Ion channel dysfunction and fibrosis in atrial fibrillation: Two sides of the same coin.

BACKGROUND: Atrial fibrillation (AF) is a common heart rhythm disorder that is associated with an increased risk of stroke and heart failure (HF). Initially, an association between AF and ion channel dysfunction was identified, classifying the pathology as a predominantly electrical disease. More recently it has been recognized that fibrosis and structural atrial remodeling play a driving role in the development of this arrhythmia also in these cases. PURPOSE: Understanding the role of fibrosis in genetic determined AF could be important to better comprise the pathophysiology of this arrhythmia and to refine its management also in nongenetic forms. In this review we analyze genetic and epigenetic mechanisms responsible for AF and their link with atrial fibrosis, then we will consider analogies with the pathophysiological mechanism in nongenetic AF, and discuss consequent therapeutic options.

The role of preoperative venography in predicting the difficulty of a transvenous lead extraction procedure.

INTRODUCTION: We hypothesized that an accurate assessment of preoperative venography could be useful in predicting transvenous lead extraction (TLE) difficulty. METHODS AND RESULTS: A dedicated preoperative venogram was performed in consecutive patients with cardiac implantable electronic device who underwent TLE. The level of stenosis was classified as without significant stenosis, moderate, severe, and occlusion. The presence of extensive lead-venous wall adherence (≥50 mm) was also assessed. A total of 105 patients (median age: 71 years; 72% male) with a median of 2 (1-2) leads to extract were enrolled. Preoperative venography showed moderate to severe stenosis in 31 (30%), complete occlusion in 15 (14%), and extensive lead-venous wall adherence in 50 (48%) patients. Complete TLE success was achieved in 103 (98%) patients. A total of 55 (52%) were advanced extractions as they required a powered mechanical and/or laser sheath. They were more prevalent in the group with extensive lead-venous wall adherence (72% vs. 34%, p < .001), while no differences were found between patients with and without venous occlusion. In multivariate analysis, the presence of adherence was a predictor of advanced extraction (odds ratio: 2.89 [1.14-7.32], p = .025). The fluoroscopy time was also significantly longer (14.0 [8.2-18.7] vs. 5.1 [2.1-10.0] min, p < .001). The rate of complications did not differ based on the presence of venous lesions. CONCLUSION: Although procedural success and complication rates were similar, patients with extensive lead-venous wall adherence required a longer fluoroscopy time and were three times more likely to need advanced extraction tools. Conversely, the presence of total venous occlusion had no impact on the procedure complexity.

Lead-related infective endocarditis with vegetations: Prevalence and impact of pulmonary embolism in patients undergoing transvenous lead extraction.

INTRODUCTION: The prevalence and impact of pulmonary embolism (PE) in patients with lead-related infective endocarditis undergoing transvenous lead extraction (TLE) are unknown. METHODS: Twenty-five consecutive patients with vegetations ≥10 mm at transoesophageal echocardiography were prospectively studied. Contrast-enhanced chest computed tomography (CT) was performed before (pre-TLE) and after (post-TLE) the lead extraction procedure. RESULTS: Pre-TLE CT identified 18 patients (72%) with subclinical PE. The size of vegetations in patients with PE did not differ significantly from those without (median 20.0 mm [interquartile range: 13.0-30.0] vs. 14.0 mm [6.0-18.0], p = 0.116). Complete TLE success was achieved in all patients with 3 (2-3) leads extracted per procedure. There were no postprocedure complications related to the presence of PE and no differences in terms of fluoroscopy time and need for advanced tools. In the group of positive pre-TLE CT, post-TLE scan confirmed the presence of silent PE in 14 patients (78%). There were no patients with new PE formation. Large vegetations (≥20 mm) tended to increase the risk of post-TLE subclinical PE (odds ratio 5.99 [95% confidence interval (CI): 0.93-38.6], p = 0.059). During a median 19.4 months follow-up, no re-infection of the implanted system was reported. Survival rates in patients with and without post-TLE PE were similar (hazard ratio: 1.11 [95% CI: 0.18-6.67], p = 0.909). CONCLUSION: Subclinical PE detected by CT was common in patients undergoing TLE with lead-related infective endocarditis and vegetations but was not associated with the complexity of the procedure or adverse outcomes. TLE procedure seems safe and feasible even in patients with large vegetations.

