Randomized Trial of Stand-Alone Use of the Antimicrobial Envelope in High-Risk Cardiac Device Patients

BACKGROUND

Cardiac implantable electronic device (CIED) infection has a high mortality. Previous investigations showed reduced postoperative infections using skin preparation with chlorhexidine, preoperative intravenous antibiotics, and a TYRX-a antibacterial envelope. The additional benefit of antibiotic pocket wash and postoperative antibiotics has not been systematically studied.

METHODS

ENVELOPE was a prospective, multicenter, randomized, controlled trial enrolling patients undergoing CIED procedures with ≥2 risk factors for infection. The control arm received standard chlorhexidine skin preparation, intravenous antibiotics, and the TYRX-a antibiotic envelope. The study arm received pocket wash (500 mL antibiotic solution) and postoperative antibiotics for 3 days along with the prophylactic control measures. The primary end point was CIED infection and system removal at 6 months.

RESULTS

One thousand ten subjects (505 per arm) were enrolled and randomized. Patients were seen in person for a wound check with digital photo 2 weeks postimplant and at 3 and 6 months. CIED infection rate was low in both groups (1.0% control arm and 1.2% study arm, P=0.74). In the 11 subjects with infection and system removal, the time to study end point was 107±92 days with a PADIT (Prevention of Arrhythmia Device Infection Trial) score of 7.4 and a 64% 1-year mortality. Prior history of CIED infection independently predicted CIED system removal at 6 months in all subjects (odds ratio, 9.77, P=0.004). Of 11 infections requiring system removal, 5 were in the setting of pocket hematoma.

CONCLUSIONS

The use of antibiotic pocket irrigation and postoperative oral antibiotics provides no additional benefit to the prophylactic measures of chlorhexidine skin preparation, preoperative intravenous antibiotics, and an antibiotic envelope in reducing CIED infection. Postoperative hematoma is a major risk factor for infection, driven by the use of antiplatelet and anticoagulant medications. The strongest predictor of CIED removal at 6 months, regardless of intervention, was prior CIED infection.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02809131.

Preclinical evaluation of a third-generation absorbable antibacterial envelope

BACKGROUND

The TYRX (Medtronic) absorbable antibacterial envelope has been shown to stabilize implantable cardiac devices and reduce infection. A third-generation envelope was developed to reduce surface roughness with a redesigned multifilament mesh and enhanced form factor but identical polymer coating and antibiotic concentrations as the currently available second-generation envelope.

OBJECTIVE

The purpose of this study was to compare drug elution, bacterial challenge efficacy, stabilization, and absorption of second- vs third-generation envelopes.

METHODS

Antibiotic elution was assessed in vitro and in vivo. For efficacy against gram-positive/gram-negative bacteria, 40 rabbits underwent device insertions with or without third-generation envelopes. For stabilization (migration, rotation), 5 sheep were implanted with 6 devices each in second- or third-generation envelopes. Prespecified acceptance criteria were <83-mm migration and <90° rotation. Absorption was assessed via gross pathology.

RESULTS

Elution curves were equivalent (similarity factors ≥50 per Food and Drug Administration guidance). Third-generation envelopes eluted antibiotics above minimal inhibitory concentration (MIC) in vivo at 2 hours postimplant through 7 days, consistent with second-generation envelopes. Bacterial challenge showed reductions (P <.05) in infection with second- and third-generation envelopes. Device migration was 5.5 ± 3.5 mm (third-generation) vs 9. 9 ±7.9 mm (second-generation) (P <.05). Device rotation was 18.9° ± 11.4° (third-generation) vs 17.6° ± 15.1° (second-generation) and did not differ (P = .79). Gross pathology confirmed the absence of luminal mesh remainders and no differences in peridevice fibrosis at 9 or 12 weeks.

CONCLUSION

The third-generation TYRX absorbable antibacterial envelope demonstrated equivalent preclinical performance to the second-generation envelope. Antibiotic elution curves were similar, elution was above MIC for 7 days, infections were reduced compared to no envelope, and acceptance criteria for migration, rotation, and absorption were met.

Ambulatory atrioventricular synchronous pacing over time using a leadless ventricular pacemaker: Primary results from the AccelAV study

BACKGROUND

Previous studies demonstrated that accelerometer-based, mechanically timed atrioventricular synchrony (AVS) is feasible using a leadless ventricular pacemaker.

OBJECTIVE

The purpose of this study was to determine the performance of a leadless ventricular pacemaker with accelerometer-based algorithms that provide AVS pacing.

METHODS

AccelAV was a prospective, single-arm study to characterize AVS in patients implanted with a Micra AV, which uses the device accelerometer to mechanically detect atrial contractions and promote VDD pacing. The primary objective was to characterize resting AVS at 1 month in patients with complete atrioventricular block (AVB) and normal sinus function.

RESULTS

A total of 152 patients (age 77 ± 11 years; 48% female) from 20 centers were enrolled and implanted with a leadless pacemaker. Among patients with normal sinus function and complete AVB (n = 54), mean resting AVS was 85.4% at 1 month, and ambulatory AVS was 74.8%. In the subset of patients (n = 20) with programming optimization, mean ambulatory AVS was 82.6%, representing a 10.5% improvement (P <.001). Quality of life as measured by the EQ-5D-3L (EuroQol Five-Dimensions Three-Level questionnaire) improved significantly from preimplant to 3 months (P = .031). In 37 patients with AVB at both 1 and 3 months, mean AVS during rest did not differ (86.1% vs 84.1%; P = .43). There were no upgrades to dual-chamber devices or cardiac resynchronization therapy through 3 months.

CONCLUSION

Accelerometer-based mechanical atrial sensing provided by a leadless pacemaker implanted in the right ventricle significantly improves quality of life in a select cohort of patients with AV block and normal sinus function. AVS remained stable through 3 months, and there were no system upgrades to dual-chamber pacemakers.

Clinical performance of implantable cardioverter-defibrillator lead monitoring diagnostics

BACKGROUND

Implantable cardioverter-defibrillator (ICD) lead monitoring diagnostic alerts facilitate the diagnosis of structural lead failure.

OBJECTIVE

The purpose of this study was to prospectively study the performance of Medtronic ICD lead monitoring alerts.

METHODS

A prespecified ancillary substudy, World-Wide Randomized Antibiotic Envelope Infection Prevention Trial, was conducted in patients with an ICD with all available alerts enabled. The investigators reported possible lead system events (LSEs), with or without an alert. An independent committee reviewed all data and classified events as lead failure, other LSE, or nonlead system events (NLEs).

