±13.0% (pConclusionsPatients with AIC undergo LV remodelling with CRT at rates similar to other aetiologies of NICM. Furthermore, AIC post-CRT responders have a favourable long-term mortality compared with non-responders.

Background: Heart rate score (HrSc) ≥70% in cardiac resynchronization therapy defibrillator and implantable cardioverter-defibrillator subjects predicts 5-year mortality risk. A high HrSc suggests few sensed cardiac cycles above the programmed lower rate. Objective: To determine if HrSc is related to chronotropic incompetence (CI) in pacemaker (PM) subjects. Methods: HrSc is the percentage of all atrial-paced and sensed events in the single tallest 10 beats/min histogram bin programmed to DDD 60/min. The prospective LIFE study of PM subjects examined multiple treadmill-based measures of CI. The 1-month postimplant DDD 60/min PM rate histogram prior to treadmill was retrospectively analyzed for HrSc. Measures of CI were applied to submaximal treadmill data in the DDD mode. HrSc was compared to these CI measures and to clinical indications for PM. Results: The 1-month histogram demonstrated HrSc ≥70% in 43% of subjects. HrSc ≥70% correlated with a clinical diagnosis of sick sinus syndrome (P < .001). CI was present in 34%–88% of subjects by treadmill-based measures. Agreement between treadmill-based measures for CI was poor and varied from 39% to 83%. HrSc ≥70%, as a measure of CI, was most highly correlated with unpaced heart rate

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).

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.

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.

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

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.

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: 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.

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.

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.

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.

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.

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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.

Background:We hypothesized that survival in implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) patients is predicted by baseline Heart Rate Score.Methods:Heart Rate Score is determined from the atrial paced and sensed histogram of a DDD ICD or CR

Expanded indications for cardiac resynchronization therapy and the increasing incidence of cardiac implantable electronic device infection have led to an increased need for coronary sinus (CS) lead extraction. The CS presents unique anatomical obstacles to successful lead extraction. Training and facility requirements for CS lead extraction should mirror those for other leads. Here we review the indications, technique, and results of CS lead extraction. Published success rates and complications are similar to those reported for other leads, although multiple techniques may be required. Re-implantation options may be limited, which should be incorporated into pre-procedural decision making.

Right ventricular (RV) pacing may worsen left ventricular cardiomyopathy in patients with reduced left ventricular ejection fraction (LVEF) and advanced atrioventricular block.The objectives of this study were to calculate incidence and identify predictors of RV pacing-induced cardiomyopathy (PICM) in complete heart block (CHB) with preserved LVEF and to describe outcomes of subsequent cardiac resynchronization therapy (CRT) upgrade.An analysis of consecutive patients receiving permanent pacemaker (PPM) from 2000 to 2014 for CHB with LVEF50% was performed. PICM was defined as CRT upgrade or post-PPM LVEF ≤40%. PICM association was determined via multivariable regression analysis. CRT response was defined by LVEF increase ≥10% or left ventricular end-systolic volume decrease ≥15%.Of the 823 study patients, 101 (12.3%) developed PICM over the mean follow-up of 4.3 ± 3.9 years, with post-PPM LVEF being 33.7% ± 7.4% in patients with PICM vs 57.6% ± 6.1% in patients without PICM (P.001). In multivariable analysis, lower pre-PPM LVEF (hazard ratio [HR] 1.047 per 1% LVEF decrease; 95% confidence interval [CI] 1.002-1.087; P = .042) and RV pacing % both as a continuous (HR 1.011 per 1% RV pacing; 95% CI 1.002-1.02; P = .021) and as a categorical (20% or ≥20% RV pacing) (HR 6.76; 95% CI 2.08-22.0; P = .002) variable were independently associated with PICM. Only 29 patients with PICM (28.7%) received CRT upgrade despite an 84% responder rate (LVEF increase 18.5% ± 8.1% and left ventricular end-systolic volume decrease 45.1% ± 15.0% in responders). CRT upgrade was associated with greater post-PPM LVEF decrease, lower post-PPM LVEF, and post-PPM LVEF ≤35% (P = .006, P = .004, and P = .004, respectively).PICM is not uncommon in patients receiving PPM for CHB with preserved LVEF and is strongly associated with RV pacing burden20%. CRT response rate is high in PICM, but is perhaps underutilized.