Hybrid transvenous and surgical approach for the extraction of coronary sinus leads: A case series.

BACKGROUND: Transvenous lead extraction is the standard therapy for cardiac device-related infection. In some patients, however, a hybrid surgical and transvenous approach may be necessary. METHODS AND RESULTS: We present three cases who underwent transvenous lead extraction for an infected CRT-D system. In all cases the CS lead could not be retrieved transvenously due to extensive fibrosis. The lead was successfully extracted through left minithoracotomy in two patients and midline sternotomy in one patient. CONCLUSION: In cases where the coronary sinus lead shows severe fibrosis, a transvenous approach can be used to free the proximal part of the lead, while the distal adhesions can be removed surgically through a limited thoracic incision.

Leadless pacemakers as a new alternative for pacemaker lead-related superior vena cava syndrome: A case report.

Superior vena cava (SVC) syndrome is a rare disease induced by thrombosis and consequent occlusion of SVC, negatively affecting morbidity and mortality. The incidence of SVC syndrome from central venous catheters and pacemaker or defibrillator leads is increasing. Optimal treatment of pacemaker or defibrillator-related SVC syndrome is not well defined. Lead extraction causes mechanical trauma to the vessel wall. In addition, subsequent device implantation on the contralateral side can be an added factor for venous occlusion. The use of leadless pacemakers could be an interesting option to reduce the risk of SVC restenosis after lead extraction. We report a clinical case of PM leads-related SVC syndrome referred to our centers and treated with transvenous lead extraction, leadless pacemaker implantation and subsequent percutaneous angioplasty and stenting of the SVC and left innominate vein.

Transvenous lead extraction in patients with persistent left superior vena cava.

PURPOSE: Predictors of difficulty and complications of transvenous lead extraction (TLE) have been investigated in several studies; however, little is known about the venous anatomical characteristics that can have an impact on procedural outcomes. Among them, the persistent left superior vena cava (PLSVC) is a common anomaly often discovered incidentally during cardiac device implantation and could raise concerns if TLE is indicated. We report technical considerations and outcomes of TLE for two patients with leads implanted via PLSVC. METHODS AND RESULTS: Two cardiac implantable electronic device recipients with isolated PLSVC required TLE due to infective endocarditis in one case and lead failure in the other. In the first case, TLE procedure was performed in a hybrid operating room with minimally invasive video-assisted thoracoscopic monitoring due to the high procedural risk. Two active fixation 20-year-old pacing leads were removed with a relatively short fluoroscopy time. In the second case, we successfully extracted a single-coil active fixation lead without the need of a locking stylet or advanced extraction tools. There were no procedural complications or adverse events at 1-year follow-up. CONCLUSION: TLE procedures for two patients with isolated PLSVC were successfully completed with less difficulty and tools than expected based on the characteristics of the targeted leads. If indicated, TLE in the presence of a PLSVC should be considered in experienced centers.

The MB score: a new risk stratification index to predict the need for advanced tools in lead extraction procedures.