RESULTS

In 4942 patients who were followed for 19.4 ± 8.7 months, there were 124 alerts (65 LSEs, 59 NLEs) and 19 LSEs without an alert. Lead monitoring alerts had 100% sensitivity for the 48 adjudicated lead failures (95% confidence interval 92.6%-100%) and for 10 events adjudicated as either lead failure or connection issue. The positive predictive value of alerts for lead failure was 38.7% (48 of 124). For 34 pace-sense lead failures, an alert that incorporated oversensing was more sensitive than the pacing impedance threshold alert (33 patients [97.1%] vs 9 patients [26.5%]; P < .0001). However, the sensitivity was only 13.6% for lead dislodgments or perforations. Inappropriate shocks occurred in 2 patients with pace-sense lead failure (5.9%). No patient had unnecessary lead replacement for any of the NLEs.

CONCLUSION

In this first real-world prospective study, lead monitoring alerts had 100% sensitivity for identifying lead failures. Although their positive predictive value was modest, no false-positive alerts resulted in an unnecessary lead replacement. For the diagnosis of pace-sense lead failure, an alert for oversensing was more sensitive than a pacing impedance threshold alert.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02277990.

Use of healthcare claims to validate the Prevention of Arrhythmia Device Infection Trial cardiac implantable electronic device infection risk score

Aim

The Prevention of Arrhythmia Device Infection Trial (PADIT) infection risk score, developed based on a large prospectively collected data set, identified five independent predictors of cardiac implantable electronic device (CIED) infection. We performed an independent validation of the risk score in a data set extracted from U.S. healthcare claims.

Methods and results

Retrospective identification of index CIED procedures among patients aged ≥18 years with at least one record of a CIED procedure between January 2011 and September 2014 in a U.S health claims database. PADIT risk factors and major CIED infections (with system removal, invasive procedure without system removal, or infection-attributable death) were identified through diagnosis and procedure codes. The data set was randomized by PADIT score into Data Set A (60%) and Data Set B (40%). A frailty model allowing multiple procedures per patient was fit using Data Set A, with PADIT score as the only predictor, excluding patients with prior CIED infection. A data set of 54 042 index procedures among 51 623 patients with 574 infections was extracted. Among patients with no history of prior CIED infection, a 1 unit increase in the PADIT score was associated with a relative 28% increase in infection risk. Prior CIED infection was associated with significant incremental predictive value (HR 5.66, P < 0.0001) after adjusting for PADIT score. A Harrell’s C-statistic for the PADIT score and history of prior CIED infection was 0.76.

Conclusion

The PADIT risk score predicts increased CIED infection risk, identifying higher risk patients that could potentially benefit from targeted interventions to reduce the risk of CIED infection. Prior CIED infection confers incremental predictive value to the PADIT score.

Ventricular tachycardia induced by a backup pacing stimulus in a patient with a dual chamber pacemaker with AutoCapture

Manufacturers of cardiac implantable electronic devices have incorporated automatic features to allow for remote monitoring, improve device longevity, and additional safety. Algorithms to automatically measure capture threshold and adjust output to preserve battery life are one such feature. Automatic features may occasionally result in unexpected or undesirable clinical outcomes. We report on a patient who developed ventricular tachycardia inadvertently induced by the AutoCapture. feature of an Abbott/St. Jude Medical (SJM) pacemaker.

Clinical Presentation, Timing, and Microbiology of CIED Infections: An Analysis of the WRAP-IT Trial

OBJECTIVES

This study characterized the microbiology of major cardiac implantable electronic device (CIED) infections that occurred during the WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) study.

BACKGROUND

The WRAP-IT study offers a unique opportunity for further understanding of the pathogens involved in major CIED infections in a prospective dataset, with implications for clinical practice and infection management.

METHODS

A total of 6,800 patients randomized 1:1 to receive an antibacterial envelope or not (control subjects) were included in this analysis. Patient characteristics, infection manifestation (pocket vs. systemic), and infection microbiology were evaluated through all follow-up (36 months). Data were analyzed using Cox proportional hazards regression.

RESULTS

A total of 3,371 patients received an envelope, and 3,429 patients were control subjects. Major CIED infection occurred in 32 patients who received an envelope and 51 control subjects (36-month Kaplan-Meier estimated event rate, 1.3% and 1.9%, respectively; p = 0.046). A 61% reduction in major pocket infection was observed within 12 months of the procedure in the envelope group (hazard ratio: 0.39, 95% confidence interval: 0.21 to 0.73; p = 0.003). Among 76 patients with major infections who had a sample taken, causative pathogens were identified in 47 patients. Staphylococcus species were the predominate pathogen (n = 31) and envelope use resulted in a 76% reduction in Staphylococcus-related pocket infections (n = 4 vs. 17; p = 0.010). Envelope use was not associated with delayed onset of pocket infections and did not affect the presentation of infections.

CONCLUSIONS

Antibacterial envelope use resulted in a significant reduction of major CIED pocket infections and was particularly effective against Staphylococcus species, the predominant cause of pocket infections. (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial [WRAP-IT]; NCT02277990).

Atrial fibrillation post central retinal artery occlusion: Role of implantable loop recorders

OBJECTIVE

This study evaluated the risk of subclinical atrial fibrillation (AF) in patients with central retinal artery occlusion (CRAO) compared to those with cryptogenic stroke using implantable loop recorders (ILR).

METHODS

We conducted a retrospective analysis of 273 consecutive patients who had ILRs inserted at our institution for either cryptogenic stroke (n = 227) or CRAO (n = 46). Our primary endpoint was a time to event analysis for the new diagnosis of AF by ILR. Univariable and multivariable Cox proportional hazard models were used to determine the predictors of time-to-AF.

RESULTS

A total of 64 patients were found to have newly diagnosed AF by remote monitoring of the ILR. AF was detected in 57 of 227 (25%) cryptogenic stroke patients by the end of a maximum 5.1 years follow-up and in seven of 46 (15%) CRAO patients by the end of a maximum 3.6 years follow-up (P = .215, log-rank test). The Kaplan-Meier estimates for freedom from AF was 59.4% for CRAO and 66.6% for cryptogenic stroke (P = NS, log-rank test). Baseline variables predicting AF included older patients, higher CHADS₂ VASC score, longer PR interval on initial EKG evaluation, and mitral annular calcification on transthoracic echocardiogram.

CONCLUSIONS

Patients with CRAO are at risk for subclinical AF, similar to those with cryptogenic stroke. Long-term monitoring to detect AF may lead to changes in pharmacotherapy to reduce the risk for subsequent stroke.

121. Cardiac Implantable Electronic Device-Related Infective Endocarditis (CIED-IE): Clinical Features and Outcomes of Patients with Definite IE Who Fulfill Both Major Duke Criteria

Background

Cardiac implantable electronic device-related infective endocarditis (CIED-IE) comprises 10–57% of total CIED infections. Patients with definite CIED-IE who fulfill both major modified Duke criteria have not been well characterized.

