Temporal trends in patient characteristics and outcomes among Medicare beneficiaries undergoing primary prevention implantable cardioverter-defibrillator placement in the United States, 2006-2010. Results from the National Cardiovascular Data Registry's Implantable Cardioverter-Defibrillator Registry.

BACKGROUND: Contemporary patterns of use and outcomes of implantable cardioverter-defibrillators (ICDs) in community practice settings are not well characterized. We assessed temporal trends in patient characteristics and outcomes among older patients undergoing primary prevention ICD therapy in US hospitals between 2006 and 2010. METHODS AND RESULTS: Using the National Cardiovascular Data Registry's ICD Registry, we identified Medicare fee-for-service beneficiaries aged ≥65 years and older with left ventricular ejection fraction ≤35% who underwent primary prevention ICD implantation, including those receiving concomitant cardiac resynchronization therapy between 2006 and 2010 and could be matched to Medicare claims. Outcomes were mortality and hospitalization (all-cause and heart failure) at 180 days, and device-related complications. We used multivariable hierarchical logistic regression to assess temporal trends in outcomes accounting for changes in patient, physician, and hospital characteristics. The cohort included 117 100 patients. Between 2006 and 2010, only modest changes in patient characteristics were noted. Fewer single lead devices and more cardiac resynchronization therapy devices were used over time. Between 2006 and 2010, there were significant improvements in all outcomes, including 6-month all cause mortality (7.1% in 2006, 6.5% 2010; adjusted odds ratio, 0.88; 95% confidence interval, 0.82-0.95), 6-month rehospitalization (36.3% in 2006, 33.7% in 2010; adjusted odds ratio, 0.87; 95% confidence interval, 0.83-0.91), and device-related complications (5.8% in 2006, 4.8% in 2010; adjusted odds ratio, 0.80; 95% confidence interval, 0.74-0.88). CONCLUSIONS: The clinical characteristics of this national population of Medicare patients undergoing primary prevention ICD implantation were stable between 2006 and 2010. Simultaneous improvements in outcomes suggest meaningful advances in the care for this patient population.

Safety and efficacy of a totally subcutaneous implantable-cardioverter defibrillator.

BACKGROUND: The most frequent complications associated with implantable cardioverter-defibrillators (ICDs) involve the transvenous leads. A subcutaneous implantable cardioverter-defibrillator (S-ICD) has been developed as an alternative system. This study evaluated the safety and effectiveness of the S-ICD System (Cameron Health/Boston Scientific) for the treatment of life-threatening ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation). METHODS AND RESULTS: This prospective, nonrandomized, multicenter trial included adult patients with a standard indication for an ICD, who neither required pacing nor had documented pace-terminable ventricular tachycardia. The primary safety end point was the 180-day S-ICD System complication-free rate compared with a prespecified performance goal of 79%. The primary effectiveness end point was the induced ventricular fibrillation conversion rate compared with a prespecified performance goal of 88%, with success defined as 2 consecutive ventricular fibrillation conversions of 4 attempts. Detection and conversion of spontaneous episodes were also evaluated. Device implantation was attempted in 321 of 330 enrolled patients, and 314 patients underwent successful implantation. The cohort was followed for a mean duration of 11 months. The study population was 74% male with a mean age of 52±16 years and mean left ventricular ejection fraction of 36±16%. A previous transvenous ICD had been implanted in 13%. Both primary end points were met: The 180-day system complication-free rate was 99%, and sensitivity analysis of the acute ventricular fibrillation conversion rate was >90% in the entire cohort. There were 38 discrete spontaneous episodes of ventricular tachycardia/ventricular fibrillation recorded in 21 patients (6.7%), all of which successfully converted. Forty-one patients (13.1%) received an inappropriate shock. CONCLUSIONS: The findings support the efficacy and safety of the S-ICD System for the treatment of life-threatening ventricular arrhythmias.

Automatic determination of timing intervals for upper limit of vulnerability using ICD electrograms.

