Cardiac Resynchronization Therapy-defibrillator Device Research Articles

The Micra Transcatheter Pacing System: past, present and the future.

Leadless permanent pacemakers represent an important innovation in cardiac device developments. Althoughtransvenous permanent pacemakers have become indispensable in managing bradyarrhythmia and saving numerous lives, the use of transvenous systems comes with notable risks tied to intravascular leads and subcutaneous pockets. This drawback has spurred the creation of leadless cardiac pacemakers. Within this analysis, we compile existing clinical literature and proceed to evaluate the efficacy and safety of the Micra Transcatheter Pacing System. We also delve into the protocols for addressing a malfunctioning or end-of-life Micra as well as device extraction. Lastly, we explore prospects in this domain, such as the emergence of entirely leadless cardiac resynchronization therapy-defibrillator devices.

Gender-specific differences in young patients receiving implantable cardioverter-defibrillator therapy - a subgroup analysis of the german device registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillators (CRT-D) are well established therapies in heart failure. Therapeutic and technological advancements led to increasing numbers of younger patients receiving these devices. Distinguishing patient characteristics among this younger patient cohort, especially gender-specific differences, are important to optimize patient care. Methods Between 2007-2014 the German DEVICE registry enrolled patients from 50 German centers undergoing ICD/CRT-D implantation. Patient characteristics, data on procedural outcome and adverse events during index hospitalization and 1-year follow-up were recorded. All patients under the age of 45 years were identified, separated into two groups according to their gender and analyzed. Results Out of 4181 patients enrolled, 236 patients (5.6%) were under the age of 45 years, of which 162 patients (68.6%) were male and 72 patients were female (31.4%). Male patients were older (39.5 [35.0; 42.0] vs. 34.0 [28.0; 40.0] years, p<0.001) and were more likely to suffer from cardiac disease (77.2 vs. 59.5%, p=0.005) and non-cardiac comorbidities (24.1 vs. 12.2%, p=0.035). The prevalence of Long-QT syndrome was markedly increased in female patients (1.9 vs. 10.8%, p=0.002). Male patients had lower mean left-ventricular ejection fraction (39.8±18.5 vs. 49.5±16.7%, p=0.003), were less likely to be in NYHA functional class I (44.0 vs. 61.4%, p=0.047) and received more betablockers (80,2% vs. 64,9%; p=0,011), ACE-inhibitors (56,2% vs. 46,5%; p=0,005) and statins (27,5% vs. 10,8%, p=0,005). Dual-chamber ICD were more common in female patients (13.0 vs. 27.8%, p=0.006) with a trend towards higher prevalence of pathological AV-conduction in female patients (6.2% vs. 13.5%, p=0.06). There were no differences in the number of implanted CRT-D devices between groups (9.3 vs. 6.9%, p=0.56). There was no detectable difference in overall post-operative complications (1.9 vs. 5.4%, p=0.21) with no cases of in-hospital mortality in both groups. However, there were more pneumothoraces requiring a chest tube insertion in female patients (0.0% vs. 4,1%, p=0.03). Median follow-up time was 514 [398; 669] days. There were no differences in neither device-associated complications requiring revision (15.0 vs. 19.1%, p=0.52), nor in all-cause mortality (3.7 vs. 1.9%, p=0.52; HR 0.5, 95%CI: 0.06-4.27) after 1-year of follow-up, but female patients had a higher mean number of rehospitalizations (1.6±1.5 vs. 2.1±1.3; p=0.026). Conclusion In young patients under 45 years, there were no differences in overall device complications and overall mortality between male and female patients after implantation and after 1-year follow-up. Even though female patients had less cardiac and non-cardiac (co-)morbidities, the number of rehospitalizations after 1-year follow up were higher.

PO-02-028 NEGATIVE EFFECTS OF COVID-19 ON THE IMPLANTATION RATE OF CARDIAC RESYNCHRONIZATION THERAPY WITH DEFIBRILLATOR DEVICE.