Methods

Data from the Multicenter Electrophysiologic Device Infection Cohort, a prospective, multinational study of CIED infections were used to describe a subset of patients with CIED-IE who met both major Duke criteria for definite IE (bloodstream infection and intracardiac vegetations [VEG]).

Results

Of 433 patients with CIED infection, 144 (33.3%) had definite CIED-IE. The median age was 68 years and 77.1% were male. Twelve (8.3%) had past CIED infection. Seventy-seven patients (53.5%) had permanent pacemakers, 38 (26.4%) had implantable cardioverter defibrillators, and 29 (20.1%) had combination devices. The median time following the last device procedure was 550 days. CIED-IE was early in 60 patients (41.7%) and late in 84 (58.3%). Most patients presented with fever (77.8%) and sepsis (44.4%) with a median symptom duration of 7 days. On echocardiography, lead VEG was noted in 125 patients (86.8%) and valvular VEG in 54 patients (37.5%) with the tricuspid valve involved in 56.5%. On the basis of VEG location, there were 90 patients (62.5%) with isolated lead-associated IE (LAE), 19 patients (13.2%) with isolated valve-associated IE (VAE), and 35 patients (24.3%) with both (LVAE). All patients had positive blood cultures and 63/119 (52.9%) had positive lead cultures. The predominant organism in blood was Staphylococcus aureus (42.4%), followed by coagulase-negative staphylococci (20.1%). CIED removal occurred in 131 patients (91%). There were 25 deaths during the index hospitalization and 34 total deaths (24.3%) by 6 months. Mortality correlated with age >75 (P = 0.023) and sepsis on presentation (P = 0.052). Infecting organism, site of VEG, and device removal did not impact the risk of death.

Conclusion

Definite CIED-IE is relatively common. The majority of patients tend to have late-onset infection and often present with sepsis. S. aureus is the dominant organism causing definite CIED-IE. Isolated LAE occurs in 63% of patients. Older age and sepsis on admission are associated with higher mortality.

Disclosures

All authors: No reported disclosures.

Cardiovascular implantable electronic device infections due to enterococcal species: Clinical features, management, and outcomes

BACKGROUND

Enterococcal cardiovascular implantable electronic device (CIED) infections are not well characterized.

METHODS

Data from the Multicenter Electrophysiologic Device Infection Cohort, a prospective study of CIED infections, were used for descriptive analysis of adults with enterococcal CIED infections.

RESULTS

Of 433 patients, 21 (4.8%) had enterococcal CIED infection. Median age was 71 years. Twelve patients (57%) had permanent pacemakers, five (24%) implantable cardioverter defibrillators, and four (19%) biventricular devices. Median time from last procedure to infection was 570 days. CIED-related bloodstream infections occurred in three patients (14%) and 18 (86%) had infective endocarditis (IE), 14 (78%) of which were definite by the modified Duke criteria. IE cases were classified as follows: valvular IE, four; lead IE, eight; both valve and lead IE, six. Vegetations were demonstrated by transesophageal echocardiography in 17 patients (81%). Blood cultures were positive in 19/19 patients with confirmed results. The most common antimicrobial regimen was penicillin plus an aminoglycoside (33%). Antibiotics were given for a median of 43 days. Only 14 patients (67%) underwent device removal. There was one death during the index hospitalization with four additional deaths within 6 months (overall mortality 24%). There were no relapses.

CONCLUSIONS

Enterococci caused 4.8% of CIED infections in our cohort. Based on the late onset after device placement or manipulation, most infections were likely hematogenous in origin. IE was the most common infection syndrome. Only 67% of patients underwent device removal. At 6 months follow-up, no CIED infection relapses had occurred, but overall mortality was 24%.

1085. Enterococcal Cardiac Implantable Electronic Device (CIED) Infections: Clinical Features and Outcomes

Background

Unlike enterococcal native and prosthetic valve infective endocarditis (IE), enterococcal CIED infections are not well described.

Methods

Data from the Multicenter Electrophysiologic Device Infection Collaboration (MEDIC), a prospective, observational, multinational cohort study of CIED infections, were used to provide a descriptive analysis of adult patients with CIED infections due to enterococcal species.

Results

Of 433 patients, 21 (4.8%) were diagnosed with enterococcal CIED infection. Specific data on enterococcal species and antimicrobial susceptibilities were not recorded. The mean age was 70.8 years. No patient had previous CIED infection. Twelve patients (57%) had permanent pacemakers, 5 (24%) had implantable cardioverter defibrillators, and 4 (19%) had biventricular devices. Among the 21 infections, 3 (14%) were categorized as CIED-related bloodstream infections and 18 (86%) as IE; no patient had isolated pocket infection. Of the IE cases, four were valvular IE, eight were lead IE, and six were both. Fourteen cases of IE (78%) were definite by the modified Duke criteria. Median time from last device procedure to infection was 510 days (range 37–2,952 days). The most common presenting symptom was fever (48%); five patients (24%) exhibited local signs of pocket infection. All 21 patients underwent TEE with vegetations demonstrated in 17 (81%). Blood cultures grew enterococci from all patients. The most common antimicrobial regimen was a penicillin plus aminoglycoside (38%); two patients (9.5%) received ampicillin + ceftriaxone. Antibiotics were given for a median of 43 days. Only 14 patients (67%) had complete device removal; the seven patients retaining their device were judged to be at high risk for extraction. There was one death during the index hospital stay with four additional patients dying over the 6 months after therapy (overall mortality 24%); two of the seven patients retaining their CIED died.

Conclusion

Enterococci caused 4.8% of all CIED infections in our cohort. Most infections appeared to be hematogenous in origin with late onset. IE was the most common infectious syndrome. A penicillin plus aminoglycoside, given for 6 weeks, was the most frequent therapy. Only 67% of patients underwent device removal. At 6 months follow-up, no relapses had occurred but overall mortality was 24%.