BACKGROUND Cardiac resynchronization therapy (CRT) is indicated in patients with medically refractory heart failure and wide QRS duration. While much is known about predictors of left ventricular (LV) remodeling after CRT implantation and short-term mortality, limited data exist on long-term outcomes after CRT placement. METHODS We retrospectively reviewed all patients undergoing CRT implantation at our center between 2003 and 2008 and examined mortality using institutional electronic records, social security death index, and online obituary search. We included only patients with preimplant echoes with LV ejection fraction (LVEF) 35% or below. Variable selection was performed using stepwise regression and models were compared using goodness-of-fit criteria. A final model was validated with the bootstrap regression method. RESULTS Out of the 877 CRT patients undergoing implantation during this time, 287 (32.7%) survived longer than 10 years. Significant (P

Heart Rate Score (HrSc), a novel index found to predict mortality in patients with implantable defibrillator (ICD) and cardiac resynchronization defibrillator (CRT-D) devices, is associated with mortality in ICD and CRT-D recipients when HrSc is ≥ 70%. Implantable defibrillator shocks have also been associated with increased mortality in ICD and CRT-D recipients. The objective of this study was to evaluate the relationships between HrSc, shocks, and mortality in ICD and CRT-D patients.HrSc was calculated from atrial sensed and paced rate histograms collected from the 2006-2011 ALTITUDE remote interrogation database. Shocks were determined in the first year of follow-up. Mortality was assessed over the next 4 years by the Social Security Death Index. Four multivariable models were run: ICD and CRT-D, shock and no shock, with mortality as the outcome and HrS as predictor.Data from 49,358 ICD and 55,953 CRT-D patients were divided into HrSc: ≥ 70%, 30-69%, and 30%. Shock rates differed between HrSc groups (p 0.001) for ICD and CRT-D patients. However, the lowest mortality risk HrSc ( 30%) had the highest shock rate. Both highest HrSc ( 70%; p 0.001) and shocks (p 0.001) predicted mortality during follow-up. Mortality was unrelated to interactions between HrSc and shocks in ICD patients (p = 0.275) or CRT-D patients (p 0.079). Comparing HrSc ≥ 70% to HrSc 30%, HrSc ≥ 70% predicted mortality in CRT-D (HR 1.40; 95% CI 1.29-1.52) and ICD (HR 1.23; 95% CI 1.11-1.36) patients regardless of shocks (P 0.001 for both).Patients with ICDs or CRT-Ds having the lowest mortality risk HrSc had the highest shock rate. Shocks and HrSc appear to complement each other as predictors of mortality.

OBJECTIVES To develop a protocol for using a pre-existing, permanent pacemaker or defibrillator device for rapid ventricular pacing during transcatheter valve procedures and demonstrate feasibility. BACKGROUND Placement of a passive fixation, temporary pacemaker wire is considered routine during most transcatheter valve procedures to facilitate controlled or rapid ventricular pacing at the time of balloon expansion or valve deployment. Many patients presenting for such procedures have a pre-existing, permanent pacemaker or defibrillator device which could be used for the same function, obviating the need for temporary pacemaker wire placement. METHODS We developed a strategy for rapid pacing from the pre-existing device using a programmer during transcatheter valve procedures in consecutive patients over a 3-month period. Complications and clinical outcomes were recorded. RESULTS There were 135 transcatheter valve procedures performed during the study. Of these, 28 (20.7%) had pre-existing devices (17 transcatheter aortic valve replacement, 3 aortic valve-in-valve, 2 mitral valve-in-valve, and 6 balloon aortic valvuloplasty). All patients underwent rapid ventricular pacing using a commercially available device programmer. There were no adverse events related to device pacing and no patients required placement of a temporary pacemaker wire during the procedure. At 30-days follow-up, there were no deaths, one major vascular complication related to arterial access, and one patient with renal failure requiring dialysis. CONCLUSION Pacing from a commercially available device programmer is safe, feasible, and may reduce both procedural cost and complications such as cardiac tamponade by avoiding placement of a temporary pacemaker lead during transcatheter valve procedures.

