Accurate Detection of Lead Malfunction From ECG-derived Bipolar Pacing Stimulus Amplitude.

BACKGROUND: One common mode of lead failure is insulation breach which may result in myopotential noise and device malfunction. "Pseudo-unipolarization" of bipolar pacing stimuli, as observed from a routine 12-lead ECG due to stimulus current leak has been observed with insulation breaches. OBJECTIVE: We sought to characterize this ECG finding to detect lead this type of lead malfunction. METHODS: 138 transvenous leads were analyzed, including 88 with known malfunction and 50 normal leads. The amplitude of a bipolar pacing stimulus on ECG was recorded and compared to a control dataset of newly implanted leads with bipolar stimuli normalized for output. RESULTS: The malfunction group consisted of 61% RA and 39% RV leads with mean pacing output 2.74V at 0.5ms. There was a significant difference in ECG bipolar stimulus amplitudes at time of identification of failure (7.89 ± 7.56mm per V, p<0.001) compared to those of normal leads (0.86 ± 0.41mm per V). ROC curve for the prediction of lead malfunction based on absolute EKG amplitude displayed an area under curve of 0.93 (95% CI 0.891- 0.969). When normalized for programmed stimulus output, a cutoff of 5mm/V demonstrated a sensitivity of 91% and a specificity of 92% (AUC 0.967 95% CI 0.938-0.996). CONCLUSION: The maximum amplitude of a bipolar pacing stimulus on ECG is significantly lower in normal functioning leads compared to those with known malfunction. This simply-derived variable demonstrated good accuracy at identifying lead failure due to insulation breach.

Impact of omitting the intravenous heparin bolus on outcomes of leadless pacemaker implantation.

BACKGROUND: Early guidance recommended a bolus of intravenous heparin at the beginning of leadless pacemaker (LP) implantation procedures. However, due to concern about bleeding complications, more recent practice has tended toward omitting the bolus and only running a continuous heparin infusion through the introducer sheath. The impact of omitting the heparin bolus on procedural outcomes is not clear. METHODS: We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. The decision to bolus with heparin was at operator discretion. RESULTS: Among 621 LP implants, 326 received an intravenous heparin bolus, 243 did not, and 52 patients were excluded because heparin bolus status could not be confirmed. There was a trend toward more frequent omission of the heparin bolus with more recent implants. Median follow-up after LP implant was 14.3 (interquartile range [IQR]: 8.4-27.9) months. There was no difference between heparin bolus and no bolus groups in the number of device deployments/recaptures (1.42 ± 0.81 vs. 1.31 ± 0.66, p = .15). Implant-related adverse events were also similar between heparin bolus and no bolus groups: access-site hematoma requiring intervention (7 vs. 5, p = .99), pseudoaneurysm (1 vs. 1, p = .99), cardiac perforation (1 vs. 1, p = .99), intraprocedural device thrombus formation (2 vs. 4, p = .41), 30-day rehospitalization (21 vs. 15, p = .98), and 30-day all-cause mortality (16 vs. 14, p = .70). There was one additional nonfatal cardiac perforation in a patient who was excluded due to unknown heparin bolus status. Regarding device electrical parameters between heparin bolus and no bolus groups, there were no significant differences at the time of implant: pacing capture threshold 0.5 ± 0.4 vs. 0.5 ± 0.3, p = .10; pacing impedance 739.9 ± 226.4 vs. 719.1 ± 215.4, p = .52; R wave sensing 11.7 ± 5.7 vs. 12.0 ± 5.4, p = .34). Long-term device performance was also similar between groups. CONCLUSION: Omission of the systemic heparin bolus at the time of LP implantation appears safe in appropriately selected patients. Heparin bolus may still be considered in long cases requiring multiple device deployments or in patients at high risk for thrombotic complications.

Pacing and Defibrillation Consideration in the Era of Transcatheter Tricuspid Valve Replacement.

