Right-sided Implantation Research Articles

Right-sided implantation with left-sided connection of a left bundle branch area pacing lead.

Right-sided implantation with left-sided connection of a left bundle branch area pacing lead.

Amiodarone does not significantly affect the success rate of ventricular fibrillation induction tests performed during or after ICD implantation. Insights from the German DEVICE registry

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): The DEVICE registries were financed by “Stiftung Institut für Herzinfarktforschung (IHF)”, with additional support by grants from Biotronik, Medtronic, and St. Jude Medical. Background Experimental data and early clinical trials suggested that amiodarone may alter the defibrillation threshold of ICD systems. However, because of its potent antiarrhythmic effect and lack of alternatives, amiodarone is frequently used for antiarrhythmic therapy in ICD or CRT-D patients, leading to the question of whether ICD testing with ventricular fibrillation induction should be repeated in these patients after starting amiodarone. Objective This study was designed to assess the impact of amiodarone therapy on the success of ventricular fibrillation induction tests in this "real life" cohort of ICD recipients of the German DEVICE registry. Methods 3,680 patients who underwent ICD implantation, revision, or upgrade in 49 centers participating in the German DEVICE Registry were enrolled 03/2007-02/2014. Results Intraoperative defibrillation testing was conducted in 2,705 patients receiving only beta-blockes as antiarrhythmic therapy and in 422 patients under betablocker plus amiodarone therapy. With regard to ineffective defibrillation tests, no difference could be described between the two groups (0.6% vs. 0.5%; p=0.77). In a similar fashion 488 patients receiving beta-blockers only and 65 patients under beta-blocker plus amiodarone therapy who were scheduled for postoperative defibrillation testing showed comparable rates of ineffective testing (14.5% vs. 15.4%; p=0.86). Conclusions Based on 3,127 intraoperative and 553 postoperative defibrillator testings, our study failed to show a significant association of amiodarone therapy and ineffective defibrillator testings in this "real life" cohort of ICD recipients of the German DEVICE registry. Our results thus underline that, apart from special situations such as right-sided implantation, HCM, extravenous ICD systems, etc., it might not be necessary to perform a DFT test after the start of an amiodarone therapy in ICD patients.

Right-sided approach to left bundle branch area pacing combined with atrioventricular node ablation in a patient with persistent left superior vena cava and left bundle branch block: a case report

BackgroundLeft bundle branch area pacing (LBBAP) is an alternative to right ventricular (RV) and biventricular (BiV) pacing in patients scheduled for pace and ablate treatment strategy. However, current delivery sheaths are designed for left-sided implantation, making the right-sided LBBAP lead implantation challenging.Case presentationWe report a case of a right-sided LBBAP approach via right subclavian vein in a heart failure patient with a persistent left superior vena cava scheduled for pace and ablate treatment of refractory atrial flutter. To enable adequate lead positioning and support for transseptal screwing, the delivery sheath was manually modified with a 90-degree curve at the right subclavian vein and superior vena cava junction to allow right-sided implantation. The distance between the reshaping point and the presumed septal region was estimated by placing the sheath on the body surface under fluoroscopy. With the reshaping of the delivery sheath, we were able to achieve LBBAP with relatively minimal torque. Radiofrequency ablation of the atrioventricular node was performed the next day and the pacing parameters remained stable in short-term follow-up.ConclusionWith the modification of currently available tools, LBBAP can be performed with the right-sided approach.

Severity and Extent of Lead-Related Venous Obstruction in More Than 3000 Patients Undergoing Transvenous Lead Extraction.

BackgroundLead-related venous stenosis/obstruction (LRVSO) may be a major challenge in patients with cardiac implantable electronic devices (CIED) when device upgrade, insertion of central lines, or creation of an arteriovenous fistula for hemodialysis is indicated. The aim of this study was to evaluate the extent and severity of LRVSO.MethodsWe performed a retrospective analysis of 3002 venograms from patients awaiting transvenous lead extraction (TLE) to assess the occurrence, severity, and extent of LRVSO.ResultsMild LRVSO occurred in 19.9%, moderate in 20.7%, severe in 19.9% and total venous occlusion in 22.5% of the patients. Moderate/severe stenosis or total occlusion of the subclavian and brachiocephalic veins was found in 38.2% and 22.5% of the patients, respectively. LRSVO was not detected in 16.9% of the patients. Moderate and severe superior vena cava (SVC) obstruction and total SVC occlusion were rare (0.4%, 0.3%, and 0.3%, respectively). Lead insertion on the left side of the chest contributed to an increased risk of LRVSO compared to right-sided implantation. Major thoracic veins on the opposite side may be narrowed in varying degrees.ConclusionA total of 60% of the patients with pacemaker or high-voltage leads have an advanced form of LRVSO. Any attempt to insert new pacing leads, central lines, venous ports, or catheters for hemodialysis, or to create dialysis fistula on the same side as the existing lead should be preceded by venography. Furthermore, venography may provide useful information, if it is planned to implant the lead or the catheter on the opposite side of the chest.

