Permanent Transvenous Pacemaker Research Articles

Electrical performance of a novel extravascular temporary pacing lead system

Abstract Background An investigational extravascular (EV) cardiac temporary pacing system has been developed that includes a parasternally-positioned temporary pacing lead within the anterior mediastinum. The pacing lead is inserted using a custom delivery tool through a parasternal skin incision. This novel system may provide clinical advantages over existing device alternatives that require intravascular, endocardial, or epicardial contact. Objective The purpose of this study was to evaluate electrical performance of an EV temporary pacing lead over 48 hours. Methods In this single-center study, patients who underwent a transvenous (TV) permanent pacemaker implant or replacement were simultaneously implanted with the investigational EV temporary pacing lead. Electrical performance was evaluated through analysis of capture thresholds, impedance, and R-wave amplitudes during multiple times on the day of the procedure and on the subsequent 2 days of follow-up. Results Lead insertions with acute capture were successful in all 8 patients (40% female, 71 ± 8 years, BMI 27 ± 3 kg/m2). Mean acute measurements for pacing capture threshold at 1.5 ms, impedance and R-wave amplitude were 6.2 mA, 1396 Ω, 5.4 mV, respectively. Pacing capture was maintained in 100% of assessments conducted over 3 days (Figure 1). There were no serious complications during insertion, removal or chronic use of the lead. Conclusions Results support that the investigational EV temporary pacing lead is capable of safely providing temporary pacing with thresholds typically well below the maximum output of temporary pacemakers.

Serial GLS assessments over time in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement

Abstract Background Chronic right-ventricular (RV) pacing can exacerbate heart failure in patients with a low ejection fraction (EF), but little is known about pacing-induced cardiomyopathy (PICM) in patients with preserved EF. We aimed to investigate risk factors of PICM in these patients during long-term follow-up. Methods The prospective registry at our University Hospital, South Korea, included de novo patients with preserved EF undergoing transvenous permanent pacemaker (PPM) implantation for atrioventricular blockage from 2018 to 2022. Patients with EF > 50% and expected ventricular pacing > 40% were included. All patients were followed with serial echocardiography (preimplant, post implant, 12 months). All patients enrolled in this study were seen as outpatients every 3–6 months. Composite outcomes were cardiac death (pump failure), hospitalization because of heart failure, PICM, and biventricular pacing (BVP) upgrade. Results 71 patients (28 men, 73.1 ± 9.5 years) were included. After PPM implantation, EF and GLS were significantly decreased. During three years of follow-up, 2 patient died, 6 were hospitalized, 7 suffered PICM, and 3 underwent BVP upgrade. Cox regression analysis identified reduced post-implant global longitudinal strain (GLS) (HR, 1.524; 95% CI, 1.149–2.021; P = 0.003) as independent predictors of PICM. Post-implant GLS showed high predictive accuracy for PICM, with an area under the curve of 0.92 (95% CI 0.829–0.971; P < 0.001) Conclusion Post-implant GLS, rather than pre-implant GLS could help identify individuals at high risk of PICM. After PPM implantation, it is important to measure GLS, and patients with reduced GLS should be monitored more frequently and echocardiographic surveillance, with a view to an upgrade to BVP.Serial EF and GLS assessmentGLS ROC curve

Single center retrospective clinical audit and comparison of outcome between epicardial and transvenous endocardial permanent pacemaker implantations in dogs.

The aim of this retrospective cohort study was to provide a single-center clinical audit of complications for single chamber permanent pacemaker implantation (PPI) techniques and determine if the clinical parameters, PPI technique or complications were associated with outcome. The electronic medical records were searched for dogs treated for bradyarrhythmia with PPI. Data related to presenting complaint, signalment of the dog, ECG diagnosis, echocardiographic findings, PPI technique, and programing of the pacemaker were recorded. Survival length (days) was recorded as the last veterinary visit; if the dog was dead the reason was documented. Cumulative survival of each pacemaker was examined by a Kaplan-Meier survival curve and the two techniques compared with a logrank test. Chi-square was used to determine the association between major complications and death. A total of 66 dogs with 52 transvenous and 30 epicardial PPIs were included. All epicardial pacemakers were implanted via transdiaphragmatic approach. A total of 31 life-threatening complications were reported. There were nine deaths related to major complications (13.6% of the study sample). The median follow-up period was 366 days, with a median survival of 255 days, and a significant difference in cumulative survival of each pacemaker (P = 0.01) between epicardial (93 days, range 0-1882 days) and transvenous (334 days, range 0-2745) PPIs but no significant difference in cumulative survival between the two techniques when only the first pacemaker was considered (p = 0.07). The presence of a major complications had a significant association with death due to pacemaker complications (P<0.001). The decision to perform epicardial PPI in failed transvenous PPI patients may have skewed the cumulative survival as was evident in the lack of significant difference in survival when only first PPI were examined. Major complication rates between the two techniques were similar and the authors consider both techniques equally reliable to manage symptomatic bradycardia in dogs.

The impact of chronic kidney disease on healthcare utilization and costs associated with pacemaker infection

Abstract Background Patients with CKD are at increased risk of bleeding and device-related infections due to their chronic illness. CKD complicates treatment which could lead to an increase in duration of hospitalizations and higher costs. Purpose The goal of this study is to compare hospitalizations and the total costs associated with permanent pacemaker (PPM) infection in patients with and without CKD. Methods This retrospective analysis used Medicare Fee for service (FFS) claims to identify patients implanted with a transvenous PPM from June 2016-December 2020. Device infections, hospitalizations and costs were identified in a 12-month follow-up period post-device implant. Costs include all inpatient and outpatient hospital costs. Patients with CKD and infections were identified based on ICD-10 diagnostic codes. A generalized linear model was utilized to calculate non-infection and infection costs by CKD status. The simple differences between these cohorts represent the total infection cost with CKD and total infection cost without CKD highlighting the incremental cost of infected patients with CKD. Results A total of 439,679 Medicare FFS patients had PPM insertion from June 2016-December 2020, of which 13% had CKD and 1.2% had a device infection within 12-months post-implant. Infected patients with CKD incurred two admissions on average (p-value = &amp;lt;0.001), versus 1.4 (p-value = &amp;lt;0.001) for an infected patient without CKD. The total days in hospital for infected patients with CKD were 32 days (p-value = &amp;lt;0.001) versus 22 days (p-value=&amp;lt;0.001) for infected patients without CKD (Figure 1). The average cost of an infection in the US for a CKD patient was $176,483 (p-value = &amp;lt;0.001) versus $65,792 (p-value =&amp;lt;0.001) for a patient without CKD. The incremental costs of an infection in CKD as compared to no CKD was $110,691 (p-value of interaction = 0.0160). Conclusion In our analysis PPM-related infection in patients with CKD were characterized by more health care utilizations and higher costs compared to patients without CKD.Figure 1

Abstract 13661: In-Hospital Outcomes, Rates of Development of Complete Heart Block and Rates of Pacemaker Placement in TAVR and SAVR Cases: A 5-year Nationwide Inpatient Sample Analysis

Introduction: Complete Heart Block (CHB) is a commonly observed post-procedural complication associated with Transcatheter aortic valve replacement (TAVR) and Surgical aortic valve replacement (SAVR). Since 2016, limited data exists on In-hospital outcomes of TAVR and SAVR cases and rates of development of CHB. Methods: National Inpatient Sample 2016-2020 was used to identify and group TAVR and SAVR cases using appropriate ICD codes. Logistic regression was used to compare baseline characteristics and in-hospital outcomes. Results: 590,615 patients underwent aortic valve replacement (AVR) from 2016-2020, of which 49.6% were TAVR and 50.4% were SAVR. The most common diagnosis for AVR in both groups was nonrheumatic trileaflet aortic stenosis (AS) (86.6% in TAVR group and 53.5% in SAVR group, p&lt;0.001). In TAVR cases, development of CHB was more common (8.9%-vs-7.2%, p=0.235) along with increased need for transvenous pacing (16.6%-vs-8.7%, p=0.010) and permanent pacemaker placement (9.4%-vs-6.4%, p&lt;0.001). An upward trend in CHB occurrence and pacemaker placement (PPM) was noted in the TAVR group as shown in Image 1. TAVR group was observed to have higher rates of acute myocardial infarction (MI) (14.5%-vs-12.8%, p=0.074). SAVR group had higher rates of cardiogenic shock (8.10%-vs-2.20, p&lt;0.001) and in-hospital mortality (3.6%-vs-1.30%, p=0.02). Conclusions: Over the past few years, CHB has been more commonly observed with TAVR as compared to SAVR, necessitating increasing use for PPM placement. Despite these trends, in-hospital mortality and complications are lower with TAVR procedure.

Abstract 16163: Low Dose Alteplase for Treatment of Pacemaker Lead Associated Thrombosis

Multiple previously published case reports highlighted the thromboembolic risks associated with permanent transvenous pacemaker leads. Even though mostly clinically silent, pacemaker lead associated thrombosis has been linked to fatal outcomes via pulmonary or paradoxical embolism in the case of large mobile RA or RV thrombi formation. There is a lack of consensus on the optimal strategy for managing this condition. Oral and IV anticoagulation, thrombolysis, surgical and percutaneous thrombectomy have been attempted previously with mixed results. A 72 year old gentleman with a history of CAD requiring PCI, paroxysmal atrial fibrillation, and AV node ablation with subsequent biventricular pacemaker implant was admitted to our hospital with a few weeks of worsening dyspnea, now present at rest. Surface echocardiogram showed multiple mobile echo densities in the right ventricle and right atrium, attached to the pacemaker leads, confirmed by TEE, most likely thrombi. The venous duplex was positive for right lower extremity DVT. Bilateral pulmonary emboli with mild right-sided heart strain were noted on CTA chest. The patient was initially treated with IV unfractionated heparin. We subsequently decided to start low-dose tPA infusion for 24 hrs, similar to current off-label protocols for mechanical prosthetic valves or bioprosthetic valve thrombosis. After an initial IV bolus of 5 mg, 1 mg/hour of alteplase was continued for 24 hours. Our team has decided to use percutaneous thrombectomy as a last resort.Follow-up ECHO immediately post tPA infusion showed complete thrombi resolution. The patient was asymptomatic at this point. He was discharged the following day on Lovenox and Coumadin. To our knowledge, this is the first case demonstrating complete resolution of pacemaker lead-associated thrombi by using a 24 hr low dose tPA infusion in addition to IV anticoagulation. This can be entertained as a simple conservative initial strategy in stable patients with pacemaker lead/catheter-associated intracardiac thrombi.

Pacing-induced cardiomyopathy in patients with preserved ejection fraction undergoing permanent cardiac pacemaker placement.

Chronic right-ventricular (RV) pacing can worsen heart failure in patients with a low ejection fraction (EF), but little is known about pacing-induced cardiomyopathy (PICM) in patients with preserved EF. We aimed to investigate risk factors of PICM in these patients during long-term follow-up. The prospective registry at Chosun University Hospital, South Korea, included de novo patients with preserved EF undergoing transvenous permanent pacemaker (PPM) implantation for atrioventricular blockage from 2017 to 2021. Patients with EF ≥ 50% and expected ventricular pacing ≥ 40% were included. Composite outcomes were cardiac death (pump failure), hospitalization because of heart failure, PICM, and biventricular pacing (BVP) upgrade. A total of 168 patients (69 men, 76.3 ± 10.4 years) were included. During three years of follow-up, one patient died, 14 were hospitalized, 16 suffered PICM, and two underwent BVP upgrade. PICM were associated with reduced global longitudinal strain (GLS), prolonged paced QRS duration (pQRSd) and diastolic variables (E/e', LAVI). Cox regression analysis identified pQRSd (hazard ratio [HR], 1.111; 95% confidence interval [CI], 1.011-1.222; P = 0.03) and reduced GLS (HR, 1.569; 95% CI, 1.163-2.118; P = 0.003) as independent predictors of PICM. GLS showed high predictive accuracy for PICM, with an area under the curve of 0.84 (95% CI 0.779-0.894; P < 0.001) [GLS -12.0, 62.5% sensitivity, and 86.1% specificity]. RV pacing increased the risk of PICM in patients with preserved EF. Reduced GLS and prolonged pQRSd could help identify individuals at high risk of PICM even with preserved EF.

