Leadless pacemaker tine damage and fracture: novel complications of a novel device fixation mechanism.

Background: Leadless pacemakers represent a paradigm-changing advancement. However, they required innovative and novel device design, including the use of nitinol tines for fixation. Objective: We aimed to understand the potential for fracture in the novel tine-based fixation mechanism. Methods: A retrospective approach was used to search the MAUDE (Manufacturer and User Facility Device Experience) database for events related to Micra pacemaker tine fracture and damage. Review of each report was performed to ascertain frequency of tine fracture and damage. Results: Of 4241 MAUDE reports (2104 Micra VR, 2167 Micra AV), 230 included the terms "fracture" or "tine," which yielded 7 tine fractures and 19 reports of tine damage. Overall, 2 (29%) of 7 tine fractures were noted during implantation, whereas 2 (29%) of 7 were discovered ≥1 week after implantation; 5 (71%) of 7 tine fracture reports described no associated patient signs or symptoms, and 4 (57%) of 7 described no change in pacing parameters. Tine damage occurred during implantation in 16 (84%) of 19, compared with 2 (11%) of 19 noted ≥1 week after implantation; 15 (79%) of 19 tine damage cases reported no associated signs or symptoms, and 7 (37%) of 19 described no changes in pacing parameters. Among all cases, there was 1 case of device embolization. Conclusion: The novel tine-based fixation mechanism appears susceptible to a novel failure mechanism-tine fracture and/or damage. Our analysis suggests these events may not always be associated with adverse signs or symptoms. Diligent attention at implantation, and future bench or clinical studies are needed to understand the rate, clinical impact, and mechanism of such failures, and role of surveillance.

Protocol Development and Initial Experience With Intravenous Sotalol Loading for Atrial Arrhythmias.

BACKGROUND: Oral sotalol is a class III antiarrhythmic commonly used for the maintenance of sinus rhythm in patients with atrial fibrillation (AF). Recently, the Food and Drug Administration (FDA) approved the use of IV sotalol loading, based primarily on modeling data for the infusion. We aimed to describe a protocol and experience with IV sotalol loading for elective treatment of adult patients with AF and atrial flutter (AFL). METHODS: We present our institutional protocol and retrospective review of initial patients treated with IV sotalol for AF/AFL at the University of Utah Hospital between September 2020 and April 2021. RESULTS: Eleven patients received IV sotalol for initial loading or dose escalation. All patients were male, aged 56-88 years (median 69). Mean QT interval (QTc) intervals increased from baseline (mean 384 ms) immediately after infusion of IV sotalol (mean change 42ms), but no patient required discontinuation of the medication. Six patients were discharged after 1 night; 4 patients were discharged after 2 nights; and 1 patient was discharged after 4 nights. Nine patients underwent electrical cardioversion prior to discharge (2 prior to load; 7 post-load on the day of discharge). There were no adverse events during the infusion or within 6 months of discharge. Persistence of therapy was 73% (8 of 11) at mean 9.9 weeks to follow up, with no discontinuations for adverse effects. CONCLUSIONS: We employed a streamlined protocol that was successfully implemented to facilitate the use of IV sotalol loading for atrial arrhythmias. Our initial experience suggests feasibility, safety, and tolerability while reducing hospitalization duration. Additional data are needed to augment this experience as IV sotalol use is broadened across different patient populations.

Externalized conductors and electrical dysfunction in transvenous ventricular leads: Results of the Cardiac Lead Assessment Study.

Background: The Cardiac Lead Assessment Study (CLAS) was a large prospective, multicenter, international postmarket surveillance study conducted at 45 sites. Objective: The purpose of CLAS was to examine the prevalence and incidence of externalized conductors and electrical dysfunction in subjects with selected St. Jude Medical defibrillator and left ventricular leads. Methods: Cinefluoroscopy was used to determine the presence of externalized conductors at enrollment and at 12-, 24-, and 36-month follow-up visits. Lead electrical measurements were collected systematically. Results: The study enrolled 2216 subjects with a total of 2847 study leads. The prevalence of externalized conductors through 36 months for Riata leads was 30.9%, Riata ST leads 12.6%, Durata leads 0.5%, and QuickSite/QuickFlex leads 4.7%. The prevalence of electrical dysfunction through 36 months for Riata was 4.0%, Riata ST 3.3%, Durata 2.4%, and QuickSite/QuickFlex 0.3%. In Riata and Riata ST leads with externalized conductors, there was a low risk of electrical dysfunction. None of the Durata or QuickSite/QuickFlex leads with externalized conductors developed electrical dysfunction. There was no evidence of an electrical short in a high-voltage shocking circuit leading to failed shock. Conclusion: A high prevalence of externalized conductors was found in Riata and Riata ST defibrillator leads, with a higher risk of externalization for 8F Riata leads than for 7F Riata ST leads. The 98% reduction in prevalence of externalized conductors in Durata leads compared to Riata/Riata ST leads confirms that the design improvements culminating in Durata leads significantly improved abrasion resistance and durability.

