Dual-chamber Permanent Pacemaker Research Articles

Perforation of the Left Anterior Descending Artery Following Insertion of a Dual Chamber Permanent Pacemaker

Perforation of the Left Anterior Descending Artery Following Insertion of a Dual Chamber Permanent Pacemaker

Clinico-demographic Profile of Patients Receiving Permanent Pacemakers as Bradyarrhythmia Therapy: The Srinagar Registry

Introduction Cardiac conduction disorders can interrupt the normal electrical conduction in the heart and cause a decrease or cessation of pulse generation and a fall in organ perfusion in the body. This can lead to significant morbidity and mortality. This study was conceived to illustrate the clinical profile, presentation, management, and complications of bradyarrhythmia therapy in this population. Methods This descriptive cross-sectional study included prospective and retrospective data over a period of 16 years. All patient’s demographic data and data of any complications and adverse outcomes were documented. Results A total of 3489 cases having permanent pacemakers (PPMs) implanted in them were included in this study. There were 2254 (64.6%) men and 1235 (35.4%) were women. Age of the patients ranged from 25 to 100 years with a mean age of 62.9 ± 11.14 years. Mean ejection fraction of patients was 59.3 ± 2.57%. The indication for PPM implantation was complete heart block in 2079 (59.6%), sick sinus syndrome in 422 (12.1%), Mobitz type 2 heart block in 345 (9.9%), symptomatic left bundle branch block in 295 (8.5%), symptomatic bifasicular block in 176 (5.0%), symptomatic trifascicular block in 109 (3.1%), vasovagal syncope with symptomatic sinus bradycardia in 21 (0.6%), left anterior hemiblock with syncope in 3 (0.1%), and atrial fibrillation with heart block in 11 (0.3%) patients. Cardiac syncope was presented in 80%, presyncope in 15%, and 5% presented with features of chronotropic incompetence. No significant seasonal variation was observed in the incidence of PPM implantation. Single-chamber PPM was implanted in 58.8% and dual-chamber PPM in 41.2% of the cases. PPM-related complications were seen in 139 (3.98%) of the cases. Pneumothorax was seen in 21 (0.6%) of the cases, lead displacement in 39 (1.12%), lead replacement in 31 (0.89%), pocket site infection in 20 (0.57%), generator extrusion in 25 (0.70%), and lead extrusion in 3 (0.08%). Conclusion Conduction disorders affect men more than women and complete heart block is the most common form of conduction disorder in our population. There has been a significant improvement in bradyarrhythmia detection and its management, leading to wider penetration and safety of device therapy provided to the patient population.

Safety and efficacy of adaptive atrial pacing regulated by blood pressure during low-level exercise: a proof-of-concept study.

Despite half of all heart failure patients suffering from heart failure with preserved ejection fraction (HFpEF), treatment options are limited. This study aims to compare safety and efficacy of standard pacemaker programming (DDD or DDDR) and a novel pacing algorithm PressurePace™ (BaroPace Inc, Issaquah, WA, USA) which modulates atrial pacing rate based on blood pressure (BPAP). This prospective, randomized, double-blind, non-significant risk proof of concept study was conducted at two large cardiology clinics in Los Angeles, California, USA. Subjects underwent two modified Bruce protocol graded treadmill exercise tests in which pacemaker programming was randomized to either standard programming (DDD or DDDR), or BPAP at least 1week apart. Physiological measurements of heart rate (HR), and systolic and diastolic blood pressure (BP) were collected at 2min intervals. During the BPAP treadmill test, the pacemaker activity sensor was disabled. The PressurePace algorithm instructed the pacemaker technician to modify or leave unchanged the atrial pacing rate based on these BP measurements. Subjects and clinical staff were blinded to pacemaker programming, only the pacemaker technician was unblinded. Ten subjects with HFpEF associated with hypertension who also had permanent dual-chamber pacemakers, previously implanted for standard clinical indications, participated in the study. Mean age was 70.1±6.8 years, left ventricular ejection fraction of 54.8±1.9%. Exercise duration increased in all 10 subjects, when paced in the BPAP mode compared with standard pacemaker programming, showing a mean increase of 117s (26%, P=0.0016). The algorithm could adjust HR at each 2min interval. The majority of subjects (60%) had their atrial pacing rate increased an average of 20% at t=2min. In the remaining 40% of subjects, the algorithm instructed HR to be unchanged. In two subjects, the pacing rate was not increased until t=6min. In contrast, subjects programmed to DDDR experienced an average of 45% increase in atrial pacing rate at t=2min. In the post-treadmill recovery period, SBP was higher for subjects who underwent BPAP. This difference in SBP was most pronounced immediately post-treadmill and diminished as subjects progressed through the 30min recovery period. Statistical significance was achieved at t=0, 20, and 30min post-treadmill. An increase in exercise duration was reported in HFpEF subjects using a pacing algorithm that modulated HR based on BP compared with standard programming. These encouraging results form the basis for a larger, randomized cross-over trial to confirm these initial observations, further characterize the safety, efficacy, and possible mechanisms of action in both acute and longer-term treatment.