Disclosures

J. E. Peacock Jr., Pfizer, Inc.: Shareholder, Owns common stock in Pfizer which was inherited and held in a trust. M. R. Sohail, TyRx Inc.: Investigator, Research support. Medtronic Inc.: Investigator, Research support. Medtronic Inc.: Consultant, Speaker honorarium. Spectranetics: Consultant, Speaker honorarium. Boston Scientific Corp: Consultant, Speaker honorarium. L. M. Baddour, UpToDate: Collaborator, Royalty payment. J. M. Miro, Abbvie: Consultant and Grant Investigator, Consulting honoraria and Research grant. Bristol-Myers Squibb: Consultant and Grant Investigator, Consulting honoraria and Research grant. Genentech: Consultant and Grant Investigator, Consulting honoraria and Research grant. Medtronic: Consultant and Grant Investigator, Consulting honoraria and Research grant. Novartis: Consultant and Grant Investigator, Consulting honoraria and Research grant. Gilead Sciences: Consultant and Grant Investigator, Consulting honoraria and Research grant. Pfizer: Consultant and Grant Investigator, Consulting honoraria and Research grant. ViiV Healthcare: Consultant and Grant Investigator, Consulting honoraria and Research grant. A. J. Greenspon, Medtronic: Consultant, Speaker honorarium. Boston Scientific: Consultant, Speaker honorarium. St. Jude: Consultant, Speaker honorarium. R. G. Carrillo, St. Jude Medical Group: Speaker’s Bureau, Research support. Spectranetics: Consultant, Speaker honorarium. Sorin Group: Speaker’s Bureau, None. Boston Scientific Corp: Speaker’s Bureau, None. D. Z. Uslan, Medtronic: Investigator, Research support. Boston Scientific: Consultant, Speaker honorarium.

Attempted salvage of infected cardiovascular implantable electronic devices: Are there clinical factors that predict success?

BACKGROUND

Published guidelines mandate complete device removal in cases of cardiovascular implantable electronic device (CIED) infection. Clinical predictors of successful salvage of infected CIEDs have not been defined.

METHODS

Data from the Multicenter Electrophysiologic Device Infection Collaboration, a prospective, observational, multinational cohort study of CIED infection, were used to investigate whether clinical predictors of successful salvage of infected devices could be identified.

RESULTS

Of 433 adult patients with CIED infections, 306 (71%) underwent immediate device explantation. Medical management with device retention and antimicrobial therapy was initially attempted in 127 patients (29%). "Early failure" of attempted salvage occurred in 74 patients (58%) who subsequently underwent device explantation during the index hospitalization. The remaining 53 patients (42%) in the attempted salvage group retained their CIED. Twenty-six (49%) had resolution of CIED infection (successful salvage group) whereas 27 patients (51%) experienced "late" salvage failure. Upon comparing the salvage failure group, early and late (N = 101), to the group experiencing successful salvage of an infected CIED (N = 26), no clinical or laboratory predictors of successful salvage were identified. However, by univariate analysis, coagulase-negative staphylococci as infecting pathogens (P = 0.0439) and the presence of a lead vegetation (P = 0.024) were associated with overall failed salvage.

CONCLUSIONS

In patients with definite CIED infections, clinical and laboratory variables cannot predict successful device salvage. Until new data are forthcoming, device explantation should remain a mandatory and early management intervention in patients with CIED infection in keeping with existing expert guidelines unless medical contraindications exist or patients refuse device removal.

Clinical presentation of CIED infection following initial implant versus reoperation for generator change or lead addition

Objective

To explore differences in clinical manifestations and outcomes in those patients who develop infection after undergoing initial implantation versus reoperation.

Methods

We compared cases of cardiac implantable electronic device (CIED) infection based on initial implantation versus reoperation from 11 centres.

Results

There were 432 patients with CIED infection, 178 occurring after initial device placement and 254 after repeat reoperation. No differences were seen in age, sex or device type. Those with infection after initial implant had a higher Charlson Comorbidity Score (median 3 (IQR 2–6) vs 2 (IQR 1–4), p<0.001), shorter time since last procedure (median 8.9 months (IQR 0.9–33.3) vs 19.5 months (IQR 1.1–62.9), p<0.0001) and fewer leads (2.0±0.6vs 2.5±0.9, p<0.001). Pocket infections were more likely to occur after a reoperation (70.1%vs48.9%, p<0.001) and coagulase negative staphylococci (CoNS) was the most frequently isolated organism in this group (p=0.029). In contrast, initial implant infections were more likely to present with higher white cell count (10.5±5.1 g/dL vs 9.5±5.4 g/dL, p=0.025), metastatic foci of infection (16.9%vs8.7%, p=0.016) and sepsis (30.9%vs19.3%, p=0.006). There were no differences in in-hospital (7.9%vs5.2%, p=0.31) or 6-month mortality (21.9%vs14.0%, p=0.056).

Conclusions

CIED infections after initial device implant occur earlier, more aggressively, and often due to Staphylococcus aureus. In contrast, CIED infections after reoperation occur later, are due to CoNS, and have more indolent manifestations with primary localisation to the pocket.

Treatment patterns, costs, and mortality among Medicare beneficiaries with CIED infection

BACKGROUND

Cardiac implantable electronic device (CIED) infection is a serious adverse event, but there are limited contemporary real-world data on treatment pathways and associated costs in the Medicare population following diagnosis of CIED infection. Hence, this study evaluates postinfection treatment pathways and associated healthcare expenditures and mortality among Medicare fee-for-service beneficiaries with CIED infection.

METHODS

Retrospective cohort analysis of 5,401 beneficiaries who developed a device-related infection in the year following implantation/upgraded CIED (1/1/2010-12/31/2012). Patients were followed-up to 12 months/death following diagnosis of infection and were divided into mutually exclusive groups based on whether they underwent CIED system removal (Group I), or no CIED system intervention (Group II; IIA with or IIB without infection hospitalization). All-cause healthcare resource utilization/expenditures were also measured.

RESULTS

In the year following infection, 64.1% of patients underwent device extraction, of who 2,109 (39.0%) had their device replaced (Group IA) and 1,355 (25.1%) had their device extracted without replacement (Group IB); 62.2% of patients were hospitalized and 25.3% of patients died. Mean Medicare payments-per-patient for facility-based services by group were: IA = $62,638 (standard deviation [SD]: $46,830), IB = $50,079 (SD: $45,006), IIA = $77,397 (SD: $79,130), and IIB = $22,856 (SD: $31,167).

CONCLUSIONS

Hospitalizations were the largest cost driver; infection-related costs, including cost of extraction/replacement, accounted for >50% of expenditures for patients with surgical/hospital intervention. Management of CIED infection in Medicare beneficiaries is associated with high healthcare expenditures in the year following infection. Additional measures to prevent device infection are needed to improve the outcomes and reduce costs in these patients.

Impact of Abandoned Leads on Cardiovascular Implantable Electronic Device Infections: A Propensity Matched Analysis of MEDIC (Multicenter Electrophysiologic Device Infection Cohort)

OBJECTIVES

This study sought to evaluate the impact of abandoned cardiovascular implantable electronic device (CIED) leads on the presentation and management of device-related infections.

BACKGROUND

Device infection is a serious consequence of CIEDs and necessitates removal of all hardware for attempted cure. The merits of extracting or retaining presumed sterile but nonfunctioning leads is a subject of ongoing debate.