Pacemaker-lead-associated thrombosis in dogs: a multicenter retrospective study

Pacemaker implantation is the treatment of choice for clinically relevant bradyarrhythmias. Pacemaker-lead-associated thrombosis (PLAT) occurs in 23.0-45.0% of people with permanent transvenous pacemakers. Serious thromboembolic complications are reported in 0.6-3.5%. The incidence of PLAT in dogs is unknown. multicenter retrospective study of seven centers with 606 client-owned dogs undergoing permanent pacemaker implantation between 2012 and 2019. 260 dogs with a transvenous pacemaker with echocardiographic follow-up, 268 dogs with a transvenous pacemaker without echocardiographic follow-up and 78 dogs with an epicardial pacemaker. 10.4% (27/260) of dogs with transvenous pacemakers and echocardiographic follow-up had PLAT identified. The median time to diagnosis was 175 days (6-1853 days). Pacemaker-lead-associated thrombosis was an incidental finding in 15/27 (55.6%) dogs. Of dogs with a urine protein:creatinine ratio measured at pacemaker implantation, dogs with PLAT were more likely to have proteinuria at pacemaker implantation vs. dogs without PLAT (6/6 (100.0%) vs. 21/52 (40.4%), P=0.007). Urine protein:creatinine ratio was measured in 12/27 (44.4%) dogs at PLAT diagnosis, with proteinuria identified in 10/12 (83.3%) dogs. Anti-thrombotic drugs were used following the identification of PLAT in 22/27 (81.5%) dogs. The thrombus resolved in 9/15 (60.0%) dogs in which follow-up echocardiography was performed. Dogs with PLAT had shorter survival times from implantation compared to those without PLAT (677 days [9-1988 days] vs. 1105 days [1-2661 days], P=0.003). Pacemaker-lead-associated thrombosis is identified in 10.4% (27/260) of dogs following transvenous pacing, is associated with proteinuria, can cause significant morbidity, and is associated with reduced survival times.

Intracardiac leadless versus transvenous permanent pacemaker implantation: Impact on clinical outcomes and healthcare utilization

Transvenous permanent pacemakers are used frequently to treat cardiac rhythm disorders. Recently, intracardiac leadless pacemakers offer potential treatment using an alternative insertion procedure due to their novel design. Literature comparing outcomes between the two devices is scarce. We aim to assess the impact of intracardiac leadless pacemakers on readmissions and hospitalization trends. We analyzed the National Readmissions Database from 2016 to 2019, seeking patients admitted for sick sinus syndrome, second-degree-, or third-degree atrioventricular block who received either a transvenous permanent pacemaker or an intracardiac leadless pacemaker. Patients were stratified by device type and assessed for 30-day readmissions, inpatient mortality, and healthcare utilization. Descriptive statistics, Cox proportional hazards, and multivariate regressions were used to compare the groups. Between 2016 and 2019, 21,782 patients met the inclusion criteria. The mean age was 81.07 years, and 45.52 % were female. No statistical difference was noted for 30-day readmissions (HR 1.14, 95 % CI 0.92-1.41, p = 0.225) and inpatient mortality (HR 1.36, 95 % CI 0.71-2.62, p = 0.352) between the transvenous and intracardiac groups. Multivariate linear regression revealed that length of stay was 0.54 (95 % CI 0.26-0.83, p < 0.001) days longer for the intracardiac group. Hospitalization outcomes associated with intracardiac leadless pacemakers are comparable to traditional transvenous permanent pacemakers. Patients may benefit from using this new device without incurring additional resource utilization. Further studies are needed to compare long-term outcomes between transvenous and intracardiac pacemakers.

Incidence and Risk Factors of Subclavian Vein Stenosis after Permanent Transvenous Pacemaker in Pediatric Population

Incidence and Risk Factors of Subclavian Vein Stenosis after Permanent Transvenous Pacemaker in Pediatric Population

Successful Clindamycin Therapy of an Infected Subcutaneous Permanent Pacing Lead in a Dog after a Failed Course with Potentiated Amoxicillin and Enrofloxacin