EVALUATION OF EARLY OUTCOMES OF PERMANENT PACEMAKER IMPLANTATION IN HYPERTENSIVE PATIENTS WITH BRADYARRHYTHMIAS

Objective: This study aims to describe the clinical characteristics and the features of bradyarrhythmias on 24-hour Holter monitoring and to evaluate the early outcomes of permanent pacemaker implantation in hypertensive patients with bradyarrhythmias. Subjects and method: This cross-sectional study was conducted on 57 subjects with hypertension and bradyarrhythmias who were indicated for permanent pacemaker implantation. Results: The most common clinical symptoms recorded were fatigue, dizziness, and chest pain, accounting for 47.4%, 45.6%, and 42.1% respectively. The majority of patients had sinus node dysfunction (73.7%) and most underwent dual-chamber permanent pacemaker implantation (87.7%). The 24-hour Holter monitoring results showed that 42.1% had sinus atrial block - sinus pause in the sinus node dysfunction group and 15.8% of patients had third-degree atrioventricular block (AV block) in the AV block group. A good treatment outcome was observed in 72.0% of cases. Age > 70 (OR: 6.1; 95% CI: 1.2-30.1), female gender (OR: 4.2; 95% CI: 1.2-15.4), and single-chamber pacemaker (OR: 8.9; 95% CI: 1.5-52.1) were associated with a higher risk of moderate to poor treatment outcomes. Conclusion: Permanent pacemaker implantation generally tends to have good short-term outcomes. However, it should be noted that older age, female, and single-chamber pacemaker implantation in association with worse outcomes.

Impact of COVID-19 pandemic on the volume, cost, and outcomes of cardiac electrophysiology procedures in the United States

BackgroundDuring the COVID-19 pandemic, professional societies recommended deferral of elective procedures for optimal resource utilization. ObjectiveWe sought to assess changes in procedural trends and outcomes of electrophysiology (EP) procedures during the pandemic. MethodsNational Inpatient Sample databases were used to identify all EP procedures performed in the United States (2016–2020) by International Classification of Diseases, Tenth Revision codes. We evaluated trends in utilization, cost/revenue, and outcomes from EP procedures performed. ResultsAn estimated 1.35 million EP procedures (82% devices and 18% catheter ablations) were performed (2016–2020) with significant yearly uptrend. During the pandemic, there was a substantial decline in EP procedure utilization from a 5-year peak of 298 cases/million population in the second quarter of 2019 to a nadir of 220 cases in the second quarter of 2020. In 2020, the pandemic was associated with the loss of 50,233 projected EP procedures (39,337 devices and 10,896 ablations) with subsequent revenue loss of $7.06 billion. This deficit was driven by revenue deficit from dual-chamber permanent pacemaker (PPM) utilization ($2.88 billion, 49.3% of lost cases), ablation procedures ($1.84 billion, 21.7% of lost cases), and implantable cardioverter-defibrillator implantation ($1.36 billion, 12.0% of lost cases). To the contrary, there was a 9.4% increase in the utilization of leadless PPM. EP device implantation during the pandemic was associated with higher adverse in-hospital events (9.4% vs 8.0%; P < .001). ConclusionIn the United States, the significant decline in EP procedures during the pandemic was primarily driven by the reduction in dual-chamber PPM utilization, followed by arrhythmia ablation and implantable cardioverter-defibrillator implantation. There was a substantial increase in leadless PPM utilization during the pandemic.