BACKGROUND: Implantable cardioverter defibrillator (ICD) implant testing based on the upper limit of vulnerability, or vulnerability testing, permits assessment of defibrillation safety margins without inducing ventricular fibrillation (VF) in most patients. Vulnerability testing requires that T-wave shocks be timed at the most vulnerable intervals of the cardiac cycle, defined as intervals at which the strongest shock induces VF. Our goal was to develop and test an automated method to select these timing intervals using ICD intracardiac electrograms (EGMs). METHODS: At ICD implant in 22 patients, we determined the range of the most vulnerable intervals by scanning the T wave with shocks. Simultaneously, EGMs were recorded for 351 pacing sequences used for measurement of timing intervals or T-wave shocks. EGMs were analyzed off-line using a novel automated method to identify a stable point near the maximum slope of the T wave in the far-field (shock) EGM. Fiducial timing points based both on the EGM and on the electrocardiogram (ECG) were used to predict the most vulnerable intervals. We compared the predicted most vulnerable to the measured most vulnerable intervals determined by T-shock scans. RESULTS: Automatically determined timing points from EGMs and operator-determined timing points from the surface ECG had comparable accuracy in identifying the measured most vulnerable intervals (91% EGM vs 86% ECG, P = NS). CONCLUSIONS: An automated method based on ICD EGMs identifies the most vulnerable intervals with accuracy comparable to the operator-performed, clinical method based on the surface ECG. This EGM method can be implemented efficiently in an ICD to automate vulnerability testing.

Performance of the subcutaneous implantable cardioverter-defibrillator in patients with a primary prevention indication with and without a reduced ejection fraction versus patients with a secondary prevention indication.

BACKGROUND: The subcutaneous implantable defibrillator (S-ICD) provides an alternative to the transvenous ICD for the prevention of sudden cardiac death, but has not been well studied in the most commonly treated transvenous ICD patient population, namely, primary prevention (PP) patients with left ventricular dysfunction. OBJECTIVE: The analyses in the present study were designed to compare clinical outcomes for PP patients with and without a reduced ejection fraction (EF) and secondary prevention (SP) patients implanted with the S-ICD. METHODS: All patients 18 years and older from the S-ICD IDE study and the EFFORTLESS Registry with available data as of November 18, 2013, were included (n = 856; mean follow-up duration 644 days). Outcomes were evaluated in 2 analyses: (1) comparing all PP patients (n = 603, 70.4%) with all SP patients (n = 253, 29.6%) and (2) comparing all PP patients with an EF ≤35% (n = 379) with those with an EF >35% (n = 149, 17.4%). RESULTS: No differences were observed in mortality, complications, inappropriate therapy, or ability to convert ventricular tachyarrhythmias between SP and PP patients. However, SP patients had a higher incidence of appropriate therapy than did PP patients (11.9% vs 5.0%; P = .0004). In the PP subanalysis, the cohort with an EF ≤35% had significantly older patients with more comorbidities and higher mortality (3.0% annually vs 0.0%). Despite these differences, device-related complications, conversion efficacy, and incidence of inappropriate shock therapies were not significantly different between PP subgroups. CONCLUSION: The S-ICD performs well in protecting patients with either PP or SP implant indications from sudden cardiac death. Within PP patients, device performance was independent of EF.

Trends in U.S. Cardiovascular Care: 2016 Report From 4 ACC National Cardiovascular Data Registries.

Cardiovascular disease is a leading cause of death and disability in the United States. National programs, such as the National Cardiovascular Data Registry, facilitate assessments of the quality of care and outcomes for broad populations of patients with cardiovascular disease. This report provides data for 2014 from 4 National Cardiovascular Data Registry hospital quality programs: 1) CathPCI (Diagnostic Catheterization and Percutaneous Coronary Intervention) for coronary angiography and percutaneous coronary intervention (667,424 procedures performed in 1,612 hospitals); 2) ICD Registry for implantable cardioverter-defibrillators (158,649 procedures performed in 1,715 hospitals); 3) ACTION-GWTG (Acute Coronary Treatment and Intervention Outcomes Network-Get With The Guidelines) for acute coronary syndromes (182,903 patients admitted to 907 hospitals); and 4) IMPACT (Improving Pediatric and Adult Congenital Treatment) for cardiac catheterization and intervention for pediatric and adult congenital heart disease (20,169 procedures in 76 hospitals). The report provides perspectives on the demographic and clinical characteristics of enrolled patients, characteristics of participating centers, and selected measures of processes and outcomes of care in these programs.

The effect of atrial pacing therapies on atrial tachyarrhythmia burden and frequency: results of a randomized trial in patients with bradycardia and atrial tachyarrhythmias.

