Temporary Transvenous Pacemaker Research Articles

Regional cerebral blood flow in a patient with asystole episodes associated with anti-NMDA receptor encephalitis

ABSTRACT Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare and severe autoimmune encephalitis that displays neuropsychiatric symptoms and autonomic instability, e.g., hypoventilation and cardiac arrhythmia. Severe arrhythmia including asystole associated with this encephalitis is rare. Several causes have been suggested. Nevertheless, no report of the literature has described examination by functional brain imaging of a patient with asystole during anti-NMDA receptor encephalitis. This case is that of a 34-year-old woman diagnosed as having anti-NMDA receptor encephalitis. She repeatedly showed 10–20 s asystole episodes necessitating a temporary transvenous pacemaker. After resection of the bilateral ovarian cystic tumor, her symptoms improved. Regional cerebral blood flow (rCBF) was evaluated using single-photon emission computed tomography. The rCBF was increased in the amygdala, hypothalamus, anterior cingulate, hippocampus, and anterior temporal lobes, but decreased in the dorsolateral frontal lobes, parietal lobes, and occipital lobes. Findings in this case suggest that altered rCBF in the patient with asystole episodes associated with anti-NMDA receptor encephalitis was observed in several brain lesions. The rCBF increases in the central autonomic networks, i.e., the amygdala, hypothalamus, and anterior cingulate, might be associated with dysregulation of sympathetic and parasympathetic nervous systems leading to asystole.

Challenges Experienced by Iranian Patients with Temporary Transvenous Cardiac Pacemakers: A Phenomenological Study

Background: One of the main causes of mortality in patients with heart disease is arrhythmia. A temporary pacemaker is inserted to control arrhythmias, particularly when an intervention is urgently needed. Since this procedure is not benign, patients might experience many challenges. As the first step in the development of nursing interventions, identifying these experiences can help reinforce evidence in this field and enhance the quality of nursing care. Objectives: The present study aimed to explore the challenges experienced by patients with temporary transvenous cardiac pacemakers (TTCPs). Methods: This qualitative, interpretive phenomenological study was conducted on 18 patients with pacemakers who were selected by purposive sampling. The data were collected through in-depth semi-structured interviews. All the interviews were recorded and simultaneously analyzed via van Manen’s analytical method. Results: The results of data analysis resulted in three major themes: "Disregard for patient’s dignity”, “dependent life”, and "physical and psychological problems”. Conclusions: This study showed the challenges of patients with TTCPs. This group of patients is facing challenges related to the care and hospitalization matter and facing an uncertain future. Therefore, there is a need to pay more attention to patients' needs during hospitalization, such as informing patients about the procedure, respecting patients’ dignity and rights, and controlling physical and psychological problems.

An electrogram-guided transvenous temporary pacemaker implant simulator.

Transvenous temporary pacemaker (TvTP) implantation is a critical procedure often performed under time limitations, playing a crucial role in patient survival. However, the amount of training provided for resident cardiologists is variable, due to the availability of patients. Thus, the use of simulators for this cardiologic procedure could be used as training tools. The present study aimed to develop a simulator system for TvTP implantation based on electrograms, called ETTIS (Electrogram-guided Transvenous Temporary-pacemaker Implantation Simulator), and to evaluate its educational potential and cardiology residents' perceived learning efficacy as a training tool. The development of the ETTIS involved three stages: (1) Adaptation of an anatomical mannequin; (2) Design and manufacture of electronic circuits and software capable of identifying the catheter contact site within the heart chambers and reproducing electrograms in both surfaces (mode-on) and intracavitary (mode-off); (3) To evaluate its educational potential, a modified Likert questionnaire was administered to nine cardiology experts. Additionally, to evaluate the perceived learning efficacy, another modified Likert questionnaire was given to six cardiology residents both before and after training with the ETTIS. Descriptive statistics with measures of position and dispersion were employed, and the weighted Kappa test was used for agreement analysis. A high rate of acceptance (over 90%) was found among experts who evaluated the ETTIS. The cardiology residents showed significant self-perceived learning gains, as evidenced by a lack of agreement between their responses to a questionnaire before and after training. The ETTIS is a promising tool for medical training, displaying both educational potential and efficacy. It has been shown to be effective in learning a variety of skills, including cardiac catheterization and electrophysiology. Additionally, the ETTIS is highly engaging and allows cardiology residents to practice in a safe and controlled environment.

Abstract 16716: Clinical Parameters Associated With Temporary Transvenous Pacing for Patients Presenting With Complete Heart Block

Introduction: Patients presenting with Complete Heart Block (CHB) are emergently referred for placement of a temporary transvenous pacemaker (TTVP) for hemodynamic stability. Data on the immediate management and outcomes of such patients are lacking. Methods: Data collected through retrospective chart review of patients presenting to the Emergency Department (ED) at 3 regional referral hospitals from 10/2017 to 9/2022 with a diagnosis of new CHB; included age, sex, clinical, laboratory and ECG data, medications, interventions and length of stay(LOS). Results: There were 230 patients (106 women), mean age 77 years. Of these 94 were on beta blockers, 55 on calcium channel blockers. Syncope, dizziness and dyspnea were common symptoms. Pause > 3 seconds was seen in 50 patients. Sympathomimetics were used in 55 patients and 179 patients were admitted to the ICU. There was no statistical difference in demographics, clinical features, ICU utilization and LOS. A TTVP was placed in 72(31%) and a Permanent Pacemaker (PPM) prior to discharge in 182 patients, a median of 1 day from ED presentation. By site, there were 71, 74 and 85 patients of whom TTVP was placed in 38%, 15% and 40% and a PPM in 76%, 82% and 79% in the 3 regional centers. The median LOS was 3 days. Univariate logistic regression was used to assess for predictors of TTVP placement (SAS® Version 9.4, Cary, NC). Syncope, Initial SBP, Shock, Pause > 3 seconds, Acute MI, and Serum K were associated with higher odds of patients getting TTVP. SBP > 160mmHg was associated with lower odds of needing TTVP. Conclusions: TTVP was infrequently needed (31%) among patients presenting to the ED with CHB. Initial SBP, Shock, Acute MI, Pause > 3sec and Serum K were associated with TTVP placement. Higher SBP was associated with lower odds of needing a TTVP. There seems to be a difference in TTVP utilization rate between centers. Prospective data related to the acute management of CHB is needed to identify variations in utilization of TTVP between centers.

An Overweight Woman with Profound Symptomatic Nocturnal Bradycardia: A Case Report

Case Report: An overweight 48-year-old Thai female presented with syncope while she was lying down and watching television. Telemonitoring during she was unconscious demonstrated that there was long pause due to sinus arrest without escape rhythm. She was inserted with temporary transvenous pacemaker because of profound symptomatic bradycardia during nighttime. She was diagnosed as syncope due to nocturnal bradyarrhythmia. The sleep apnea syndrome (SAS) related bradycardia was the most likely diagnosis. Type 1 polysomnography was performed and compatible with moderate obstructive sleep apnea (OSA). The patient received continuous positive airway pressure (CPAP) for treatment of moderate OSA and remained no syncope or long pause during one year follow-up period. Conclusion: This was an unusual case of an overweight woman presenting with profound symptomatic nocturnal bradycardia due to moderate OSA treated with CPAP. Patients presenting with nocturnal bradycardia should always be investigated SAS related bradycardia. Keywords: Nocturnal bradycardia; Overweight; Obstructive sleep apnea; Sleep disordered breathing; Polysomnography

P131 ACUTE RIGHT HEART FAILURE: MASSIVE PULMONARY EMBOLISM OR RIGHT INFARCTION?

Abstract Right ventricular infarction is often unrecognized. Rarely isolated, it complicates up to 50% of inferior infarction, conditioning morbidity and mortality. Clinical presentation, characterized by hypotension, and echocardiografic features, with right ventricular involvement, can often mimic high risk pulmonary embolism. This case report focuses on an 85–years–old woman who called 118 for chest pain and asthenia. The patient is in shock, when accepted into the emergency room. ECG reveals a third–degree AV block with escape rhythm at rate of 35bpm and ST segment elevation in inferior leads, requiring temporary transvenous pacemaker placement. Bedside echo shows a borderline LV systolic function (EF 50%) with inferior wall akinesis and a dilated and hypokinetic right ventricle (TAPSE 15mm). In emergency we perform a coronary angiogram, that reveals a total occlusion of the ostial right coronary artery, treated by PCI 2 DES. During clinical course, no complications occur. At hospital discharge, the patient is hemodynamically compensated, without neurological sequelae and with cardiac enzymes in decrease (Trp I HS peak 94 000pg/ml). The aim of this case report is to focus cardiologist’s attention on right ventricular infarction, knowing its clinical presentation and its laboratory, electrocardiographic and echocardiographic features.