AIMS: A validated risk stratification schema for transvenous lead extraction (TLE) could improve the management of these procedures. We aimed to derive and validate a scoring system to efficiently predict the need for advanced tools to achieve TLE success. METHODS AND RESULTS: Between November 2013 and March 2018, 1960 leads were extracted in 973 consecutive TLE procedures in two national referral sites using a stepwise approach. A procedure was defined as advanced extraction if required the use of powered sheaths and/or snares. The study population was a posteriori 1:1 randomized in derivation and validation cohorts. In the derivation cohort, presence of more than two targeted leads (odds ratio [OR] 1.76, P = 0.049), 3-year-old (OR 3.04, P = 0.001), 5-year-old (OR 3.48, P < 0.001), 10-year-old (OR 3.58, P = 0.008) oldest lead, implantable cardioverter-defibrillator (OR 3.84, P < 0.001), and passive fixation lead (OR 1.91, P = 0.032) were selected by a stepwise procedure and constituted the MB score showing a C-statistics of 0.82. In the validation group, the MB score was significantly associated with the risk of advanced extraction (OR 2.40, 95% confidence interval 2.02-2.86, P < 0.001) and showed an increase in event rate with increasing score. A low value (threshold = 1) ensured 100% sensibility and 100% negative predictive value, while a high value (threshold = 5) allowed a specificity of 92.8% and a positive predictive value of 91.9%. CONCLUSION: In this study, we developed and tested a simple point-based scoring system able to efficiently identify patients at low and high risk of needing advanced tools during TLE procedures.

Leadless pacemaker: State of the art and incoming developments to broaden indications.

Theleadless pacemaker (LLPM) therapy has been developed in recent years to overcome the transvenous lead and device pocket-related complications. The LLPMs now available are self-contained right ventricular pacemakers and are limited to single-chamber ventricular pacing modality. This literature review deals with the current status of LLPM technology and current areas of clinical applicability. The safety and efficacy outcomes published from randomized clinical trials and real world registries are analyzed and compared with historical conventional transvenous pacemaker data. Furthermore, new pacing modalities and future perspectives to broaden the clinical use and cover most of pacing indications are discussed. Due to the overall safe and effective profile in the short term and intermediate term, also in fragile patients, the LLPM use is constantly growing in daily clinical practice. Actually, it can be considered a landmark innovation, through which a new era of cardiac pacing has begun.

First-in-human retrieval of chronically implanted Micra transcatheter pacing system.

We report the first-in-human retrieval of a chronically implanted Micra transcatheter pacing system (TPS; Medtronic, Minneapolis, MN, USA). A 41-year-old woman suffering from third-degree atrioventricular block was successfully implanted with a TPS in the low septum of the right ventricle. After 29 months, due to an increased electrical threshold and 100% pacing percentage, the device showed low battery voltage. Despite the long implant duration, the attempt of device retrieval using a snare loop inserted in the delivery system of a TPS was successful. In the same procedure, a new leadless pacemaker was implanted in the high right ventricular septum with optimal pacing threshold.

Management of a leadless pacemaker recall via extraction in a patient with a history of multiple previous device implants.

We describe a management strategy of a leadless pacemaker recall (LP) via extraction in a pacemaker-dependent patient with a history of multiple previous device implants. We performed a two-step procedure. First, we implanted a second LP in the right ventricle. Then, 3 days later for concerns about the stability of the newly-implanted device, we retrieved the first LP, 3 years after its original implant. The patient was hemodynamically stable throughout the two procedures and no adverse event occurred in the 3 days of coexistence of the two LPs. Although the limitation of a single case experience, this approach may be taken into consideration when facing similar high-risk cases.

Predicting the difficulty of a transvenous lead extraction procedure: Validation of the LED index.

INTRODUCTION: A lead extraction difficulty (LED) score was proposed to predict the difficult transvenous lead extraction (TLE) procedures, defined by means of the fluoroscopy time. The aim of this study was to validate the estimation model based on the LED index above 10 on an independent data set of TLE cases. METHODS: Consecutive patients undergoing TLE between January 2014 and January 2016 were included in this analysis. The fluoroscopy time related to the leads removal was dichotomized as above or below its 90th percentile (PCTL). RESULTS: In total, 446 permanent leads were removed during 233 TLE procedures. Complete procedural success was achieved in 232 (99.1%) patients. The LED index resulted >10 in 83(35.6%) procedures. Among these cases, 20 had fluoroscopy time above the 90th PCTL (23.3 minutes) and were classified as true positive. Over the 150 procedures with LED score <10, 147 were classified as true negative, and only 3 resulted false negative. The sensitivity, the specificity, and the negative predictive value of the LED index in predicting complex cases resulted 86.9 (confidence interval [CI] 66.4-97.2)%, 70.0 (CI 63.3-76.1)%, and 98.0 (CI 94.3-99.6)%, respectively. The multivariate logistic regression analysis confirmed a 12% increased risk of high fluoroscopy for each additional point of the LED score (OR 1.12, CI 1.05-1.21, P = 0.001). CONCLUSION: The validation of the estimation model based on the LED index <10 confirmed its high efficacy in predicting simple TLE procedures.