PURPOSE OF REVIEW: Tricuspid regurgitation is a commonly encountered valvular pathology in patients with trans-tricuspid pacing or implantable cardioverter-defibrillator leads. Transcatheter tricuspid valve interventions are increasingly performed in patients at high surgical risk. Implantation of these valves can lead to the "jailing" of a trans-tricuspid lead. This practice carries both short- and long-term risks of lead failure and subsequent infection without the ability to perform traditional transvenous lead extraction. Herein, this manuscript reviews available therapeutic options for lead management in patients undergoing transcatheter tricuspid valve interventions. RECENT FINDINGS: The decision to jail a lead may be appropriate in certain high-risk cases, though extraction may be a better option in most cases given the variety of options for re-implant, including leadless pacemakers, valve-sparing systems, epicardial leads, leads placed directly through prosthetic valves, and the completely subcutaneous implantable-defibrillator. A growing number of patients meet the requirement for CIED implantation in the United States. A significant proportion of these patients will have tricuspid valve dysfunction, either related to or independent of their transvenous lead. As with any percutaneous intervention that has shown efficacy, the role of TTVI is also likely to increase as this therapy advances beyond the investigational phase. As such, the role of the heart team in the management of these patients will be increasingly critical in the years to come, and in those patients that have pre-existing CIED leads, we advocate for the involvement of an electrophysiologist in the heart team.

Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers.

BACKGROUND: Leadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing. OBJECTIVE: The purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation. METHODS: Consecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4). RESULTS: Eighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m2) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V1, V2) and BMI-adjusted (I, II, aVL, aVF, aVR, V1, V2) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V1 and aVL was predictive, with specificity of 83% (95% confidence interval 67%-100%) for A4 signal ≥1 m/s2. We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013). CONCLUSION: P-wave amplitudes in ECG leads aVL and V1 can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

BACKGROUND AND AIMS: Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. METHODS: All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. RESULTS: 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). CONCLUSIONS: Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Recurrence of new-onset post-operative AF after cardiac surgery: detected by implantable loop recorders: A systematic review and Meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is one of the most common complications after cardiac surgery. New-onset post-operative AF may signal an elevated risk of AF and associated outcomes in long-term follow-up. We aimed to estimate the rate of AF recurrence as detected by an implantable loop recorder (ILR) in patients experiencing post-operative AF within 30 days after cardiac surgery. METHODS: We searched MEDLINE, Embase and Cochrane CENTRAL to April 2023 for studies of adults who did not have known AF, experienced new-onset AF within 30 days of cardiac surgery and received an ILR. We pooled individual participant data on timing of AF recurrence using a random-effects model with a frailty model applied to a Cox proportional hazard analysis. RESULTS: From 8671 citations, 8 single-centre prospective cohort studies met eligibility criteria. Data were available from 185 participants in 7 studies, with a median follow-up of 1.7 (IQR: 1.3-2.8) years. All included studies were at a low risk of bias. Pooled AF recurrence rates following 30 post-operative days were 17.8% (95% CI 11.9%-23.2%) at 3 months, 24.4% (17.7%-30.6%) at 6 months, 30.1% (22.8%-36.7%) at 12 months and 35.3% (27.6%-42.2%) at 18 months. CONCLUSIONS: In patients who experience new-onset post-operative AF after cardiac surgery, AF recurrence lasting at least 30 s occurs in approximately 1 in 3 in the first year after surgery. The optimal frequency and modality to use for monitoring for AF recurrence in this population remain uncertain.

Outcomes of tricuspid regurgitation after lead extraction.

INTRODUCTION: Transvenous leads have been implicated in tricuspid valve (TV) dysfunction, but limited data are available regarding the effect of extracting leads across the TV on valve regurgitation. The aim of this study is to quantify tricuspid regurgitation (TR) before and after lead extraction and identify predictors of worsening TR. METHODS: We studied 321 patients who had echocardiographic data before and after lead extraction. TR was graded on a scale (0 = none/trivial, 1 = mild, 2 = moderate, 3 = severe). A change of >1 grade following extraction was considered significant. RESULTS: A total of 321 patients underwent extraction of a total of 338 leads across the TV (1.05 ± 0.31 leads across the TV per patient). There was no significant difference on average TR grade pre- and postextraction (1.18 ± 0.91 vs. 1.15 ± 0.87; p = 0.79). TR severity increased after extraction in 84 patients, but was classified as significantly worse (i.e., >1 grade change in severity) in only 8 patients (2.5%). Use of laser lead extraction was associated with a higher rate of worsening TR postextraction (44.0% vs. 31.6%, p = 0.04). CONCLUSION: In our single-center analysis, extraction of leads across the TV did not significantly affect the extent of TR in most patients. Laser lead extraction was associated with a higher rate of worsening TR after extraction.