Rate of various access sites for temporary transvenous pacing and different outcomes at Lady Reading Hospital, Peshawar Pakistan.

To evaluate the various temporary transvenous pacemaker (TPM) access sites, its indications, procedural complications, and outcomes of patients. This prospective study conducted in a tertiary care hospital of Peshawar, included 100 patients, who underwent TPM for any reasons, via the trans jugular, subclavian, or trans-femoral route. The duration of the study was from October 1st, 2021 to March 31st, 2022. The demographic, procedure -related complications, causes of complete heart block and in hospital outcomes were recorded. Of the 100 patients who underwent temporary transvenous pacing, 56%were males and 44% were females, with an age range of 46-80 years. In majority of the patients, (N =54) internal jugular vein was used as the venous access site followed by the subclavian vein. (N=24). Coronary artery disease was prevalent in 42% of the patients. 50% had complete AV block, 19% had symptomatic second-degree block, and 10% had sinus nodal diseases. Seventy three percent of the patients needed TPM implantation on an emergency basis, which is statistically significant (p=0.009). Almost 40% of the patient ultimately underwent a permanent pacemaker. Out of 100 patients, 16 patients expired. The major procedure related complications were bleeding 16% overall at the puncture site and 14.8% in the internal jugular group. Other complications were local infection 13% at the insertion site followed by hemopericardium 3%, in the internal jugular group. Atrioventricular block is the commonest indication for temporary pacing in our study. The average time the TPM remained in place was significantly higher in the trans jugular approach group along with a higher complication rate in this group.

Development of severe junctional bradycardia after dexmedetomidine infusion in a polypharmacy patient: a case report and literature review

The authors report a case of newly manifested severe junctional bradycardia following dexmedetomidine administration during spinal anesthesia in a polypharmacy patient. A 77-year-old woman receiving multiple medications, including a beta-blocker and a calcium channel blocker, underwent right total knee arthroplasty. After spinal anesthesia, intravenous dexmedetomidine was initiated as a sedative; her heart rate decreased, followed by junctional bradycardia (heart rate, 37–41 beats/min). Dexmedetomidine was discontinued, and a dopamine infusion was initiated. Seven hours after surgery, junctional bradycardia persisted; a temporary transvenous pacemaker was inserted, and the beta-blocker and calcium channel blocker were discontinued. The patient was discharged on postoperative day 11 without any sequelae. Anesthesiologists should be aware of dexmedetomidine’s inhibitory effects on the cardiac conduction system, especially in geriatric patients taking medications with negative chronotropic effects and in combination with neuraxial anesthesia.

IN-HOSPITAL OUTCOME OF PATIENTS REQUIRING TEMPORARY TRANSVENOUS PACEMAKER AFTER ST ELEVATION MYOCARDIAL INFARCTION

Objectives: Bradyarrhythmias and Electrical conduction defects are common sequelae of acute myocardial ischemia (AMI). Many of these arrhythmias are symptomless and do not require urgent intervention while others are life threatening. Of all other potential causes myocardial ischemia is the commonest and important causative agent of acute and potentially dangerous conduction defect. This study will upgrade various aspects of patients’ care with Acute MI who need TPM which will improve outcome and make the cause of death along with long term sequelae clear in such patients in our local population. To determine the in hospital outcomes of patients requiring temporary transvenous pacemaker after ST elevation MI.
 Methodology: This cross-sectional descriptive study was conducted at cardiology Department, MTI-KTH, Peshawar from 25 Jan, 2020 to 25 Jun, 2020. All temporary pacemakers were implanted in our Coronary Care Unit procedures and were done in an exploration room. All procedures performed by consultant cardiologists and trainee registrars. Pacemaker malfunction was described as capture failure, failure to sense, or both. Death secondary to cardiac tamponade, a systole or ventricular arrhythmias as well as improvement and need for permanent pacing was also be documented as mentioned above in operational definitions. Data was obtained after performing the procedure and during stay of patient in the coronary care unit, as determined by set protocol. The electrocatheter used was 110 cm bipolardevices of caliber 6F. Cardiac catheterization was generally via the right subclavian or internal jugular by the Seldinger’s wire technique, with insertion in the apical region of the right ventricle under aseptic measures. A sensing threshold values for pacing of 0.5=2 mV were set. Pacing was initially deployed at values double the threshold voltages, using the TPM in WI mode.
 Results: As per in-hospital outcomes, death occurred in 14 (9.7%) died, 49 (34.0%) patients had malfunction, 10 (6.9%) patients had hematoma, 26 (18.1%) patients had fever, 27 (18.8%) patients experienced improvement while 18 (12.5%) required permanent pacing.
 Conclusion: In-hospital adverse outcomes were observed in a significant number of patients.