Cardiac resynchronization therapy (CRT) has been shown to improve survival in patients with systolic heart failure, wide QRS duration, and left-bundle-branch-block. However, CRT outcomes stratified by right ventricular (RV) function at implant have not been well studied.We retrospectively reviewed patients at Cleveland Clinic who underwent CRT implantation (n = 777) from 2003 to 2011 with a diagnosis of heart failure, echocardiography with both pre-CRT left ventricular ejection fraction (LVEF) ≤35% and available post-CRT echocardiography at 6 months post-implant. CRT response was defined as LVEF improvement ≥5%. Patients were separated into 2 groups: normal or mild RV dysfunction (n = 570) labeled Normal RV; moderate to severe dysfunction (n = 207) labeled RV DYSFXN based on qualitative echocardiography assessment. Survival was calculated as time from CRT implant to death, left ventricular assist device implant, or heart transplant.CRT response was significantly higher in patients with Normal RV (67%) compared with patients with RV DYSFXN (56%; P = .006). Kaplan-Meier analysis showed that CRT patients with Normal RV had significantly greater survival compared with patients with RV DYSFXN (P.001). In multivariable Cox regression accounting for a priori covariates, RV DYSFXN was associated with worse survival (HR 1.41 [95% CI: 1.14-1.75], P = .002) and lower CRT response (HR 0.66 [95% CI: 0.44-0.97], P = .03).Baseline RV dysfunction at CRT implant is an important predictor of worsened left ventricular remodeling and survival in CRT patients.

The 2015 HRS/EHRA/APHRS/SOLAECE Expert Consensus Statement on Optimal Implantable Cardioverter-Defibrillator Programming and Testing provided guidance on bradycardia programming, tachycardia detection, tachycardia therapy, and defibrillation testing for implantable cardioverter-defibrillator (ICD) patient treatment. The 32 recommendations represented the consensus opinion of the writing group, graded by Class of Recommendation and Level of Evidence. In addition, Appendix B provided manufacturer-specific translations of these recommendations into clinical practice consistent with the recommendations within the parent document. In some instances, programming guided by quality evidence gained from studies performed in devices from some manufacturers was translated such that this programming was approximated in another manufacturer’s ICD programming settings. The authors found that the data, although not formally tested, were strong, consistent, and generalizable beyond the specific manufacturer and model of ICD. As expected, because these recommendations represented strategic choices to balance risks, there have been reports in which adverse outcomes were documented with ICDs programmed to Appendix B recommendations. The recommendations have been reviewed and updated to minimize such adverse events. Notably, patients who do not receive unnecessary ICD therapy are not aware of being spared potential harm, whereas patients in whom their ICD failed to treat life-threatening arrhythmias have their event recorded in detail. The revised recommendations employ the principle that the randomized trials and large registry data should guide programming more than anecdotal evidence. These recommendations should not replace the opinion of the treating physician who has considered the patient’s clinical status and desired outcome via a shared clinical decision-making process.

AV nodal (AVN) ablation is often considered as a last line treatment option in patients with poorly controlled AF. However, small studies have suggested its utility in patients undergoing CRT implantation with concomitant history of AF. Its role in improving LVEF and long term survival is not well

To date, there is no evidence comparing the dosing of dofetilide in obese vs non-obese patients. Dofetilide dosing requires adjustment by glomerular filtration rate (GFR) to maximize effectiveness and avoid adverse events, however the manufacturer recommends to use actual body weight when

Augmentation of the heart rate serves as the primary driver for the heart to increase oxygen delivery during times of increased metabolic demand. Without the ability to increase the heart rate in response to metabolic demands, significant physical limitations develop. Multiple pathological processes and pharmacological agents can impair this chronotropic function of the heart and its natural pacemaker, the sinus node. Exercise testing serves as a useful diagnostic tool to both screen for and diagnose an abnormal chronotropic response. When present, an abnormal chronotropic response of the sinus node carries significant prognostic value regarding mortality and morbidity.

The aims of this study were to detect and quantify acute increases in tricuspid regurgitation (TR) severity following transvenous lead extraction (TLE) and to evaluate the associated risk factors.Although established as a safe and effective method for lead removal, TLE is sometimes complicated by TR.In 208 consecutive patients undergoing TLE, acute changes in TR severity were assessed by transesophageal echocardiography. A significant acute TR increase (TRI) was defined as a ≥1 grade increase in TR severity and post-extraction TR severity that was moderate or greater.Overall, 266 ventricular leads (mean lead age, 11.8 ± 7.3 years) were extracted from the 208 patients. A significant acute TRI was observed in 24 (11.5%) of these patients. Acute TRI was associated with longer lead implant duration, extraction of pacemaker rather than defibrillator leads, anatomic injury to the tricuspid valve (TV), and longer post-extraction hospital stays. Multivariate analysis yielded only lead implant duration as an independent predictor of TLE-related acute TRI (odds ratio: 1.05; 95% confidence interval: 1.01 to 1.11; p = 0.046). When the patients were divided into 4 subgroups according to quartiles of lead age, there was a graded elevation in the rates of acute TRI (p trend = 0.048) and TV injury (p trend = 0.009) with lead implant duration.Following TLE, TV damage and acute TRI were commonly detected by transesophageal echocardiography, particularly in patients with advanced lead age. Lead abandonment strategies, which prolong implantation duration of future leads requiring extraction, should consider the potential long-term deleterious impact on TV function.

Race has seldomly been reported in the major clinical trials of cardiac resynchronization therapy (CRT). When described, African Americans (AAs) were substantially under-represented. This study sought to compare reverse ventricular remodeling and long-term outcomes in AAs versus European Americans (EAs) with advanced heart failure who underwent CRT. We extracted demographic (including race), clinical, and echocardiographic data on patients with advanced heart failure who underwent CRT with a left ventricular ejection fraction (LVEF) ≤35% and a QRS duration ≥120 ms. Long-term outcomes were compared between AAs and EAs. In patients in whom follow-up echocardiograms were available, improvement in LVEF (defined as an absolute improvement ≥5%) was compared between races. From a cohort of 662 patients, there were 88 AAs and 574 EAs. At a mean follow-up of 5.0 ± 2.5 years, survival rate free of left ventricular assist device (LVAD) and heart transplant was 54.5% for AAs and 53.8% for EAs (log-rank p = 0.997). In multivariate analysis, there was no difference in survival free of heart transplant or LVAD based on race (hazard ratio 1.1 [0.74 to 1.56], p = 0.72, EAs race as referent); 424 patients had a follow-up echocardiogram (55.4% EAs and 64.7% AAs). In multivariate analysis, there was no difference in the incidence of response based on race (1.1 [0.6 to 2.1, p = 0.80], EAs as referent). AAs derive similar benefits with CRT compared with EAs in terms of improvement in LVEF and long-term survival free of LVAD and heart transplant.

Background— Although dofetilide is widely used in the United States for rhythm control of atrial fibrillation, there is limited postapproval safety data in the atrial fibrillation population despite its known risk of Torsade de pointes (TdP). Methods and Results— We conducted a retrospective chart review of a cohort of 1404 patients initially loaded on dofetilide for atrial fibrillation suppression at the Cleveland Clinic from 2008 to 2012 to evaluate the incidence and risk factors for in-hospital adverse events and the long-term safety of continued use. Of the 17 patients with TdP during loading (1.2%), 10 had a cardiac arrest requiring resuscitation (1 death), 5 had syncope/presyncope, and 2 were asymptomatic. Dofetilide loading was stopped for 105 patients (7.5%) because of QTc prolongation or TdP. Variables correlated with TdP were (1) female sex, 2) 500-μg dose, (3) reduced ejection fraction, and (4) increase in QTc from baseline. One-year all-cause mortality was higher in patients who continued dofetilide compared with those who discontinued use (hazard ratio, 2.48; 95% confidence interval, 1.08–5.71; P =0.03). Those patients who had a TdP event had higher one-year all-cause mortality than those who did not (17.6% versus 3% at 1 year; P Conclusions— Dofetilide loading has a low but finite risk of TdP and other adverse events that warrant the current Food and Drug Administration–mandated practice of inpatient monitoring during drug loading. In this cohort, all-cause mortality was higher at 1 year in those patients continued on dofetilide and in those patients who experienced TdP while loading.

