Assessment of Antitachycardia Pacing in Primary Prevention Patients: The APPRAISE ATP Randomized Clinical Trial.

Importance: The emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients.

Objective: To assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming.

Design, Setting, And Participants: This global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%.

Initial heart rate score predicts new-onset atrial tachyarrhythmias in pacemaker patients.

Aims: Heart rate score (HRSc), the per cent of atrial paced and sensed event in the largest 10 b.p.m.

Effects of Atrioventricular Optimization on Left Ventricular Reverse Remodeling With Cardiac Resynchronization Therapy: Results of the SMART-CRT Trial.

Background: The role of atrioventricular optimization (AVO) to improve cardiac resynchronization therapy outcomes remains controversial. Previous post hoc analyses of a multicenter trial showed that measures of electrical dyssynchrony (right ventricular-left ventricular [LV] or LV electrical delay durations) are associated with patients who benefit from AVO.

Methods: This was a global, multicenter, prospective, randomized trial of de novo cardiac resynchronization therapy implant patients with an right ventricular-LV duration ≥70 ms to determine whether AVO results in greater reverse remodeling.

Assessment of primary prevention patients receiving an ICD - Systematic evaluation of ATP: APPRAISE ATP.

Background: The value of antitachycardia pacing (ATP) in the overall cohort of primary prevention patients who receive implantable cardioverter-defibrillators (ICDs) remains uncertain. ATP success reported in prior trials potentially included a large number of patients receiving unnecessary ATP for arrhythmias that may have self-terminated owing to the prematurity of the intervention. Although some patients derive benefit from initial ATP in terminating rapid ventricular arrhythmias and thereby preventing shocks, there are limited data allowing us to identify those patients .

Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

Background: No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds).

Objective: 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.

Methods: All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried.

Heart rate score, a measure related to chronotropic incompetence in pacemaker patients.

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.

Comparison of measures of ventricular delay on cardiac resynchronization therapy response.

Background: Left ventricular (LV) pacing at sites of prolonged LV delay (QLV) or at long interventricular delay (right ventricle [RV]-LV) is strongly associated with cardiac resynchronization therapy (CRT) response. QLV and RV-LV have been independently evaluated, but little is known regarding the interrelationship between these measures or of delay to the RV.

Objective: The purpose of this study was to evaluate the relationship between measures of electrical delay on CRT response in the SMART-AV (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy) trial.

How Well Do Results From Randomized Clinical Trials and/or Recommendations for Implantable Cardioverter-Defibrillator Programming Diffuse Into Clinical Practice?.

Background Inappropriate implantable cardioverter-defibrillator programming can be detrimental. Whether trials/recommendations informing best implantable cardioverter-defibrillator programming (high-rate cutoff and/or extended duration of detection) influence practice is unknown. Methods and Results We measured reaction to publication of MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy; 2012) and the Consensus Statement (2015) providing generic programming parameters, in a national cohort of implantable cardioverter-defibrillator recipients, using the ALTITUDE database (Boston Scientific).

Development of a biomarker panel to predict cardiac resynchronization therapy response: Results from the SMART-AV trial.

Background: Predicting a favorable cardiac resynchronization therapy (CRT) response holds great clinical importance.

Objective: The purpose of this study was to examine proteins from broad biological pathways and develop a prediction tool for response to CRT.

Methods: Plasma was collected from patients before CRT (SMART-AV [SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy] trial).

Effect of Interventricular Electrical Delay on Atrioventricular Optimization for Cardiac Resynchronization Therapy.

Background: Routine atrioventricular optimization (AVO) has not been shown to improve outcomes with cardiac resynchronization therapy (CRT). However, more recently subgroup analyses of multicenter CRT trials have identified electrocardiographic or lead positions associated with benefit from AVO. Therefore, the purpose of this analysis was to evaluate whether interventricular electrical delay modifies the impact of AVO on reverse remodeling with CRT.

The rationale and design of the SMART CRT trial.

Aims: The SMART CRT study will assess the efficacy of an atrioventricular optimization algorithm to improve reverse remodeling among patients undergoing cardiac resynchronization therapy (CRT) in the presence of interventricular electrical delay.

Methods And Results: The SMART CRT study is a global, multicenter, prospective, randomized study of patients undergoing CRT implantation. The primary endpoint of this trial is response rate to CRT, defined as decrease in left ventricular end-systolic volume (LVESV) ≥15% at 6 months compared to preimplant baseline.

Addition of minute ventilation to rate-response pacing improves heart rate score more than accelerometer alone.

Background: 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.

Objective: 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).

Methods: HRSc, the percentage of all beats in the tallest 10-beat/min device histogram bin, was calculated.

Propensity score matched comparison of subcutaneous and transvenous implantable cardioverter-defibrillator therapy in the SIMPLE and EFFORTLESS studies.

Aims: Comparison of outcomes between subcutaneous and transvenous implantable cardioverter-defibrillator (S-ICD and TV-ICD) therapy is hampered by varying patient characteristics and complication definitions. The aim of this analysis is to compare clinical outcomes of S-ICD and TV-ICD therapy in a matched cohort.

