Infective Endocarditis Involving Implanted Cardiac Electronic Devices: JACC Focus Seminar 1/4.

Cardiac implantable electronic device-related infective endocarditis (CIED-IE) encompasses a range of clinical syndromes, including valvular, device lead, and bloodstream infections. However, accurately diagnosing CIED-IE remains challenging owing in part to diverse clinical presentations, lack of standardized definition, and variations in guideline recommendations. Furthermore, current diagnostic modalities, such as transesophageal echocardiography and [18F]-fluorodeoxyglucose positron emission tomography-computed tomography have limited sensitivity and specificity, further contributing to diagnostic uncertainty. This can potentially result in complications and unnecessary costs associated with inappropriate device extraction. Six hypothetical clinical cases that exemplify the diverse manifestations of CIED-IE are addressed herein. Through these cases, we highlight the importance of optimizing diagnostic accuracy and stewardship, understanding different pathogen-specific risks for bloodstream infections, guiding appropriate device extraction, and preventing CIED-IE, all while addressing key knowledge gaps. This review both informs clinicians and underscores crucial areas for future investigation, thereby shedding light on this complex and challenging syndrome.

Atrial fibrillation ablation compared to pacemaker therapy in patients with tachycardia-bradycardia syndrome: A systematic review and updated meta-analysis.

BACKGROUND: Tachycardia-bradycardia syndrome (TBS) is a subtype of sick sinus syndrome characterized by prolonged sinus pause (≥3 s) following termination of tachyarrhythmias, primarily atrial fibrillation (AF). There is controversy regarding whether the long-term prognosis of AF ablation is superior to pacemaker implantation. This study aimed to compare the effects of AF ablation and pacemaker therapy in patients with TBS. METHODS: We conducted a comprehensive search of electronic databases, including PubMed, Cochrane, EmBase, Web of Science, and Chinese BioMedical, up until December 1, 2023. We included studies that reported the effects of AF ablation vs pacemaker therapy in patients with TBS. From this search, we identified 5 studies comprising 843 participants with TBS who underwent catheter AF ablation or pacemaker therapy. RESULTS: Our meta-analysis revealed that AF ablation and pacemaker therapy had similar effects on cardiovascular death (odds ratio [OR] = 0.62 and 95% confidence interval [CI]: 0.14-2.65), procedural complications (OR = 1.53 and 95% CI: 0.67-3.48), and cardiovascular rehospitalization (OR = 0.57 and 95% CI: 0.26-1.22). However, AF ablation provided greater benefits than pacemaker therapy in terms of all-cause mortality (OR = 0.37 and 95% CI: 0.17-0.82), thromboembolism (OR = 0.25 and 95% CI: 0.12-0.49), stroke (OR = 0.28 and 95% CI: 0.13-0.57), heart failure (OR = 0.27 and 95% CI: 0.13-0.56), freedom from AF (OR = 23.32 and 95% CI: 7.46-72.92), and prevention of progression to persistent AF (OR = 0.12 and 95% CI: 0.06-0.24). Furthermore, AF ablation resulted in a reduced need for antiarrhythmic agents (OR = 0.21 and 95% CI: 0.08-0.59). CONCLUSION: AF ablation can effectively reduce the risk of all-cause mortality, thromboembolism, stroke, heart failure, and progression to persistent AF in patients with TBS. Additionally, it may eliminate the need for further pacemaker therapy in most cases after ablation. Therefore, AF ablation is considered superior to pacemaker therapy in the management of patients with TBS.

Stepwise transvenous lead extraction due to pacemaker pocket infection following lactational mastitis complicated with breast abscess.