Background Unnecessary ventricular pacing from cardiac implantable electronic devices has been associated with long-term risks (heart failure, atrial fibrillation, and possibly stroke). Several device programming strategies are available to minimize ventricular pacing, each potentially associated with unintended consequences. Occasionally, the only effective means is to program to the AAI(R) pacing mode. However, in one manufacturer's implantable cardioverter defibrillators (ICDs), the AAI(R) mode has the potential risk of prolonged pacing cessation following a nonsustained ventricular tachycardia (NSVT). Method Patients with ICDs, managed through the Cleveland Clinic device clinic, follow the Heart Rhythm Society consensus document recommendations for device monitoring with remote interrogations (every three months) and yearly in-person evaluations. Clinically significant findings also trigger additional evaluations by the nurse and physician. Results Two patients having Boston Scientific ICDs (E110 Teligen 100; Boston Scientific Corp., Natick, MA, USA), had asystole and marked bradycardia following untreated NSVT. These pauses in pacing were due to use of the AAI(R) pacing mode. In order to enhance ventricular tachycardia detection, by design atrial pacing is disabled during, and for a time after, an episode of ventricular tachycardia when the device operates in the “ventricular tachycardia response” (VTR) phase. Thus, following spontaneous termination of the NSVT, no pacing occurred in these patients until the VTR period ended. Nonconventional programming was utilized to permit AAI(R) pacing while avoiding these asystolic and bradycardic events during VTR. Conclusions Unintended consequences can occur when complex VT detection parameters interact with specific pacing modes. At times, nonconventional programming can avoid these interactions while still achieving effective AAI(R) pacing.

Biventricular pacing (BVP) may not achieve complete electrical resynchronization.The purpose of this study was to assess whether the resynchronizing effect of BVP varies among patients depending on the underlying electrical substrate.High-resolution electrocardiographic mapping with invasive measurement of the maximal rate of systolic left ventricular (LV) pressure rise (LVdP/dtmax) was performed during baseline activation and during BVP in 61 patients with heart failure with various conduction delays: 13 with narrow QRS duration (120 ms), 22 with nonspecific intraventricular conduction disturbance, and 26 with left bundle branch block. Electrical dyssynchrony, both during baseline activation and BVP, was quantified by total and LV activation times (TAT and LVTAT) and by ventricular electrical uncoupling (VEU = mean LVTAT - mean right ventricular activation time). Response to BVP was defined as a ≥10% increase in LVdP/dtmax.The electrical activation pattern during BVP was similar for all patient groups and, hence, not dependent on baseline conduction disturbance. During BVP, TAT, LVTAT, and VEU were similar for all groups and were either not correlated or weakly correlated with the change in LVdP/dtmax. In contrast, changes in electrical dyssynchrony correlated significantly with the change in LVdP/dtmax: r=0.71, 0.69, and 0.69 for ∆TAT, ∆LVTAT, and ∆VEU, respectively (all P.001). Responders showed higher baseline dyssynchrony levels and BVP-induced dyssynchrony reduction than did nonresponders (all P.001); in nonresponders, BVP worsened activation times than did baseline activation.BVP does not eliminate electrical dyssynchrony, but rather brings it to a common level independent of the patient's underlying electrical substrate. Therefore, BVP is of benefit to patients with dyssynchrony but not to patients with insufficient electrical dyssynchrony in whom it induces an iatrogenic electropathy.

