Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial.

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

Incidence and Temporal Evolution of Delayed Peridevice Leak After Left Atrial Appendage Closure.

BACKGROUND: Peridevice leak (PDL) following left atrial appendage closure (LAAC) portends adverse outcomes. OBJECTIVE: To assess the incidence, predictors, clinical implications, and temporal evolution of PDL following LAAC. METHODS: This single-center retrospective study included all patients who underwent LAAC with Watchman FLX and had no PDL detected at implant. The primary endpoint was incidence of new PDL at initial imaging. The composite secondary endpoint included continued oral anticoagulation after initial imaging, device-related thrombus, stroke or transient ischemic attack, major bleeding, and need for PDL closure at longest follow-up. Temporal evolution of PDL was assessed in patients with available surveillance imaging. RESULTS: Among 355 patients who completed imaging at 47 (IQR 6) days, 139 (39%) had a new PDL with a mean leak size of 3.2±1.4 [median 3.0 (IQR 2.0), and range 1.0-9.0 mm]. Multiple deployment attempts and larger device size were positive predictors of PDL, while increased contrast volume administration was a negative predictor of PDL. The composite secondary endpoint occurred in 42 (30%) and 33 (15%) patients with and without PDL respectively (p<0.001). Among the 139 patients with PDL, 43 (31%) had surveillance imaging where leak size regressed from 3.7±1.8mm at 46 (IQR 7) days to 1.7±2.0mm at 189 (IQR 127) days (p<0.001). The leak size regressed in 33 (77%), remained stable in 4 (9%), and progressed in 6 (14%) cases. CONCLUSION: Despite design improvements, LAAC with Watchman FLX demonstrates significant incidence of PDL with meaningful clinical implications. Regardless of initial size, most leaks regressed over time.

EsophAguS Deviation During RadiofrequencY Ablation of Atrial Fibrillation: The EASY AF Trial.

BACKGROUND: Injury to the esophagus has been reported in a high percentage of patients undergoing ablation of atrial fibrillation (AF). OBJECTIVES: This study assessed the incidence of esophageal injury in patients undergoing ablation of AF with and without an esophageal deviating device. METHODS: This prospective, randomized, multicenter, double-blinded, controlled Food and Drug Administration investigational device exemption trial compared the incidence of ablation-related esophageal lesions, as assessed by endoscopy, in patients undergoing AF ablation assigned to a control group (luminal esophageal temperature [LET] monitoring alone) compared with patients randomized to a deviation group (esophagus deviation device + LET). This novel deviating device uses vacuum suction and mechanical deflection to deviate a segment of the esophagus, including the trailing edge. RESULTS: The data safety and monitoring board recommended stopping the study early after randomizing 120 patients due to deviating device efficacy. The primary study endpoint, ablation injury to the esophageal mucosa, was significantly less in the deviation group (5.7%) in comparison to the control group (35.4%; P < 0.0001). Control patients had a significantly higher severity and greater number of ablation lesions per patient. There was no adverse event assigned to the device. By multivariable analysis, the only feature associated with reduced esophageal lesions was randomization to deviating device (OR: 0.13; 95% CI: 0.04-0.46; P = 0.001). Among control subjects, there was no difference in esophageal lesions with high power/short duration (31.8%) vs other radiofrequency techniques (37.2%; P = 0.79). CONCLUSIONS: The use of an esophageal deviating device resulted in a significant reduction in ablation-related esophageal lesions without any adverse events.

Direct current cardioversion practices following percutaneous left atrial appendage closure.