Predictive value of the PRAETORIAN score for defibrillation test success in patients with subcutaneous ICD: A subanalysis of the PRAETORIAN-DFT trial.

BACKGROUND: The PRAETORIAN score estimates the risk of failure of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy by using generator and lead positioning on bidirectional chest radiographs. The PRospective randomized compArative trial of subcutanEous implanTable cardiOverter-defibrillatoR ImplANtation with and without DeFibrillation Testing (PRAETORIAN-DFT) investigates whether PRAETORIAN score calculation is noninferior to defibrillation testing (DFT) with regard to first shock efficacy in spontaneous events. OBJECTIVE: This prespecified subanalysis assessed the predictive value of the PRAETORIAN score for defibrillation success in induced ventricular arrhythmias. METHODS: This multicenter investigator-initiated trial randomized 965 patients between DFT and PRAETORIAN score calculation after de novo S-ICD implantation. Successful DFT was defined as conversion of induced ventricular arrhythmia in <5 seconds from shock delivery within 2 attempts. Bidirectional chest radiographs were obtained after implantation. The predictive value of the PRAETORIAN score for DFT success was calculated for patients in the DFT arm. RESULTS: In total, 482 patients were randomized to undergo DFT. Of these patients, 457 (95%) underwent DFT according to protocol, of whom 445 (97%) had successful DFT and 12 (3%) had failed DFT. A PRAETORIAN score of ≥90 had a positive predictive value of 25% for failed DFT, and a PRAETORIAN score of <90 had a negative predictive value of 99% for successful DFT. A PRAETORIAN score of ≥90 was the strongest independent predictor for failed DFT (odds ratio 33.77; confidence interval 6.13-279.95; P < .001). CONCLUSION: A PRAETORIAN score of <90 serves as a reliable indicator for DFT success in patients with S-ICD, and a PRAETORIAN score of ≥90 is a strong predictor for DFT failure.

Update on Cardiovascular Implantable Electronic Device Infections and Their Prevention, Diagnosis, and Management: A Scientific Statement From the American Heart Association: Endorsed by the International Society for Cardiovascular Infectious Diseases.

The American Heart Association sponsored the first iteration of a scientific statement that addressed all aspects of cardiovascular implantable electronic device infection in 2010. Major advances in the prevention, diagnosis, and management of these infections have occurred since then, necessitating a scientific statement update. An 11-member writing group was identified and included recognized experts in cardiology and infectious diseases, with a career focus on cardiovascular infections. The group initially met in October 2022 to develop a scientific statement that was drafted with front-line clinicians in mind and focused on providing updated clinical information to enhance outcomes of patients with cardiovascular implantable electronic device infection. The current scientific statement highlights recent advances in prevention, diagnosis, and management, and how they may be incorporated in the complex care of patients with cardiovascular implantable electronic device infection.

Outcomes of patients implanted with an atrioventricular synchronous leadless ventricular pacemaker in the Medicare population.