Abstract 12770: Immune Checkpoint Inhibitor Induced Myocarditis: An Interesting Case of Reversible Complete Heart Block

BACKGROUND: Immune checkpoint inhibitors (ICI) have changed the treatment scope for malignancies. The mechanism of ICIs is targeting of immune checkpoints that can suppress a response to a stimulus which can effect any organ. Adverse effects are usually mild but myocarditis, although rare, is becoming more recognized as a life threatening entity. The increase in mortality seen with ICI-induced myocarditis is more frequent with combination therapy. Most cases of ICI-induced myocarditis are limited to direct myocardial injury but there is a lack of evidence regarding conduction disease. CASE DESCRIPTION: We present a 74-year-old man with known metastatic malignancy recently started on ICI with ipilimumab and nivolumab who presented with complaints of abdominal pain, SOB and chest pain. His ED workup was consistent with colitis and acute PE without RV strain. Troponins and BNP were elevated and his ECG showed 3rd degree AV block. A coronary angiogram was negative for obstructive CAD and a temporary trans-venous pacemaker was placed. Cardiac MR showed LGE with active inflammation of the mid-myocardium. The patient had complex presentation as a side effect of ICI leading to myocarditis, 3rd degree AV block, colitis and PE. He was started on high dose methylprednisolone 1gm daily. Within 24 hours there was improvement evidenced by intermittent return of intrinsic conduction. At 48 hours there was marked improvement with restoration of sinus rhythm without evidence of AV block and/or use of the temporary pacemaker. Discussion: Early recognition of disease processes is difficult when there is minimal data to support a cause and effect. Increasing clinical awareness regarding adverse effects of ICI is paramount in decreasing the risk for unnecessary therapies, in our case, placement of a permanent pacemaker. Although there have been case reports of ICI-induced myocarditis, there has not been expert consensus regarding management of conduction pathway abnormalities.

Abstract 14460: Aortic Valve Infective Endocarditis Complicated by Complete Heart Block and Gerbode’s Defect

Introduction: Aortic root abscess with complete heart block is a rare complication of infective endocarditis (IE). Early diagnosis and prompt surgical management are necessary to prevent fatal outcomes. Case Presentation: A 45-year-old male with past medical history of uncontrolled diabetes mellitus was referred to our cardiac intensive care unit for management of complete heart block. His symptoms including exertional dyspnea, hiccups, and dry cough started two weeks prior to presentation. The patient was bradycardic, hypoxic, and hypotensive on examination. Labs were significant for marked leukocytosis 21,000/ul with a neutrophilic predominance. Blood cultures were obtained, and the patient was started on empiric antibiotics vancomycin and piperacillin-tazobactam. Electrocardiogram (ECG) showed evidence of complete heart block and a temporary transvenous pacemaker was placed. A transthoracic echocardiogram was obtained that showed evidence of severe aortic regurgitation and aortic valve vegetations. Due to high clinical suspicion, a transesophageal echocardiogram was immediately performed that revealed aortic root abscess. Patient underwent successful debridement of aortic valve vegetations and aortic valve replacement. Intraoperative findings also included a subaortic left ventricular to right atrial (LV-RA) shunt also known as Gerbode’s defect that was repaired with pericardial patch. Blood cultures and intraoperative tissue cultures confirmed a Staphylococcus lugdunensis infection. He received six weeks of intravenous antibiotics. At 2-month follow-up, the patient reported doing well. Conclusion: New complete heart block may be a manifestation of aortic root abscess. This case illustrates the need to maintain a high level of suspicion for complicated infective endocarditis in patients with sepsis and complete heart block. Timely diagnosis with imaging and early surgical repair results in favorable outcomes.