Coronavirus-19 (COVID-19) pandemic drastically changed the landscape of the US medical system. Total surgical procedure volume declined across all specialties, primarily in elective procedures. Multiple task forces promoted the cancellation of nonurgent elective procedures, including the implantation of a Cardiac Resynchronization Therapy Defibrillator (CRT-D) in stable patients during the pandemic. The effect of COVID-19 on the rate of CRT-D implantation is poorly understood. We aim to explore the impact of the COVID-19 pandemic on CRT-D insertion rates, along with negative outcomes related to delays in care. We conducted a retrospective analysis using the National Inpatient Sample (NIS) database for patient encounters involving the insertion of CRT-D between 2017 & 2020. Variables were identified using their ICD-10 codes. Admissions were included if the patient was at least 18 years of age, presenting for a non-elective admission, had a primary diagnosis of hypertensive heart disease, hypertensive heart, and chronic kidney disease, or heart failure (ICD-10 codes I11, I13, I50), and underwent insertion of a CRT-D (ICD-10 code 0JH**9*). Between 2017 and 2020, CRT-D devices were inserted during 23,635 admissions. On average, 6,198 devices were implanted yearly from 2017 to 2019, with only 5,040 being implanted in 2020. CRT-D implant rates dropped below their previous 3-year average in every region of the US during 2020 (Figure 1). Additionally, the highest average death rate at 13.89%, but this difference was statistically insignificant (adjusted Wald test p=0.767), and COVID-19 was not associated with an increased risk of inpatient mortality (OR 0.22, 95% CI 0.03-1.82, p=0.162). Blacks were disproportionately affected by a reduction in CRT-D procedures for this demographic in 2020 as compared to other races. COVID-19 pandemic has affected all facets of the healthcare system, especially surgical volume rates. Consistent with many other procedures, CRT-D procedures significantly decreased in 2020 following multiple task force recommendations to postpone nonurgent procedures in the setting of rampant COVID-19 infections. To our knowledge, this is the first retrospective study highlighting the trend of decreased rates of CRT-D implantation as a response to the COVID-19 pandemic.

Trends in the Use and Complications of Cardiac Resynchronization Therapy Device Implantation in Chronic Kidney Disease Patients.

Large-scale multi-hospital data on cardiac resynchronization therapy (CRT) device implantation in patients with chronic kidney disease (CKD) are currently lacking. The purpose of this study was to examine the incidence of CRT device implantation in patients hospitalized with CKD and the impact of CRT device implantation on hospital complications and outcomes. We analyzed the Nationwide Inpatient Sample from 2008-2014 to identify yearly trends in CRT device implantation during CKD hospitalizations. We compared CRT biventricular pacemakers (CRT-Ps) and CRT defibrillators (CRT-Ds). We also obtained rates of comorbidities and complications associated with CRT device implantations. From 2008-2014, the proportion of hospitalized patients with a concurrent diagnosis of CKD receiving CRT-P devices consistently went up from 2008 to 2014 (from 12.3% to 23.8%, P < .0001) compared to the number of hospitalized patients with a concurrent diagnosis of CKD receiving CRT-D devices, which showed a consistent downward trend (from 87.7% to 76.2%, P < .0001). During CKD hospitalizations, most CRT device implantations were performed in patients aged 65-84 years (68.6%) and in men (74.3%). The most common complication of CRT device implantation during hospitalizations involving CKD was hemorrhage or hematoma (2.7%). Patients hospitalized with CKD who developed any complication associated with CRT device implantation had 3.35-fold increased odds of mortality compared to those without complications (odds ratio, 3.35; 95% confidence interval, 2.18-5.16; P < .0001). In summary, this study shows that CRT-P implantations became more common in CKD patients, while the rate of CRT-D implantations decreased over time. Hemorrhage or hematoma was the most common complication (2.7%), and the mortality risk was increased by 3.35 times in patients who developed periprocedural complications.