METHODS

The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled patients with CIED infections at 10 institutions in the United States and abroad between January 1, 2009, and December 31, 2012. Within a propensity-matched cohort, relevant clinical information was compared between patients who had 1 or more abandoned leads at the time of infection and those who had none.

RESULTS

Matching produced a cohort of 264 patients, including 176 with no abandoned leads and 88 with abandoned leads. The groups were balanced with respect to Charlson comorbidity index, oldest lead age, device type, sex, and race. At the time of admission, those with abandoned leads were less likely to demonstrate systemic signs of infection, including leukocytosis (p = 0.023) and positive blood cultures (p = 0.005). Conversely, patients with abandoned leads were more likely to demonstrate local signs of infections, including skin erosion (p = 0.031) and positive pocket cultures (p = 0.015). In addition, patients with abandoned leads were more likely to require laser extraction (p = 0.010).

CONCLUSIONS

The results of a large prospective registry of CIED infections demonstrated that patients with abandoned leads may present with different signs, symptoms, and microbiological findings and require laser extraction more than those without abandoned leads.

Effect of battery longevity on costs and health outcomes associated with cardiac implantable electronic devices: a Markov model-based Monte Carlo simulation

Introduction

The effects of device and patient characteristics on health and economic outcomes in patients with cardiac implantable electronic devices (CIEDs) are unclear. Modeling can estimate costs and outcomes for patients with CIEDs under a variety of scenarios, varying battery longevity, comorbidities, and care settings. The objective of this analysis was to compare changes in patient outcomes and payer costs attributable to increases in battery life of implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-D).

Methods and results

We developed a Monte Carlo Markov model simulation to follow patients through primary implant, postoperative maintenance, generator replacement, and revision states. Patients were simulated in 3-month increments for 15 years or until death. Key variables included Charlson Comorbidity Index, CIED type, legacy versus extended battery longevity, mortality rates (procedure and all-cause), infection and non-infectious complication rates, and care settings. Costs included procedure-related (facility and professional), maintenance, and infections and non-infectious complications, all derived from Medicare data (2004–2014, 5% sample). Outcomes included counts of battery replacements, revisions, infections and non-infectious complications, and discounted (3%) costs and life years. An increase in battery longevity in ICDs yielded reductions in numbers of revisions (by 23%), battery changes (by 44%), infections (by 23%), non-infectious complications (by 10%), and total costs per patient (by 9%). Analogous reductions for CRT-Ds were 23% (revisions), 32% (battery changes), 22% (infections), 8% (complications), and 10% (costs).

Conclusion

Based on modeling results, as battery longevity increases, patients experience fewer adverse outcomes and healthcare costs are reduced. Understanding the magnitude of the cost benefit of extended battery life can inform budgeting and planning decisions by healthcare providers and insurers.

Electronic supplementary material

The online version of this article (10.1007/s10840-017-0289-8) contains supplementary material, which is available to authorized users.

Reimplantation and Repeat Infection After Cardiac-Implantable Electronic Device Infections: Experience From the MEDIC (Multicenter Electrophysiologic Device Infection Cohort) Database

BACKGROUND

Infection is a serious complication of cardiovascular-implantable electronic device implantation and necessitates removal of all hardware for optimal treatment. Strategies for reimplanting hardware after infection vary widely and have not previously been analyzed using a large, multicenter study.

METHODS AND RESULTS

The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled subjects with cardiovascular-implantable electronic device infections at multiple institutions in the United States and abroad between 2009 and 2012. Reimplantation strategies were evaluated overall, and every patient who relapsed within 6 months was individually examined for clinical information that could help explain the negative outcome. Overall, 434 patients with cardiovascular-implantable electronic device infections were prospectively enrolled at participating centers. During the initial course of therapy, complete device removal was done in 381 patients (87.8%), and 220 of them (57.7%) were ultimately reimplanted with new devices. Overall, the median time between removal and reimplantation was 10 days, with an interquartile range of 6 to 19 days. Eleven of the 434 patients had another infection within 6 months, but only 4 of them were managed with cardiovascular-implantable electronic device removal and reimplantation during the initial infection. Thus, the repeat infection rate was low (1.8%) in those who were reimplanted. Patients who retained original hardware had a 11.3% repeat infection rate.

CONCLUSIONS

Our study findings confirm that a broad range of reimplant strategies are used in clinical practice. They suggest that it is safe to reimplant cardiac devices after extraction of previously infected hardware and that the risk of a second infection is low, regardless of reimplant timing.

Incidence, Treatment Intensity, and Incremental Annual Expenditures for Patients Experiencing a Cardiac Implantable Electronic Device Infection

Background—

Because of the increasing use of cardiac implantable electronic devices (CIEDs), it is important to estimate the incidence and annual healthcare expenditures associated with CIED infections.

Methods and Results—

Patients with a record of an initial or replacement (full implant or generator only) CIED implant during the calendar years 2009 to 2012 in MarketScan Commercial Claims and Medicare Supplemental database were identified. CIED infections were classified into 4 categories: (1) infection not managed by inpatient admission nor implant removal, (2) infection managed by inpatient admission but no implant removal, (3) infection managed by an implant removal either in an inpatient or in an outpatient setting, and (4) infection with severe sepsis and managed in an inpatient setting with implant removal. Using separate models for initial and replacement cohorts, annualized incidence of infection and incremental annual expenditures by treatment intensity were estimated. Cumulative incidence of infection at 1 year post implant was 1.18% for initial CIED implants and 2.37% for replacement. Median time to infection was 35 days for initial and 23 days for replacement. Incremental healthcare expenditures by treatment intensity categories for initial implant patients at 1 year were $16 651, $104 077, $45 291, and $279 744. For replacement patients, incremental expenditures at 1 year by treatment intensity categories were $26 857, $43 541, $48 759, and $362 606.

Conclusions—

The management of CIED infections results in a substantial healthcare burden with a significant increase in annual expenditures the year after implant when device infection occurs.

Outcomes of patients with definite and suspected isolated cardiac sarcoidosis treated with an implantable cardiac defibrillator

PURPOSE

Cardiac sarcoidosis (CS) patients are at increased risk for sudden death. Isolated CS is rare and can be difficult to diagnose.

METHODS

In this multicenter retrospective review, patients with CS and an implantable cardiac defibrillator (ICD) were identified.