BACKGROUND: Lactational mastitis is a common painful and debilitating inflammation of breast tissue, generally treated conservatively or with pus puncture in case of breast abscess. However, treating mastitis in patients with implantable surgical material located in the affected breast region can be extremely challenging. We present an unusual case of lactational mastitis complicated by pacemaker pocket infection in a breastfeeding mother. CASE PRESENTATION: A 35-year-old pacemaker-dependent female developed lactational mastitis seven weeks postpartum. Initially, the condition was treated conservatively with analgesics and antibiotics. After abscess formation, pus was aspirated using fine-needle aspiration technique. Four weeks after mastitis resolution, pacemaker pocket infection developed. According to current cardiovascular implantable electronic device infection treatment guidelines a complete surgical extraction of the entire electronic system, followed by targeted antibiotic treatment and reimplantation of a new device after infection resolution, was recommended. However, after thorough discussion with the young woman and her family and after detailed review of surgery-related risks, she declined a potentially high-risk surgical procedure. Thus, only the pulse generator was explanted; pacing leads positioned in the sub-pectoral pocket; new pacemaker implanted on the contralateral side and broad-spectrum antibiotic therapy continued for six weeks. After breastfeeding cessation, and with chronic fistula development at the primary pacemaker implantation site, the possibility of delayed surgical intervention including complete extraction of retained pacemaker leads was again thoroughly discussed with her. After thoughtful consideration the woman consented to the proposed treatment strategy. A surgical procedure including transvenous lead extraction through the primary implantation venous entry site, using hand-powered bidirectional rotational sheaths, was successfully performed, removing all retained leads through the left subclavian venous entry site, and leaving the fully functional and clinically uninfected pacemaker on the contralateral site intact. CONCLUSION: Although patients' decisions for delayed extraction in a case of cardiovascular implantable electronic device infection should be discouraged by attending physicians and members of interdisciplinary teams, our case shows that a stepwise treatment strategy may be successful as a bailout clinical scenario in patients with specific requests, demands and / or clinical needs.

Transient 2:1 Atrioventricular Block with Peri-Conduction System Pacing After Leadless Pacemaker Implantation.

This report discusses a case of transient 2:1 atrioventricular block with conduction system pacing 4 hours after leadless right ventricular pacemaker implantation in a 19-year-old patient with a history of cardioinhibitory syncope and asystole cardiac arrest but without preexisting atrioventricular block. The atrioventricular block was resolved spontaneously. Pacing morphology was suggestive of right bundle branch pacing. Neither 2:1 atrioventricular block nor conduction system pacing has previously been a reported outcome of right ventricular leadless pacemaker implantation. The report demonstrates that conduction system pacing with leadless devices is achievable. Further study of techniques, limitations, and complications related to intentional right ventricular leadless conduction system pacing is warranted.

Permanent Pacemaker Implantation and Long-Term Outcomes of Patients Undergoing Concomitant Mitral and Tricuspid Valve Surgery.

BACKGROUND: Tricuspid valve annuloplasty (TA) during mitral valve repair (MVr) is associated with increased risk of permanent pacemaker (PPM) implantation, but the magnitude of risk and long-term clinical consequences have not been firmly established. OBJECTIVES: This study assesses the incidence rates of PPM implantation after isolated MVr and following MVr with TA as well as the associated long-term clinical consequences of PPM implantation. METHODS: State-mandated hospital discharge databases of New York and California were queried for patients undergoing MVr (isolated or with concomitant TA) between 2004 and 2019. Patients were stratified by whether or not they received a PPM within 90 days of index surgery. After weighting by propensity score, survival, heart failure hospitalizations (HFHs), endocarditis, stroke, and reoperation were compared between patients with or without PPM. RESULTS: A total of 32,736 patients underwent isolated MVr (n = 28,003) or MVr + TA (n = 4,733). Annual MVr + TA volumes increased throughout the study period (P < 0.001, trend), and PPM rates decreased (P < 0.001, trend). The incidence of PPM implantation <90 days after surgery was 7.7% for MVr and 14.0% for MVr + TA. In 90-day conditional landmark-weighted analyses, PPMs were associated with reduced long-term survival among MVr (HR: 1.96; 95% CI: 1.75-2.19; P < 0.001) and MVr + TA recipients (HR: 1.65; 95% CI: 1.28-2.14; P < 0.001). In both surgical groups, PPMs were also associated with an increased risk of HFH (HR: 1.56; 95% CI: 1.27-1.90; P < 0.001) and endocarditis (HR: 1.95; 95% CI: 1.52-2.51; P < 0.001), but not with stroke or reoperation. CONCLUSIONS: Compared to isolated MVr, adding TA to MVr was associated with a higher risk of 90-day PPM implantation. In both surgical groups, PPM implantation was associated with an increase in mortality, HFH, and endocarditis.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

BACKGROUND AND AIMS: Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. METHODS: All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. RESULTS: 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). CONCLUSIONS: Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation.