Background A novel technology incorporates electrodes into an iPhone case that records an electrocardiographic tracing. Objectives The objectives of this study were to examine the feasibility and efficacy of this technology to monitor patients after the atrial fibrillation (AF) ablation procedure and to assess patients' feedback on its ease of use. Methods Patients with AF undergoing ablation who had iPhones were screened for enrollment. They were provided with an AliveCor heart monitor (AHM) case and a traditional transtelephonic monitor (TTM). Patients were asked to record their rhythm using both monitors simultaneously whenever they had symptoms or at least once a week. AHM recordings were sent to a secure e-mail account, and TTM recordings were transmitted to our Holter laboratory using landlines. All AHM recordings were reviewed by 1 of 2 blinded electrophysiologists. TTM recordings were reviewed by the primary electrophysiologist. The κ coefficient was calculated to assess agreement between AHM and TTM recordings. Sensitivity and specificity for the detection of AF and atrial flutter with the AHM compared to the TTM were calculated. Results Sixty patients were enrolled (mean age 60 ± 12 years), and 55 completed the study. There were 389 simultaneous AHM and TTM recordings. The κ statistic was 0.82, indicating excellent agreement between AHM and TTM recordings. If we consider AF and atrial flutter as one diseased state, the AHM had 100% sensitivity and 97% specificity for the detection of AF and atrial flutter. Only 2% of patients found it difficult to use the AHM, and the large majority (92%) preferred to use the AHM to monitor their AF as opposed to the TTM. Conclusion The AHM is an alternative method for monitoring patients with AF after the ablation procedure. Most patients found it easy to use.

Background: Although dofetilide labeling states that the drug must be initiated or reinitiated with continuous electrocardiographic monitoring and in the presence of trained personnel, the risks of dofetilide reloading justifying repeat hospitalization have not been investigated. Methods and Results: Patients admitted for dofetilide reloading for atrial arrhythmias were retrospectively reviewed. The need for dose adjustment and the incidence of torsades de pointes (TdP) were identified. The incidence of TdP in dofetilide reloading was compared with patients admitted for dofetilide initial loading. Of 138 patients admitted for dofetilide reloading for atrial arrhythmias, 102 were reloaded at a previously tolerated dose, 30 with a higher dose from a previously tolerated dose and 2 at a lower dose; prior dosage was unknown in 4 patients. Dose adjustment or discontinuation was required in 44 patients (31.9%). No TdP occurred in the same dose reloading group, but TdP occurred in 2 patients admitted to increase dofetilide dosage (0% versus 6.7%; P =0.050). Dofetilide dose adjustment or discontinuation was required in 30 of 102 patients (29.4%) reloaded at a previously tolerated dose and in 11 of 30 patients (36.7%) admitted for an increase in dose. Conclusions: Although no TdP occurred in patients admitted to reload dofetilide at the same dose as previously tolerated, dosage adjustments or discontinuation was frequent and support the need for hospitalization for dofetilide reloading. Patients admitted for reloading with a higher dose tended to be at higher risk for TdP than patients reloaded at a prior tolerated dose.

Background— We classified patients’ atrial fibrillation (AF), assessed its impact on biventricular pacing (BIVP%), and determined whether AF classification or BIVP% independently correlate with mortality in cardiac resynchronization therapy defibrillator patients. Methods and Results— Cardiac resynchronization therapy defibrillator patients were classified as permanent (daily mean AF burden ≥23 hours), persistent (≥7 consecutive days of AF ≥23 hours/d), paroxysmal (≥1 day with AF ≥6 hours), or no/little AF (all others) using device-detected AF during the 6 months postimplant. We evaluated subsequent all-cause mortality using a multivariable Cox proportional hazard regression. Among 54 019 patients (age, 70±11 years; 73% male; follow-up, 2.3±1.2 years), 8% of patients each had permanent (N=4449), persistent (N=4237), and paroxysmal AF (N=4219). A high proportion of patients with permanent (69%) and persistent (62%) AF did not achieve high BIVP (>98%). Relative to no/little AF, patients with AF had increased mortality after adjusting for age, sex, BIVP, and shocks (permanent: hazard ratio=1.28 [1.19–1.38]; P P 98%, patients with reduced BIVP had increased mortality after adjusting for age, sex, AF, and shocks (90%–98%: hazard ratio=1.20 [1.15–1.26]; P P Conclusions— High BIVP% was not achieved in two thirds of 8686 patients with persistent or permanent AF, and these patients had an increased risk of death. A shift toward more aggressive rate control and more pacing may be necessary in patients with AF to maximize the benefits of cardiac resynchronization therapy.