RESULTS

Of 235 patients with CS and ICD, 13 (5.5 %) had isolated CS, including 7 (3.0 %) with definite isolated CS (biopsy or necropsy-proven) and 6 (2.6 %) with suspected isolated CS based on a constellation of clinical, ECG, and imaging findings. Among 13 patients with isolated CS, 10 (76.9 %) were male, mean age was 53.8 ± 7.6 years, and mean left ventricular ejection fraction was 38.3 ± 16.5. Diagnosis was made by cardiac magnetic resonance (CMR) (n = 2), biopsy (n = 3), CMR and biopsy (n = 2), CMR and positron emission tomography (PET) (n = 2), PET (n = 1), late enhanced cardiac CT (n = 1), pathology at heart transplant (n = 1), and autopsy (n = 1). Eight of 13 (61.5 %) patients with isolated CS had a secondary prevention indication (VT in 6 and VF in 2) vs. 80 of 222 (36.0 %) with sarcoidosis in other organs (p = 0.04). Over a mean of 4.2 years, 9 of 13 (69.2 %) patients with isolated CS received appropriate ICD therapy, including anti-tachycardia pacing (ATP) and/or shock, compared with 75 of 222 (33.8 %) patients with cardiac and extracardiac sarcoidosis (p = 0.0150). Six of 7 (85.7 %) patients with definite isolated CS received appropriate ICD intervention, compared with 78 of 228 patients (34.2 %) without definite isolated CS (p = 0.0192.)

CONCLUSIONS

In this retrospective study, patients with isolated CS had very high rates of appropriate ICD therapy. Prospective, long-term follow-up of consecutive patients with isolated CS is needed to determine the true natural history and rates of ventricular arrhythmias in this rare and difficult-to-diagnose disease.

Variability in clinical features of early versus late cardiovascular implantable electronic device pocket infections

BACKGROUND

Cardiovascular implantable electronic device (CIED) pocket infections are often related to recent CIED placement or manipulation, but these infections are not well characterized. The clinical presentation of CIED pocket infection, based on temporal onset related to last CIED procedure, deserves further study.

METHODS

The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled subjects with CIED infection. Subjects were stratified into those whose infection occurred <12 months (early) or ≥ 12 months (late) since their last CIED-related procedure.

RESULTS

There were 132 subjects in the early group and 106 in the late group. There were more females (P = 0.009) and anticoagulation use (P = 0.039) in the early group. Subjects with early infections were more likely to have had a generator change or lead addition as their last procedure (P = 0.03) and had more prior CIED procedures (P = 0.023). Early infections were more likely to present with pocket erythema (P < 0.001), swelling (P < 0.001), and pain (P = 0.007). Late infections were more likely to have pocket erosion (P = 0.005) and valvular vegetations (P = 0.009). In bacteremic subjects, early infections were more likely healthcare-associated (P < 0.001). In-hospital and 6-month mortality were equivalent.

CONCLUSION

A total of 45% of patients with CIED pocket infection presented >12 months following their last CIED-related procedure. Patients with early infection were more likely to be female, on anticoagulation, and present with localized inflammation, whereas those with late infection were more likely to have CIED erosion or valvular endocarditis.

Recurrent orthostatic syncope due to left atrial and left ventricular collapse after a continuous-flow left ventricular assist device implantation

Left ventricular assist devices (LVADs) have become an established treatment for patients with advanced heart failure as a bridge to transplantation or for permanent support as an alternative to heart transplantation. Continuous-flow LVADs have been shown to improve outcomes, including survival, and reduce device failure compared with pulsatile devices. Although LVADs have been shown to be a good option for patients with end-stage heart failure, unanticipated complications may occur. We describe dynamic left atrial and left ventricular chamber collapse related to postural changes in a patient with a recent continuous-flow LVAD implantation.

A review of oral anticoagulants in patients with atrial fibrillation

There is a high prevalence of atrial fibrillation in the United States, particularly in the elderly population. Patients with atrial fibrillation are at an increased risk of stroke and anticoagulant therapy is recommended. However, many eligible patients are not receiving therapy due to limitations and concerns related to the use of the vitamin K antagonist warfarin, such as slow onset of action, variable drug metabolism, risk of bleeding, and requirement for monitoring. Novel oral anticoagulants (NOACs) have been developed and may be used as an alternative to warfarin. This review article summarizes the current clinical trial data for warfarin compared with the NOACs dabigatran (direct thrombin inhibitor), and rivaroxaban and apixaban (factor Xa inhibitors). Dabigatran (150 mg twice daily) demonstrated superiority in reducing the stroke or systemic embolism rate compared with warfarin (1.53% vs 1.69%; P < 0.001). The risk of major bleeding was similar for dabigatran and warfarin (3.32% per year vs 3.57% per year; P = 0.32). Rivaroxaban (20 mg once daily) demonstrated noninferiority in reducing the stroke or systemic embolism rate compared with warfarin (2.1% vs 2.4%; P < 0.001). There was no significant difference between rivaroxaban and warfarin for the risk of major bleeding and clinically relevant nonmajor bleeding (14.9% per year vs 14.5% per year; P = 0.44). Apixaban (5 mg twice daily) demonstrated superiority compared with warfarin in preventing stroke or systemic embolism (1.27% vs 1.60%; P = 0.01). Apixaban significantly reduced major bleeding compared with warfarin (2.13% per year vs 3.09% per year; P < 0.001). Compared with warfarin, all-cause mortality was numerically lower for dabigatran (P = 0.051) and similar for rivaroxaban (P = 0.15). Apixaban demonstrated significantly lower mortality rates compared with warfarin (3.52% vs 3.94%; P = 0.047). All 3 NOACS--dabigatran, rivaroxaban, and apixaban--significantly reduced intracranial hemorrhage compared with warfarin. Novel oral anticoagulants may be a suitable alternative to warfarin for different patient populations due to minimal drug interactions, lower bleeding risk, and no monitoring requirement.

Efficacy and safety of implantable cardiac defibrillators for treatment of ventricular arrhythmias in patients with cardiac sarcoidosis

AIMS

Implantable cardiac defibrillator (ICD) implantation is a class IIA recommendation for patients with cardiac sarcoidosis (CS). However, little is known about the efficacy and safety of ICDs in this population. The goal of this multicentre retrospective data review was to evaluate the efficacy and safety of ICDs in patients with CS.

METHODS AND RESULTS

Electrophysiologists at academic medical centres were asked to identify consecutive patients with CS and an ICD. Clinical information, ICD therapy history, and device complications were collected for each patient. Data were collected on 235 patients from 13 institutions, 64.7% male with mean age 55.6 ± 11.1. Over a mean follow-up of 4.2 ± 4.0 years, 85 of 234 (36.2%) patients received an appropriate ICD therapy (shocks and/or anti-tachycardia pacing) and 67 of 226 (29.7%) received an appropriate shock. Fifty-seven of 235 patients (24.3%) received a total of 222 inappropriate shocks. Forty-six adverse events occurred in 41 of 235 patients (17.4%). Patients who received appropriate ICD therapies were more likely to be male (73.8 vs. 59.6%, P = 0.0330), have a history of syncope (40.5 vs. 22.5%, P = 0.0044), lower left ventricular ejection fraction (38.1 ± 15.2 vs. 48.8 ± 14.7%, P ≤ 0.0001), ventricular pacing on baseline electrocardiogram (16.1 vs. 2.1%, P = 0.0002), and a secondary prevention indication (60.7 vs. 24.5%, P < 0.0001) compared with those who did not receive appropriate ICD therapies.