Though permanent pacemaker implantation is the only effective therapy for certain bradyarrhythmias in dogs, it is not without risks. Bacterial infection of the device is one of the most common complications. Human guidelines recommend besides systemic antibiotics, surgical explantation of the pacing lead and pulse generator in case of device-infection. This report describes a 13.5-year-old dog that received a transvenous endocardial permanent pacemaker because of syncopal episodes resulting from paroxysmal third-degree atrio-ventricular block. Five days after an uneventful surgery, a painful swelling appeared around the subcutaneous part of the lead where this was inserted into the jugular vein. A 4-week course of amoxicillin and clavulanic acid combined with enrofloxacin failed to clear the infection on long-term. Ultrasound-guided puncture of the abscess was performed to gain a sample for bacterial culture and antibiogram. Oral clindamycin of 4 weeks' duration successfully resolved the infection with Staphylococcus aureus without having to explant the device. Repeated ultrasonographic examinations and fine-needle aspiration biopsies were used to evaluate for persistent local inflammation, guiding the length of the antibiotic therapy. Though the described approach has traditionally been ill-advised because of the risk of introducing bacteria and damaging the pacemaker lead, it was successful in our case.

Permanent transvenous pacemaker placement in a Terrier with sick sinus syndrome

Pacemaker therapy is generally considered necessary in patients with symptomatic bradycardia that does not respond to medical management. Common arrhythmias requiring implantation of a permanent pacemaker include third degree atrioventricular (AV) block, high grade second degree AV block, sick sinus syndrome and persistent atrial standstill. This patient care report discusses the diagnosis and treatment of a tTrrier with sick sinus syndrome.

Feasibility of adenosine stress cardiovascular magnetic resonance perfusion imaging in patients with MR-conditional transvenous permanent pacemakers and defibrillators

BackgroundThe use of stress perfusion-cardiovascular magnetic resonance (CMR) imaging remains limited in patients with implantable devices. The primary goal of the study was to assess the safety, image quality, and the diagnostic value of stress perfusion-CMR in patients with MR-conditional transvenous permanent pacemakers (PPM) or implantable cardioverter-defibrillators (ICD).MethodsConsecutive patients with a transvenous PPM or ICD referred for adenosine stress-CMR were enrolled in this single-center longitudinal study. The CMR protocol was performed using a 1.5 T system according to current guidelines while all devices were put in MR-mode. Quality of cine, late-gadolinium-enhancement (LGE), and stress perfusion sequences were assessed. An ischemia burden of ≥ 1.5 segments was considered significant. We assessed the safety, image quality and the occurrence of interference of the magnetic field with the implantable device. In case of ischemia, we also assessed the correlation with the presence of significant coronary lesions on coronary angiography.ResultsAmong 3743 perfusion-CMR examinations, 66 patients had implantable devices (1.7%). Image quality proved diagnostic in 98% of cases. No device damage or malfunction was reported immediately and at 1 year. Fifty patients were continuously paced during CMR. Heart rate and systolic blood pressure remained unchanged during adenosine stress, while diastolic blood pressure decreased (p = 0.007). Six patients (9%) had an ischemia-positive stress CMR and significant coronary stenoses were confirmed by coronary angiography in all cases.ConclusionStress perfusion-CMR is safe, allows reliable ischemia detection, and provides good diagnostic value.

Atrial pacing in Fontan patients: The effect of transvenous lead on clot burden.

Transvenous permanent pacemaker (PPM) implantation is an available option for Fontan patients with sinus node dysfunction. However, the thrombogenic potential of leads within the Fontan baffle is unknown. The purpose of this study was to compare the clot burden in Fontan patients with a transvenous atrial PPM to those without a PPM and those with an epicardial PPM. This was a retrospective cohort study of all transvenous PPM implantations in Fontan patients followed at our institution (2000-2018). We performed frequency matching on Fontan type and age group. Primary outcome was identification of intracardiac clot, pulmonary embolus, or embolic stroke. Of 1920 Fontan patients, 58 patients (median age 23 years; interquartile range [25th-75th percentiles] 14-33) at the time of transvenous PPM implantation and 174 matched subjects formed our cohort. The type of Fontan performed in case subjects was right atrium-pulmonary artery or right atrium-right ventricle conduit (54%), lateral tunnel (43%), and extracardiac (3%). The cumulative incidence of clot was highest in patients with transvenous PPM, followed by patients with epicardial PPM and no PPM (1.2 vs 0.87 vs 0.67 per 100 person-years of follow-up, respectively). In multivariable analysis, anticoagulation and/or antiplatelet therapy were protective against clot and resulted in reduction of clot risk by 3-fold (incidence rate ratio 0.33; 95% confidence interval 0.21-0.53; P <.001). In a large cohort of Fontan patients matched for age and Fontan type, patients with transvenous PPM had a higher but not statistically significant incidence of clot compared to those with no PPM and epicardial PPM. Patients treated with warfarin/aspirin had lower clot risk.