Subacute right ventricular perforation from a passive fixation pacemaker lead - a multidisciplinary diagnostic and management work-up

Cardiac implantable electronic devices (CIEDs) implantation procedure has a complication rate of 5-6% according to most studies. Lead perforation is a possible and serious adverse event which can present with a spectrum of symptoms from asymptomatic to sudden death. Diagnostic tools in case of suspected lead perforation are X-ray, transthoracic echocardiography, pacemaker interrogation and computed tomography with the last one being the gold standard. Lead extraction could be done endovascularly or surgically. Transvenous removal is a possible option for active &amp;#64257; xation leads, while removal of passive &amp;#64257; xation leads is preferably done surgically, because of the bulky tip of the lead, which could damage the heart chambers and the vessels. In this article, we present a case of a massive ventricular perforation from a passive &amp;#64257; xation lead, further complicated by a cardiac tamponade. Surgical removal was the treatment of choice with subsequent implantation of a permanent dual-chamber pacemaker.&amp;nbsp;

Abstract 18855: Comparison of Hospital Outcomes in Sick Sinus Syndrome Patients With and Without Pacemaker- A Nationwide Inpatient Sample Analysis

Introduction: Sick sinus syndrome refers to degenerative fibrosis of the sinoatrial node, leading to bradyarrhythmias with or without tachyarrhythmias. Pacemaker implantation is a common therapeutic intervention in patients with symptomatic sick sinus syndrome (SSS). We aimed to analyze the periprocedural outcomes for patients with SSS who undergo pacemaker implantation. Hypothesis: Pacemaker implantation is associated with lower odds of mortality in patients with sick sinus syndome. Methods: Retrospective cohort study with data from 2016-18 combined National Inpatient Sample database. ICD-10 codes used to include admissions with SSS and dichotomized based on permanent dual chamber pacemaker implantation. The primary and secondary outcomes were studies between the two cohorts. Multivariate linear and logistic regression were used to adjust for confounders Results: Out of 190,625 sick sinus syndrome, admissions in 2016-18 NIS database, 115,195 (60%) received a permanent pacemaker. Permanent pacemaker implantation in SSS patients was associated with lower adjusted odds of inpatient mortality (aOR 0.22, 95% CI 0.17-0.29, p&lt;0.001), decrease in mean LOS by 0.31 days (5.55 vs 5.86, p&lt;0.001) and higher adjusted THC by a difference of 35,489 USD (116,474 USD vs 80,985 USD, p&lt; 0.001). Secondary outcomes are shown in Fig. Conclusions: Pacemaker implantation in sick sinus syndrome patients is associated with 80% decrease in mortality, shorter length of stay, and significantly lower odds of inpatient complications including sepsis, pulmonary embolism, ventricular fibrillation, acute kidney injury when compared to patients without a pacemaker.