OBJECTIVES: The Atrial Therapy Efficacy and Safety Trial (ATTEST) was a prospective, randomized study to evaluate preventive pacing and antitachycardia pacing (ATP) in patients with symptomatic atrial fibrillation (AF) or atrial tachycardia (AT). BACKGROUND: The effect of the combination of atrial prevention and termination algorithms on AT/AF burden and frequency in pacemaker patients is unknown. METHODS: A DDDRP pacemaker (AT500, Medtronic Inc., Minneapolis, Minnesota) with three atrial preventive pacing algorithms and two ATP algorithms was implanted in 368 patients. Patients were randomized one-month post-implant to all prevention and ATP therapies ON or OFF and followed for three months. The OFF group had DDDR pacing at a lower programmed rate of 60 ppm. The AT/AF burden and frequency were determined from daily device counters in 324 patients treated according to protocol. RESULTS: In 17,018 episodes with stored electrograms, appropriate detection was confirmed in 17,004 (99.9%). The median percentage of atrial pacing was 98% in the ON group versus 75% in the OFF group (p < 0.001). Using device-defined criteria for successful termination, ATP terminated 8,590 (54%) of 15,789 treated episodes. The median AT/AF burden during the three-month study period was 4.2 h/month ON versus 1.1 h/month OFF (p = 0.20). The median AT/AF frequency was 1.3 episodes/month ON versus 1.2 episodes/month OFF (p = 0.65). System-related, complication-free survival at four months was 90.2% (Kaplan-Meier estimate). CONCLUSIONS: This DDDRP pacemaker is safe, has accurate AT/AF detection, and provides ATP with 54% efficacy as defined by the device. The atrial prevention and termination therapies combined did not reduce AT/AF burden or frequency in this patient population.

Developing a risk model for in-hospital adverse events following implantable cardioverter-defibrillator implantation: a report from the NCDR (National Cardiovascular Data Registry).

OBJECTIVES: To better inform patients and physicians of the expected risk of adverse events and to assist hospitals' efforts to improve the outcomes of patients undergoing implantable cardioverter-defibrillator (ICD) implantation, we developed and validated a risk model using data from the NCDR (National Cardiovascular Data Registry) ICD Registry. BACKGROUND: ICD prolong life in selected patients, but ICD implantation carries the risk of periprocedural complications. METHODS: We analyzed data from 240,632 ICD implantation procedures between April 1, 2010, and December 31, 2011 in the registry. The study group was divided into a derivation (70%) and a validation (30%) cohort. Multivariable logistic regression was used to identify factors associated with in-hospital adverse events (complications or mortality). A parsimonious risk score was developed on the basis of beta estimates derived from the logistic model. Hierarchical models were then used to calculate risk-standardized complication rates to account for differences in case mix and procedural volume. RESULTS: Overall, 4,388 patients (1.8%) experienced at least 1 in-hospital complication or death. Thirteen factors were independently associated with an increased risk of adverse outcomes. Model performance was similar in the derivation and validation cohorts (C-statistics = 0.724 and 0.719, respectively). The risk score characterized patients into low- and-high risk subgroups for adverse events (≤10 points, 0.3%; ≥30 points, 4.2%). The risk-standardized complication rates varied significantly across hospitals (median: 1.77, interquartile range 1.54, 2.14, 5th/95th percentiles: 1.16/3.15). CONCLUSIONS: We developed a simple model that predicts risk for in-hospital adverse events among patients undergoing ICD placement. This can be used for shared decision making and to benchmark hospital performance.

The disconnect between the guidelines, the appropriate use criteria, and reimbursement coverage decisions: the ultimate dilemma.

Recently, the American College of Cardiology Foundation in collaboration with the Heart Rhythm Society published appropriate use criteria (AUC) for implantable cardioverter-defibrillators and cardiac resynchronization therapy. These criteria were developed to critically review clinical situations that may warrant implantation of an implantable cardioverter-defibrillator or cardiac resynchronization therapy device, and were based on a synthesis of practice guidelines and practical experience from a diverse group of clinicians. When the AUC was drafted, the writing committee recognized that some of the scenarios that were deemed "appropriate" or "may be appropriate" were discordant with the clinical requirements of many payers, including the Medicare National Coverage Determination (NCD). To charge Medicare for a procedure that is not covered by the NCD may be construed as fraud. Discordance between the guidelines, the AUC, and the NCD places clinicians in the difficult dilemma of trying to do the "right thing" for their patients, while recognizing that the "right thing" may not be covered by the payer or insurer. This commentary addresses these issues. Options for reconciling this disconnect are discussed, and recommendations to help clinicians provide the best care for their patients are offered.

Standardized cardiovascular data for clinical research, registries, and patient care: a report from the Data Standards Workgroup of the National Cardiovascular Research Infrastructure project.