Abstract 10735: Brash Syndrome: Frequently Under-Recognized and Often Confused With Simple Hyperkalemia

Introduction: BRASH syndrome is a relatively newly recognized and under-reported clinical entity characterized by bradycardia, renal dysfunction, atrioventricular node blockade (AVNB), shock, and hyperkalemia. We report a case of BRASH syndrome that was refractory to medical therapy alone, requiring transvenous pacing, hemodialysis, and vasopressor support. Case presentation: An 82-year-old female with hypertension, diabetes, and paroxysmal atrial fibrillation (on metoprolol and verapamil) was found unresponsive at a nursing home. She had refractory shock (99/34 mmHg) and symptomatic bradycardia with heart rate (HR) of 33 BPM. EKG showed atrial fibrillation rhythm with ventricular rate of 31 BMP and peaked T-waves. Labs revealed creatinine of 1.98 mg/dL, potassium of 6.8 mmol/L, and TSH of 2.90 ulU/ml. She had no signs of infection and echocardiogram showed normal left ventricular systolic function. She was intubated for airway protection. AVNB agents were immediately held. Potassium-lowering agents and vasoactive drugs were administered. Temporary transvenous pacemaker was placed due to persistent bradycardia with hemodynamic instability even after transcutaneous pacing. Temporary hemodialysis was started for worsening renal failure and refractory hyperkalemia. She was weaned off vasopressor support, mechanical ventilation, hemodialysis and temporary pacing over the next few days. Renal function improved and HR stabilized at 70 BPM. Discussion: In our case, AVNB agent overdose caused bradycardia which in turn led to decreased cardiac output and renal hypoperfusion. Resultant acute kidney injury led to decreased clearance of renally excreted metoprolol and verapamil and worsening hyperkalemia, which locked the patient in a vicious cycle of BRASH syndrome leading to hemodynamic compromise. Therefore, rapid diagnosis and correct management with transvenous pacemaker and renal replacement therapy are crucial to reduce mortality.

A novel temporary atrioventricular sequential pacing catheter-Characteristics and first-in-human application.

Sequential synchronized atrioventricular (AV) pacing provides enhanced electrophysiologic parameters which contribute to improved hemodynamic parameters and increased cardiac performance to subsequently confer a clinical advantage over traditional ventricular pacing. Current temporary transvenous pacemaker catheters are limited to only one electrode which paces solely the right ventricle, thus lacking the capability to provide the optimal pacing mode. A new multilead pacemaker device was developed in response to the need for improved temporary pacing through the utilization of sequential synchronized atrioventricular pacing (TAVSP). It consists of seven preformed, preshaped nitinol wires electrodes, of which four are for intra-atrial and three for intraventricular positioning and endocardial contact, respectively. Each wire carries a ball tip designed to minimize tissue trauma and provide a high current density for adequate myocardial capture. The device is not yet Food and Drug Administration approved. To present the unique structural components and mechanical properties of a novel sequential synchronized AV pacing device for temporary insertion and to report its first-in-human application with an analysis of the early clinical experience. Following a process of development and proof of concept of the novel pacing modality in an animal model which demonstrated feasibility and safety, a series of patients who were candidates for the device application was identified. During left and right heart catheterization, the novel temporary pacing catheter was inserted transvenously and delivered in most patients under fluoroscopy or echocardiography. The catheter was deployed to its target right heart anatomic sites and then activated in an AV sequential mode. The technical aspects, the corresponding clinical utilization, and device performance were documented and analyzed. The series included 10 enrolled subjects. During planned left and right heart catheterization, the novel TAVSP device was inserted transvenously and then delivered and deployed successfully in a timely fashion in all patients. The pacing catheter achieved proper threshold and impedance in all (100%) patients. The performance of all ventricular leads was adequate; however, in 1 (10%)patient poor performance of the atrial leads was detected. The device was successfully retrieved in all patients. No adverse arrhythmia, impaired hemodynamics, or clinical adverse events occurred. No technical difficulties, component failure, or wires thrombosis were detected. All patients sustained the device application without sequala and were discharged home. Initial clinical experience with the utilization of a novelTAVSPdemonstrates feasibility and safety in humans. The TAVSP modality potentially offers improved pacing capability and subsequent hemodynamic benefits over the current temporary pacing catheters. Further experience with the clinical application of this pacing catheter is warranted.

Cardiac Sarcoidosis Managed by Biventricular Pacing: A Case Report

Background: Cardiac sarcoidosis (CS) is a rare pathology that affects the middle-aged population. Its diagnosis, as well as its treatment, can be quite challenging, especially dealing with device management. We hereby discuss a case of CS, managed by a biventricular pacemaker in a 43-year-old man. Case Report: A 43-year-old male presented to the emergency department with a 15-day history of chronic cough and worsening dyspnea. On examination, he was found to be bradycardic in the context of a third-degree heart block on ECG as well as bilateral hilar lymphadenopathy on chest radiography. Based on these findings, cardiac sarcoidosis was suspected. A temporary right internal jugular transvenous pacemaker was implanted in the right ventricle and empiric corticosteroid management was commenced. Lung tissue biopsies were obtained via bronchoscopy and were positive for granulomas consistent with a diagnosis of sarcoidosis. Even though the patient showed a partial positive response to corticosteroid treatment, he required a permanent pacemaker. A dual-chamber implantable cardioverter-defibrillator (ICD) was implanted and the patient was discharged on prednisone. His follow-up plan consisted of serial echocardiography and consideration of a new coronary sinus lead in the event of left ventricular dysfunction in the future. Conclusion: Cardiac rhythm management in the context of CS is often difficult, with decisions that need to be made between a pacemaker, a defibrillator, or a cardiac resynchronization device. The idea that biventricular pacing has a preventative role against heart failure in patients with normal left ventricular ejection fraction and CS deserves more attention and discussion.

Usefulness of Temporary Pacing in Patients With New Left Bundle Branch Block During Transcatheter Aortic Valve Implantation

New-onset left bundle branch block (NLBBB) is the most common complication after transcatheter aortic valve implantation (TAVI). Expert consensus recommends temporary transvenous pacemaker (TTVP) support for 24 hours in these patients. To date, no study has examined TTVP use during the index hospitalization in detail. Therefore, we aimed to assess TTVP use in patients with TAVI who developed NLBBB. In this prospective observational study, we performed a detailed analysis of 24-hour telemetry in patients who developed NLBBB during TAVI. Baseline characteristics and procedural and postprocedural data were recorded. The primary outcome was pacing by the TTVP. We evaluated inappropriate TTVP use, electrophysiology study findings, permanent pacemaker (PPM) implantation, and NLBBB resolution. A total of 83 patients (74.4 ± 8.7 years, 41% female) developed NLBBB during TAVI. During index hospitalization, 1 patient (1%) required TTVP because of complete heart block and received a PPM. Five of the 83 (6%) patients were inappropriately paced, and 1 patient (1%) had ventricular fibrillation, likely secondary to TTVP. A total of 34 patients (41%) underwent electrophysiology study during hospitalization, with 4 of 83 (5%) subsequently receiving a PPM. One (1%) patient died during hospitalization, and 9 patients were lost to follow-up because of the COVID-19 pandemic. Of the remaining 73 patients with a 30-day follow-up, NLBBB had resolved in 36 (49%) at 30 days, and 2 (3%) were readmitted with complete heart block and received PPM. In conclusion, in patients with TAVI who develop NLBBB, temporary pacing is rarely necessary, may carry additional risks to the patient, and prolong hospitalization time.

VDI pacing with temporary esophageal and transvenous pacemaker leads to treat post-cardiac surgery cardiogenic shock

BackgroundPost-operative atrio-ventricular (AV) block after cardiac surgery is not uncommon in high-risk patients.Case presentationOur case highlights the management of a 62-year-old female with cardiogenic shock post-cardiac surgery with concomitant complete heart block. With VVI pacing proving ineffective, it was postulated that the patient may benefit hemodynamically from AV sequential pacing, re-establishing her atrial kick. We describe a novel technique of attaching a temporary pacemaker wire to an orogastric tube to sense atrial p-waves and pace the ventricle transvenously to perform AV sequential pacing. This was done temporarily to stabilize the patient’s hemodynamic status while awaiting a permanent pacemaker implantation.ConclusionsIn hemodynamically unstable post-cardiac surgery patients with complete heart block in whom VVI pacing fails to improve their clinical status, clinicians should consider VDI pacing with an orogastric atrial sensing pacemaker lead, in consultation with the cardiac surgeon and the electrophysiology team. Of note, the patient needs to have underlying organized atrial activity for this setup to work.