Octogenarian with Severe Left Ventricular Dysfunction and Cardiac Resynchronization TherapyDefibrillator Device: Successful Anesthesia Management for Hip Arthroplasty

Cardiac resynchronization therapy has emerged as a key component in management of advanced heart failure with reduced ejection fraction in selected subset of geriatric patients. The burgeoning burden of comorbidities, complexity of these devices and aging population presenting for surgeries necessitates peri-operative physicians to be cognizant and confident to handle these challenging cases. Limited literature about anesthesia management of patients implanted with these devices add to the situational challenge. We present a case of elderly gentleman with ischemic cardiomyopathy and cardiac resynchronization therapy-defibrillator device who underwent hip replacement under general anesthesia. Understanding the disease and the device are the crucial and definitive exigencies to manage such cases.

Image-Based Modelling of Cardiac Mechanics

The main objective of this study was to model the left ventricle (LV) based on 2D echocardiography imaging technique to assess the cardiac mechanics for group of patients affected by heart failure. A prospective study has been made at Ibn Al-Bitar center for cardiac surgery, for 13 patients with heart failure (HF), 9 patients were males (69%) and 4 females (31%). The mean age was 54±7 years. Those patients were supposed to undergo a CRT-D (Cardiac Resynchronization Therapy Defibrillator) implant as they didn’t respond to drug therapy. Before CRT-D implantation, 2D echocardiography was performed for all the patients, to model the left ventricle and to measure indices that were used to evaluate cardiac mechanics which are LV pressure, wall stresses, global longitudinal strain, and cardiac output. After 3-months of follow-up, 2D echocardiography was re-assessed and the left ventricular mechanics has been re-measured. Post CRT-D implantation, significant improvement in the cardiac mechanics was observed in 54% of the patients which were called responders (patients that respond to CRT-D device) and the other patients were called non-responders. It has been seen that, the circumferential wall stresses were decreased in responder’s group while increased or remain unchanged in non-responders. Global longitudinal strain for the responder’s group were increased while remain unchanged in the non-responders. So, patients were divided into responders and non-responders, based on improvement of the cardiac mechanics after 3-moths of follow up. It has been concluded that the modelling of the left ventricle based on images obtained from 2D echocardiography imaging techniques, was an important computational tool that was used to enhance understanding and support the evaluation, surgical guidance and treatment management of basic biophysics underlying cardiac mechanics.

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

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

Corynebacterium striatum Cardiac Device-Related Infective Endocarditis: The First Case Report in a Patient With a Cardiac Resynchronization Therapy Defibrillator Device and Review of the Literature

Corynebacterium striatum (C. striatum) is a skin commensal agent, rarely described as a cause of infective endocarditis. We describe a case of a 48-year-old man, with multiple comorbidities with cardiac resynchronization therapy defibrillator (CRT-D) device implanted 1 year before. A cardiac device-related infective endocarditis (CDRIE) due to C. striatum, with vegetations in the tricuspid valve adjacent to the electrode lead and concomitant lumbar spondylodiscitis were diagnosed. The patient was treated initially with a 6-week course of vancomycin with sterile blood cultures and reduction of inflammatory parameters. Surgery was refused at this stage. Six weeks later, he was readmitted due to C. striatum bacteriemia recurrence, with vegetations adhering to the electrode wire, being treated with daptomycin 10mg/kg body weight, after presenting renal toxicity to vancomycin. CRT-D device was removed with implantation of epicardial cardiac resynchronization therapy pacemaker (CRT-P). To our knowledge, this might be the first description of C. striatum CDRIE in a patient with a CRT-D. In the five cases described in the literature of CDRIE by this agent, early removal of the pacemaker was performed with good results. In this case, the device was removed only after failure of medical treatment alone.