Successful avoidance of superior vena cava injury during transvenous lead extraction using a tandem femoral-superior approach.

BACKGROUND: Transvenous pacemaker and defibrillator lead extraction is a higher risk procedure with variation in preferred technique. A frequently fatal complication of this procedure is perforation of the superior vena cava. We have developed a tandem femoral-superior technique that incorporates snaring of targeted leads from a femoral approach combined with use of a rotational cutting sheath advanced over the lead from the subclavian vein. OBJECTIVE: We sought to evaluate the safety and efficacy of a tandem femoral-superior approach to lead extraction. METHODS: Consecutive patients undergoing transvenous extraction of at least 1 pacemaker or defibrillator lead with implant duration ≥1 year in which a tandem femoral-superior technique was used as the initial extraction strategy were included. The registry spanned 2010-2018 and consisted of procedures performed by a single primary operator. RESULTS: A total of 131 patients were included. A total of 267 leads with a mean implant duration of 9.8 years, including 90 defibrillator leads (33.7%), were targeted for extraction. No superior vena cava perforation or other vascular damage occurred. Clinical procedural success was achieved in 96.2% of cases. There were 5 major complications (3.8% of patients), with 3 being pericardial effusion requiring intervention. There were no deaths. CONCLUSION: A tandem femoral-superior approach to lead extraction effectively eliminated superior vena cava injury. This is a safe and effective technique for transvenous lead extraction.

ILEEM-survey on the Heart Team approach and team training for lead extraction procedures.

BACKGROUND: The Heart Team approach has become an integral part of modern cardiovascular medicine. To evaluate current opinions and real-world practice among lead extraction practitioners, an online survey was created and distributed among a pool of lead extraction specialists participating in the International Lead Extraction Expert Meeting (ILEEM) 2018. METHODS: The online survey consisted of 10 questions and was performed using an online survey tool (www.surveymonkey.com). The collector link was sent to 48 lead extraction experts via email. RESULTS: A total of 43 answers were collected (89% return rate) from lead extraction experts in 16 different countries. A great majority (83.7%) of the respondents performed more than 30 lead extraction procedures per year. The most common procedural environment in this survey was the hybrid operating room (67.4%). Most procedures were performed by electrophysiologists and cardiologists (80.9%). Important additional members of the current lead extraction teams were cardiac surgeons (79.1%), anesthesiologists (95.3%) and operating room scrub nurses (76.7%). An extended Heart Team is regarded beneficial for patient care by 86.0%, with potential further members being infectious diseases specialists, intensivists and radiologists. Team training activities are performed in 48.8% of participating centers. CONCLUSIONS: This survey supports the importance of establishing lead extraction Heart Teams in specialized lead extraction centers to potentially improve patient outcomes. The concept of a core and an extended Heart Team approach in lead extraction procedures is introduced.

Long-term outcomes in patients treated with flecainide for atrial fibrillation with stable coronary artery disease.

BACKGROUND: Class 1C antiarrhythmic drugs (AAD) have been associated with harm in patients treated for ventricular arrhythmias with a prior myocardial infarction. Consensus guidelines have advocated that these drugs not be used in patients with stable coronary artery disease (CAD). However, long-term data are lacking to know if unique risks exist when these drugs are used for atrial fibrillation (AF) in patients with CAD without a prior myocardial infarction. METHODS: In 24,315 patients treated with the initiation of AADs, two populations were evaluated: (1) propensity-matched AF patients with CAD were created based upon AAD class (flecainide, n = 1,114, vs class-3 AAD, n = 1,114) and (2) AF patients who had undergone a percutaneous coronary intervention or coronary artery bypass graft (flecainide, n = 150, and class-3 AAD, n = 1,453). Outcomes at 3 years for mortality, heart failure (HF) hospitalization, ventricular tachycardia (VT), and MACE were compared between the groups. RESULTS: At 3 years, mortality (9.1% vs 19.3%, P < .0001), HF hospitalization (12.5% vs 18.3%, P < .0001), MACE (22.9% vs 36.6%, P < .0001), and VT (5.8% vs 8.5%, P = .02) rates were significantly lower in the flecainide group for population 1. In population 2, adverse event rates were also lower, although not significantly, in the flecainide compared to the class-3 AAD group for mortality (20.9% vs 25.8%, P = .26), HF hospitalization (24.5% vs 26.1%, P = .73), VT (10.9% vs 14.7%, P = .28) and MACE (44.5% vs 49.5%, P = .32). CONCLUSIONS: Flecainide in select patients with stable CAD for AF has a favorable safety profile compared to class-3 AADs. These data suggest the need for prospective trials of flecainide in AF patients with CAD to determine if the current guideline-recommended exclusion is warranted.