INTRODUCTION: Among patients with non-valvular atrial fibrillation (AF) and percutaneous left atrial appendage closure (LAAC) undergoing direct current cardioversion (DCCV), the need for and use of LAA imaging and oral anticoagulation (OAC) is unclear. OBJECTIVE: The purpose of this study is to evaluate the real-world use of transesophageal echocardiography (TEE) or cardiac computed tomography angiography (CCTA) before DCCV and use of OAC pre- and post-DCCV in patients with AF status post percutaneous LAAC. METHODS: This retrospective single center study included all patients who underwent DCCV after percutaneous LAAC from 2016 to 2022. Key measures were completion of TEE or CCTA pre-DCCV, OAC use pre- and post-DCCV, incidence of left atrial thrombus (LAT) or device-related thrombus (DRT), incidence of peri-device leak (PDL), and DCCV-related complications (stroke, systemic embolism, device embolization, major bleeding, or death) within 30 days. RESULTS: A total of 76 patients with AF and LAAC underwent 122 cases of DCCV. LAAC consisted of 47 (62%), 28 (37%), and 1 (1%) case of Watchman 2.5, Watchman FLX, and Lariat, respectively. Among the 122 DCCV cases, 31 (25%) cases were identified as "non-guideline based" due to: (1) no OAC for 3 weeks and no LAA imaging within 48 h before DCCV in 12 (10%) cases, (2) no OAC for 4 weeks following DCCV in 16 (13%) cases, or (3) both in 3 (2%) cases. Among the 70 (57%) cases that underwent TEE or CCTA before DCCV, 16 (23%) cases had a PDL with a mean size of 3.0 ± 1.1 mm, and 4 (6%) cases had a LAT/DRT on TEE resulting in cancellation. There were no DCCV-related complications within 30 days. DISCUSSION: There is a widely varied practice pattern of TEE, CCTA, and OAC use with DCCV after LAAC, with a 6% rate of LAT/DRT. LAA imaging before DCCV appears prudent in all cases, especially within 1 year of LAAC, to assess for device position, PDL, and LAT/DRT.

Cardiac magnetic resonance imaging for left atrial appendage closure planning.

BACKGROUND: Transesophageal echocardiography (TEE) and cardiac computed tomography angiography (CCTA) are currently utilized for left atrial appendage closure (LAAC) planning. During the recent global iodine contrast media shortage in 2022, cardiac magnetic resonance imaging (CMR) was utilized for the first time for LAAC planning. This study sought to assess the utility of CMR versus TEE for LAAC planning. METHODS: This single center retrospective study consisted of all patients who underwent preoperative CMR for LAAC with Watchman FLX or Amplatzer Amulet. Key measures were accuracy of LAA thrombus exclusion, ostial diameter, depth, lobe count, morphology, accuracy of predicted device size, and devices deployed per case. Bland-Altman Analysis was used to compare CMR versus TEE measurements of LAA ostial diameter and depth. RESULTS: 25 patients underwent preoperative CMR for LAAC planning. A total of 24 (96%) cases were successfully completed with 1.2 ± 0.5 devices deployed per case. Among the 18 patients who underwent intraoperative TEE, there was no significant difference between CMR versus TEE in LAA thrombus exclusion (CMR 83% vs. TEE 100% cases, p = .229), lobe count (CMR 1.7 ± 0.8 vs. TEE 1.4 ± 0.6, p = .177), morphology (p = .422), and accuracy of predicted device size (CMR 67% vs. TEE 72% cases, p = 1.000). When comparing the difference between CMR and TEE measurements, Bland-Altman analysis demonstrated no significant difference in LAA ostial diameter (CMR-TEE bias 0.7 mm, 95% CI [-1.1, 2.4], p = .420), but LAA depth was significantly larger with CMR versus TEE (CMR-TEE bias 7.4 mm, 95% CI [1.6, 13.2], p = .015). CONCLUSIONS: CMR is a promising alternative for LAAC planning in cases where TEE or CCTA are contraindicated or unavailable.

Three-dimensional functional anatomy of the human sinoatrial node for epicardial and endocardial mapping and ablation.