Association Between Industry Payments to Physicians and Device Selection in ICD Implantation

Little is known about the association between industry payments and medical device selection. To examine the association between payments from device manufacturers to physicians and device selection for patients undergoing first-time implantation of a cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D). In this cross-sectional study, patients who received a first-time ICD or CRT-D device from any of the 4 major manufacturers (January 1, 2016-December 31, 2018) were identified. The data from the National Cardiovascular Data Registry ICD Registry was linked with the Open Payments Program's payment data. Patients were categorized into 4 groups (A, B, C, and D) corresponding to the manufacturer from which the physician who performed the implantation received the largest payment. For each patient group, the proportion of patients who received a device from the manufacturer that provided the largest payment to the physician who performed implantation was determined. Within each group, the absolute difference in proportional use of devices between the manufacturer that made the highest payment and the proportion of devices from the same manufacturer in the entire study cohort (expected prevalence) was calculated. Manufacturers' payments to physicians who performed an ICD or CRT-D implantation. The primary outcome of the study was the manufacturer of the device used for the implantation. Over a 3-year period, 145 900 patients (median age, 65 years; 29.6% women) received ICD or CRT-D devices from the 4 manufacturers implanted by 4435 physicians at 1763 facilities. Among these physicians, 4152 (94%) received payments from device manufacturers ranging from $2 to $323 559 with a median payment of $1211 (interquartile range, $390-$3702). Between 38.5% and 54.7% of patients received devices from the manufacturers that had provided physicians with the largest payments. Patients were substantially more likely to receive devices made by the manufacturer that provided the largest payment to the physician who performed implantation than they were from each other individual manufacturer. The absolute differences in proportional use from the expected prevalence were 22.4% (95% CI, 21.9%-22.9%) for manufacturer A; 14.5% (95% CI, 14.0%-15.0%) for manufacturer B; 18.8% (95% CI, 18.2%-19.4%) for manufacturer C; and 30.6% (95% CI, 30.0%-31.2%) for manufacturer D. In this cross-sectional study, a large proportion of ICD or CRT-D implantations were performed by physicians who received payments from device manufacturers. Patients were more likely to receive ICD or CRT-D devices from the manufacturer that provided the highest total payment to the physician who performed an ICD or CRT-D implantation than each other manufacturer individually.

Appropriate and inappropriate therapy in patients with single- or multi-chamber implantable cardioverter-defibrillators

BackgroundInappropriate ICD therapy is associated with adverse outcome. Previous studies indicated that patients with a cardiac resynchronization therapy-defibrillator (CRT-D) might have a lower risk for inappropriate device activations than patients with a single (VVI) or dual chamber (DDD) ICD. MethodsAll ICD recipients from a university cardiac center between 2000 – 2015 were included in this analysis. Outcome parameters were incidence of appropriate and inappropriate therapy and overall mortality. ResultsA total of 1471 patients were analyzed: 629 (43%) patients with a VVI-ICD, 486 (33%) patients with a DDD-ICD and 356 (24%) with a CRT-D device. During an average follow-up of 4.1 ± 3.6 years, CRT-D patients had the lowest risk to receive at least one inappropriate shock therapy (p < 0.001). Rates of appropriate (RR (Rate Ratio) = 0.45, p = 0.019) and inappropriate shock therapy (RR = 0.38, p = 0.021) were significantly lower in CRT-D patients compared to VVI-patients. CRT-D recipients had a lower rate of appropriate shock therapy (RR = 0.323, p = 0.043) compared to DDD patients, but not of inappropriate shock therapy (p = 0.371). Kaplan Meier Analysis did not reveal a significant difference in overall survival (p = 0.396). However, after adjustment for relevant confounding factors, VVI-patients had a higher risk for overall-death (HR = 1.28, p = 0.030). ConclusionsCRT-D recipients have a significantly lower rate of appropriate shock therapy and a lower rate of inappropriate shock therapy. More frequent inappropriate therapies in VVI-ICD recipients may account for their higher overall mortality.