Conventional transvenous or leadless ventricular permanent pacemakers: post-operative complications and mid-term follow-up

Abstract Introduction/Background Leadless ventricular permanent pacemakers (leadless VVI, LPM) were designed to reduce lead-related complications of conventional VVI pacemakers (CPM). Purpose The aim of our study was to assess and compare real-life clinical outcomes within the first 30 days and during a mid-term follow-up with the two techniques at a nationwide level. Methods This French longitudinal cohort study was based on the national hospitalization database covering hospital care from for the entire population. All adults (age ≥18 years) hospitalized in French hospitals From January 1, 2017 to September 1, 2020, who underwent a first LPM or CPM implantation were included. Importantly, patients with dual chamber pacemaker were not included in our study. Results Of 42,315 patients included in the cohort, 40,828 patients (96%) had a CPM and 1,487 had a LPM. Using propensity score, 1,344 patients with CPM were adequately matched in a 1:1 fashion with LPM patients. Clinical outcomes at day 30 In the unmatched population, within the 30 days after implantation, patients with LPM had a lower rate of all-cause mortality (OR: 0.635, 95% CI: 0.527–0.765, p&amp;lt;0.0001) and from a cardiovascular cause (OR: 0.568, 95% CI: 0.405–0.797, p=0.001). They also had lower rates of major bleeding and need for transfusion. There was no significant difference between groups regarding tamponade, pneumothorax or hemothorax. In the matched population, LPM implantation was still significantly associated with a lower rate of all-cause death (OR: 0.583, 95% CI: 0.456–0.744, p&amp;lt;0.0001), cardiovascular death (OR: 0.413, 95% CI: 0.271–0.629, p&amp;lt;0.0001), major bleeding (OR: 0.523, 95% CI: 0.348–0.786, p=0.002) or transfusion (OR: 0.481, 95% CI: 0.296–0.780, p&amp;lt;0.0001). However, tamponade, pneumothorax or hemothorax were not significantly different between the two groups. Clinical outcomes during mid-term follow-up In the unmatched patients, mean follow-up was 8.6±10.5 months. Annual incidence of all-cause death was high in both groups, and significantly higher in the LPM group than in CPM group (31%/year vs. 20%/year, p&amp;lt;0.0001) with a HR of 1.519 (95% CI: 1.296–1.780). Cardiovascular death was not significantly different between groups. Infective endocarditis was higher in the LPM group than in the CPM group with a HR of 2.108 (95% CI: 1.119–3.973). In the matched patients, mean follow-up was 6.2±8.7 months. All-cause death, cardiovascular death and infective endocarditis were not significantly different between groups. Conclusion Mortality is high among unselected patients implanted with ventricular permanent pacemakers, whether leadless or conventional pacemaker are used. Implantation of leadless pacemakers seems to be a safe procedure in this high-risk population, with better outcomes at 1 month. Mid-term outcomes appear relatively similar in LPM and CPM patients. Funding Acknowledgement Type of funding sources: None. Central illustration