Major procedure-related complications in a real-world cohort of patients undergoing transvenous lead extraction

Abstract Funding Acknowledgements Type of funding sources: None. Background Transvenous lead extraction (TLE) is the mainstay therapy for device-related infections. Though TLE procedures are associated with low complication and high success rates, risk factors for major procedure-related complications remain not well defined. Purpose To evaluate the safety and efficacy of TLE in a large single centre cohort and to identify risk factors for major complications. Methods All consecutive patients undergoing TLE in our department between May 2012 and December 2021 were included in a prospective registry. Our protocol for TLE followed a stepwise approach according to lead dwell time and estimated complexity of the procedure: use of simple traction ± locking stylet (LS) ± mechanical and/or powered sheaths ± snare technique via a femoral or jugular access. Patient characteristics, procedural data and complications were gathered and analysed. Logistic regression analysis was applied to identify risk factors for major procedure related complications. Results A total of 2218 leads (25.7% ICD leads) were targeted for TLE in 1060 patients (67.7 ± 14.8 years; 74% male). The mean lead dwell time was 82 ± 62 months. The leading indication for TLE was cardiac device related infection (CDRI) in 695 patients (65.6%), 373 (35.2%) had systemic and 322 (30.4%) localized infection. Leads were extracted by simple traction in 30%, traction with LS in 3.7%, dilator sheaths with LS in 47.7%, and additional use of powered mechanical sheaths in 14.6%. The snare technique was used in 3.9%, with additional venous entry from femoral in 3.5% and jugular in 1.0% of all targeted leads. TLE was completely successful in 92.6%, partially successful with lead fragments <4cm in 4.2%, and failed in 3.1% of all patients, which translated to a clinical success rate of 96.9%. Twenty-nine patients (2.7%) experienced minor and 18 patients (1.7%) had major procedure-related complications (cardiac tamponade/perforation) including 2 intraprocedural deaths (0.2%). Presence of abandoned leads (HR 8.41, 95% CI 3.21–22.02; p<0.001), lead-years-per-patient (HR 1.063, 95% CI 1.037–1.090; p<0.001), dwelling time of the oldest lead (HR 1.011, 95% CI 1.006–1.016; p<0.001), and a right-sided implantation (HR 2.68, 95% CI 1.05–6.83; p=0.04) were significant predictors of major complications in logistic regression analysis. Conclusion TLE is feasible, effective and safe in our large single centre experience. Overall complication and failure rates are low. Following our TLE protocol, the presence of abandoned leads, a right-sided implantation and dwelling time of the extracted leads were associated with major procedure-related complications.

PO-708-06 FEASIBILITY OF RIGHT SIDED LEFT BUNDLE BRANCH AREA PACEMAKER INSERTION: A SINGLE CENTER PROSPECTIVE STUDY

Conduction system pacing with the left bundle branch area (LBBAP) is gaining traction as an alternative to traditional right ventricular (RV) pacing. Current implantation systems are designed for insertion through left axillary venous system, which is not always feasible. To evaluate the feasibility of right sided LBBAP lead implantations. Consecutive patients undergoing LBBAP implantation between Feb 2019 and July 2021 at Virginia Commonwealth University were analyzed. Laterality of site access and success rates were recorded. Baseline patient characteristics were tabulated. A total of 422 patients with LBBAP had procedural data available. 408 patients underwent left-sided device insertion with a success rate of 92% and 14 patients underwent right-sided insertion with a success rate of 79% (P=0.10, Table 1). Baseline demographics and indications for pacemaker implantation are listed in Table 1. Patients with right-sided implants were more likely to be referred for CRT (36% vs 9%, p=0.01) and had left bundle branch block (46% vs 14%, p=0.01) compared with left-sided implants. Procedural times were longer in right-sided implants compared with left-sided implants (113±27 vs 93±31 minutes, p=0.02). There was no difference in the mean LVAT and paced QRSd between right sided and left sided implants (Table 2). Lead parameters such as sensing, thresholds and impedances were comparable between the 2 groups. There was no difference in complications. LBBAP success rates may be influenced by the laterality of device insertion. Equipment designed specifically for right-sided implantation may improve success rates, but larger patient populations will be needed to confirm these results. Operator experience with right sided implants is also likely to affect success rates.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Outflow cannula position for left ventricular assist device: A propensity score-matched study.