Abstract 13737: Two Episodes of Intermittent Complete Heart Block Following Elective Procedures

Background: Iatrogenic bradycardia and complete heart block can occur with medications commonly administered during general anesthesia. Case: A 79-year-old male with past medical history of coronary artery disease, hypertension, paroxysmal atrial fibrillation and a left bundle branch block, underwent elective lithotripsy procedure, baseline ECG demonstrated in Figure A. Post-operatively, he developed asymptomatic complete heart block approximately 3 minutes after receiving sugammadex, a paralytic reversal agent (see Figure B). He was admitted for monitoring and spontaneously converted to sinus rhythm after 10 hours. The patient was discharged home with a 30-day event monitor; no pauses or high-grade atrioventricular block was noted during the monitoring period. Three months later, he underwent ureteroscopy stent exchange; during the induction with propofol he developed asystole followed by cardiac arrest. CPR was initiated and had return to spontaneous circulation after 3 minutes. The patient was transferred to the ICU, however, once again complete heart block was observed. Clinical decision-making: This case highlights recurrent episodes of transient complete heart block in the setting of an underlying left bundle branch and first-degree AV block that were exacerbated by medications during general anesthesia. Because of his underlying conduction disease and recurrent complete heart block and subsequent cardiac arrest, he ultimately underwent insertion of permanent dual chamber pacemaker. Conclusion: Iatrogenic transient complete heart block is a rare but potentially fatal complication. Prompt diagnosis and clinical suspicion of reversible causes are warranted. Significant underlying conduction disease should be considered to decide the ideal therapeutic option.

Abstract 14310: Evaluation of Ventricular Pacing Suppression Algorithmsin Dual Chamber Pacemaker: Results of 'Leader' Study

Introduction: Several algorithms have been proposed to reduce unnecessary right ventricular (RV) pacing, and their operations are based on two different mechanisms: (i) atrioventricular (AV) hysteresis (AVH) and (ii) DDD to AAI pacing mode change. Hypothesis: The purpose of our study was to evaluate the efficacy and safety of two ventricular pacing suppression algorithms: Intrinsic Rhythm Support (IRS) plus algorithm (using AVH, IRSplus) and VP suppression (DDD to AAI mode change) algorithm (VpS). Methods: This was a multicenter, randomized study conducted in 11 tertiary hospitals in South Korea. Patients with sinus node dysfunction and receiving dual-chamber permanent pacemaker implantation were included in this study. After the implantation, patients maintained a fixed AV interval for three months. The AV conduction time was determined as the "atrial pacing to ventricular sensing interval" observed from the marker channel during the PPM implantation was set as the sensed AV delay. The paced AV delay was set to be the sensed AV delay+30ms. Subsequently, patients were randomly assigned to either the VpS or IRSplus algorithm group and were followed for 12 months with assessments every 6 months. Results: A total of 118 patients were enrolled, and the total RV pacing percentage (Vp%) of the patients during the 3 months with a fixed AV interval was 10.9±16.0 on average. They were randomly assigned to VpS and IRSplus groups, with 62 and 56 patients in each group. Six months later, the average Vp% was 14.6±18.8 to 2.7±6.0, P&lt;0.001 and 6.8±10.9 to 1.1±4.0, P&lt;0.001 for the VpS and IRSplus groups, respectively. This trend was maintained for additional 6 months (VpS group: 4.6±9.5; IRSplus group: 1.2±3.8). The effects of algorithms were more pronounced in groups with an intrinsic PR interval of &lt; 200ms, and the IRSplus showed better efficacy (Figure). Conclusions: The two ventricular pacing suppression algorithms were effective in reducing Vp% compared to the fixed AV interval.

The relationship of epicardial fat and atrial high-rate episodes in patients with permanent pacemaker

Objectives: Atrial high-rate episodes (AHRE) can occur in patients who have permanent pacemakers (PPM). AHRE is classified as subclinical atrial fibrillation (AF). Also, AHRE is related to clinical AF. Epicardial fat tissue (EFT) thickness is linked to AF. The purpose of this study was to examine the relation between AHRE and EFT thickness in PPM patients. Methods: Forty patients with dual-chamber PPM were enrolled. Transthoracic echocardiography was used to measure the thickness of the EFT. Patients were examined in 2 groups according to whether there was AHRE in the records: group 1 (AHRE) and group 2 (AHRE-free). A high atrial rate of more than 175 beats per minute for more than 5 minutes was defined as AHRE. The findings of the standard 2-dimensional echocardiography and the Doppler echocardiography were all recorded. A statistical relationship between EFT thickness and the development of AF was investigated. Results: Group 1 had ten patients, while Group 2 included thirty individuals. When the demographic features of the two groups were compared, they were similar. Both groups had similar 2-D echocardiographic and Doppler results. The difference in EFT thickness between groups 1 (2.0 ± 1.1 mm) and 2 (2.9 ± 1.8 mm) was not statistically significant (p = 0.138). Conclusions: In patients with PPM, AHRE may develop after implantation and may be detected asymptomatically in periodic follow-up. In this population, we did not observe a significant association between EFT thickness and the development of AF.