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

Postoperative Atrioventricular Block in Pediatric Patients: Impact of Congenital Cardiac Malformations and Medications.

Postoperative atrioventricular block may occur after pediatric cardiac surgery. A small proportion of those who develop atrioventricular block will require pacemaker placement. The primary aim of this study was to determine factors associated with postoperative atrioventricular block. Secondary aims included determining factors associated with pacemaker placement in those with atrioventricular block. Data from the PHIS data were utilized to identify patients under 18 years of age who underwent cardiac surgery. Those who did and did not develop atrioventricular block. Univariable analyses and regression analyses were conducted to determine factors associated with postoperative atrioventricular block. Similar analyses were conducted to determine factors associated with pacemaker placement in those with atrioventricular block. A total of 43,716 admissions were identified. Of these, 2093 (5%) developed atrioventricular block and 480 (1% of total admissions) underwent pacemaker placement. Approximately 70% of those with atrioventricular block received steroids but this was not associated with a decrease in pacemaker placement. Risk factors (congenital malformations of the heart, comorbidities, medications) associated with increased risk of atrioventricular block and pacemaker placement were identified. Postoperative atrioventricular block occurred in 5% of pediatric admissions for cardiac surgery. Of these admissions with postoperative atrioventricular block, 23% required pacemaker placement. Isoproterenol and steroids were not associated with a reduction in the likelihood of pacemaker placement.

Flecainide causing elevated capture thresholds on pacemaker implantation.

Flecainide is a Vaughan Williams class 1c antiarrhythmic used to treat supraventricular and ventricular arrhythmias. It has been described as a rare cause for increased pacemaker capture thresholds. We describe a report of a patient, in her early 80s, presenting with tachy-brady syndrome on a background of permanent atrial fibrillation. She was treated with metoprolol and flecainide by her private cardiologist. Permanent right ventricular chamber pacing was recommended for her slow heart rate. At insertion of her single chamber pacemaker, she was noted to have elevated capture thresholds despite appropriate lead positioning. A flecainide level was elevated at 1.1 µg/mL, and it was subsequently ceased. This was associated with a rapid improvement in her capture threshold. Flecainide should be considered as a cause for elevated pacing thresholds at the time of implant. Particular care should be taken for at-risk groups such as the elderly and patients with renal impairment.

Cardiac implantable electronic device-induced tricuspid regurgitation: Implications and management.

Tricuspid regurgitation (TR) secondary to cardiac implantable electronic devices (CIEDs) has been well documented and is associated with worse cardiovascular outcomes. A variety of mechanisms have been proposed including lead-induced mechanical disruption of the tricuspid valvular or subvalvular apparatus and pacing-induced electrical dyssynchrony. Patient characteristics such as age, sex, baseline atrial fibrillation, and pre-existing TR have not been consistent predictors of CIED-induced TR. While two-dimensional echocardiography is helpful in assessing the severity of TR, three-dimensional echocardiography has significantly improved accuracy in identifying the etiology of TR and whether lead position contributes to TR. Three-dimensional echocardiography may therefore play a future role in optimizing lead positioning during implant to reduce the risk of CIED-induced TR. Optimal lead management strategies in addition to percutaneous interventions and surgery in alleviating TR are very important.

Transvenous Pacemaker Placement: A Review for Emergency Clinicians.