The clinical consequences of alternative outflow cannula positioning in patients undergoing left ventricular assist device implantation are unknown. We evaluated clinical outcomes in patients who underwent implantation with the outflow cannula implanted from the right side into the ascending aorta versus the left side of the pericardium. Fifty consecutive patients with terminal left heart failure underwent implantation using the Medtronic Heartware Ventricular Assist Device at Toronto General Hospital. Patients were divided between left and right outflow cannula positioning during implantation where anastomosis occurred in the ascending aorta. Propensity score matching using exact matching on the following pre-specified covariates: Interagency Registry for Mechanically Assisted Circulatory Support score, previous cardiac surgery, and preoperative inotrope use. Fifty consecutive patients (25 left implantation and 25 right implantation) were included in the unmatched cohort and 45 patients (25 left implantation and 20 right implantation) were included in the matched cohort. No significant differences in baseline demographics. Pump thrombosis occurred in 10% (n = 2) receiving right-sided implantation and 8% (n = 2) with left implantation (p = 1.00). Postoperative stroke occurred in 10% (2/20) with right implantation and 16% (4/25) with left implantation (p = .88). No difference in 1-year mortality between right 20% (5/25) and left 25% (5/20) implantation (p = .97). No observed difference in mortality when adjusting for competing risk of heart transplantation. There was also no difference in stroke, pump thrombosis, driveline infection. Larger studies are required to confirm these findings. These preliminary data support the use of left-sided anastomoses to facilitate subsequent re-entry during heart transplantation.

Successful right-sided azygos coil implantation for failed defibrillation thresholds using a 3D mapping system

Successful right-sided azygos coil implantation for failed defibrillation thresholds using a 3D mapping system

Safety and Long-term Outcomes of Defibrillator Therapy in Patients With Right-Sided Implantable Cardiac Devices in Adults With Congenital Heart Disease

BackgroundImplantable cardioverter-defibrillators (ICDs) have been proven to prevent sudden cardiac death in adult congenital heart disease (ACHD) patients. Although the left side is chosen by default, implantation from the right side is often required. However, little is known about the efficacy and safety of right-sided ICDs in ACHD patients. MethodsIn this study we reviewed a total of 191 ACHD patients undergoing ICD/cardioverter resynchronisation therapy-defibrillator (CRT-D) implantation at our hospital between 2001 and 2019 (134 men and 57 women; age [mean ± standard deviation], 41.5 ± 14.8 years). ResultsTwenty-seven patients (14.1%) had right-sided devices. The most common causes of right-sided implantation were persistent left superior vena cava and vein occlusion (37.0%). Although procedure time (202.8 ± 60.5 minutes vs 143.8 ± 69.1 minutes, P = 0.008) was longer and the procedural success was lower (92.6% vs 99.4%, P = 0.008) for right-sided devices, no difference in R-wave and pacing threshold were noted. Among the 47 patients (24.6%) who underwent defibrillation threshold testing (DFT), no difference in DFT was observed (25.2 ± 5.3 J vs 23.8 ± 4.1 J, P = 0.460). During the median follow-up of 42.4 months, appropriate ICD therapy was observed in 5 (18.5%) and 30 (18.3%) patients for right- and left-sided ICDs/CRTDs, respectively (P = 0.978). No significant difference was seen in complications between them. ConclusionsImplantation of an ICD on the right side is technically challenging, but it is feasible as an alternative approach for ACHD patients with contraindications to left-sided device implantation.

Evolution of placentation in cattle and antelopes.