Patient-reported outcomes and subsequent management in atrial fibrillation clinical practice: Results from the Utah mEVAL AF program.

BACKGROUND: Atrial fibrillation (AF) significantly reduces health-related quality of life (HRQoL), previously measured in clinical trials using patient-reported outcomes (PROs). We examined AF PROs in clinical practice and their association with subsequent clinical management. METHODS: The Utah My Evaluation (mEVAL) program collects the Toronto AF Symptom Severity Scale (AFSS) in AF outpatients at the University of Utah. Baseline factors associated with worse AF symptom score (range 0-35, higher is worse) were identified in univariate and multivariable analyses. Secondary outcomes included AF burden and AF healthcare utilization. We also compared subsequent clinical management at 6 months between patients with better versus worse AF HRQoL. RESULTS: Overall, 1338 patients completed the AFSS symptom score, which varied by sex (mean 7.26 for males vs. 10.27 for females; p < .001), age (<65, 9.73; 65-74, 7.66; ≥75, 7.58; p < .001), heart failure (9.39 with HF vs. 7.67 without; p < .001), and prior ablation (7.28 with prior ablation vs. 8.84; p < .001). In multivariable analysis, younger age (mean difference 2.92 for <65 vs. ≥75; p < .001), female sex (mean difference 2.57; p < .001), pulmonary disease (mean difference 1.88; p < .001), and depression (mean difference 2.46; p < .001) were associated with higher scores. At 6-months, worse baseline symptom score was associated with the use of rhythm control (37.1% vs. 24.5%; p < .001). Similar cofactors and results were associated with increased AF burden and health care utilization scores. CONCLUSIONS: AF PROs in clinical practice identify highly-symptomatic patients, corroborating findings in more controlled, clinical trials. Increased AFSS score correlates with more aggressive clinical management, supporting the utility of disease-specific PROs guiding clinical practice.

Systematic collection of patient-reported outcomes in atrial fibrillation: feasibility and initial results of the Utah mEVAL AF programme.

AIMS: Incorporating patient-reported outcomes (PROs) into routine care of atrial fibrillation (AF) enables direct integration of symptoms, function, and health-related quality of life (HRQoL) into practice. We report our initial experience with a system-wide PRO initiative among AF patients. METHODS AND RESULTS: All patients with AF in our practice undergo PRO assessment with the Toronto AF Severity Scale (AFSS), and generic PROs, prior to electrophysiology clinic visits. We describe the implementation, feasibility, and results of clinic-based, electronic AF PRO collection, and compare AF-specific and generic HRQoL assessments. From October 2016 to February 2019, 1586 unique AF patients initiated 2379 PRO assessments, 2145 of which had all PRO measures completed (90%). The median completion time for all PRO measures per visit was 7.3 min (1st, 3rd quartiles: 6, 10). Overall, 38% of patients were female (n = 589), mean age was 68 (SD 12) years, and mean CHA2DS2-VASc score was 3.8 (SD 2.0). The mean AFSS symptom score was 8.6 (SD 6.6, 1st, 3rd quartiles: 3, 13), and the full range of values was observed (0, 35). Generic PROs of physical function, general health, and depression were impacted at the most severe quartiles of AF symptom score (P < 0.0001 for each vs. AFSS quartile). CONCLUSION: Routine clinic-based, PRO collection for AF is feasible in clinical practice and patient time investment was acceptable. Disease-specific AF PROs add value to generic HRQoL instruments. Further research into the relationship between PROs, heart rhythm, and AF burden, as well as PRO-guided management, is necessary to optimize PRO utilization.

Salvage of Threatened Cardiovascular Implantable Electronic Devices: Case Series and Review of Literature.

BACKGROUND: The treatment of infected or exposed cardiac pacing and defibrillator devices is controversial. The conservative and widely accepted management calls for removal of the device and leads with immediate or delayed replacement of new components in a new site. Lead extraction carries a 2% major complication risk. In this article, we describe our experience with device salvage techniques and review the current literature. METHODS: This is a retrospective case series of consecutive patients with infected, exposed, or at-risk implanted cardiac devices that were treated with aggressive surgical debridement, local pocket irrigation, and revision. A comprehensive review of the literature regarding device infection management was performed. RESULTS: Ten patients with threatened devices were identified. Surgical revision with the aim to salvage the device was successful in 8 (80%) of 10 cases. Seventeen retrospective publications were reviewed. All indicate success with attempted salvage surgery, but heterogeneity of data limits formal meta-analysis and prevents management recommendations. CONCLUSIONS: Cardiac pacing and defibrillator devices with low-grade infection or threatened exposure may be salvaged without explantation. Despite the lack of clear management guidelines or data, plastic surgeons may be asked to assist in the management of threatened cardiac devices. Further prospective trials are required to evaluate the safety, efficacy, and cost-effectiveness of attempted implant salvage.