B-PO05-031 AETIOLOGY OF ATRIOVENTRICULAR HEART BLOCK IN YOUNG AND MIDDLE AGED ADULTS FROM SOUTH AFRICA

There is a paucity of data regarding the aetiology of atrioventricular (AV) heart block in young and middle-aged patients particularly from the from low and middle income countries. To determine the aetiology of AV heart block in patients ≤ 55 years who were treated with a transvenous pacemaker from a middle income country. We performed a retrospective review of all patients who received a transvenous pacemaker for newly diagnosed AV block from 1 January 2013 to 31 December 2020 at Groote Schuur Hospital, Cape Town, South Africa. The cohort of patients ≤ 55 years were the focus of this study. During the study period, 1101 consecutive patients received a permanent transvenous pacemaker for AV block. 136 patients (12.4%) were ≤55 years. The mean (standard deviation) age of the study patients was 41 (11) years and 48.5% were female. Third degree AV block was diagnosed in 73.5% and 2:1 AV block in 8.1%. The aetiology of heart block could be determined in 97 (71.3%) patients. 43 (31.6%) patients were post-surgical, predominantly for isolated mitral valve (MVR) replacement (27.9%) and isolated aortic valve (AVR) replacement (20.9%). 16 had developed complete heart block from an acute myocardial infarction; inferior myocardial infarction in 9/16 and anterior myocardial infarction in 7/16 patients. Congenital complete heart block was diagnosed in 15 (11%) cases. Cardiac Magnetic Resonance (CMR) imaging was performed in 26 patients: cardiac sarcoidosis was diagnosed in 7/26 patients, prior myocarditis in 3/26, left ventricular non-compaction in 3/26, interatrial cardiac tumour in 1 patient, cardiac amyloid in patient with multiple myeloma in 1 patient and hypertrophic cardiomyopathy in 1 patient. No pathology could be identified 10/26 patients who had CMR. The aetiology of AV block remained unknown in 39 patients (28.7%). Prior valve surgery is the leading cause of AV block treated with transvenous pacemaker in patients ≤ 55 years at our institution. Cardiac magnetic resonance imaging identifies disease processes that require further management in a significant proportion of cases.

Leadless or conventional transvenous ventricular permanent pacemakers: a nationwide matched control study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction / Background Leadless ventricular permanent pacemakers (leadless VVI, LPM) were designed to reduce lead-related complications of conventional VVI pacemakers (CPM). Purpose The aim of our study was to assess and compare real-life clinical outcomes within the first 30 days and during a mid-term follow-up with the two techniques at a nationwide level. Methods This French longitudinal cohort study was based on the national hospitalization database covering hospital care from for the entire population. All adults (age ≥18 years) hospitalized in French hospitals From January 1, 2017 to September 1, 2020, who underwent a first LPM or CPM implantation were included. Results Of 42,315 patients included in the cohort, 40,828 patients (96%) had a CPM and 1,487 had a LPM. Using propensity score, 1,344 patients with CPM were adequately matched in a 1:1 fashion with LPM patients. Clinical outcomes at day 30 In the unmatched population, within the 30 days after implantation, patients with LPM had a lower rate of all-cause mortality (OR: 0.635, 95%CI: 0.527-0.765, p &amp;lt;0.0001) and from a cardiovascular cause (OR: 0.568, 95%CI: 0.405-0.797, p = 0.001). They also had lower rates of major bleeding and need for transfusion. There was no significant difference between groups regarding tamponade, pneumothorax or hemothorax. In the matched population, LPM implantation was still significantly associated with a lower rate of all-cause death (OR: 0.583, 95%CI: 0.456-0.744, p &amp;lt; 0.0001), cardiovascular death (OR: 0.413, 95%CI: 0.271-0.629, p &amp;lt; 0.0001) or transfusion (OR: 0.481, 95%CI: 0.296-0.780, p &amp;lt; 0.0001). However, tamponade, pneumothorax or hemothorax and major bleeding were not significantly different between the two groups. Clinical outcomes during mid-term follow-up In the unmatched patients, mean follow-up was 8.6 ± 10.5 months. Annual incidence of all-cause death was high in both groups, and significantly higher in the LPM group than in CPM group (31%/year vs. 20%/year, p &amp;lt; 0.0001) with a HR of 1.519 (95%CI: 1.296-1.780). Cardiovascular death was not significantly different between groups. Infective endocarditis was higher in the LPM group than in the CPM group with a HR of 2.108 (95%CI: 1.119-3.973). In the matched patients, mean follow-up was 6.2 ± 8.7 months. All-cause death, cardiovascular death and infective endocarditis were not significantly different between groups. Conclusion Patients treated with leadless VVI pacemakers had better clinical outcomes in the first month compared to the patients treated with conventional VVI pacing. During a mid-term follow-up, risk of all-cause death, cardiovascular death and endocarditis in patients treated with leadless VVI pacemaker was not statistically different after propensity score matching.