Relatively little attention has been focused on standardization of data exchange in clinical research studies and patient care activities. Both are usually managed locally using separate and generally incompatible data systems at individual hospitals or clinics. In the past decade there have been nascent efforts to create data standards for clinical research and patient care data, and to some extent these are helpful in providing a degree of uniformity. Nonetheless, these data standards generally have not been converted into accepted computer-based language structures that could permit reliable data exchange across computer networks. The National Cardiovascular Research Infrastructure (NCRI) project was initiated with a major objective of creating a model framework for standard data exchange in all clinical research, clinical registry, and patient care environments, including all electronic health records. The goal is complete syntactic and semantic interoperability. A Data Standards Workgroup was established to create or identify and then harmonize clinical definitions for a base set of standardized cardiovascular data elements that could be used in this network infrastructure. Recognizing the need for continuity with prior efforts, the Workgroup examined existing data standards sources. A basic set of 353 elements was selected. The NCRI staff then collaborated with the 2 major technical standards organizations in health care, the Clinical Data Interchange Standards Consortium and Health Level Seven International, as well as with staff from the National Cancer Institute Enterprise Vocabulary Services. Modeling and mapping were performed to represent (instantiate) the data elements in appropriate technical computer language structures for endorsement as an accepted data standard for public access and use. Fully implemented, these elements will facilitate clinical research, registry reporting, administrative reporting and regulatory compliance, and patient care.

Cardiovascular care facts: a report from the national cardiovascular data registry: 2011.

OBJECTIVES: The aim of this report was to characterize the patients, participating centers, and measures of quality of care and outcomes for 5 NCDR (National Cardiovascular Data Registry) programs: 1) ACTION (Acute Coronary Treatment and Intervention Outcomes Network) Registry-GWTG (Get With The Guidelines) for acute coronary syndromes; 2) CathPCI Registry for coronary angiography and percutaneous coronary intervention; 3) CARE (Carotid Artery Revascularization and Endarterectomy) Registry for carotid revascularization; 4) ICD Registry for implantable cardioverter defibrillators; and the 5) PINNACLE (Practice INNovation And CLinical Excellence) Registry for outpatients with cardiovascular disease (CVD). BACKGROUND: CVD is a leading cause of death and disability in the United States. The quality of care for patients with CVD is suboptimal. National registry programs, such as NCDR, permit assessments of the quality of care and outcomes for broad populations of patients with CVD. METHODS: For the year 2011, we assessed for each of the 5 NCDR programs: 1) demographic and clinical characteristics of enrolled patients; 2) key characteristics of participating centers; 3) measures of processes of care; and 4) patient outcomes. For selected variables, we assessed trends over time. RESULTS: In 2011 ACTION Registry-GWTG enrolled 119,967 patients in 567 hospitals; CathPCI enrolled 632,557 patients in 1,337 hospitals; CARE enrolled 4,934 patients in 130 hospitals; ICD enrolled 139,991 patients in 1,435 hospitals; and PINNACLE enrolled 249,198 patients (1,436,328 individual encounters) in 74 practices (1,222 individual providers). Data on performance metrics and outcomes, in some cases risk-adjusted with validated NCDR models, are presented. CONCLUSIONS: The NCDR provides a unique opportunity to understand the characteristics of large populations of patients with CVD, the centers that provide their care, quality of care provided, and important patient outcomes.

Bachmann's bundle versus right atrial appendage capture.

The tissue in the high intraatrial septum in the region of Bachmann's Bundle (BB) exhibits electrophysiological properties that differ from the right atrial appendage (RAA). As BB pacing emerges as an alternative to RAA pacing, the feasibility of using automatic capture recognition technology in this location should be examined. At implant, active-fixation leads were consecutively placed in the RAA, then the BB in 18 patients (55.5% men, mean age 77.1 +/- 9.1). There was no significant difference between BB and RAA in the average capture threshold (1.12 vs 1.77 V, P = 0.09), sensing threshold (3.85 vs 3.69 mV, P = 0.84), impedance (508 vs 529 Ohms, P = 0.64), evoked response (1.78 vs 1.67 mV, P = 0.83), and polarization (0.41 vs 0.46 mV, P = 0.84) between. The difference in tissue characteristics was not associated with a different evoked response measured by the ventricular capture recognition algorithm. Based on the analogous evoked response and polarization values, capture recognition technology designed for the atrium will most likely be applicable at both pacing sites.