Bovids have enjoyed great evolutionary success as evidenced by the large number of extant species. Several important domestic animals are from this family. They derive from both subfamilies: cattle and their kin belong to Bovinae and sheep and goats to Antilopinae. The premise of this review, therefore, is that evolution of reproduction and placentation is best understood in a context that includes antelope-like bovines and antelopes. Many key features of placentation, including hormone secretion, had evolved before bovids emerged as a distinct group. Variation nevertheless occurs. Most striking is the difference in fusion of the binucleate trophoblast cell with uterine epithelium that yields a transient trinucleate cell in bovines and many antelopes, but a more persistent syncytium in wildebeest, sheep and goat. There is considerable variation in placentome number and villus branching within the placentome. Many antelopes have right-sided implantation in a bicornuate uterus whilst others have a uterus duplex. Finally, there has been continued evolution of placental hormones with tandem duplication of PAG genes in cattle, differences in glycosylation of placental lactogen and the emergence of placental growth hormone in sheep and goats. The selection pressures driving this evolution are unknown though maternal-fetal competition for nutrients is an attractive hypothesis.

Evolution of placentation in cattle and antelopes

Bovids have enjoyed great evolutionary success as evidenced by the large number of extant species. Several important domestic animals are from this family. They derive from both subfamilies: cattle and their kin belong to Bovinae and sheep and goats to Antilopinae. The premise of this review, therefore, is that evolution of reproduction and placentation is best understood in a context that includes antelope-like bovines and antelopes. Many key features of placentation, including hormone secretion, had evolved before bovids emerged as a distinct group. Variation nevertheless occurs. Most striking is the difference in fusion of the binucleate trophoblast cell with uterine epithelium that yields a transient trinucleate cell in bovines and many antelopes, but a more persistent syncytium in wildebeest, sheep and goat. There is considerable variation in placentome number and villus branching within the placentome. Many antelopes have right-sided implantation in a bicornuate uterus whilst others have a uterus duplex. Finally, there has been continued evolution of placental hormones with tandem duplication of PAG genes in cattle, differences in glycosylation of placental lactogen and the emergence of placental growth hormone in sheep and goats. The selection pressures driving this evolution are unknown though maternal-fetal competition for nutrients is an attractive hypothesis.

Plug-based closure in completely percutaneous right-sided transaxillary transcatheter aortic valve implantation.

Plug-based closure in completely percutaneous right-sided transaxillary transcatheter aortic valve implantation.

Visualisation of coronary venous anatomy by computed tomography angiography prior to cardiac resynchronisation therapy implantation.

BackgroundThe purpose of this study was to illustrate the additive value of computed tomography angiography (CTA) for visualisation of the coronary venous anatomy prior to cardiac resynchronisation therapy (CRT) implantation.MethodsEighteen patients planned for CRT implantation were prospectively included. A specific CTA protocol designed for visualisation of the coronary veins was carried out on a third-generation dual-source CT platform. Coronary veins were semi-automatically segmented to construct a 3D model. CTA-derived coronary venous anatomy was compared with intra-procedural fluoroscopic angiography (FA) in right and left anterior oblique views.ResultsCoronary venous CTA was successfully performed in all 18 patients. CRT implantation and FA were performed in 15 patients. A total of 62 veins were visualised; the number of veins per patient was 3.8 (range: 2–5). Eighty-five per cent (53/62) of the veins were visualised on both CTA and FA, while 10% (6/62) were visualised on CTA only, and 5% (3/62) on FA only. Twenty-two veins were present on the lateral or inferolateral wall; of these, 95% (21/22) were visualised by CTA. A left-sided implantation was performed in 13 patients, while a right-sided implantation was performed in the remaining 2 patients because of a persistent left-sided superior vena cava with no left innominate vein on CTA.ConclusionImaging of the coronary veins by CTA using a designated protocol is technically feasible and facilitates the CRT implantation approach, potentially improving the outcome.Electronic supplementary materialThe online version of this article (10.1007/s12471-018-1132-2) contains supplementary material, which is available to authorized users.

Totally Implantable Central Venous Port Catheters: Radiation Exposure as a Function of Puncture Site and Operator Experience.