Methods And Results: Patients implanted with de novo implantable cardioverter-defibrillators without need for pacing were selected from two studies: SIMPLE (n = 1091 single and n = 553 dual chamber TV-ICDs) and EFFORTLESS (n = 798 S-ICDs).

Risk Factors and Temporal Trends of Complications Associated With Transvenous Implantable Cardiac Defibrillator Leads.

Background: The transvenous implantable cardioverter-defibrillator (ICD) lead is the most common source of complications in a traditional ICD system. This investigation aims to determine the incidence, predictors, and costs associated with these complications using a large insurance database.

Methods And Results: Data from the OptumLabs™ Data Warehouse, which include diagnosis, physician and procedure codes, and claims from patient hospitalizations, were analyzed.

The role of interventricular conduction delay to predict clinical response with cardiac resynchronization therapy.

Background: Pacing at sites with late electrical activation or greater interventricular delay is associated with improvement in measures of cardiac resynchronization therapy (CRT) response, primarily reverse remodeling. However, little is known about whether such lead positions improve heart failure (HF) clinical outcomes.

Objective: The purpose of this study was to assess the association between interventricular electrical delay and HF clinical outcomes.

Safety and effectiveness of a 6-French MRI conditional pacemaker lead: The INGEVITY clinical investigation study results.

Background: The design of pacemaker leads has continued to evolve; ease of lead handling, improved electrical performance, and magnetic resonance imaging (MRI) conditional aspects have become more important, while safety remains critical. The INGEVITY™ family leads was designed to provide MRI conditional aspects, decreased diameter, and improved performance of pacemaker leads. The INGEVITY study is an investigational device exemption trial evaluating the acute and chronic safety and effectiveness of these leads.

Long-term vagal stimulation for heart failure: Eighteen month results from the NEural Cardiac TherApy foR Heart Failure (NECTAR-HF) trial.

Background: The NECTAR-HF study evaluated safety and feasibility of vagal nerve stimulation (VNS) for the treatment of heart failure patients. The first six-month randomized phase of the study did not show improvement in left ventricular remodelling in response to VNS. This study reports the 18-month results and provides novel findings aiming to understand the lack of efficacy of VNS, including a new technique assessing the effects of VNS.

A Device Histogram-Based Simple Predictor of Mortality Risk in ICD and CRT-D Patients: The Heart Rate Score.

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 CRT-D, and defined as percent of beats in the histogram in the tallest 10 beats/min range bin. It was calculated at initial remote monitoring for patients enrolled in LATITUDE® without persistent atrial fibrillation, and with pulse generators implanted in 2006-2011.

Longer Left Ventricular Electric Delay Reduces Mitral Regurgitation After Cardiac Resynchronization Therapy: Mechanistic Insights From the SMART-AV Study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy).

Background: Mitral regurgitation (MR) is associated with worse survival in those undergoing cardiac resynchronization therapy (CRT). Left ventricular (LV) lead position in CRT may ameliorate mechanisms of MR. We examine the association between a longer LV electric delay (QLV) at the LV stimulation site and MR reduction after CRT.

Survival After Rate-Responsive Programming in Patients With Cardiac Resynchronization Therapy-Defibrillator Implants Is Associated With a Novel Parameter: The Heart Rate Score.

Background: Rate-responsive pacing (DDDR) versus nonrate-responsive pacing (DDD) has shown no survival benefit for patients undergoing cardiac resynchronization therapy defibrillator (CRT-D) implants. The heart rate score (HRSc), an indicator of heart rate variation, may predict survival. We hypothesized that high-risk HRSc CRT-D patients will have improved survival with DDDR versus DDD alone.

Interventricular Electrical Delay Is Predictive of Response to Cardiac Resynchronization Therapy.

Objectives: This study was conceived to evaluate the relationship between interventricular electrical delay, as measured by the right ventricle-left ventricle (RV-LV) interval, and outcomes in a prospectively designed substudy of the SMART-AV (SMARTDELAY determined AV Optimization) trial.

Background: Despite the well-documented benefit of cardiac resynchronization therapy (CRT), the nonresponder rate remains an important clinical problem. Implanting LV leads by traditional anatomic criteria has limited impact on outcomes.

Influence of patients' age at implantation on mortality and defibrillator shocks.

Aims: Patients have increasing comorbidities and competing causes of death with advancing age, raising questions about the effectiveness of the implantable cardioverter defibrillators (ICD) in older age. We therefore investigated the effect of patients' age at initial device implantation on all-cause mortality and on the risk of ICD shocks in single-chamber (V-ICD), dual-chamber (D-ICD), and cardiac resynchronization therapy defibrillator (CRT-D) recipients.

Methods And Results: We reviewed de-identified records of 67 128 ICD recipients enrolled in the Boston Scientific ALTITUDE database of remote monitored patients [V-ICD (n = 11 422), D-ICD (n = 23 974), and CRT-D (n = 31 732)].

The learning curve associated with the introduction of the subcutaneous implantable defibrillator.

Aims: The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs).