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BACKGROUND Little is known about health status and quality of life (QoL) after implantable cardioverter-defibrillator (ICD) generator exchange (GE). METHODS We prospectively followed patients undergoing first-time ICD GE. Serial assessments of health status were performed by administering the 36-Item Short Form Survey (SF-36). RESULTS Mean age was 67.5 ± 14.3 years, left ventricle ejection fraction (LVEF) was 36.5% ± 15.0% and over 40% of the cohort had improved LVEF to > 35% at the time of GE. SF-36 scores were significantly worse in physical/general health domains compared to domains of emotional/social well-being (P < 0.001 for each comparison). Physical health scores were significantly worse among those with medical comorbidities including diabetes, chronic obstructive pulmonary disease and atrial fibrillation. Mean follow-up was 1.6 ± 0.5 years after GE. Overall SF-36 scores remained stable across all domains during follow-up. Survival at 3 years post-GE was estimated at 80%. Five patients died during follow-up and most deaths were adjudicated as non-arrhythmic in origin. Four patients experienced appropriate ICD shocks after GE, three of whom had LVEF which remains impaired LVEF (i.e., < 35%) at the time of GE. CONCLUSION Patients undergoing ICD GE have significantly worse physical health compared to emotional/social well-being, which is associated with the presence of medical comorbidities. In terms of clinical outcomes, the incidence of appropriate shocks after GE among those with improvement in LVEF is very low, and most deaths post-procedure appear to be non-arrhythmic in origin. These data represent an attempt to more fully characterize the spectrum of QoL and clinical outcomes after GE. [ABSTRACT FROM AUTHOR]

Background: Wider availability of continuous rhythm monitoring has made feasible the incorporation of metrics of atrial fibrillation (AF) burden and duration into the decision to initiate anticoagulation. However, the relationship between thresholds of burden and duration and underlying risk factors at which anticoagulation should be considered remains unclear.Objective: The purpose of this study was to evaluate the relationships of these metrics with each other and the outcome of stroke/transient ischemic attack (TIA).Methods: We identified patients with cardiovascular implantable electronic devices (CIEDs) with atrial leads who had at least 1 interrogation in 2016 demonstrating nonpermanent AF and were not receiving oral anticoagulation (OAC). We evaluated the relationship between burden (ie, percentage of time spent in AF), the longest single episode of AF, and risk factors (ie, CHA2DS2-VASc score) in predicting risk of stroke/TIA.Results: The study included 384 patients with mean follow-up of 3.2 ± 0.8 years and incidence of stroke/TIA of 14.8% during follow-up (∼4.6% per year). The burden of AF and the duration of longest episode demonstrated a significant positive correlation to each other but not CHA2DS2-VASc score. Importantly, although the CHA2DS2-VASc score was predictive of stroke/TIA, neither burden nor duration was associated with stroke/TIA.Conclusion: Among patients with CIED-detected AF not receiving OAC, the amount of AF (measured by either burden or duration) does not seem to significantly impact stroke risk, whereas CHA2DS2-VASc score does. These data suggest that among patients with CIED-detected AF, once AF occurs, stroke risk seems to be predominantly driven by underlying risk factors. [ABSTRACT FROM AUTHOR]

Micra leadless pacemaker has progressed from a single chamber pacemaker that can deliver VVIR pacing to a pacing device that can provide atrio‐ventricular (AV) synchrony via a unique pacing algorithm that relies on identifying mechanical atrial contraction. This novel algorithm has its own limitations and intricacies. In this paper, we review this algorithm, suggest steps for troubleshooting and programming these devices and provide clinical examples of Micra AV cases that required changes in programming for adequate tracking of atrial activity. [ABSTRACT FROM AUTHOR]

Background: Data on the management of Micra transcatheter pacing system (TPS) at the time of an upgrade or during battery depletion is limited. Objective: We sought to evaluate the management patterns of patients implanted with a Micra TPS during long‐term follow‐up. Methods: We retrospectively identified patients who underwent Micra implantation from April 2014 to November 2019. We identified patients who underwent extraction (n = 11) or had an abandoned Micra (n = 12). Results: We identified 302 patients who received a Micra during the period of the study. Mean age was 72.7 ± 15.4 years, 54.6% were men, and left ventricular ejection fraction was 51.9 ± 5.2%. Mean follow‐up was 1105.5 ± 529.3 days. Procedural complications included pericardial tamponade (n = 1) treated with pericardiocentesis, significant rise in thresholds (n = 6) treated with reimplantation (n = 4), and major groin complications (n = 2). Indications for extraction included an upgrade to cardiac resynchronization therapy (CRT) device (n = 3), bridging after extraction of an infected transvenous system (n = 3), elevated thresholds (n = 3), and non‐Micra‐related bacteremia (n = 2). The median time from implantation to extraction was 78 days (interquartile range: 14–113 days), with the longest extraction occurring at 1442 days. All extractions were successful, with no procedural or long‐term complications. Indications for abandonment included the need for CRT (n = 6), battery depletion (n = 2), increasing thresholds/failure to capture (n = 3), and pacemaker syndrome (n = 1). All procedures were successful, with no procedural or long‐term complications. Conclusion: In this large single‐center study, 6% of patients implanted with a Micra required a system modification during long‐term follow‐up, most commonly due to the requirement for CRT pacing. These patients were managed successfully with extraction or abandonment. [ABSTRACT FROM AUTHOR]