BACKGROUND: Transvenous pacemaker placement is an integral component of therapy for severe dysrhythmias and a core skill in emergency medicine. OBJECTIVE: This narrative review provides a focused evaluation of transvenous pacemaker placement in the emergency department setting. DISCUSSION: Temporary cardiac pacing can be a life-saving procedure. Indications for pacemaker placement include hemodynamic instability with symptomatic bradycardia secondary to atrioventricular block and sinus node dysfunction; overdrive pacing in unstable tachydysrhythmias, such as torsades de pointes; and failure of transcutaneous pacing. Optimal placement sites include the right internal jugular vein and left subclavian vein. Insertion first includes placement of a central venous catheter. The pacing wire with balloon is then advanced until electromechanical capture is obtained with the pacer in the right ventricle. Ultrasound can be used to guide and confirm lead placement using the subxiphoid or modified subxiphoid approach. The QRS segment will demonstrate ST segment elevation once the pacing wire tip contacts the endocardial wall. If mechanical capture is not achieved with initial placement of the transvenous pacer, the clinician must consider several potential issues and use an approach to evaluating the equipment and correcting any malfunction. Although life-saving in the appropriate patient, complications may occur from central venous access, right heart catheterization, and the pacing wire. CONCLUSIONS: An understanding of transvenous pacemaker placement is essential for emergency clinicians.

Effect of age on in-hospital outcomes of transvenous lead extraction for infected cardiac implantable electronic device.

BACKGROUND: The real-world data on the safety profile of transvenous lead extraction (TLE) for infected cardiac implantable electronic devices (CIED) among elderly patients is not well-established. This study aimed to evaluate the hospital outcomes between patients of different age groups who underwent TLE for infected CIED. METHOD: Using the Nationwide Readmissions Database, our study included patients aged ≥18 years who underwent TLE for infected CIED between 2017 and 2020. We divided the patients into four groups: Group A. Young (<50 years), Group B. Young intermediate (50-69 years old), Group C. Older intermediate (70-79 years old), and Group D. Octogenarian (≥80 years old). We then analyzed the in-hospital outcome and 30-day readmission between these age groups. RESULTS: A total of 10,928 patients who were admitted for TLE of infected CIED were included in this study: 982 (9.0%) patients in group A, 4,234 (38.7%) patients in group B, 3,204 (29.3%) patients in group C and 2,508 (23.0%) of patients in group D. Our study demonstrated that the risk of early mortality increased with older age (Group B vs. Group A: OR: 1.92, 95% CI: 1.19-3.09, p < .01; Group C vs. Group A: OR: 2.47, 95% CI: 1.51-4.04, p < .01; Group D vs. Group A: OR: 2.82, 95% CI: 1.69-4.72, p < .01). The risk of non-home discharge also increased in elderly groups (Group B vs. Group A: OR: 1.89; 95% CI: 1.52-2.36; p < .01; Group C vs. Group A: OR: 2.82; 95% CI 2.24-3.56; p < .01; Group D vs. Group A: OR: 4.16; 95% CI: 3.28-5.28; p < .01). There was no significant difference in hospitalization length and 30-day readmission between different age groups. Apart from a higher rate of open heart surgery in group A, the procedural complications were comparable between these age groups. CONCLUSION: Elderly patients had worse in-hospital outcomes in early mortality and non-home discharge following the TLE for infected CIED. There was no significant difference between elderly and non-elderly groups in prolonged hospital stay and 30-day readmission. Elderly patients did not have a higher risk of procedural complications.

Cardiac implantable electronic devices in female patients: Esthetic, breast implant, and anatomic considerations.