Acute lymphocytic myocarditis presenting as complete heart block in an adult: a case report

BackgroundComplete heart block (CHB) as a first presentation of acute viral myocarditis is a rare occurrence associated with increased morbidity and mortality. In such cases, an endomyocardial biopsy is recommended to make a clear histological diagnosis aiding to differentiate from other possible conditions such as sarcoiditic myocarditis, giant cell myocarditis, and eosinophilic myocarditis. Insertion of a permanent pacemaker may be considered on a case-to-case basis.Case presentationA previously healthy 21-year-old female presented to the emergency department after having suffered two episodes of syncope on a background of a few days’ history of myalgias, chills, and rigors. Electrocardiogram showed high-grade Mobitz II block with intermittent periods of CHB. A bedside echocardiogram upon admission demonstrated normal biventricular systolic function. Given the patient’s unstable haemodynamic status and lack of obvious reversible causes for the CHB, a permanent dual-chamber pacemaker was inserted urgently. Initial blood investigations indicated an ongoing inflammatory process highlighting the possibility of myocarditis as a cause of the CHB. Therefore, a troponin level was taken and was noted to be elevated confirming the suspicion of myocarditis. The left ventricular ejection fraction (LVEF) decreased over the following days to approximately 20%, clinically resulting in pulmonary oedema and acute shortness of breath. The patient required aggressive intravenous diuresis and anti-heart failure medication. An endomyocardial biopsy (EMB) confirmed the diagnosis of lymphocytic myocarditis. The patient’s condition improved secondary to an improvement in LVEF and resolution of the heart block. A cardiac magnetic resonance (CMR) imaging performed 6 weeks from admission reported an improved LVEF of 51% with no late gadolinium enhancement (LGE). Based on the reassuring CMR findings and the resolution of CHB on follow-up pacemaker checks, it was deemed safe to explant the pacemaker.ConclusionsAcute myocarditis may be complicated with high-degree AV block and cardiogenic shock necessitating close observation in a critical care unit. A permanent pacemaker may provide atrio-ventricular synchrony which helps stabilise the patient’s condition and protect from a prolonged period of heart block. Early myocardial fibrosis on EMB and degree of LGE on CMR are indicators of persistent atrioventricular block. Guideline-directed treatment of heart failure is essential.

Assessment of Extent of Myocardial Injury in Patients Undergoing Transvenous Implantation of Pacemaker Using Cardiac Troponin I (cTnI) as a Marker of Structural Heart Damage and It’s Relation to Different Sites of RV Implantation