Background: The Micra transcatheter pacemaker is a safe and effective alternative to transvenous permanent pacemakers (TV-PPMs). However, the safety profile and mortality outcomes of Micra implantation in patients deemed poor candidates for TV-PPM are incompletely understood.Objective: The purpose of this study was to evaluate safety and all-cause mortality in patients undergoing Micra implantation stratified by whether they were precluded for therapy with a TV-PPM.Methods: Patients from the Micra clinical trials were divided into groups on the basis of whether the implanter considered the patient to be precluded from receiving a TV-PPM. Micra groups were compared with one another as well as with a historical cohort of patients who received a single-chamber TV-PPM.Results: A total of 2817 patients underwent a Micra implantation attempt, of whom 546 (19%) patients deemed ineligible for TV-PPM implantation for reasons such as venous access issues or prior device infections. Both acute mortality (2.75% vs 1.32%; P=.022) and total mortality at 36 months (38.1% vs 20.6%; P<.001) were significantly higher in the precluded group than in the nonprecluded group. Mortality was similar among nonprecluded patients and patients implanted with a TV-PPM. The major complication rate through 36 months was similar between the 2 Micra groups (3.81% vs 4.30%; P=.40).Conclusion: All-cause mortality is higher in Micra patients deemed ineligible for TV-PPM implantation than in nonprecluded Micra patients and those who received a TV-PPM, in part related to a higher incidence of chronic comorbidities in these patients. The overall major complication rate was low and did not differ by preclusion status.Clinical Trial Registration: Micra Post-Approval Registry ClinicalTrials.gov identifier: NCT02536118; Micra Continued Access Study ClinicalTrials.gov identifier: NCT02488681; Micra Transcatheter Pacing Study ClinicalTrials.gov identifier: NCT02004873; Medtronic Product Surveillance Registry ClinicalTrials.gov identifier: NCT01524276. [ABSTRACT FROM AUTHOR]

Background: Patients with chronic renal disease on hemodialysis (HD) have limited vascular access and are at high risk of bacteremia. The subcutaneous implantable cardioverter-defibrillator (S-ICD) avoids vascular access, so it may be advantageous in this patient population.Objective: The purpose of this study was to report outcomes of patients with end-stage renal disease enrolled in the multicenter S-ICD post-approval study (PAS).Methods: S-ICD PAS patients were stratified on the basis of the presence (group 1) or absence (group 2) of HD at the time of implantation. Baseline demographic and clinical characteristics were collected. Perioperative and intermediate-term outcomes 365 days postimplantation were compared between the 2 groups.Results: There were 220 patients on HD (13.4%) at the time of implantation out of 1637 patients enrolled in the S-ICD PAS. Patients on HD (group 1) were older (57.4 ± 13.2 years vs 52.5 ± 15.2 years; P < .0001), more likely to be of African descent (48.6% vs 25.1%; P < .0001), and had lower ejection fraction (28.6% ± 11.3% vs 32.6% ± 14.9%; P < .0001) as compared with patients not on HD (group 2). Group 1 had more comorbidities and mortality was higher (17.4% vs 3.7%) than did group 2. The rate of complications calculated using the Kaplan-Meier estimate did not differ between the 2 groups (overall P = .9169), with a 1-year rate of 7.9% and 7.7% for groups 1 and 2, respectively. The rate of appropriate shocks was significantly higher in group 1 (Kaplan-Meier analysis, P = .0003), as was inappropriate shocks (P = .0137).Conclusion: S-ICD is associated with similar adverse event rates but a higher risk of inappropriate and appropriate therapy in dialysis patients than in nondialysis patients. [ABSTRACT FROM AUTHOR]

Pacemaker-related infections remain a constant concern due to increased risk of patient morbidity and mortality. Although transvenous pacemakers are expected to have an infection rate ranging from 0.77% to 2.08%, no cases of leadless pacemaker infection have been reported in clinical trials enrolling more than 3000 patients. Many potential reasons why leadless pacemakers may be resistant to infection include the absence of a subcutaneous pocket and leads, reduced skin and glove contact, size, location, and device material. This review summarizes the current state of evidence regarding the apparent infection resistance of leadless pacemakers. [ABSTRACT FROM AUTHOR]