BACKGROUND: The Micra AV Coverage with Evidence Development study is a novel analysis of utilization and outcomes associated with Micra AV leadless pacing in US Medicare patients. OBJECTIVE: The purpose of this study was to describe patient characteristics, complications, and outcomes of patients implanted with a Micra AV leadless pacemaker compared with a contemporaneous cohort of patients implanted with a dual chamber transvenous pacemaker. METHODS: Patients implanted with Micra AV (n = 7471) or a dual chamber transvenous pacemaker (n = 107,800) from February 5, 2020, through December 1, 2021, were identified using device registry-linked Medicare claims data. Acute complications were assessed at 30 days, and chronic complications, reinterventions, and all-cause mortality were assessed at 6 months. RESULTS: Patients implanted with Micra AV had higher rates of end-stage renal disease (14.9% vs 2.0%; P < .0001) and overall comorbidity burden (mean Charlson Comorbidity Index 4.9 vs 3.8; P < .0001). There was no difference in the unadjusted rate of complications at 30 days (9.1% vs 8.7%; P = .61), and patients implanted with Micra AV had a significantly lower adjusted rate of complications (8.6% vs 11.0%; P < .0001). At 6 months, patients implanted with Micra AV had significantly lower rates of complications (adjusted hazard ratio 0.50; 95% confidence interval 0.43-0.57; P < .0001) and reinterventions (adjusted hazard ratio 0.46; 95% confidence interval 0.36-0.58; P < .0001). Patients implanted with Micra AV had higher all-cause mortality at 30 days and 6 months, likely because of differences in the underlying risk of mortality. CONCLUSION: Patients implanted with Micra AV had similar rates of complications at 30 days and significantly lower rates of complications and reinterventions at 6 months, despite being sicker than patients implanted with a transvenous pacemaker.

Long-term performance of single-connector (DF4) implantable defibrillator leads.

AIMS: Single-connector (DF4) defibrillator leads have become the predominantly implanted transvenous implantable cardioverter-defibrillator lead. However, data on their long-term performance are derived predominantly from manufacturer product performance reports. METHODS AND RESULTS: We reviewed medical records in 5289 patients with DF4 leads between 2011 and 2023 to determine the frequency of lead-related abnormalities. We defined malfunction as any single or combination of electrical abnormalities requiring revision including a sudden increase (≥2×) in stimulation threshold, a discrete jump in high-voltage impedance, or sensing of non-physiologic intervals or noise. We documented time to failure, predictors of failure, and management strategies. Mean follow-up after implant was 4.15 ± 3.6 years (median = 3.63), with 37% of leads followed for >5 years. A total of 80 (1.5%) leads demonstrated electrical abnormalities requiring revision with an average time to failure of 4 ± 2.8 years (median = 3.5). Of the leads that malfunctioned, 62/80 (78%) were extracted and replaced with a new lead and in the other 18 cases, malfunctioned DF4 leads were abandoned, and a new lead implanted. In multivariable models, younger age at implant (OR 1.03 per year; P < 0.001) and the presence of Abbott/St. Jude leads increased the risk of malfunction. CONCLUSION: DF4 defibrillator leads demonstrate excellent longevity with >98.3% of leads followed for at least 5 years still functioning normally. Younger age at implant and lead manufacturer are associated with an increased risk of DF4 lead malfunction. The differences in lead survival between manufacturers require further investigation.

Complex repolarization dynamics in ex vivo human ventricles are independent of the restitution properties.

AIMS: The mechanisms of transition from regular rhythms to ventricular fibrillation (VF) are poorly understood. The concordant to discordant repolarization alternans pathway is extensively studied; however, despite its theoretical centrality, cannot guide ablation. We hypothesize that complex repolarization dynamics, i.e. oscillations in the repolarization phase of action potentials with periods over two of classic alternans, is a marker of electrically unstable substrate, and ablation of these areas has a stabilizing effect and may reduce the risk of VF. To prove the existence of higher-order periodicities in human hearts. METHODS AND RESULTS: We performed optical mapping of explanted human hearts obtained from recipients of heart transplantation at the time of surgery. Signals recorded from the right ventricle endocardial surface were processed to detect global and local repolarization dynamics during rapid pacing. A statistically significant global 1:4 peak was seen in three of six hearts. Local (pixel-wise) analysis revealed the spatially heterogeneous distribution of Periods 4, 6, and 8, with the regional presence of periods greater than two in all the hearts. There was no significant correlation between the underlying restitution properties and the period of each pixel. CONCLUSION: We present evidence of complex higher-order periodicities and the co-existence of such regions with stable non-chaotic areas in ex vivo human hearts. We infer that the oscillation of the calcium cycling machinery is the primary mechanism of higher-order dynamics. These higher-order regions may act as niduses of instability and may provide targets for substrate-based ablation of VF.