The sinoatrial node (SAN) is the primary pacemaker of the human heart. It is a single, elongated, 3-dimensional (3D) intramural fibrotic structure located at the junction of the superior vena cava intercaval region bordering the crista terminalis (CT). SAN activation originates in the intranodal pacemakers and is conducted to the atria through 1 or more discrete sinoatrial conduction pathways. The complexity of the 3D SAN pacemaker structure and intramural conduction are underappreciated during clinical multielectrode mapping and ablation procedures of SAN and atrial arrhythmias. In fact, defining and targeting SAN is extremely challenging because, even during sinus rhythm, surface-only multielectrode mapping may not define the leading pacemaker sites in intramural SAN but instead misinterpret them as epicardial or endocardial exit sites through sinoatrial conduction pathways. These SAN exit sites may be distributed up to 50 mm along the CT beyond the ∼20-mm-long anatomic SAN structure. Moreover, because SAN reentrant tachycardia beats may exit through the same sinoatrial conduction pathway as during sinus rhythm, many SAN arrhythmias are underdiagnosed. Misinterpretation of arrhythmia sources and/or mechanisms (eg, enhanced automaticity, intranodal vs CT reentry) limits diagnosis and success of catheter ablation treatments for poorly understood SAN arrhythmias. The aim of this review is to provide a state-of-the-art overview of the 3D structure and function of the human SAN complex, mechanisms of SAN arrhythmias and available approaches for electrophysiological mapping, 3D structural imaging, pharmacologic interventions, and ablation to improve diagnosis and mechanistic treatment of SAN and atrial arrhythmias.

Leadless left ventricular stimulation with WiSE-CRT System - Initial experience and results from phase I of SOLVE-CRT Study (nonrandomized, roll-in phase).

BACKGROUND: Left ventricular (LV) endocardial pacing is a promising method to deliver cardiac resynchronization therapy (CRT). WiSE-CRT is a wireless LV endocardial pacing system, and delivers ultrasonic energy to an LV electrode. OBJECTIVE: The purpose of this study was to present short-term outcomes with the WiSE-CRT system in centers with no prior implanting experience. METHODS: Data were prospectively collected from 19 centers where WiSE-CRT systems were implanted during the roll-in phase of the SOLVE-CRT trial. Patients were followed at 1, 3, and 6 months, including transthoracic echo (TTE) at 6 months. RESULTS: The WiSE-CRT was successfully implanted in all 31 attempted cases, and 30 patients completed the 6-month follow-up. One patient underwent heart transplantation 1 month after implantation, and was excluded. Fourteen (46.7%) patients demonstrated ≥1 NYHA class improvement. TTE data were available in 29 patients. LV ejection fraction, LV end-systolic volume, and LV end-diastolic volume improved from 28.3% ± 6.7% to 33.5% ± 6.9% (P < .001), 134.9 ± 51.3 mL to 111.1 ± 40.3 mL (P = .0004), and 185.4 ± 58.8 mL to 164.9 ± 50.6 mL (P = .0017), respectively. There were 3 (9.7%) device-related type 1 complications: 1 insufficient LV pacing, 1 embolization of an unanchored LV electrode, and 1 skin infection. CONCLUSIONS: We demonstrated a high success rate of LV endocardial electrode placement in centers with no prior implanting experience. Favorable clinical responses in heart failure symptoms and significant LV reverse remodeling were noted.

Temporal Changes and Clinical Implications of Delayed Peridevice Leak Following Left Atrial Appendage Closure.