Purpose: Sizing of the left atrial appendage (LAA) ostium prior to occlusion (LAAO) is routinely performed with transesophageal echocardiography (TEE). We sought to compare the utility of sizing via fluoroscopy to TEE for percutaneous LAAO.Methods: We retrospectively evaluated all patients undergoing percutaneous LAAO at our institution from April 2015 through January 2018 (n = 195). We evaluated baseline characteristics, maximum measured ostium size (for both TEE and fluoroscopy), and differences in measured size to device size for both techniques.Results: Of the total cohort, 185 (95%) had both intraoperative TEE and fluoroscopic images available for analysis and were included in the final analysis. The mean age was 74 years and 64% were male. Hypertension was present in 89%, diabetes in 30%, and stroke in 32% of patients. The mean ejection fraction was 51%. The most common LAA morphology was "wind sock" (52%). Measured ostial diameter on fluoroscopy was larger compared with TEE (2.04 ± 3.43 mm larger on fluoroscopy, p < 0.001). Ostium diameter on TEE was more closely correlated to the size of the device implanted compared with fluoroscopy (0.76 vs. 0.61, p = 0.001).Conclusions: Fluoroscopy results in larger estimated LAA ostium diameter compared with TEE. Despite this, TEE was more strongly correlated to operator choice in device sizing, which may reflect practice patterns. Because compression of the ostium on the device is necessary for long-term procedural success, under-sizing may lead to a higher rate of leaks. Prospective evaluation of the utility of routine fluoroscopic sizing compared with TEE is warranted. [ABSTRACT FROM AUTHOR]

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) has shown favorable outcomes in large registries with broad inclusion criteria. The cohorts reported had less heart disease and fewer comorbidities than standard ICD populations.Objective: The purpose of this study is to characterize acute performance for primary prevention patients with a left ventricular ejection fraction (LVEF) ≤35% (primary prevention ≤35%).Methods: Primary prevention ≤35% patients with no prior documented sustained ventricular tachycardia (VT), pacing indication, end-stage heart failure, or advanced renal failure were prospectively enrolled. Analyses included descriptive statistics, Kaplan-Meier time to event, and multivariable linear and logistic regression.Results: In 1112 of 1116 patients, an S-ICD was successfully implanted (99.6%). Predictors for longer procedure time included 3-incision technique, higher body mass index (BMI), performing defibrillation testing (DFT), imaging, younger age, black race, and European vs North American centers. Patients undergoing DFT (82%) were successfully converted (99.2%; 93.5% converting at ≤65 J). Higher BMI was predictive of failing DFT at ≤65 J. The rate of 30-day freedom from complications was 95.8%. Most complications involved postoperative healing (45%) or interventions after DFT or impedance check (19%).Conclusion: The procedural outcome data of UNTOUCHED reinforce that S-ICD therapy has low perioperative complication rates and high conversion efficacy of induced ventricular fibrillation, even in a higher-risk cohort with low LVEF and more comorbidities than previous S-ICD studies. Higher BMI warrants more careful attention to implant technique. [ABSTRACT FROM AUTHOR]

Aims: Patient selection is a key component of securing optimal patient outcomes with leadless pacing. We sought to describe and compare patient characteristics and outcomes of Micra patients with and without a primary pacing indication associated with atrial fibrillation (AF) in the Micra IDE trial.Methods and Results: The primary outcome (risk of cardiac failure, pacemaker syndrome, or syncope related to the Micra system or procedure) was compared between successfully implanted patients from the Micra IDE trial with a primary pacing indication associated with AF or history of AF (AF group) and those without (non-AF group). Among 720 patients successfully implanted with Micra, 228 (31.7%) were in the non-AF group. Reasons for selecting VVI pacing in non-AF patients included an expectation for infrequent pacing (66.2%) and advanced age (27.2%). More patients in the non-AF group had a condition that precluded the use of a transvenous pacemaker (9.6% vs. 4.7%, P = 0.013). Atrial fibrillation patients programmed to VVI received significantly more ventricular pacing compared to non-AF patients (median 67.8% vs. 12.6%; P < 0.001). The overall occurrence of the composite outcome at 24 months was 1.8% with no difference between the AF and non-AF groups (hazard ratio 1.36, 95% confidence interval 0.45-4.2; P = 0.59).Conclusion: Nearly one-third of patients selected to receive Micra VVI therapy were for indications not associated with AF. Non-AF VVI patients required less frequent pacing compared to patients with AF. Risks associated with VVI therapy were low and did not differ in those with and without AF. [ABSTRACT FROM AUTHOR]