"Vasovagal" response during ventricular fibrillation: incidence and implications.

BACKGROUND: The purpose of this study was to assess the relationship between changes in sinus node cycle length (SNCL) during ventricular fibrillation (VF) and the peripheral changes in blood pressure (BP) and sympathetic nerve activity (SNA) in human subjects. We hypothesized that patients with no SNCL shortening during VF have a vasovagal-like response with a greater decrease in BP and SNA when compared to patients with SNCL shortening. METHODS: SNCL, BP, and SNA recordings were attempted in 24 patients undergoing the implantation of a dual-chamber implantable defibrillator. Changes were measured during the first 5 seconds of VF and compared with the 5 seconds prior to VF induction. RESULTS: SNCL shortened during VF in nine patients (mean%∆SNCL = -12 ± 8%) and remained unchanged or lengthened in seven patients (mean%∆SNCL = 7 ± 7%). Eight patients had ventriculoatrial (VA) conduction prohibiting assessment of SNCL changes. In patients with SNCL shortening, the %∆MBP (mean BP) was -47 ± 6% compared to -58 ± 8% in patients with no SNCL shortening (P < 0.01). In patients with VA conduction, the %∆MBP was -54 ± 3%. SNA recordings were successfully obtained in four patients. When compared to baseline, SNA increased by 34 ± 30% in two patients with SNCL shortening, decreased by 25% in one patient with SNCL lengthening, and by 90% in the fourth patient with VA conduction. CONCLUSIONS: We have shown that patients with no SNCL shortening have a significantly greater decrease in MBP during VF when compared to patients with SNCL shortening. The underlying mechanism appears to be reflex mediated with a vasovagal-like response in patients with no SNCL shortening.

Utility of intracardiac echocardiography for atrial baffle leak closure in repaired transposition of the great arteries.

A 27-year-old male with dextro-transposition of great arteries had Senning atrial switch repair in childhood and dual-chamber pacemaker placement for sinus node dysfunction in adulthood. Transthoracic echocardiography showed a lead in the systemic (anatomic right) ventricle. Multidetector computed tomography showed the lead perforating the baffle in the region of the body of the systemic venous atrium into the systemic ventricle. The lead was extracted, and a new lead was placed in the pulmonary (anatomic left) ventricle. A bidirectional baffle shunt persisted. The iatrogenic baffle leak was percutaneously closed with an Amplatzer septal occluder device using both intracardiac echocardiography (ICE) and three-dimensional transesophageal echocardiography (3D-TEE). We report the first use of ICE for baffle leak closure, which provided a good definition of the complex anatomy and guided the procedure.

Bipolar lumenless lead performance in children and adults with congenital heart disease.

BACKGROUND: Because of small size and anatomic variation, implantation of intracardiac leads for permanent pacing in pediatric and congenital heart disease (CHD) patients can be challenging. A novel 4.1F bipolar catheter-delivered lead offers potential advantages for this population. OBJECTIVE; The purpose of this study was to retrospectively evaluate this lead performance in this specific population. METHODS: We performed a retrospective descriptive analysis of all pediatric and adult CHD patients at a single center implanted with a 4.1F bipolar catheter-delivered active fixation pacemaker lead (Medtronic model 3830, Medtronic, Inc, Minneapolis, MN, USA). RESULTS: Over 10 months, 42 leads were implanted in 27 patients. Twenty-six atrial and 16 ventricular leads were placed. Patient ages were 1-28 years (mean 15 +/- 7), and weights were 7.8-104 kg (mean 51.5 +/- 26.6). Ventricular septal defect and D-transposition of great arteries were the most prevalent CHD diagnoses. Implant capture thresholds were 1.2 +/- 0.8 V at 0.5 ms in the atrium and 0.8 +/- 0.5 V at 0.5 ms in the ventricle. Implant sensing thresholds were 4.1 +/- 2.7 mV in the atrium and 12.1 +/- 4.9 mV in the ventricle. Phrenic nerve stimulation was avoided in all, and selective site pacing was achieved in most cases. Pacing and sensing thresholds remained stable during 90 +/- 52 days follow-up. No lead related complications, failures, or extractions were observed. CONCLUSIONS: In our single-center experience with pediatric and CHD patients, a novel small, catheter-delivered bipolar lead has proven safe and effective for atrial and ventricular pacing in acute and subacute time periods. Longer performance trends will be required to determine chronic efficacy.