Economic Implications of Longer Battery Longevity of Cardiac Resynchronization Therapy Defibrillator Devices in the United States

Introduction The economic impact of generator longevity differs by indicated patient population, as the magnitude of Cardiac Resynchronization Therapy Defibrillator devices (CRT-Ds) survival benefit varies by indication and so does the expected survival of the patient. The objective of this study is to understand cost savings associated with incremental years of battery life from a U.S. payer perspective. Methods Patient data from 7 prospective trials were used to project expected patient survival. Weibull/Gompertz statistical models were fitted to data from: (a) InSync III Marquis, MIRACLE, MIRACLE ICD, PROSPECT and Adaptive CRT for Class III/IV patients, (b) REVERSE for Class II patients, and (c) BLOCK-HF for AV Block patients. Mean battery longevity scenarios used half-yearly increments. A payer perspective based on the 2018 U.S. Centers for Medicare and Medicaid Services (CMS) Medicare program was used. Results Testing mean battery scenarios from 5.5 to 8.5 years, 6 additional months of device longevity result in average Medicare savings of $2,692 for Class III/IV patients, $5,429 for Class II patients and $3,754 for AV Block patients. Additional economic benefits associated with avoiding changeout-related complications were not included in these device cost projections. Conclusions Increasing CRT-D battery life can result in reductions in device-related cost across all indicated patient groups, with economic benefits being maximized among NYHA Class II subjects. But the relative impact lessens as additional battery years are added.

Association of Titin-Truncating Genetic Variants With Life-threatening Cardiac Arrhythmias in Patients With Dilated Cardiomyopathy and Implanted Defibrillators

There is a need for better arrhythmic risk stratification in nonischemic dilated cardiomyopathy (DCM). Titin-truncating variants (TTNtvs) in the TTN gene are the most common genetic cause of DCM and may be associated with higher risk of arrhythmias in patients with DCM. To determine if TTNtv status is associated with the development of life-threatening ventricular arrhythmia and new persistent atrial fibrillation in patients with DCM and implanted cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) devices. This retrospective, multicenter cohort study recruited 148 patients with or without TTNtvs who had nonischemic DCM and ICD or CRT-D devices from secondary and tertiary cardiology clinics in the United Kingdom from February 1, 2011, to June 30, 2016, with a median (interquartile range) follow-up of 4.2 (2.1-6.5) years. Exclusion criteria were ischemic cardiomyopathy, primary valve disease, congenital heart disease, or a known or likely pathogenic variant in the lamin A/C gene. Analyses were performed February 1, 2017, to May 31, 2017. The primary outcome was time to first device-treated ventricular tachycardia of more than 200 beats/min or first device-treated ventricular fibrillation. Secondary outcome measures included time to first development of persistent atrial fibrillation. Of 148 patients recruited, 117 adult patients with nonischemic DCM and an ICD or CRT-D device (mean [SD] age, 56.9 [12.5] years; 76 [65.0%] men; 106 patients [90.6%] with primary prevention indications) were included. Having a TTNtv was associated with a higher risk of receiving appropriate ICD therapy (shock or antitachycardia pacing) for ventricular tachycardia or fibrillation (hazard ratio [HR], 4.9; 95% CI, 2.2-10.7; P < .001). This association was independent of all covariates, including midwall fibrosis measured by late gadolinium enhancement on cardiac magnetic resonance images (adjusted HR, 8.3; 95% CI, 1.8-37.6; P = .006). Having a TTNtv was also associated with the risk of receiving a shock (HR, 3.6; 95% CI, 1.1-11.6; P = .03). Individuals with a TTNtv and fibrosis had a greater rate of receiving appropriate device therapy than those with neither (HR, 16.6; 95% CI, 3.5-79.3; P < .001). Having a TTNtv was also a risk factor for developing new persistent atrial fibrillation (HR, 3.9; 95% CI, 1.3-12.0; P = .01). Having a TTNtv was an important risk factor for clinically significant arrhythmia in patients with DCM and ICD or CRT-D devices. Having a TTNtv, especially in combination with midwall fibrosis confirmed with cardiovascular magnetic resonance imaging, may provide a risk stratification approach for evaluating the need for ICD therapy in patients with DCM. This hypothesis should be tested in larger studies.

Preliminary Safety and Performance Results of a Two Lead Cardiac Resynchronization Therapy Device: Sub-analysis of the QP ExCELs Post-approval Study

Background Re-intervention due to lead dislodgment and malfunctioning of conventional three lead cardiac resynchronization therapy defibrillator (CRT-D) devices can increase the risk of infection, hospitalization costs, and mortality. Two lead CRT-D (CRT-DX) devices are designed to eliminate the atrial lead while providing physicians with critical diagnostic information based on an atrial signal detected by a floating dipole on the right ventricular lead and can promote fewer lead complications, reduced mortality, reduced procedural complexity, and economic benefit. Objective This analysis evaluates a preliminary subset of patients that have been implanted with a two lead CRT-DX system in the QP ExCELs study. QP ExCELs is a multi-center, prospective, non-randomized post-approval study to confirm long-term safety and efficacy of the BIOTRONIK Sentus QP LV lead. Methods Patients with a standard CRT-D indication were enrolled from the investigators’ general population. Follow-up is scheduled at the pre-discharge/wound check, 3, 6, and 12 months post-implant then every 6 months through 5 years to assess for related adverse events (AEs) and LV lead performance. All lead/system related AEs were adjudicated by an independent clinical events committee. Results At the time of this interim analysis, 39 subjects in the QP ExCELs study had been successfully implanted with a BIOTRONIK Intica 7 HF-T QP CRT-DX (66.7% male, age 63.4 ± 11.9 yrs) at 15 U.S. investigational sites. For all subjects, there were no adverse events adjudicated as related or possibly related to the CRT-DX pulse generator or the DX lead. LV lead performance with the CRT-DX is compared to a conventional three lead system in Table 1 . Conclusion These preliminary results suggest two lead cardiac resynchronization therapy devices are safe, reliable and infrequently associated with AEs. Additional data will be collected and analyzed as subjects continue to be enrolled and followed through 5 years.

Periprocedural Risk and Survival after ICD Placement in Patients with Advanced Heart Failure

Background Implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) are not provided to all patients with heart failure (HF) who qualify clinically for these treatments. Little is known about utilization and outcomes of ICD/CRT-D in patients with advanced HF. Methods A post-hoc analysis was performed of Medicare fee-for-service beneficiaries enrolled in the National Cardiovascular Data Registry's (NCDR®) ICD Registry™ with a diagnosis of HF, an EF ≤35% and evidence of advanced HF defined as NYHA class IV symptoms, inotrope use within the past 60 days, left ventricular assist device (LVAD) in situ , or currently listed for orthotopic heart transplant (OHT). All eligible patients underwent initial ICD/CRT-D placement for primary prevention of sudden cardiac death before January 2015. Cox hazards model was used to test for association with baseline covariates. Results Among 81,492 Medicare patients with EF ≤35% that underwent primary prevention ICD/CDRT-D placement, there were 3,343 advanced-HF patients (4.1%). Amongst advanced HF patients 2,506 (75%) had NYHA class IV symptoms, 676 (20.2%) were currently or recently on inotropes, 129 (3.9%) had an LVAD, and 158 (4.7%) were listed for OHT. Patients had a mean age of 74±9 years and 28.3% were female (N=946). The majority received a CRT-D device (N=2,424, 72.6%). The aggregate in-hospital periprocedural complication rate was 3.74% (95% CI 3.12-4.44) with the majority of adverse events being in-hospital fatalities (1.82%, 95% CI 1.40-2.34) or resuscitated cardiac arrests (1.05%, 95% CI 0.73-1.45). All-cause survival rates are shown in the Figure . Median survival following device implantation was 1,178 days (95% CI 1,013-1,364). After adjusting for potential confounders, females had a lower rate of all-cause death (HR 0.81, 95% CI 0.71-0.93, p Conclusion A small proportion of older patients with advanced HF undergo initial ICD/CRT-D placement for primary prevention. These patients experience clinically important periprocedural complication rates driven by in-hospital deaths and aborted sudden cardiac arrest. Additional prospective research is necessary to clarify the role of primary prevention ICDs in patients with advanced HF.