Gentle Giant: An Unusual Cause of Heart Block

<h3>Introduction</h3> Inflammatory cardiomyopathies can be a diagnostic dilemma. Early management can lead to reduced morbidity and mortality for patients. We describe a rare presentation of an unusual cardiomyopathy. <h3>Case Report</h3> A 58-year-old female presented with a 10-day prodrome of cough, NYHA class III dyspnea, and fatigue with minimal symptoms of orthopnea, paroxysmal nocturnal dyspnea or peripheral edema. She was previously healthy with no cardiac medications. Family history was significant for granulomatosis with polyangiitis. COVID-19 swab was negative. She was symptomatic with transient complete heart block and junctional escape of 20bpm. A temporary transvenous pacemaker was placed. Echocardiogram showed biventricular dysfunction with left ventricular ejection fraction < 30%. Troponin and brain-natriuretic peptide were elevated. Coronary angiogram showed no significant occlusions. CT excluded pulmonary embolism, pneumonia, or adenopathy. She was initiated on heart failure medications but beta blocker was not started given heart block. Six days into admission, her heart failure improved but she developed transient complete heart block without junctional escape. There was no ventricular ectopy. Evaluation for rheumatologic, infectious, and inflammatory causes showed elevated C-reactive protein and antineutrophil cytoplasmic antibodies. The remainder of the workup was negative. Leading diagnoses were idiopathic giant cell myocarditis or cardiac sarcoidosis. An endomyocardial biopsy revealed multinucleated giant cells and myocyte necrosis. She was diagnosed with giant cell myocarditis. Prior to discharge, she had defibrillator insertion and was initiated on prednisone and tacrolimus. Shortly after this time, she returned with critical cardiogenic shock despite intensification of immunosuppressive therapies and was listed for cardiac transplant. <h3>Summary</h3> Giant cell myocarditis (GCM) is a rare and often fatal autoimmune cause of heart failure. Patients frequently present with congestive heart failure, ventricular arrhythmia and a rapid progression of symptoms. In GCM, it is rare to present with atrioventricular conduction delays. Given the crossover in symptoms with sarcoidosis and GCM, diagnosis may be challenging. In this case of an acute presentation of heart failure and complete heart block, endomyocardial biopsy was central to the diagnosis and management of GCM.

616 Endocardial lead placement guided by high resolution voltage mapping in a patient with recurrent failure of transvenous pacing system

Abstract Methods and results A 58 years-old man was admitted to our intensive care unit for syncope due to inconstant capture of epicardial ventricular lead. His cardiovascular history began 20 years before when he underwent single chamber pacemaker implantation with insertion of a passive fixation ventricular lead for symptomatic complete atrio ventricular block (AVB). Electrical parameters were good at implantation. However, during follow-up a gradual and progressive increase of pacing threshold occurred, with no changes in impedance values, finally leading to complete loss of ventricular capture. Hence, 2 years later, the lead was extracted and a new transvenous ventricular lead was placed in septal position. All electrical parameters were optimal at the end of the procedure. However, in the following months threshold values gradually increased as previously observed. The referring clinicians decided to surgically extract both the device and transvenous lead and to implant an epicardial ventricular lead connected to an abdominal generator. The pacemaker worked properly for about 17 years until he was transferred to our institution with evidence of inconstant lead capture at maximum pacing outputs. A temporary transvenous pacemaker was immediately inserted. Clinical examination, laboratory exams, and echocardiography were normal. Cardiac magnetic resonance (MRI) was not feasible due to the epicardial lead. Thus, in order to obtain cardiac substrate characterization, we decided to perform high density multielectrode voltage mapping of the right ventricular endocardium with HD Grid multielectrode mapping catheter (HD Grid mapping catheter sensor enabled, Abbott Technologies, Minneapolis, MN). Electroanatomic voltage map allows distinction of areas of healthy myocardium (&amp;gt;1.5 mV) from scar tissue (&amp;lt;0.5 mV). Unexpectedly, voltage mapping highlighted no scar zones, showing a globally normal endomyocardial surface. Therefore, a new endocavitary pacemaker was inserted in right prepectoral region and an active fixation right ventricular lead was placed on mid-ventricular septum. A backup pacing lead was placed in a more apical position in an area of endocardial healthy myocardium. Post-procedural sensing, impedance and capture threshold were optimal (0.3 V × 0.4 ms for mid-septal lead and 0.3 × 0.4 ms for the other one). At 1 month follow-up mid-septal lead’s threshold was slightly increased (1.0 V × 0.4 ms) and further increase was observed at 3-month outpatient visit (1.75 V × 0.4 ms). Capture threshold of the other lead and other parameters were stable. The patient received remote monitoring for home surveillance of the implanted system. Home monitoring shows a trend toward a progressive increase of pacing threshold of the mid-septal lead and stable value of the other electrode. Conclusions The present report suggests an innovative use of high-density mapping with HD Grid catheter to characterize endocardial right ventricular myocardium in a patient with contraindication to cardiac MRI and recurrent failure of previous implanted pacing systems for unknown reason and to guide effective lead placement in areas of normal endocardial voltage. Combined use of telemedicine and high-resolution mapping technique allowed us to avoid unnecessary high risk reintervention for novel epicardial lead placement.