Outcomes of leadless pacemaker implantation after cardiac surgery and transcatheter structural valve interventions.

INTRODUCTION: Permanent pacing indications are common after cardiac surgery and transcatheter structural valve interventions. Leadless pacemakers (LPs) have emerged as a useful alternative to transvenous pacemakers. However, current commercially available LPs are unable to provide atrial pacing or cardiac resynchronization and relatively little is known about LP outcomes after cardiac surgery and transcatheter valve interventions. METHODS: This retrospective study included patients who received a Micra VR (MicraTM MC1VR01) or Micra AV (MicraTM MC1AVR1) (Medtronic) leadless pacemaker following cardiac surgery or transcatheter structural valve intervention between September 2014 and September 2022. Device performance and clinical outcomes, including ventricular pacing burden, ejection fraction, and need for conversion to transvenous pacing systems, were evaluated during follow-up. RESULTS: A total of 78 patients were included, of whom 40 received a Micra VR LP implant, and 38 received a Micra AV LP implant. The mean age of the cohort was 65.9 ± 17.9 years, and 48.1% were females. The follow-up duration for the entire cohort was 1.3 ± 1.1 years: 1.6 ± 1.3 years for the Micra VR group and 0.8 ± 0.5 years for the Micra AV group. Among the cohort, 50 patients had undergone cardiac surgery and 28 underwent transcatheter structural valve interventions. Device electrical performance was excellent during follow-up, with a small but clinically insignificant increase in ventricular pacing threshold and a slight decrease in pacing impedance. The mean right ventricle pacing (RVP) burden significantly decreased over time in the entire cohort (74.3% ± 37.2% postprocedure vs. 47.7% ± 40.6% at last follow-up, p < .001), and left ventricle ejection fraction (LVEF) showed a modest but significant downward trend during follow-up (55.0% ± 10.6% vs. 51.5% ± 11.2% p < .001). Patients with Micra VR implants had significantly reduced LVEF during follow-up (54.1% ± 11.9% vs. 48.8% ± 11.9%, p = .003), whereas LVEF appeared stable in the Micra AV group during follow-up (56.1% ± 9.0% vs. 54.6% ± 9.7%, p = .06). Six patients (7.7%) required conversion to transvenous pacing systems, four who required cardiac resynchronization for drop in LVEF with high RVP burden and two who required dual-chamber pacemakers for symptomatic sinus node dysfunction. CONCLUSION: Leadless pacemakers provide a useful alternative to transvenous pacemakers in appropriately selected patients after cardiac surgery and transcatheter structural valve interventions. Device performance is excellent over medium-term follow-up. However, a significant minority of patients require conversion to transvenous pacing systems for cardiac resynchronization or atrial pacing support, demonstrating the need for close electrophysiologic follow-up in this cohort.

Adaptive versus conventional cardiac resynchronisation therapy in patients with heart failure (AdaptResponse): a global, prospective, randomised controlled trial.

BACKGROUND: Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block. METHODS: This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual. FINDINGS: Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group. INTERPRETATION: Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials. FUNDING: Medtronic.

Safety of same-day discharge after lead extraction procedures.