Abstract Aim and objectives The aim of the study is to assess the extent of myocardial injury in patients undergoing trans-venous implantation of pacemaker using cardiac troponin I (cTnI) as a marker of myocardial injury and it’s relation to different sites of RV pacing and number of screwing. Patients and Methods This study included 50 patients undergoing Trans-venous Implantation of single or dual chamber permanent pacemakers at Ain Shams University Hospitals during the period from February 2020 to August 2020, divided into 2 equal groups according to the site of RV lead implantation, 25 patients RV lead implanted in the Apex and 25 patients RV lead implanted in the Septum. Results All patients had rise in Troponin I after implantation of pacemaker indicating that there is significant relationship between trans-venous implantation of permanent pacemaker and incidence of myocardial injury. Comparing the RV septal pacing group to the RV apical pacing group, results showed that septal RV pacing caused more rise in cardiac troponin I after implantation than in apical pacing group indicating that there is a significant relationship between site of RV pacing and extent of myocardial injury being more in septal RV pacing than apical RV pacing. Furthermore, our study showed that regarding active fixation of RV lead into the myocardium, increasing number of trials of screwing the lead in different sites to achieve the best pacing threshold causes more rise in cardiac troponin I. So, there is a significant relationship between number of screwing and extent of myocardial injury. Conclusion We conclude that trans-venous implantation of permanent pacemakers is associated with an increased incidence of myocardial injury and septal RV pacing is associated with more extent of myocardial injury than apical RV pacing. Also, increasing number of trials of active fixation by screwing the RV leads into the myocardium is associated with more extent of myocardial injury.

Impact of Right Ventricle Lead Position on Left Ventricular Function in Permanent Single and Dual Chamber Pacemakers

Abstract Aim and objectives To identify the short term effect of the pacemaker RV lead position related electric remodeling on LV systolic function Patients and Methods The study included 30 patients who presented with an indication of permanent pacing to the cardiology department of Ain Shams university hospitals and underwent permanent single or dual-chamber pacemaker insertion, 15 patients each with right ventricular (RV) apical pacing (RV apex), and 15 patients nonapical pacing (mid septal). 2D speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and dyssynchrony evaluation before pacemaker implantation and after a 3-month follow-up. Results 2D speckle tracking echocardiography 3 months follow up post pacing revealed impairment of global longitudinal strain in all patients and Intraventricular dyssynchrony was significantly more in apical location compared to a non-apical location (radial dyssynchrony: 108.67 ± 11.68 msec vs. 80.53 ± 8.17 msec, p-value &amp;lt; 0.001) with more difference (50.53 ± 13.30 msec) in apical location compared to non-apical location difference (29.87 ± 6.64 msec), p-value &amp;lt; 0.001. Conclusion By the analysis of 2D speckle tracking echocardiography, In the short-term follow-up, we found that radial dyssynchrony was more in apical location when compared to the non-apical location of RV lead. The RV septal pacing is a better alternative in terms of less dyssynchrony compared to RV apical pacing. Older age, the higher percentage of pacing, and device type are prognostic factors for the development of pacemaker-induced cardiomyopathy.

Increased whole blood viscosity is associated with primary idiopathic complete atrioventricular block and poor clinical outcomes in these patients.

Complete atrioventricular block is most commonly caused by age-related degeneration and fibrosis in the cardiac conduction system and is called primary idiopathic complete atrioventricular (iCAVB). Although many factors affect this situation, which increases with age in the cardiac conduction system, the relationship between whole blood viscosity (WBV) and iCAVB has not been clarified until now. In this study, we aim to reveal the relationship between iCAVB and WBV. 141 patients with dual-chamber permanent pacemaker implanted for iCAVB and 140 age- and sex-matched subjects were included in this study. The WBV values of the study groups were compared in both high shear rate (HSR) and low shear rate (LSR). Both WBV at HSR and WBV at LSR were significantly higher in the iCAVB group compared to the control group (16.11 [15.14-16.89] vs 14.40 [13.62-15.58]; 39.82 [17.43-55.23] vs 1.38 [-13.14-26.73]; p < 0.001, respectively). The patient population was followed up for an median of 38 months for all-cause mortality. Higher mortality rates were found in higher WBV at HSR and WBV at LSR (p < 0.001,for both). In this study, WBV was found to be an independent predictor for iCAVB, and in these patients WBV was associated with poor clinical outcomes.