Abstract 12071: Emergent Temporary Transvenous Pacemakers Were Infrequently Needed for Patients Presenting With Complete Heart Block at a Regional Hospital

Introduction: Patients presenting with Complete heart block (CHB) are emergently referred for placement of a temporary transvenous pacemaker (TTVP) for hemodynamic stability. Data on the immediate management and outcomes of such patients are lacking. Methods: Data collected; through retrospective chart review of patients presenting to the Emergency Department (ED) at a regional hospital from October 2017 to January 2021 with a diagnosis of new CHB; included age, sex, clinical, laboratory and ECG data, medications, interventions and length of stay. Results: There were 71 patients (31 women) of whom 19 were on beta blocker or Calcium channel blockers. Data (see Table 1) for all variables was available in 68 patients. Syncope, lightheadedness and dyspnea were common symptoms. The median age was 77 years. The median heart rate was 41bpm. Atropine was used in 13 patients. Five patients with initial Systolic Blood Pressure (SBP) &lt; 100mmHg received sympathomimetics. Syncope with pause occurred in 3 patients. A TTVP was placed in 12 patients. Among 22 patients with initial SBP &gt; 160mmHg one patient with a recent TAVR had a TTVP placed. All but five were managed in the ICU setting. On Univariate logistic regression (R statistical software 3.6.1) initial SBP, SBP &lt; 100mmHg and Initial Serum K level were clinically significant. In multivariate analysis, SBP was significant with a lower SBP predicting need for a TTVP [OR 0.96 (CI 0.91 - 0.99, p = 0.019)]. A permanent pacemaker (PPM) prior to discharge was placed in 64 patients on average in 1.6 days from presentation. 3 patients with STEMI and TTVP did not need a PPM. 1 transitioned to hospice and 1 patient died of sepsis. In 1 it was attributed to COVID-19 infection. Conclusions: TTVP was infrequently needed (16.66%) among patients presenting to the ED with CHB. Initial SBP and Serum K were clinically relevant factors. Prospective data related to the acute management of CHB is needed to identify predictors that can improve the care for such patients.

Abstract 13744: Carotid Sinus Syndrome With Symptomatic Bradycardia Due to Papillary Thyroid Cancer

The patient is a 45-year-old male with no significant past medical history who presents to the hospital for an elective surgical neck mass biopsy. The patient started noticing a slow-growing neck mass six years ago, although he did not seek medical attention. While he was monitored in preoperative room, he developed symptomatic bradycardia. Telemetry showed a complete heart block rhythm. Upon further questioning, he had been having increasing episodes of near syncope for the past two months. Physical examination was significant for bradycardia without an audible murmur. A neck exam revealed a fixed right neck mass palpable across the midline to the left with a prominent thyroid isthmus. Carotid pulses were palpable bilaterally with no bruits. A temporary transvenous pacemaker was placed and the patient was admitted to the hospital for observation. Upon further workups, CT images 1 and 2 in supplemental section. A cervical lymph node biopsy eventually revealed metastatic papillary thyroid carcinoma. The patient was diagnosed with carotid sinus syndrome secondary to papillary thyroid cancer with a vasovagal component. He was discharged with a plan for radiation and close follow-up with an electrophysiologist to evaluate permanent pacemaker eligibility after receiving treatment for thyroid cancer.