Hybrid Minimally Invasive Approach for Transvenous Lead Extraction: A Feasible Technique in High-Risk Patients.

INTRODUCTION: Despite the overall safety, transvenous lead extraction (TLE) remains a challenging procedure with inherent risks, where surgery can still be required in elective cases. In this study, we report our experience with a minimally invasive "hybrid" approach, defined as a procedure performed by an electrophysiologist with the support of a cardiac surgeon in the same operative session. METHODS AND RESULTS: We reported 12 cases of planned hybrid lead extraction; minithoracotomy and thoracoscopy were performed on 10 (83%) and 2 (17%) patients, respectively. A total of 25 leads out of 27 (median lead age 19 years) were successfully extracted with laser, mechanical or combined transvenous sheath. In 3 patients, the direct monitoring of vascular and myocardial integrity allowed for prompt treatment of potential vascular injury during the lead extraction maneuvers. Mean in-hospital stay was 4 ± 2 days. There were no major intraoperative complications and no deaths occurred after 30 days' follow-up. CONCLUSION: The hybrid approach, with minithoracotomy or thoracoscopy, is feasible and it might increase the safety in the most challenging TLE procedures: the minimally invasive surgical intervention allows for continuous monitoring of the critical cardiac structures and prompt treatment of potential complications.

The novel active fixation coronary sinus lead: efficacy and safety of transvenous extraction procedure.

AIMS: Benefits of cardiac resynchronization therapy (CRT) are well known for heart failure; however, some patients might experience complications related to the coronary sinus (CS) lead (high pacing threshold, phrenic nerve stimulation, and dislodgment) with unfavourable impact on quality of life, costs, and management. Lead stability is one of the most common unmet needs for CRT procedures. METHODS AND RESULTS: Recently, new model Medtronic 20066 Attain Stability(®) (Maastricht, The Netherlands) active fixation LV lead has been released, to overcome this issue. The lead has a small side helix of 0.20 mm (0.008 in.) that allows for secure placement of the lead within the vein at the desired location. We report our first experience with the extraction of this novel active fixation left ventricular lead. CONCLUSION: In our case, to our knowledge the first reported in humans, the extraction of this new model of active fixation lead was proved to be a safe and effective procedure at 8 months after implantation. Indeed, under angiographic and fluoroscopic check, there was no documented dissection or damage to the CS during and after removal of the lead. The rotation manoeuvre was effective when combined with moderate traction of the lead itself.

ICD early after myocardial infarction: it is really necessary to wait 40 days before implantation?

ESC Guidelines don't recommend ICD implantation within 40 days after MI, on the basis of old evidence with several limitations. However, a significant number of patients remain at high risk of arrhythmic death also in the early period after ACS, in these patients early ICD implantation or LifeVest may be use with benefit on survival.

Implantable loop recorder in Brugada syndrome: Insights from a single-center experience.