Post-cardiac injury syndrome occurred two months after permanent dual-chamber pacemaker implantation

BackgroundPost cardiac injury syndrome (PCIS) is characterized by the development of pericarditis with or without pericardial effusion due to a recent cardiac injury. The relatively low incidence makes diagnosis of PCIS after implantation of a pacemaker easily be overlooked or underestimated. This report describes one typical case of PCIS.Case presentationWe present a case report of a 94-year-old male with a history of sick sinus syndrome managed with a dual-chamber pacemaker who presented with PCIS after two months of pacemaker implantation. He gradually developed chest discomfort, weakness, tachycardia and paroxysmal nocturnal dyspnea and cardiac tamponade after two months of pacemaker. Post-cardiac injury syndrome related to dual-chamber pacemaker implantation was considered based on exclusion of other possible causes of pericarditis. His therapy was drainage of pericardial fluid and managed with a combination of colchicine and support therapy. He was placed on long-term colchicine therapy to prevent any recurrences.ConclusionThis case illustrated that PCIS can occur after minor myocardial injury, and that the possibility of PCIS should be considered if there is a history of possible cardiac insult.

Left Ventricular Mass Index Predicts Pacemaker-Induced Cardiomyopathy in Patients with Dual Chamber Permanent Pacemakers Implanted Due to Complete Atrioventricular Block.

Pacing-induced cardiomyopathy (PICM) occurs as a result of high-burden right ventricular (RV) pacing, which usually develops in patients with complete atrioventricular (AV) block. There is a paucity of data on the association between PICM and pre-implantation left ventricular mass index (LVMI). Thus, the purpose of this study was to analyze the influence of LVMI on PICM in patients who had dual chamber permanent pacemakers (PPMs) implanted secondary to complete AV block. Overall, 577 patients with dual chamber permanent pacemakers (PPMs) were classified into three tertiles according to their pre- implantation LVMI. The average follow-up period was 57 ± 38 months. The baseline characteristics, laboratory and echocardiographic variables were compared between the tertiles. PICM was defined as a ≥ 10% drop in left ventricular ejection fraction (LVEF) from pre-implantation with a resultant LVEF < 50%. PICM occurred in 42 (7.2%) patients. The independent predictors of PICM development, as well as the impact of LVMI on PICM, were investigated. After controlling for confounding baseline variables, the tertile with the greatest LVMI had a 1.8 times higher risk for the development of long-term PICM compared with the tertile with the lowest LVMI, which was accepted as the reference group. A receiver operating characteristic curve analysis revealed that the best LVMI cut- off value for predicting long-term PICM was 109.8 g/m2 with 71% sensitivity and 62% specificity (area under curve: 0.68; 95% confidence interval: 0.60-0.76; p < 0.001). This investigation revealed that pre-implantation LVMI had a prognostic role in predicting PICM in patients with an implanted dual chamber PPM due to complete AV block.

PO-04-080 AN UNUSUAL CASE OF LEFT BUNDLE BRANCH AREA PACING LEAD MALFUNCTION

Left Bundle Branch Area Pacing (LBBAP) is being used for conduction system/physiological pacing. It is important to be aware of manifestations and causes of LBBAP lead malfunction. Identify set screw and connector block damage as a cause of LBBAP lead malfunction with varying pacing parameters. N/A 78 years old lady with dual chamber permanent pacemaker for sick sinus syndrome developed progressive rate related left bundle branch block with left ventricular (LV) systolic dysfunction. She underwent upgrade to a cardiac resynchronization therapy-pacemaker device with addition of LBBAP lead (SelectSecure 3830 Medtronic lead) with confirmation of lead position by typical LBBAP parameters and demonstration of optimal septal penetration on contrast administration (Figure). Unipolar and bipolar lead tip impedance was found to be extremely elevated at follow-up interrogation with elevated LBBAP threshold. Over the next few weeks, LBBAP lead impedance varied between 1000 to >3000 Ohms with variable capture threshold 1.2 to >5 Volt at 0.4 milliseconds (ms) (Figure). Bipolar pacing at capture threshold was septal morphology with only variable typical LBBAP pattern, consistent with anodal capture. LBBAP lead position appeared stable on chest X-ray and transthoracic echocardiogram without clear lead discontinuity. Available near-field electrogram (EGM) on device interrogation showed no noise with provocative maneuvers. Patient underwent elective lead revision. Trans esophageal echocardiogram (TEE) prior to pocket access confirmed stable lead position with adequate septal penetration without protrusion into LV (Figure). On opening the pocket, the 3830 lead was found to be minimally retracted in the header and was easily pulled out manually. Lead parameters including sensing, impedance and capture threshold were normal with selective LBBAP and local LBB potential (Figure). The lead remained loose within the header after set screw deployment. These findings were reproduced with right ventricular (model 5076) lead indicating set screw failure. A new pacemaker generator was implanted with consistently stable LBBAP parameters on follow-up. The explanted generator analysis showed LV setscrew socket and connector block damage (Figure). Set screw failure is a rare cause of pacemaker lead failure. LBBAP lead set screw failure may manifest in an atypical manner without lead noise and should be suspected in acute lead malfunction.