Background Although improvement in left ventricular (LV) function has been shown to portend superior short-term outcomes in patients with heart failure undergoing cardiac resynchronization therapy (CRT), the durability of this effect at 5 years has not been established. Objective To determine the long-term outcomes of patients undergoing CRT on the basis of the degree of echocardiographic response. Methods We extracted clinical data on a cohort of 880 consecutive patients undergoing the new implantation of a CRT device between September 30, 2003, and August 6, 2007. Patients with an ejection fraction (EF) ≤35% undergoing initial CRT implantation, with an available pre-CRT and follow-up echocardiogram, were included in the final cohort. On the basis of changes in LVEF, patients were categorized into "nonresponders" (change in EF ≤4%), "responders" (EF change 5%–20%), and "super-responders" (change in EF >20%). A Cox multivariate model was performed to determine the effect of response on long-term survival free of LV assist device or heart transplant. Results A total of 526 patients met inclusion criteria, of whom 196 (37.3%) were classified as nonresponders, 236 (44.9%) as "responders," and 94 (17.9%) as "super-responders." In multivariate analysis, "super-responders" had the best survival and nonresponders the worst over a mean of follow-up of 5.3 ± 2.4 years. At 5 years, survival free of LV assist device or heart transplant among super-responders was 82%; responders, 70%; and nonresponders, 48%. Conclusions In patients with heart failure undergoing CRT, survival benefit is durable at 5 years of follow-up and its degree intimately tied to the level of improvement in ventricular function. The prognosis of nonresponders is exceptionally poor.

There is scant data about outcomes in patients with left ventricular epicardial (LVE) leads who develop endocarditis or device-related infection. This retrospective study evaluated mortality and recurrence of infection among patients with LVE leads in comparison to patients with endovascular coronary sinus (CS) leads after the development of endocarditis or device-related infection. Patients with cardiac resynchronization therapy (CRT) devices who developed endocarditis or pocket infection over 5 years at Cleveland Clinic were included in the study. The groups were all patients with LVE leads versus CRT devices without epicardial leads that developed endocarditis or pocket infection. Mortality was assessed using the Social Security Death Index and re-infection was assessed by reviews of the medical record. Prospective extraction of the CRT device and leads occurred among all 50 patients with CS leads and 8 of the 14 patients with LVE leads. The survival rate was 92.9 versus 92 % and freedom from re-infection rate was 64.3 versus 80 % in the patients with LVE leads versus CS leads, respectively, over 1 year (P value = 0.918 and 0.226, respectively). At 3 years, the survival rate in LVE lead group was 92.9 % and freedom from re-infection rate was 64.3 % in comparison to survival rate of 90 % and freedom from re-infection rate of 68 % in the CS group (P value = 0.751 and 0.798, respectively). After development of endocarditis or pocket infection, no statistically significant differences were seen in mortality, or recurrent infection between patients with LVE leads and those with CS leads.