Background: This study aimed to investigate the characteristics and outcomes of patients diagnosed with Brugada syndrome (BrS) who underwent implantable loop recorder (ILR) insertion during routine clinical activity. Methods: We conducted a comprehensive screening of all consecutive patients diagnosed with BrS at our institution. We analyzed baseline clinical characteristics, arrhythmic findings, and outcomes. Results: Out of 147 BrS patients, 42 (29 %) received an ILR, 13 (9 %) underwent implantable cardioverter-defibrillator (ICD) placement, and 92 patients (63 %) continued regular cardiological follow-up. Patients who received an ILR had a higher prevalence of suspected arrhythmic syncope (43 % vs. 22 %, p = 0.012) and tended to be younger (median age 38 years, interquartile range 30-52, vs. 43 years, 35-55, p = 0.044) with a higher presence of SCN5A gene mutations (17 % vs. 6 %, p = 0.066) compared to those who continued regular follow-up. Additionally, compared to patients with an ICD, those with an ILR had a significantly lower frequency of positive programmed ventricular stimulation (0 % vs. 91 %, p < 0.001). During a median follow-up period of 14.7 months (4.7-44.8), no deaths occurred among the patients with ILR. Eight individuals (19 %) were diagnosed with arrhythmic findings through continuous ILR monitoring, primarily atrial fibrillation, and asystolic pauses. The median time from insertion to the occurrence of these events was 8.7 months (3.6-46.4). No adverse events related to ILR were reported. Conclusion: Continuous monitoring with ILR may facilitate the timely detection of non-malignant rhythm disorders in BrS patients with risk factors but without an indication for primary prevention ICD implantation.

Transvenous lead extraction, factors affecting procedural difficulty.

BACKGROUND: A complex transvenous lead extraction (TLE) procedure could be associated with lower success and higher complication rates in inexperienced hands. In this study, we aim to assess the factors that determine procedural difficulty in TLE. METHODS: We retrospectively studied 200 consecutive patients undergoing TLE in a single referral centre from June 2020 to December 2021. Lead extraction difficulty was assessed by the success of simple manual traction with or without a locking stylet, the need for advanced extraction tools and the number of tools required to extract the lead. Logistic and linear regression analyses were used to determine the factors independently affecting these 3 parameters. RESULTS: 363 leads were extracted from 200 patients (79% males, mean age 66.85 years). The indication for TLE was device-related infection in 51.5%. Multivariate analysis revealed the lead indwelling time to be the only factor affecting the 3 parameters of difficulty. Passive fixation leads and dual coil leads increased procedural difficulty by affecting 2 parameters each. Factors that affected one parameter included infected leads, coronary sinus leads, older age of the patient and a history of valvular heart disease, all associated with a simpler procedure. Right ventricular leads were associated with a more complex one. CONCLUSION: The most important factor that increased TLE procedural difficulty was a longer lead indwelling time, followed by passive fixation and dual-coil leads. Other contributing factors were the presence of infection, coronary sinus leads, older patients, a history of valvular heart disease and right ventricular leads.

Long-term outcomes following transvenous lead extraction: Data from a tertiary referral center.

BACKGROUND: Transvenous lead extraction (TLE) has shown a safe and efficacy profile in the intraoperative and short-term setting; however, data on long-term outcomes are limited. OBJECTIVE: The purpose of this study was to assess long-term outcomes and prognostic factors in patients who underwent TLE. METHODS: Consecutive patients with cardiac implantable electronic device (CIED) who underwent TLE between 2014 and 2016 were retrospectively studied. The primary outcome was the composite endpoint of death and repeated TLE stratified by infective/non-infective indication. Individual components of the primary outcome were also evaluated. RESULTS: One hundred ninety-one patients were included in the analysis, 50% extracted for CIED-related infection. Complete procedural success was achieved in 189 patients (99%) with no major acute complications. After a median of 6.5 years, infection indication was associated with significantly lower event-free survival (67% vs. 83% non-infection group, adjusted hazard ratio [aHR] 1.97, 95% confidence interval [CI] 1.02-3.81, p = 0.04). All-cause mortality rate was higher in the TLE infection group (30% vs. 10%, p < 0.01). The rate of repeated TLE did not differ between groups (4% vs. 7%, p = 0.62). Among patients who had TLE for infection, the presence of vegetation (aHR 2.56; 95%CI 1.17-5.63, p = 0.02) and positive blood cultures (aHR 2.64; 95%CI 1.04-6.70, p = 0.04) were independently associated with the primary outcome. CONCLUSION: Patients who underwent TLE for CIED-related infection exhibit a high mortality risk during long-term follow-up. Vegetation and positive blood cultures in patients with CIED-related infection are associated with a worse prognosis regardless of successful and uncomplicated TLE.