INTRODUCTION: The implantation of a cardiac implantable electronic device (CIED) can have esthetic and psychological consequences on patients. We explore a heart team model for care coordination and discuss esthetic approaches for improved cosmetic outcomes in patients undergoing (CIED)-related procedures or de novo implantation. METHODS: Patients undergoing CIED surgery for approved indications between June 2015 and June 2022 were identified. Patients were included when surgical care was provided by a collaborative relationship between the primary electrophysiologist and the plastic surgeon. Patient demographics, details of the surgical procedure, information on breast implants, complications, and outcomes related to cosmesis were recorded. RESULTS: Twenty-two female patients were included in this study. The mean age was 50.2 ± 18.2 years. The mean follow-up duration was 2.2 ± 5.5 months. The top two indications for the procedure included CIED generator change (n = 9, 41%) and implantable cardioverter-defibrillator (ICD) implantation (n = 7, 32%). The most common reasons for involving plastic surgery in the procedure included surgery near breast implants (n = 10, 45%) and device displacement or discomfort (n = 8, 36%). CIED pocket position was prepectoral in 10 cases (45%), subpectoral in 11 patients (50%), and intramuscular in one patient (4.5%). The majority of the patients (20, 91%) had cosmetically acceptable results postprocedure. One patient (4.5%) had breast asymmetry on the CIED side, and another continued to have skin erosion over the CIED and leads. CONCLUSION: A heart team approach incorporating the expertize of cardiac electrophysiology and plastic surgery is essential for providing optimal care for patients with breast implants and patients requesting esthetic appeal.

Multilevel Venous Obstruction in Patients with Cardiac Implantable Electronic Devices.

Background and Objectives: The nature of multilevel lead-related venous stenosis/occlusion (MLVSO) and its influence on transvenous lead extraction (TLE) as well as long-term survival remains poorly understood. Materials and Methods: A total of 3002 venograms obtained before a TLE were analyzed to identify the risk factors for MLVSO, as well as the procedure effectiveness and long-term survival. Results: An older patient age at the first system implantation (OR = 1.015; p < 0.001), the number of leads in the heart (OR = 1.556; p < 0.001), the placement of the coronary sinus (CS) lead (OR = 1.270; p = 0.027), leads on both sides of the chest (OR = 7.203; p < 0.001), and a previous device upgrade or downgrade with lead abandonment (OR = 2.298; p < 0.001) were the strongest predictors of MLVSO. Conclusions: The presence of MLVSO predisposes patients with cardiac implantable electronic devices (CIED) to the development of infectious complications. Patients with multiple narrowed veins are likely to undergo longer and more complex procedures with complications, and the rates of clinical and procedural success are lower in this group. Long-term survival after a TLE is similar in patients with MLVSO and those without venous obstruction. MLVSO probably better depicts the severity of global venous obstruction than the degree of vein narrowing at only one point.

Staged therapeutic surgery for progressive pulmonary regurgitation and pacemaker induced cardiomyopathy after the tetralogy of fallot repair.

BACKGROUND: Recently, improvements in the repair of tetralogy of Fallot have increased the need for reoperation in adulthood, and it's not rare that these reoperation candidates suffer from biventricular failure. However, there are no firm treatment guidelines, and each country, and even each facility, treats each case individually. CASE PRESENTATION: We report the successful staged treatment of pulmonary regurgitation and pacemaker-induced cardiomyopathy with biventricular failure in adulthood in a case of complete atrioventricular block after tetralogy of Fallot repair in childhood. We planned a staged therapeutic strategy with preoperative left ventricular volume reduction with medication, following surgical pulmonary valve replacement concomitant epicardial lead implantation on the lateral basal wall, placed just beneath the generator pocket through 3rd intercostal space. in addition to postoperative intervention with a defibrillator to adjust cardiac resynchronization therapy, resulted in improvement of symptoms. CONCLUSION: In a patient with biventricular failure after TOF repair, a staged treatment strategy involving medication, PVR, and CRT with a combination of epicardial and intravenous leads could be a useful treatment worth trying before heart transplantation.

Temporal relationship between haemodynamic changes and activation of closed-loop stimulation during a tilt-induced vasovagal syncope.