New Insights into Predictors of Cardiac Implantable Electronic Device Infection.

Infection is an important complication of cardiac implantable electronic device procedures. To further study the factors associated with infection, we retrospectively reviewed the records of 3,205 consecutive patients who had undergone de novo or revision cardiac electronic device implantation at our institution from March 2011 through March 2015. We recorded all infections and specified whether they were related to the characteristics of the patient, device, or procedure. To identify predictors of infection, we performed multivariate analysis. Device infections were identified in 85 patients (2.7%), at a mean follow-up time of 27 ± 11 months. The main predictors of device infection were use of an implantable cardioverter-defibrillator or a cardiac resynchronization therapy defibrillator device (odds ratio [OR]=16; 95% CI, 4.14-61.85; P=0.0001), stage 3 chronic kidney disease (OR=9.41; 95% CI, 1.77-50.04; P=0.009), a revision procedure (OR=8.8; 95% CI, 3.37-23.2; P=0.0001), or postoperative hematoma (OR=6.9; 95% CI, 1.58-30.2; P=0.01). We also identified 2 novel predictors of infection: a low body mass index of <20 kg/m2 (OR=1.03; 95% CI, 1.01-1.06; P=0.005), and use of povidone-iodine rather than chlorhexidine-alcohol for topical antisepsis (OR=4.4; 95% CI, 2.01-9.4; P=0.03). We conclude that comorbidities, device characteristics, procedure types, and postoperative noninfective complications all increase the risk of device infection after a cardiac implantable electronic device procedure.

Beat-to-Beat Variability of Ventricular Action Potential Duration Oscillates at Low Frequency During Sympathetic Provocation in Humans.

Background: The temporal pattern of ventricular repolarization is of critical importance in arrhythmogenesis. Enhanced beat-to-beat variability (BBV) of ventricular action potential duration (APD) is pro-arrhythmic and is increased during sympathetic provocation. Since sympathetic nerve activity characteristically exhibits burst patterning in the low frequency range, we hypothesized that physiologically enhanced sympathetic activity may not only increase BBV of left ventricular APD but also impose a low frequency oscillation which further increases repolarization instability in humans.Methods and Results: Heart failure patients with cardiac resynchronization therapy defibrillator devices (n = 11) had activation recovery intervals (ARI, surrogate for APD) recorded from left ventricular epicardial electrodes alongside simultaneous non-invasive blood pressure and respiratory recordings. Fixed cycle length was achieved by right ventricular pacing. Recordings took place during resting conditions and following an autonomic stimulus (Valsalva). The variability of ARI and the normalized variability of ARI showed significant increases post Valsalva when compared to control (p = 0.019 and p = 0.032, respectively). The oscillatory behavior was quantified by spectral analysis. Significant increases in low frequency (LF) power (p = 0.002) and normalized LF power (p = 0.019) of ARI were seen following Valsalva. The Valsalva did not induce changes in conduction variability nor the LF oscillatory behavior of conduction. However, increases in the LF power of ARI were accompanied by increases in the LF power of systolic blood pressure (SBP) and the rate of systolic pressure increase (dP/dtmax). Positive correlations were found between LF-SBP and LF-dP/dtmax (rs = 0.933, p < 0.001), LF-ARI and LF-SBP (rs = 0.681, p = 0.001) and between LF-ARI and LF-dP/dtmax (rs = 0.623, p = 0.004). There was a strong positive correlation between the variability of ARI and LF power of ARI (rs = 0.679, p < 0.001).Conclusions: In heart failure patients, physiological sympathetic provocation induced low frequency oscillation (~0.1 Hz) of left ventricular APD with a strong positive correlation between the LF power of APD and the BBV of APD. These findings may be of importance in mechanisms underlying stability/instability of repolarization and arrhythmogenesis in humans.