Totally implantable central venous port systems provide a safe and effective, long-term means of access for administration of hyperosmolar, local irritant medication, such as chemotherapy, antibiotics and parenteral nutrition. To evaluate the combination of access site and level of experience on fluoroscopy times (FT) and dose area products (DAP) during implantation of port catheters in a large patient population. A total of 1,870 patients (992 women, 878 men; age: 61±13.14 years) were reviewed investigating two groups of junior (≤50 implantations) and senior (>50) radiologists. Senior radiologists required less FT/DAP (0.24 s/57.3 μGy m2 versus 0.43 s/68.2 μGy m2, respectively; p<0.001). Right jugular vein access required the least FT/DAP (0.25 s/56.15 μGy m2) and right-sided implantation lower FT/DAP (right: 0.26 s/56.4 μGy m2, left: 0.40 s/85.10 μGy m2, p<0.001). Due to DAP/FT reductions, the right jugular vein seems to be the most favorable implantation side for port systems. For further dose reduction, residents should be well-trained.

Effectiveness Evaluation of ICDs Implanted in the Right Side vs. Left Side

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; The implantation of ICDs left pectorally is the conventional normal practice, but pathological reasons may obly to insert the devices on the right side. The aim of our evaluation was to define the outcome of right-sided implantation (n=52) on defibrillation effectiveness in comparison to the left-sided ICD implantation (n=210).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;A cohort of patients received standard therapy for primary or secondary prevention of sudden cardiac death (SCD) in patients with the structural cardiac disease, lay open to the ICD-DR implantation. The 262 individuals who had all the inclusion criteria were comprised in the assessment.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The defibrillation threshold testing (DFT), at the end of implantation showed that the mean energy to revert a programmed induced sustained ventricular tachycardia/ventricular fibrillation was 33.4±6.3 J for the patients that had the ICD implanted on the right side, and 23.9±5.3 J for the ones that presented the ICD positioned on the left side, P&amp;lt;0.0001. However the mean and the sum of shock events recorded by ICD during 1 year of monitoring, according to the side of ICD implantation, did not show any difference.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;Our results show that ICD implantation on the right side caused an elevated DFT in comparison to the left side insertion. This study also reported that there is no difference regarding safety and effectiveness about the amount of appropriate and inappropriate shock therapies, the mean and the sum of shock events recorded by ICD during 1 year of monitoring, according to the side of ICD implantation.&lt;/p&gt;

Conventional and right-sided screening for subcutaneous ICD in a population with congenital heart disease at high risk of sudden cardiac death.

Information regarding suitability for subcutaneous defibrillator (sICD) implantation in tetralogy of Fallot (ToF) and systemic right ventricle is scarce and needs to be further explored. The main objective of our study was to determine the proportion of patients with ToF and systemic right ventricle eligible for sICD with both, standard and right-sided screening methods. Secondary objectives were: (i) to study sICD eligibility specifically in patients at high risk of sudden cardiac death, (ii) to identify independent predictors for sICD eligibility, and (iii) to compare the proportion of eligible patients in a nonselected ICD population. We recruited 102 patients with ToF, 33 with systemic right ventricle, and 40 consecutive nonselected patients. Conventional electrocardiographic screening was performed as usual. Right-sided alternative screening was studied by positioning the left-arm and right-arm electrodes 1cm right lateral of the xiphoid midline. The Boston Scientific ECG screening tool was utilized. In high-risk patients with ToF, eligibility was higher with right-sided screening in comparison with standard screening (61% vs. 44%; p=.018). Eligibility in high-risk right ventricle population was identical with both screening methods (77%, p=ns). The only independent predictor for sICD eligibility was QRS duration. In high-risk patients with ToF, right-sided implantation of the sICD could be an alternative to a conventional ICD. In patients with a systemic right ventricle, implantation of a sICD is an alternative to a conventional sICD.

Intraoperative Defibrillation Testing Should Not Be Generally Abandoned for All ICD Procedures-A Multicenter Study on 4,572 Consecutive Patients.