OBJECTIVES: The aim of this study was to assess temporal changes and clinical implications of peridevice leak (PDL) after left atrial appendage closure. BACKGROUND: Endocardial left atrial appendage closure devices are alternatives to long-term oral anticoagulation (OAC) for patients with atrial fibrillation. PDL >5 mm may prohibit discontinuation of OAC. METHODS: Patients included in the study had: 1) successful Watchman device implantation without immediate PDL; 2) new PDL identified at 45 to 90 days using transesophageal echocardiography; 3) eligibility for OAC; and 4) 1 follow-up transesophageal echocardiographic study for PDL surveillance. Relevant clinical and imaging data were collected by chart review. The combined primary outcome included failure to stop OAC after 45 to 90 days, transient ischemic attack or stroke, device-related thrombi, and need for PDL closure. RESULTS: Relevant data were reviewed for 1,039 successful Watchman device implantations. One hundred eight patients (10.5%) met the inclusion criteria. The average PDL at 45 to 90 days was 3.2 ± 1.6 mm. On the basis of a median PDL of 3 mm, patients were separated into ≤3 mm (n = 73) and >3 mm (n = 35) groups. In the ≤3 mm group, PDL regressed significantly (2.2 ± 0.8 mm vs 1.6 ± 1.4 mm; P = 0.002) after 275 ± 125 days. In the >3 mm group, there was no significant change in PDL (4.9 ± 1.4 mm vs 4.0 ± 3.0 mm; P = 0.12) after 208 ± 137 days. The primary outcome occurred more frequently (69% vs 34%; P = 0.002) in the >3 mm group. The incidence of transient ischemic attack or stroke in patients with PDL was significantly higher compared with patients without PDL, irrespective of PDL size. CONCLUSIONS: New PDL detected by transesophageal echocardiography at 45 to 90 days occurred in a significant percentage of patients and was associated with worse clinical outcomes. PDL ≤3 mm tended to regress over time.

Altered microRNA and mRNA profiles during heart failure in the human sinoatrial node.

Heart failure (HF) is frequently accompanied with the sinoatrial node (SAN) dysfunction, which causes tachy-brady arrhythmias and increased mortality. MicroRNA (miR) alterations are associated with HF progression. However, the transcriptome of HF human SAN, and its role in HF-associated remodeling of ion channels, transporters, and receptors responsible for SAN automaticity and conduction impairments is unknown. We conducted comprehensive high-throughput transcriptomic analysis of pure human SAN primary pacemaker tissue and neighboring right atrial tissue from human transplanted HF hearts (n = 10) and non-failing (nHF) donor hearts (n = 9), using next-generation sequencing. Overall, 47 miRs and 832 mRNAs related to multiple signaling pathways, including cardiac diseases, tachy-brady arrhythmias and fibrosis, were significantly altered in HF SAN. Of the altered miRs, 27 are predicted to regulate mRNAs of major ion channels and neurotransmitter receptors which are involved in SAN automaticity (e.g. HCN1, HCN4, SLC8A1) and intranodal conduction (e.g. SCN5A, SCN8A) or both (e.g. KCNJ3, KCNJ5). Luciferase reporter assays were used to validate interactions of miRs with predicted mRNA targets. In conclusion, our study provides a profile of altered miRs in HF human SAN, and a novel transcriptome blueprint to identify molecular targets for SAN dysfunction and arrhythmia treatments in HF.

A 10 J shock impedance in sinus rhythm correlates with a 65 J defibrillation impedance during subcutaneous defibrillator implantation using an intermuscular technique.

INTRODUCTION: Defibrillation testing (DT) is recommended during the subcutaneous defibrillator (S-ICD) placement. We sought to compare 10 J shock impedance in sinus rhythm (SR) with 65 J defibrillation impedance and evaluate device position on a postimplant chest X-ray (CXR) using an intermuscular (IM) technique. METHODS: Consecutive S-ICD implantations between 12/2019 and 12/2020 at The Ohio State University were reviewed. All implantations were performed using a two-incision IM technique. Standard DT with 65 J shock and 10 J shock in SR were performed unless contraindicated. The PRAETORIAN score was calculated based on CXR. RESULTS: A total of 37 patients (age: 47.2 ± 15.8 years old, male: n = 26 [70.3%], body mass index: 30.1 ± 6.7 kg/m2 ) underwent IM S-ICD implantation, and of those, 27 (73%) underwent both 65 J shock and 10 J shock in SR. The coefficient of determination (R2 ) between 10 J shock impedance and 65 J shock impedance was 0.84. The mean of an impedance difference was 1.6 ± 4.8 Ω (minimum - 11 and maximum 8). Postimplant CXR was available for 33 out of 37 patients (89.2%). The PRAETORIAN score was less than 90 in all patients and the mean score was 32.7 ± 8.8. CONCLUSION: We demonstrated that 10 J shock impedance in SR correlated well with 65 J defibrillation impedance during IM S-ICD implantation. An IM implantation technique provides excellent generator location on postimplant CXR. The IM technique combined with 10 J shock in SR may be sufficient to predict and ensure the defibrillation efficacy of the S-ICD.