CONCLUSION

Patients with CS and ICDs are at high risk for ventricular arrhythmias. This population also has high rates of inappropriate shocks and device complications.

Cardiac device-related endocarditis complicated by spinal abscess

BACKGROUND

Infective endocarditis is the most serious manifestation of cardiac device infection and metastatic seeding of distant sites has been reported. However, the association between device-related endocarditis and spinal abscess has not been fully described.

METHODS

We reviewed hospital records at three high-volume cardiovascular referral centers from January 2005 to October 2010. Device-related endocarditis was confirmed in all cases with positive blood cultures and transesophageal echocardiogram revealing lead and/or valvular vegetations. Six patients with spinal abscesses in association with device-related endocarditis were identified.

RESULTS

A total of 384 patients met the clinical criteria for device-related endocarditis. Among these, infection was complicated by spinal abscess formation in six (1.5%) cases. The mean age of patients was 69.3 ± 11.8 years (47-82 years). The predominant clinical manifestations in these six patients included a recent history of fever (six), malaise (four), and neurological or meningeal signs (five). Spinal abscesses were diagnosed by magnetic resonance imaging in two and computed tomography scans in four of the cases. The causative pathogens were methicillin-resistant Staphylococcus aureus (three), methicillin-sensitive S. aureus (one), coagulase-negative Staphylococci (two), and Enterococcus fecalis (one). All patients underwent complete device removal with no procedure-related complications. Two patients died in the hospital, two were discharged with permanent neurological deficits, and the remaining two recovered with no permanent neurologic sequelae.

CONCLUSION

Device-related endocarditis must be considered in patients who present with a spinal abscess and bacteremia. Early recognition of this scenario is imperative in order to avoid permanent neurological sequelae and patient mortality. Early imaging, appropriate parenteral antimicrobial therapy, and expedited removal of all cardiac hardware are pivotal for optimal management.

Lead extraction in the contemporary setting: the LExICon study: an observational retrospective study of consecutive laser lead extractions

OBJECTIVES

This study sought to examine the safety and efficacy of laser-assisted lead extraction and the indications, outcomes, and risk factors in a large series of consecutive patients.

BACKGROUND

The need for lead extraction has been increasing in direct relationship to the increased numbers of cardiovascular implantable electronic devices.

METHODS

Consecutive patients undergoing transvenous laser-assisted lead extraction at 13 centers were included.

RESULTS

Between January 2004 and December 2007, 1,449 consecutive patients underwent laser-assisted lead extraction of 2,405 leads (20 to 270 procedures/site). Median implantation duration was 82.1 months (0.4 to 356.8 months). Leads were completely removed 96.5% of the time, with a 97.7% clinical success rate whereby clinical goals associated with the indication for lead removal were achieved. Failure to achieve clinical success was associated with body mass index <25 kg/m(2) and low extraction volume centers. Procedural failure was higher in leads implanted for >10 years and when performed in low volume centers. Major adverse events in 20 patients were directly related to the procedure (1.4%) including 4 deaths (0.28%). Major adverse effects were associated with patients with a body mass index <25 kg/m(2). Overall all-cause in-hospital mortality was 1.86%; 4.3% when associated with endocarditis, 7.9% when associated with endocarditis and diabetes, and 12.4% when associated with endocarditis and creatinine > or =2.0. Indicators of all-cause in-hospital mortality were pocket infections, device-related endocarditis, diabetes, and creatinine > or =2.0.

CONCLUSIONS

Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m(2). Centers with smaller case volumes tended to have a lower rate of successful extraction.

The Changing Face of Postoperative Atrial Fibrillation Prevention

Atrial fibrillation is the most common postoperative arrhythmia with significant consequences on patient health. Postoperative atrial fibrillation (POAF) complicates up to 8% of all noncardiac surgeries, between 3% and 30% of noncardiac thoracic surgeries, and between 16% and 46% of cardiac surgeries. POAF has been associated with increased morbidity, mortality, and longer, more costly hospital stays. The risk of POAF after cardiac and noncardiac surgery may be affected by several epidemiologic and intraoperative factors, as well as by the presence of preexisting cardiovascular and pulmonary disorders. POAF is typically a transient, reversible phenomenon that may develop in patients who possess an electrophysiologic substrate for the arrhythmia that is present before or as a result of surgery. Numerous studies support the efficacy of beta-blockers in POAF prevention; they are currently the most common medication used in POAF prophylaxis. Perioperative amiodarone, sotalol, nondihydropyridine calcium channel blockers, and magnesium sulfate have been associated with a reduction in the occurrence of POAF. Biatrial pacing is a nonpharmacologic method that has been associated with a reduced risk of POAF. Additionally, recent studies have demonstrated that hydroxymethylglutaryl-CoA reductase inhibitors may decrease the risk of POAF. Finally, based on recent evidence that angiotensin converting enzyme inhibitors and angiotensin receptor blockers reduce the risk of permanent atrial fibrillation, these medications may also hold promise in POAF prophylaxis. However, there is a need for further large-scale investigations that incorporate standard methodologies and diagnostic criteria, which have been lacking in past trials.

Comparing classifications of death in the Mode Selection Trial: agreement and disagreement among site investigators and a clinical events committee

Clinical events committees (CECs) are the current standard for endpoint adjudication in clinical trials. However, little data exist with which to compare CEC and site investigator determinations or to evaluate internal agreement among CEC members. Using data from the Mode Selection Trial in Sinus Node Dysfunction (MOST), we analyzed classifications of death in order to compare internal agreement among CEC physician reviewers and agreement between the CEC and site investigators. Death was classified at 2 levels: by major cause (cardiac, noncardiac, or unknown) and by minor subclassification of the major classifications. Reviewer agreement was tabulated at the major and minor levels, and standard and weighted kappa statistics were calculated. Disagreement at both levels was also determined. Individual decision-making was tabulated in terms of frequency in classifying death as unknown. All 404 deaths were classified by the CEC. Site investigators determined major classifications in 382 cases and minor classification in 379 cases. The CEC and the site investigators disagreed in classifying 41 cases (10.7%) at the major level and 117 (30.9%) at the minor level. CEC reviewers disagreed internally at the major level in 64 cases (15.8%), at the minor level in 63 cases (15.6%), and at any level in 127 cases (31.4%) (kappa = 0.60, 95% confidence interval (CI) [0.55, 0.66]; weighted kappa = 0.66, 95% CI [0.62, 0.75]). In resolving internal disagreements, the full CEC agreed with 1 of 2 CEC reviewers in 85.9% of cases. Disagreements occurred between site investigators and CEC reviewers in classifying deaths. Endpoint determination and decision-making varied among individual CEC reviewers, but second-tier reviews by the full CEC resolved all disagreements. These findings support continued use of CECs for endpoint adjudication in clinical trials.