PP-178 - A Novel Use of Cardiac Resynchronization Therapy - Defibrillator Device in Hypertrophic Cardiomyopathy

Dual-chamber implantable cardioverter-defibrillator is generally used in patients with atrioventricular block and hypertrophic cardiomyopathy with preserved left ventricular ejection fraction. In the current case, a cardiac resynchronization therapy-defibrillator device was implanted in a patient with non-obstructive hypertrophic cardiomyopathy with preserved ejection fraction and atrioventricular block to achieve both more physiological pacing and life-threatening ventricular arrhythmia management.

Evaluation of QRS dispersion and its association withtachyarrhythmia events in patients with implantedcardiac resynchronization therapy defibrillator device

Introduction: Heart failure (HF) is one of the major problems of health system in the countries. In a subgroup of these patients, cardiac resynchronization therapy defibrillator (CRT-D) improves the quality of life by enhancing the function of the left ventricle (LV) and preventing of arrhythmias. The present study intends to discuss the effect of CRT-D on the QRS dispersion, as a predisposing factor to arrhythmias. Methods: 45 patients treated with CRT-D during 2012-2015 were enrolled in this study. QRS dispersion in various V-V delays was measured and its association with the incidence of arrhythmias, at least six months after insertion, was assessed. Results: The results showed that QRS dispersion in the intrinsic mode was significantly lower than the other modes of the CRT-D device (P < 0.001). Besides, it was revealed that mean QRS duration in the intrinsic mode had a higher association with arrhythmic events than max QRS duration. QRS dispersion after CRT-D implantation had a significant increase compared to the intrinsic mode. However, it did not correlate with the arithmetic events. Further decrease in the duration of QRS after CRT-D implantation improved arrhythmias. Conclusion: QRS dispersion after CRT-D implantation is not an indicative of arrhythmia risk, and a decrease in the duration of QRS had a more significant effect on the incidence of arrhythmias.

Long-term impact of intrathoracic impedance findings on survival and heart failure hospitalizations after cardiac resynchronization therapy in ICD Registry patients.

To determine adjusted associations among OptiVol® threshold crossings, long-term survival, and hospitalizations among heart failure (HF) patients with Medicare coverage in the United States. A cohort with OptiVol®-enabled cardiac resynchronization therapy defibrillators (CRT-D) devices from the Implantable Cardioverter Defibrillator Registry was linked to both Medicare claims/summary data and Medtronic's CareLink® Network data. An extended multivariable Cox model was used to analyse associations among OptiVol® threshold crossings (treated as time-dependent covariates), mortality, and HF-related hospitalizations (HFH). We analysed N = 1565 patients with OptiVol®-enabled CRT-D devices (mean age 72.8, 28% women). The median follow-up was 6.3 years. Patients with >15.1% of days above OptiVol® threshold (highest quartile) had more than a 4-fold increase in mortality [hazard ratio (HR) 4.2, 95% confidence interval (CI): 3.3-5.3] and more than a 3-fold increase in HFH (HR 3.2, 95% CI: 2.4-4.2) compared with patients having <4.1% of days above threshold (lowest quartile) after adjustment for key covariates. In addition, a single OptiVol® crossing was associated with significantly increased rates of both mortality (HR 1.87, 95% CI: 1.27-2.75) and HFH (HR 1.70, 95% CI: 1.28-2.27). In a CRT-D cohort with over 6 years of follow-up, both single OptiVol® crossings and time above OptiVol® threshold were associated with increased rates of mortality and hospitalization, which has important implications for clinical care. This is the first study integrating device data with Medicare outcomes to validate the long-term significance of OptiVol® findings.

PCI techniques to aid implantation of CRT-D in a senior patient with persistent left superior vena cava.

Persistent left superior vena cava (PLSVC) is a rare congenital anomaly of the vena cava, affecting about 0.5% of the general population, which poses a particular obstacle during transvenous electronic device implantation. Here, we report a successful cardiac resynchronization therapy-defibrillator device (CRT-D) implantation strategy in which techniques and devices for percutaneous coronary intervention were used via a PLSVC.