Tips and Tricks for Safe Retrieval of Tine-based Leadless Pacemakers.

As leadless pacing (LP) use is expected to increase, it becomes increasingly essential that operators become familiar with the tools and techniques needed to retrieve an LP successfully. The purpose of this review is to describe a stepwise approach for the successful retrieval of tine-based LP devices, including ways to minimize complications.

Resource Use and Economic Implications of Remote Monitoring With Subcutaneous Cardiac Rhythm Monitors.

OBJECTIVES: This study reports resource use and economic implications of rhythm monitoring with subcutaneous cardiac rhythm monitors (SCRMs). BACKGROUND: SCRMs generate a substantial amount of data that requires timely adjudication for appropriate clinical care. Resource use for SCRM monitoring is not known. METHODS: The study included consecutive transmissions during 4 weeks from 1,811 SCRMs. Resource use was quantified by assessment of time commitment of device clinic personnel and electrophysiologists for data adjudication. Incidence and characteristics of false positive (FP) episodes were assessed. Impact of custom programming for arrhythmia detection on incidence of FP episodes and resource use was analyzed. RESULTS: A total of 1,457 transmissions (alerts = 462; full downloads = 995) were received during study period. Average device clinic personnel time for adjudication of 1 transmission was 15 ± 6 min. This totaled to 364 h spent (2.3 full-time staff) over the 4-week period, which translated into a salary cost of $12,000 U.S. dollars (USD). Average time spent by an electrophysiologist for 1 transmission was 1.5 ± 1 min and totaled to 37 h for 4 weeks, which translated into an estimated cost of $9,600 USD. Of 1,457 total transmissions, 512 (35%) represented multiple transmissions from the same patients, which resulted in no additional reimbursement. Incidence of FP episodes in the entire cohort was 50% and was variable in alert (60%) and full download (49%) (p = 0.04) transmissions. When SCRMs with manufacturer suggested nominal programming and institutional custom programming were compared, there was a reduction in FP episodes (55% vs. 16%; p = 0.01), which translated to a 34% reduction in resource use for data adjudication. CONCLUSIONS: SCRM data adjudication requires significant resources. Custom programming for SCRMs may overcome the data deluge.

Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms.

Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.

Incidence of pacing-induced cardiomyopathy in pacemaker-dependent patients is lower with leadless pacemakers compared to transvenous pacemakers.

INTRODUCTION: Frequent right AQ4ventricular pacing (≥40%) with a transvenous pacemaker (TVP) is associated with the risk of pacing-induced cardiomyopathy (PICM). Leadless pacemakers (LPs) have distinct physical and mechanical differences from TVP. The risk of PICM with LP is not known. To identify incidence, predictors, and long-term outcomes of PICM in LP and TVP patients. METHODS: The study comprised all pacemaker-dependent patients with LP or TVP who had left ventricular ejection fraction (LVEF) of ≥50 from 2014 to 2019. The incidence of PICM (≥10% LVEF drop) was assessed with an echocardiogram. Predictors for PICM were identified using multivariate analysis. Long-term outcomes after cardiac resynchronization (CRT) were assessed in both groups. RESULTS: A total of 131 patients with TVP and 67 with LP comprised the study. All patients in the TVP group and the majority in the LP group underwent atrioventricular node ablation. The mean follow-up duration in TVP and LP groups was 592 ± 549 and 817 ± 600 days, respectively. A total of 18 (13.7%) patients in TVP and 2 (3%) in LP developed PICM after a median duration of 254 (interquartile range: 470) days. The incidence of PICM was significantly higher with TVP compared with LP (p = .02). TVP as pacing modality was a positive (odds ratio [OR]: 1.07) while age was negative (OR: 0.94) predictor for PICM on multivariable analysis. Both patients in LP and all except two in the TVP group responded to CRT. CONCLUSION: Incidence of PICM is significantly lower with LP compared with TVP in pacemaker-dependent patients. Age and TVP as pacing modality were predictors for PICM.