AIMS: A dual-chamber pacemaker with closed-loop stimulation (CLS) mode is effective in reducing syncopal recurrences in patients with asystolic vasovagal syncope (VVS). In this study, we explored the haemodynamic and temporal relationship of CLS during a tilt-induced vasovagal reflex. METHODS AND RESULTS: Twenty patients underwent a tilt test under video recording 3.9 years after CLS pacemaker implantation. Three patients were excluded from the analysis because of no VVS induced by the tilt test (n = 1) and protocol violation (n = 2). In 14 of the remaining 17 patients, CLS pacing emerged during the pre-syncopal phase of circulatory instability when the mean intrinsic heart rate (HR) was 88 ± 12 b.p.m. and systolic blood pressure (SBP) was 108 ± 19 mmHg. The CLS pacing rate thereafter rapidly increased to 105 ± 14 b.p.m. within a median of 0.1 min [inter-quartile range (IQR), 0.1-0.7 min] when the SBP was 99 ± 21 mmHg. At the time of maximum vasovagal effect (syncope or pre-syncope), SBP was 63 ± 17 mmHg and the CLS rate was 95 ± 13 b.p.m. The onset of CLS pacing was 1.7 min (IQR, 1.5-3.4) before syncope or lowest SBP. The total duration of CLS pacing was 5.0 min (IQR, 3.3-8.3). Closed-loop stimulation pacing was not observed in three patients who had a similar SBP decrease from 142 ± 22 mmHg at baseline to 69 ± 4 mmHg at the time of maximum vasovagal effect, but there was no significant increase in HR (59 ± 1 b.p.m.). CONCLUSION: The reproducibility of a vasovagal reflex was high. High-rate CLS pacing was observed early during the pre-syncopal phase in most patients and persisted, although attenuated, at the time of maximum vasovagal effect. REGISTRATION: ClinicalTrials.gov identifier: NCT06038708.

Atrioventricular block secondary to transient causes and long-term recurrence after an index event.

BACKGROUND: Atrioventricular block (AVB) secondary to transient causes can recover with its correction. However, studies assessing predictors of recovery and long-term recurrence are lacking. METHODS: Patients with advanced or complete AVB who had a reversible cause admitted in a single expert center were retrospectively studied. Patients with AVB secondary to acute coronary syndromes were excluded from analysis. RESULTS: In a population of 162 patients, the main factors associated with recovery of rhythm without a permanent pacemaker (PPM) implantation were the presence of chronic kidney disease (CKD) on dialysis (OR 7.6; CI 95% 1.2-47.5 (p = .03)); greater serum potassium levels (OR 2.3; CI 95% 1.28-4.0 (p < .01)), higher dosage of bradycardic drugs (OR 2.2; CI 95% 1.13-4.4 (p = .02)), the association between different bradycardic drugs (OR 9.0; CI 95% 2.02-40.3 (p < .01)) and between drug therapy and hyperkaliemia (OR 5.2; CI 95% 1.8-15.1 (p < .01)). There was an overall high burden of conductions abnormalities which did not correlate with recovery of rhythm (OR 0.5; CI 95% 0.19-1.5 (p = .23)). In 29 patients (17.9%) there was a correction of the AVB. During a maximum follow-up of 130 months, 24 patients (82.8%) had a recurrence which warranted a PPM. In the overall cohort only five patients (3%) had sustained recovery of rhythm. CONCLUSIONS: Recovery of AVB was mainly observed with higher doses of drug therapy, higher serum potassium levels or a combination of factors and regardless of baseline conduction abnormalities. The high rate of recurrence during follow-up warrants a close follow-up or PPM implantation at index admission.

Case report: accidental finding of mobile pacemaker lead structures.

We present a case of a 79-year-old man on apixaban for atrial fibrillation who suffered multiple ischaemic strokes and was found to have mobile structures attached to his pacemaker lead on transesophageal echocardiography. Based on the Modified Duke Criteria, there was no evidence of infectious endocarditis. Since there were no signs of a patent foramen ovale or arteriovenous malformations in the lungs, the mobile structures probably were not the cause of the ischaemic strokes. After the visualisation of the mobile structures, apixaban was switched to dabigatran with a clear decrease in the size of the structures. Blood cultures remained negative and there was no fever or increase in inflammatory parameters. It was therefore suspected that the structures were thrombus material rather than vegetations of infectious endocarditis.There is uncertainty surrounding the clinical relevance and indication for treatment of incidentally found mobile structures on pacemaker leads. Multiple studies with different imaging modalities show a significant difference in the prevalence of thrombi. More studies with longer follow-ups are needed to investigate the prevalence and need for treatment of these incidentally found structures on pacemaker leads.