First Case Report of Transvenous Pacemaker Placement in a Patient with Congenital Absence of the Clavicles Due to Cleidocranial Dysplasia

Cleidocranial dysplasia is a rare, autosomal dominant disease that is associated with clavicular absence or hypoplasia. Permanent pacemakers are most commonly implanted using percutaneous subclavian venous access. The clavicle is typically used as a bony landmark to guide venous access. Transvenous pacemaker implantation in the setting of clavicular hypoplasia, resection or other anomalies has not been described in literature. This is the first case report of a patient with clavicular absence undergoing transvenous permanent pacemaker implantation. This patient has a rare condition called cleidocranial dysplasia resulting in the congenital absence of his clavicles, along with other skeletal abnormalities. Cardiac anomalies are not associated with this disorder. This patient presented for permanent pacemaker placement in the setting of trifascicular block, symptomatic intermittent second-degree Mobitz type II atrioventricular block, and syncope. Using intra-procedural subclavian venography and intraprocedural Sonosite ultrasound imaging to identify vascular anatomy and surrounding anatomic landmarks, this patient underwent successful placement of a dual chamber transvenous pacemaker. Images from the intraprocedural venogram and the post-procedure chest x-ray illustrate the anatomy in this patient with congenital absence of the clavicles. This case has important implications in subclavian access and pacemaker placement in patients with clavicular abnormalities that may include absent, deformed, or resected clavicles.

Successful transcutaneous pacing following ventricular standstill during anaesthetic induction in a dog with third‐degree atrioventricular block

Third‐degree atrioventricular block is a haemodynamically unstable bradycardia frequently resulting in signs of lethargy, weakness and collapse. In this reported case, a four year‐four month‐old male neutered Cavalier King Charles spaniel diagnosed with third‐degree atrioventricular block was referred for transvenous permanent pacemaker implantation. During induction of general anaesthesia, the dog suffered cardiac arrest consistent with ventricular standstill, as indicated by cessation of ventricular electrical activity on the ECG monitor and the absence of a peripheral pulse. The prior placement of transthoracic pacing pads under sedation allowed for rapid commencement of temporary transcutaneous pacing and proved effective in achieving ventricular capture with re‐establishment of cardiac output. The subsequent general anaesthesia for implantation of a permanent pacemaker was uneventful. This report considers the possible causes of ventricular escape rhythm suppression and highlights the importance of ensuring availability of a temporary pacing method from the outset when anaesthetising animals with unstable and symptomatic bradycardias.

Morbidity and mortality in patients precluded for transvenous pacemaker implantation: Experience with a leadless pacemaker

The Micra transcatheter pacemaker is a safe and effective alternative to transvenous permanent pacemakers (TV-PPMs). However, the safety profile and mortality outcomes of Micra implantation in patients deemed poor candidates for TV-PPM are incompletely understood. The purpose of this study was to evaluate safety and all-cause mortality in patients undergoing Micra implantation stratified by whether they were precluded for therapy with a TV-PPM. Patients from the Micra clinical trials were divided into groups on the basis of whether the implanter considered the patient to be precluded from receiving a TV-PPM. Micra groups were compared with one another as well as with a historical cohort of patients who received a single-chamber TV-PPM. A total of 2817 patients underwent a Micra implantation attempt, of whom 546 (19%) patients deemed ineligible for TV-PPM implantation for reasons such as venous access issues or prior device infections. Both acute mortality (2.75% vs 1.32%; P=.022) and total mortality at 36 months (38.1% vs 20.6%; P<.001) were significantly higher in the precluded group than in the nonprecluded group. Mortality was similar among nonprecluded patients and patients implanted with a TV-PPM. The major complication rate through 36 months was similar between the 2 Micra groups (3.81% vs 4.30%; P=.40). All-cause mortality is higher in Micra patients deemed ineligible for TV-PPM implantation than in nonprecluded Micra patients and those who received a TV-PPM, in part related to a higher incidence of chronic comorbidities in these patients. The overall major complication rate was low and did not differ by preclusion status. Micra Post-Approval Registry ClinicalTrials.gov identifier: NCT02536118; Micra Continued Access Study ClinicalTrials.gov identifier: NCT02488681; Micra Transcatheter Pacing Study ClinicalTrials.gov identifier: NCT02004873; Medtronic Product Surveillance Registry ClinicalTrials.gov identifier: NCT01524276.