Unmasking Arrhythmogenic Hubs of Reentry Driving Persistent Atrial Fibrillation for Patient-Specific Treatment.

Background Atrial fibrillation (AF) driver mechanisms are obscured to clinical multielectrode mapping approaches that provide partial, surface-only visualization of unstable 3-dimensional atrial conduction. We hypothesized that transient modulation of refractoriness by pharmacologic challenge during multielectrode mapping improves visualization of hidden paths of reentrant AF drivers for targeted ablation. Methods and Results Pharmacologic challenge with adenosine was tested in ex vivo human hearts with a history of AF and cardiac diseases by multielectrode and high-resolution subsurface near-infrared optical mapping, integrated with 3-dimensional structural imaging and heart-specific computational simulations. Adenosine challenge was also studied on acutely terminated AF drivers in 10 patients with persistent AF. Ex vivo, adenosine stabilized reentrant driver paths within arrhythmogenic fibrotic hubs and improved visualization of reentrant paths, previously seen as focal or unstable breakthrough activation pattern, for targeted AF ablation. Computational simulations suggested that shortening of atrial refractoriness by adenosine may (1) improve driver stability by annihilating spatially unstable functional blocks and tightening reentrant circuits around fibrotic substrates, thus unmasking the common reentrant path; and (2) destabilize already stable reentrant drivers along fibrotic substrates by accelerating competing fibrillatory wavelets or secondary drivers. In patients with persistent AF, adenosine challenge unmasked hidden common reentry paths (9/15 AF drivers, 41±26% to 68±25% visualization), but worsened visualization of previously visible reentry paths (6/15, 74±14% to 34±12%). AF driver ablation led to acute termination of AF. Conclusions Our ex vivo to in vivo human translational study suggests that transiently altering atrial refractoriness can stabilize reentrant paths and unmask arrhythmogenic hubs to guide targeted AF driver ablation treatment.

Tine-Based Leadless Pacemaker: Strategies for Safe Implantation in Unconventional Clinical Scenarios.

Leadless pacemakers (LPs) have emerged as a meaningful alternative to transvenous pacemakers for single-ventricular pacing. LPs eliminate many of lead- and pocket-associated complications observed with transvenous pacemakers. Owing to the lack of atrioventricular synchronous pacing until recently, the use of LP was generally reserved for those patients who either required minimal ventricular pacing or had permanent atrial fibrillation. The only commercially available LP is the Micra transcatheter pacing system (Micra-TPS, Medtronic Inc. Fridley, Minnesota), which requires insertion of a 27-F (outer diameter) introducer sheath in the femoral vein. The LP is delivered to the right ventricle using a 23-F delivery catheter. Owing to the need for a large-bore sheath, the pivotal studies for the Micra transcatheter pacing system excluded patients with indwelling inferior vena cava filters and included only a few patients with bioprosthetic or repaired tricuspid valve. Subsequent real-world experience has demonstrated the overall safety and feasibility of LP placement, and use in various unconventional clinical settings has been validated, albeit with specific precautions. Additionally, incorporation of adjunctive techniques and strategies can improve the safety of the procedure in routine clinical settings as well. The objective of this state-of-the-art review is to highlight the key procedural elements to facilitate safe and efficient implantation of LP in routine as well as in unique clinical settings.