Background The ongoing technical advances in development of new implantable cardioverter defibrillator (ICD) systems led some investigators to question the routine use of intraoperative defibrillation testing (DT). Therefore, we evaluated retrospectively in a multicenter study effectiveness, safety, and usefulness of intraoperative DT on unbiased large patient population. Methods Data from 4,572 consecutive patients undergoing any ICD intervention were retrospectively analyzed. Besides efficacy of DT, risk factors for DT failure were identified in a multiple logistic regression analysis. Results Overall 5,483 shock data from 4,532 patients were available. Not tested for medical reasons were 13.5%. DT-associated complications were not noted. Primary DT effectiveness was 95.8%, whereas 4.2% were ineffective. Optimization (51.6% increase of DT energy, 10.1% subcutaneous lead array (SQ array), 2% generator exchange, 4.8% lead reposition, 9.3% lead exchange, and 22.2% change of shock parameters) led to successful DT in 152 patients (96.2%). Subanalyses and logistic regression identified implantation of generator in any other position than left subpectoral, age, body mass index and left ventricular ejection fraction as independent predictors for primary DT failure. Conclusion The number of patients, including those undergoing generator exchange, system upgrade, or system revision, with inappropriate intraoperative testshock is relatively high. The results of recent prospective clinical trials can be extrapolated only on first ICD implantations with high-energy generators. For patients undergoing subcutaneous ICD implantation, right-sided implantation, patients with channelopathies and hypertrophic cardiomyopathy, as well as for procedures on already implanted ICD systems, the intraoperative DT might still be recommended.

MRI-safe pacemakers and reduction of cardiac MRI artefacts with right-sided implantation

Patients with implanted cardiac pacing devices have a 50–75% likelihood of an indication for cardiac MRI (CMR) during the device lifetime. Three pacemakers (Medtronic Ensura™, St Jude Accent™, and Biotronik Evia™) and one implantable cardioverter-defibrillator (Biotronik Lumax 740™) are approved for CMR. Pacing devices cause CMR artefacts due to differing magnetic susceptibilities in metal and human tissue. These can render scans suboptimal ( Panels B–D ). Devices are typically implanted on the non-dominant side (left), but resultant artefacts can degrade image quality. A 69-year-old male was …

Right‐Sided Implantation and Subpectoral Position are Predisposing Factors for Fracture of a 6.6 French ICD Lead

The Medtronic Sprint Fidelis (Medtronic Inc., Minneapolis, MN, USA) lead family is associated with an unacceptable incidence of premature lead failure. There are limited data on risk factors for lead fracture. We hypothesized that factors leading to potential increased forces on the lead related to device implantation or technique may be associated with premature lead failure. We reviewed the implant data from our group and identified 176 patients who received active fixation Medtronic Fidelis (Model 6931, single coil and Model 6949, dual coil) leads. Implant data, including age, sex, venous access site, implant side, implant location, and number of venous leads were reviewed. Hospital, pacemaker clinic, and Medtronic registration databases were reviewed for evidence of lead failure, replacement, or abandonment. Data was evaluated in univariate and multivariate regression analyses. Of the 176 leads implanted, 10 (5.7%) were noted to develop malfunction. This presented as inappropriate shocks from sensed noise or elevated impedance measurements. Of the above noted implant features, only right-sided (vs left-sided) implant (hazard ratio [HR] 18.8, 95% confidence intervals [CI] 3.8, 93.3), and subpectoral implant (vs prepectoral; HR 14.31, 95% CI 3.2, 64.0) were predictive of lead failure in maximally adjusted models. We have identified both right-sided implantation and subpectoral generator positioning as factors associated with premature lead malfunction in Fidelis active fixation leads. Clinical decisions regarding patient management should incorporate these findings in regard to lead replacement in high-risk patients.

Short-term Venous Patency after Implantation of Permanent Pacemakers or Implantable Cardioverter Defibrillators

There is little information on venous patency after pacing leads are inserted in veins during pacemaker or implantable cardioverter defibrillator (ICD) implantation. Herein we present a report on venous patency during the immediate postoperative period after permanent pacemaker or ICD implantation.Subjects and Methods: Twenty-five patients underwent a permanent pacemaker or ICD implantation by venous puncture method, and venography was performed 1 week later. We assessed the pacemaker-implantation side, approach used, implanted device, number of implanted leads, and clinical symptoms.Results: Narrowing of the vein was found in 14 patients (56%), including 7 patients (28%) with occlusion. Stenosis and occlusion were seen more in patients with left-sided implantation than those with right-sided implantation (71% vs. 25%, P < 0.05). ICD implantation was more frequently associated with venous stenosis or occlusion than pacemaker implantation (65% vs. 37.5%, P < 0.05). The approach used and the number of leads implanted did not correlate with venous stenosis or occlusion. Six of the 7 patients who developed complete occlusion showed clinical symptoms.Conclusion: Thrombus formation after pacemaker implantation can occur in the acute stage within 1 week. The incidence of venous stenosis or thrombus formation was higher with leftsided implantation and ICD.