The association of the heart failure score with mortality and heart failure hospitalizations in elderly patients: insights from the Mode Selection Trial (MOST)

BACKGROUND

Patient and physician preferences as well as cost favor an increasingly higher threshold for hospital admission for heart failure (HF) treatment. This trend risks masking the severity and prevalence of HF as hospitalization for HF may decrease.

METHODS

Heart Failure Score (HFS) has 4 ordinal subscales assessing (1) HF symptoms, physical signs of left (2) and (3) right HF, and (4) therapy changes for HF. Heart Failure Score was calculated for 1257 of 2010 (63%) patients enrolled in the MOST trial in sinus node dysfunction, who survived and had complete first-year HFS data at 4 postpacemaker implant visits (1, 3, 6, and 12 months). Heart Failure Score was summed and ranged from 0 to 14, with lower scores representing less HF.

RESULTS

There were 1257 patients (median age 74 years [interquartile range 68-79], 47% were women, 61% had hypertension, 20%, diabetes mellitus, and 23%, prior myocardial infarction). The median HFS accumulated during 1 year was 4 (interquartile range 1-8). Of patients with a benign first year, those with a higher HFS were more likely to die during subsequent follow-up compared with patients with lower HFS (hazard ratio 1.07, 95% CI 1.04-1.10 for each 1-point increase, P < .001).

CONCLUSIONS

Increasing HFS is associated with an increased risk of mortality in mostly elderly patients without pre-existing HF. Heart Failure Score may be a useful surrogate HF end point for clinical trials.

Cardiac resynchronization therapy in patients with right bundle branch block: Analysis of pooled data from the MIRACLE and Contak CD trials

BACKGROUND

Clinical trials of cardiac resynchronization therapy (CRT) have not included many patients with right bundle branch block (RBBB).

OBJECTIVES

We pooled data from two randomized controlled trials of CRT (Multicenter InSync Randomized Clinical Evaluation [MIRACLE] and Contak CD) in order to assess outcomes of patients with RBBB.

METHODS

A total of 61 patients with RBBB were identified, 34 of whom were randomized to the CRT group and 27 to the control group. The data from these patients were entered into a new database and analyzed.

RESULTS

Baseline demographics were not different between the two groups (mean age 65.5 +/- 11.3 years vs 69.5 +/- 9.6 years; male gender 91% vs 85%; patients with coronary disease 76.5% vs 88%; QRS duration 167 ms vs 164 ms; all P = NS). Outcome variables (New York Heart Association [NYHA] class, 6-minute hall walk distance, peak oxygen consumption (VO2), Minnesota Living with Heart Failure quality-of-life scores, left ventricular ejection fraction, and norepinephrine levels) were analyzed at randomization, 3 months, and 6 months.

CONCLUSIONS

(1) With the exception of NYHA class, patients with RBBB as the qualifying wide QRS did not derive significant benefit from CRT in any of the other parameters studied at 3 or 6 months. (2) RBBB patients who received active CRT showed significant improvements in NYHA class by 6 months and trends toward improvement in 6-minute walk distance, quality-of-life scores, and norepinephrine levels. However, control patients also showed significant improvement in NYHA class by 6 months but showed no improvement in objective measurements (VO2, 6-minute walk distance, left ventricular ejection fraction, and norepinephrine levels), consistent with a placebo effect. Analysis of a larger cohort of patients with RBBB undergoing CRT may demonstrate significant benefit, but the current analysis does not support the use of CRT in patients with RBBB.

Unique self-perpetuating cycle of atrioventricular block and phase IV bundle branch block in a patient with bundle branch reentrant tachycardia

Bundle branch reentrant tachycardia (BBRT) is an uncommon form of ventricular tachycardia involving diseased bundle branches. Phase IV bundle branch block also accompanies severe His-Purkinje disease. We present an unusual case of BBRT in a patient who also manifests a unique self-perpetuating cycle of AV block and phase IV left bundle branch block following aortic valve surgery. BBRT was treated successfully by ablation of the right bundle.

Predictors of stroke in patients paced for sick sinus syndrome

OBJECTIVES

This study was an analysis of factors associated with stroke in a population of patients paced for sinus node dysfunction in a large prospective clinical trial (Mode Selection Trial [MOST]).

BACKGROUND

The effects of dual-chamber versus single-chamber ventricular pacing on subsequent stroke in patients with sinus node dysfunction are not known.

METHODS

A total of 2,010 patients with sinus node dysfunction were randomized to ventricular or dual-chamber pacing and followed for a median of 33.1 months.

RESULTS

The median participant age was 74 years. During 5,664 patient-years of follow-up, 90 strokes (11 hemorrhagic) occurred. By life-table analysis, the rate of stroke was 2.2% (95% confidence interval [CI] 1.6 to 2.9) at one year and 5.8% (95% CI 4.5 to 7.1) at four years. The incidence of stroke was not significantly different in dual-chamber (4%) as compared with ventricular-paced patients (4.9%) (hazard ratio [HR] 0.82, 95% CI 0.54 to 1.25, p = 0.36). Multivariable analysis demonstrated that significant predictors of stroke included prior stroke or transient ischemic attack, Caucasian race, hypertension, prior systemic embolism, and New York Heart Association functional class III or IV (p < 0.05); pacing mode remained non-significant after adjustment for these factors (p = 0.37). Clinically reported atrial fibrillation after implantation was a risk factor for stroke in this cohort after adjustment for other predictors of stroke (p = 0.042, HR 1.68 [95% CI 1.02 to 2.76]).

CONCLUSIONS

Clinical characteristics, but not mode of pacing, were associated with subsequent stroke in patients paced for sinus node dysfunction.

Dual Antegrade Response Tachycardia Induced Cardiomyopathy

We report a rare case of tachycardia induced cardiomyopathy resulting from nearly incessant dual antegrade response tachycardia. Criteria necessary for sustaining dual antegrade responses are discussed, including: (1) sufficient antegrade dissociation of the AV node; (2) absence of retrograde conduction over each AV nodal pathway following antegrade conduction over its counterpart; (3) difference between fast and slow pathway conduction times exceeding His-Purkinje refractoriness; and (4) critical timing of sinus impulses relative to preceding AV nodal conduction. Both the arrhythmia and cardiomyopathy were successfully treated by slow pathway ablation.