Pregnancy and complete atrioventricular block: a case report.

The case of a 20-year-old primigravida with previously undiagnosed CAVB who attended the obstetric emergency service in labor is presented. The route of delivery was vaginal without complications. The decision was made to implant a permanent dual-chamber pacemaker on the third day of the puerperium, and the patient did no present cardiovascular symptoms during outpatient follow-up. CAVB is a rare but serious condition in pregnancy that can be congenital or acquired. While some cases are relatively benign, others can lead to decompensation and fetal complications. There is no consensus on the best delivery route, but vaginal delivery is generally safe unless contraindicated for obstetric reasons. Pacemaker implantation may be necessary in some cases and can be performed safely during pregnancy. This case highlights the importance of cardiac evaluation in pregnant patients, especially those with a history of syncope. It also highlights the need for adequate and urgent management in symptomatic cases of CAVB in pregnancy and adequate evaluation to decide when to implant the pacemaker as a definitive measure.

An Unusual Cause of AV Dyssynchrony: Dual AV Node Physiology With Retrograde Decremental Conduction

A 71-year-old male with persistent atrial fibrillation and a dual chamber permanent pacemaker presented complaining of dyspnea on exertion, easy fatiguability, and intermittent cough. A 12-lead electrocardiogram revealed ventricular paced complexes, native QRS complexes, and irregular atrial activity. Herein we present an unusual mechanism of atrioventricular dyssynchrony. (Level of Difficulty: Intermediate.)

Prolonged PR interval and incidence of atrial fibrillation, heart failure admissions, and mortality in patients with implanted cardiac devices: A real-world survey

Prolongation of the PR interval has long been considered a benign condition, particularly in the setting of nonstructural heart disease. The purpose of this study was to investigate the effect of PR interval on various well-adjudicated cardiovascular outcomes using a large real-world population data of patients with implanted dual-chamber permanent pacemakers or implantable cardioverter-defibrillators. PR intervals were measured during remote transmissions in patients with implanted permanent pacemakers or implantable cardioverter-defibrillators. Study endpoints (time to the first occurrence of AF, heart failure hospitalization [HFH], or death) were obtained between January 2007 and June 2019 from the deidentified Optum de-identified Electronic Health Record dataset. A total of 25,752 patients (age 69.3 ± 13.9 years; 58% male) were evaluated. The average intrinsic PR interval was 185 ± 55 ms. In the subset of 16,730 patients with available long-term device diagnostic data, a total of 2555 (15.3%) individuals developed AF during 2.59 ± 2.18 years of follow-up. The incidence of AF was significantly higher (up to 30%) in patients with a longer PR interval (ie, PR interval ≥270 ms; P < .05). Time-to-event survival analysis and multivariable analysis showed that PR interval ≥190 ms was significantly associated with higher incidence of AF, HFH, or HFH or death when compared with shorter PR intervals (P< .05 for all 3 parameters). In a large real-world population of patients with implanted devices, PR interval prolongation was significantly associated with increased incidence of AF, HFH, or death.