Owing to potential patient harm, magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices has traditionally been contraindicated. Following the EnRhythm MRI SureScan Study, an MR conditional pacemaker with modified leads was approved by the Food and Drug Administration. Electrical and handling characteristics of MR conditional pacing leads compared with those of traditional leads have not been established.To compare short- and long-term performance of the Medtronic 5086MRI lead with that of the Medtronic 5076 lead.Patients (n = 466) implanted with 2 5086MRI leads (EnRhythm MRI Study) and 316 patients implanted with 2 5076 leads in 2 prospective clinical investigations were analyzed.Electrical characteristics were stable in both groups at implant and at 12 months and were clinically acceptable throughout. Ventricular capture thresholds were slightly higher at 12 months for the 5086MRI lead than for the 5076 lead (0.93 ± 0.47 V vs 0.74 ± 0.42 V; P.001). Ventricular sensing amplitudes for the 5086MRI lead were lower at implant (9.0 ± 4.7 mV vs 13.9 ± 6.9 mV; P.001) and 12 months (9.8 ± 4.8 mV vs 15.4 ± 7.5 mV; P.001) than for the 5076 lead. There was no statistical difference in lead handling. At 12 months, the estimated right atrial lead-related complication-free survival rate was 99.3% for the 5086MRI lead and 99.6% for the 5076 lead (log-rank P = .65), and the estimated right ventricular lead-related complication-free survival rates were 98.5% and 100% (log-rank P = .03). Acute lead dislodgments occurred in 12 patients with the 5086MRI leads (2.6%) compared with 2 patients with 5076 leads (0.6%) (p = .05) than in 0.6% of the patients with the 5076 lead (P = .05).The 5086MRI lead demonstrates clinically acceptable electrical characteristics while providing safe access to MR-guided diagnostics. However, compared with the 5076 lead, the 5086MRI lead exhibits lower ventricular sensing, slightly higher ventricular capture thresholds, and higher acute lead dislodgement rate.

Prediction Rule to Identify Patients at High Risk for Early Demise Following CRT Background In patients with advanced heart failure, the decision of whether to pursue cardiac resynchronization therapy (CRT) or to proceed directly to advanced heart failure therapies can be challenging. We sought to create a prediction rule to identify patients with advanced systolic heart failure at heightened risk of rapid deterioration despite receiving CRT. Methods Clinical data were collected on consecutive patients with advanced heart failure presenting for a new CRT device at the Cleveland Clinic between February 12, 2002 and July 8, 2008. Early demise was defined as death, left ventricular assist device, or heart transplant within 6 months following CRT implant. Using a multivariate model, variables associated with early demise were identified and a prediction rule created. Results A total of 879 patients were included of whom 47 met criteria for early demise. Using forward stepwise regression followed by a bootstrapping analysis, the final model included: left ventricular end-diastolic diameter ≥6.5 cm (OR 3.23 [1.72–6.06 g], P < 0.001), the presence of a non-left bundle branch block (non-LBBB) morphology (OR 2.18 [1.18–4.04, P = 0.013]), creatinine ≥1.5 mg/dL (OR 2.98 [1.52–5.49], P < 0.001), and lack of or intolerance to β-blocker use (OR 2.80 [1.46–5.39], P = 0.002). The specificity for ≥2 and ≥3 risk factors was 72.6% and 94.6%, respectively. Conclusions Left ventricular dilatation, the presence of a non-LBBB morphology, renal dysfunction, and lack of or intolerance to β-blockers are associated with early demise following CRT. In patients with at least 3 of these factors, bypassing CRT with early adoption of advanced heart failure therapies may be considered given the high specificity for rapid decline.

Introduction Multiple clinical factors are associated with improved CRT response including QRS duration, morphology, gender, height and HF etiology. Prior studies have suggested that QRS duration is the strongest independent predictor of clinical response The AdaptResponse trial is the first large multicenter trial that is well represented with women, with gender being strongly related to QRS duration and height Hypothesis Gender and height affect intrinsic QRS duration in CRT patients with LBBB Methods The AdaptResponse trial randomized CRT indicated patients with NYHA Class II-IV HF, LBBB by Strauss criteria (QRS ≥140 ms in men, ≥130 ms in women), and baseline PR interval ≤200ms to CRT optimization with LV fusion pacing or conventional CRT Multivariable linear regression was used to assess the relation of gender, height and other baseline covariates (table) with QRS duration Results In total, 3372 subjects were randomized in 218 centers worldwide, including 1460 (43.3%) females Major baseline differences exist between male and female patients (table), including a difference of 14 cm in height (p Conclusion AdaptResponse is the largest randomized CRT trial to date, with a proportion of women (43 3%) approaching the actual proportion in the HF population AdaptResponse results will provide a better understanding of the relationship of CRT response to QRS duration and patient gender and height.

CRT is indicated in patients with medically refractory heart failure and wide QRS duration. While much is known about predictors of LV remodeling after CRT implantation and short-term mortality, limited data exists on long-term outcomes after CRT placement. We retrospectively reviewed all patients