Outcomes of leadless pacemaker implantation following transvenous lead extraction in high-volume referral centers: Real-world data from a large international registry.

BACKGROUND: Limited data on the real-world safety and efficacy of leadless pacemakers (LPMs) post-transvenous lead extraction (TLE) are available. OBJECTIVE: The purpose of this study was to assess the long-term safety and effectiveness of LPMs following TLE in comparison with LPMs de novo implantation. METHODS: Consecutive patients who underwent LPM implantation in 12 European centers joining the International LEAdless PacemakEr Registry were enrolled. The primary end point was the comparison of LPM-related complication rate at implantation and during follow-up (FU) between groups. Differences in electrical performance were deemed secondary outcomes. RESULTS: Of the 1179 patients enrolled, 15.6% underwent a previous TLE. During a median FU of 33 (interquartile range 24-47) months, LPM-related major complications and all-cause mortality did not differ between groups (TLE group: 1.6% and 5.4% vs de novo group: 2.2% and 7.8%; P = .785 and P = .288, respectively). Pacing threshold (PT) was higher in the TLE group at implantation and during FU, with very high PT (>2 V@0.24 ms) patients being more represented than in the de novo implantation group (5.4% vs 1.6 %; P = .004). When the LPM was deployed at a different right ventricular (RV) location than the one where the previous transvenous RV lead was extracted, a lower proportion of high PT (>1-2 V@0.24 ms) patients at implantation, 1-month FU, and 12-month FU (5.9% vs 18.2%, P = .012; 3.4% vs 12.9%, P = .026; and 4.3% vs 14.5%, P = .037, respectively) was found. CONCLUSION: LPMs showed a satisfactory safety and efficacy profile after TLE. Better electrical parameters were obtained when LPMs were implanted at a different RV location than the one where the previous transvenous RV lead was extracted.

Intraoperative sensing increase predicts long-term pacing threshold in leadless pacemakers.

PURPOSE: High pacing threshold (HPT) and very high pacing threshold (VHPT) are known to have a negative impact on leadless pacemaker battery longevity, representing the most common reason for device repositioning. In this study, we evaluated if intraoperative electrical parameters recorded during Micra™ VR implant would be able to predict device performance during follow-up (FU). METHODS: A total of 93 patients undergoing Micra™ VR implant were retrospectively considered. Patients were enrolled in the study if electrical assessment was performed at least twice at implant, at Micra™ final positioning and after removal of the delivery system. All patients received a FU visit at 1 and 12 month after discharge. R-wave sensing amplitude, pacing threshold (PT), and impedance were recorded at each visit. RESULTS: When compared to the first assessment, R-wave sensing amplitude increased by 19.1% after 13 ± 4 min (+ 1.71 ± 0.2 mV, 95% CI 1.4 to 2.02; p < .001). Conversely, there was a significant PT decrease of 22.1% at 12-month FU (- 0.22 ± 0.03 V, 95% CI - 0.13 to - 0.31; p < .001). Among patients with HPT, acute increase of R-wave sensing of 1.5 mV after 14 ± 4 min predicted a significant reduction of PT below 1 V/0.24, at 12-month post-implant (R = 0.72, 95% CI 0.13 to 0.33, p < .001), with a sensitivity of 87.5% (95% CI 0.61-0.98) and a specificity of 88.8% (95% CI 0.51-0.99). CONCLUSION: A 1.5-mV increase in R-wave amplitude at implant is predictive of PT normalization (< 1.0 V/0.24 ms) at 12-month FU. This finding may have practical implications for device repositioning in case of HPT recording at implant.