BACKGROUND: Same-day discharge (SDD) after cardiovascular procedures is rapidly gaining ground. OBJECTIVE: We sought to evaluate the safety of SDD after transvenous lead extraction (TLE). METHODS: We performed a retrospective chart review of patients who underwent elective TLE between January 2020 and October 2021 at our institution. The primary outcome was SDD, and major procedural complications and readmissions within 30 days of the procedure were secondary outcomes. RESULTS: In this analysis of 111 patients who underwent elective TLE, 80 patients (72%) were discharged on the same day (SDD group) while 31 patients (28%) stayed overnight (overnight group). Lead malfunction was the most common indication for TLE in both groups. Patients in the overnight group were more likely to have a lead dwell time of ≤10 years than those in the SDD group (38.7% vs 20% of all leads in each group; P = .042), have laser sheaths used for extraction and a higher number of leads extracted. No major complications were reported in both groups. In a multivariate analysis, lower body mass index and the use of laser sheath during TLE were predictors of overnight stay. Patients who underwent a procedure using advanced extraction techniques were 3.5 times more likely to stay overnight (95% confidence interval 1.27-9.78; P = .016). CONCLUSION: In appropriately selected patients undergoing elective lead extraction, SDD is feasible and safe. Higher body mass index, fewer extracted leads, shorter lead dwell times (<10 years), and less frequent use of laser-powered extraction sheaths were associated with an increased likelihood of SDD.

Postapproval Study of a Subcutaneous Implantable Cardioverter-Defibrillator System.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to avoid complications related to transvenous implantable cardioverter-defibrillator (TV-ICD) leads. Device safety and efficacy were demonstrated previously with atypical clinical patients or limited follow-up. OBJECTIVES: The S-ICD PAS (Subcutaneous Implantable Cardioverter-Defibrillator System Post Approval Study) is a real-world, multicenter, registry of U.S. centers that was designed to assess long-term S-ICD safety and efficacy in a diverse group of patients and implantation centers. METHODS: Patients were enrolled in 86 U.S. centers with standard S-ICD indications and were observed for up to 5 years. Efficacy endpoints were first and final shock efficacy. Safety endpoints were complications directly related to the S-ICD system or implantation procedure. Endpoints were assessed using prespecified performance goals. RESULTS: A total of 1,643 patients were prospectively enrolled, with a median follow-up of 4.2 years. All prespecified safety and efficacy endpoint goals were met. Shock efficacy rates for discrete episodes of ventricular tachycardia or ventricular fibrillation were 98.4%, and they did not differ significantly across follow-up years (P = 0.68). S-ICD-related and electrode-related complication-free rates were 93.4% and 99.3%, respectively. Only 1.6% of patients had their devices replaced by a TV-ICD for a pacing need. Cumulative all-cause mortality was 21.7%. CONCLUSIONS: In the largest prospective study of the S-ICD to date, all study endpoints were met, despite a cohort with more comorbidities than in most previous trials. Complication rates were low and shock efficacy was high. These results demonstrate the 5-year S-ICD safety and efficacy for a large, diverse cohort of S-ICD recipients. (Subcutaneous Implantable Cardioverter-Defibrillator [S-ICD] System Post Approval Study [PAS]; NCT01736618).

Novel use of an irrigated ablation catheter to monitor real-time hemodynamics during ablation.

INTRODUCTION: Hemodynamic decompensation during catheter ablation occurs due to prolonged procedure time and irrigant delivery directly into the cardiac chambers. Real-time hemodynamic monitoring of patients undergoing catheter ablation procedures may identify patients at risk of decompensation; we set out to assess the feasibility of a novel, real-time, intracardiac pressure monitoring system using a standard irrigated ablation catheter. METHODS: We studied 13 consecutive who underwent pressure measurement of the left atrium (LA) and left ventricle (LV) via transeptal access with a Swan Ganz (SG) catheter followed by two commercially available irrigated ablation catheters. Pressure waveform data was extracted to compare LA peak pressure, LV peak systolic pressure, LV end-diastolic pressure, and waveform analysis. RESULTS: Comparison between the SG and ablation catheters (AblA; AblB) demonstrated that LV systolic pressure (0.61-16.8 mmHg; 1.32-18.2 mmHg), and LV end-diastolic pressure (-3.4 to 2.8 mmHg; -3.0 to 3.35 mmHg) were well correlated and had accepted repeatability. Ablation waveforms demonstrated an 89.9 ± 6.4% correlation compared to SG waveforms. CONCLUSION: Pressure measurements derived from an irrigated ablation catheter are accurate and reliable when compared to an SG catheter. Further studies are needed to determine how real-time pressure monitoring can improve outcomes during ablation procedures.