Second-degree Atrioventricular Block Research Articles

Second-degree Heart Block in a Patient on Zanubrutinib

Zanubrutinib is a Bruton’s tyrosine kinase (BTK) inhibitor recently approved by the Food and Drug Administration for treatment of chronic lymphocytic leukemia (CLL) in January 2023. As a second generation BTK inhibitor, zanubrutinib is more selective for “on-target” BTK and have less cardiac side effects. Although atrial flutter and atrial fibrillation were noted side effects during clinical trials, heart block is not a known side effect. Here we present a case of a patient with CLL on zanubrutinib who presented with a second-degree heart block.

Isolated non-immune mediated second-degree atrioventricular block in fetus: natural history and predictive factors for spontaneous recovery.

To uncover the clinical course of fetal isolated non-immune mediated second-degree AVB and determine the factors associated with the spontaneous recovery for fetal non-immune second-degree atrioventricular block (AVB). A total of 20 fetuses with isolated, non-immune mediated second-degree AVB were prospectively recruited between 2014 and 2022. These fetuses were divided into the spontaneous recovery group (n=12) and the non-spontaneous recovery group (n=8). Maternal and fetal basic characteristics, intrauterine and postnatal outcomes were compared between groups. Twelve fetuses restored 1:1 atrioventricular conduction in utero and did not recur during the postnatal follow-up period. The residual eight fetuses maintained as second-degree AVB and six of them were aborted due to parental request in utero. Of the two live children with second-degree AVB, one of them progressed to complete AVB at the latest follow up at the age of 34 months, but without any symptoms, heart enlargement or dysfunction. The residual one progressed to complete AVB and was finally diagnosed with type 2 long-QT syndrome. Fetuses in the spontaneous recovery group presented with earlier gestational age at diagnosis (20.0[17.0-26.0] vs. 24.5[18.0-35.0] weeks, p=0.004) and higher atrial rate (147[130-160] vs 138.00[125.00-149.00] bpm, p=0.006) in comparison with the non-spontaneous recovery group. A cut-off value of 22.5 weeks of gestational age and 144 bpm of atrial rate at diagnosis could predict the failure of spontaneous recovery, with sensitivities of 87.5%, 75%, and specificities of 92.0%, 87.5%, respectively. The outcome of fetal non-immune second-degree AVB was favorable. Earlier gestational age at diagnosis and higher atrial rate were related to spontaneous reversion for isolated non-immune-mediated second-degree AVB. However, prenatal gene test should be performed for those with persistent AVB to exclude the heritable disorders including LQTS. These findings may provide important references for clinical management and prenatal counseling. This article is protected by copyright. All rights reserved.

The Association Between Components of Metabolic Syndrome and Abnormal Electrocardiograms in the Saudi Population: A Retrospective Study.

Saudi Arabia has a high metabolic syndrome (MetS) prevalence. Having MetS increases the risk of cardiovascular disease (CVD), CVD mortality, and myocardial infarction (MI). There is a lack of information regarding MetS and electrocardiogram (ECG) abnormalities in Saudi Arabian populations. Further, it is unclear to what extent MetS components are associated with abnormal ECGs in Saudi populations. We investigated whether ECG abnormalities and MetS are associated with Saudi adults. Furthermore, we assessed the relationship between ECG abnormalities and the components of MetS based on the age and gender of the individuals. Materials and methods: A retrospective study was conducted at Dr Soliman Fakeeh Hospital in Jeddah, Saudi Arabia, on 208 patients with MetS. Participants' clinical and laboratory data were examined. A detailed analysis of the ECG was performed. ECG abnormalities were divided into minor and major abnormalities based on Novacode criteria. In addition to ischemic ECG findings, the ECG showed prolonged PR intervals, prolonged P duration, prolonged QRS duration, and prolonged QTc intervals. Results: One hundred and thirty-seven participants (65.9%) had elevated fasting blood glucose (FBS), 129 had central obesity (62%), 93 had high blood pressure (BP) (44.7%), 74 had elevated triglycerides (35.6%), and 49 had low high-density lipoprotein (23.6%).An abnormal ECG was found in 86 (41.3%) participants. It consisted of ischemic ECGs, atrioventricular (AV) block (first and second degrees), bundle branch block (right bundle branch block [RBBB], left bundle branch block [LBBB], RBBB with left anterior hemiblock, RBBB with right anterior hemiblock), arrhythmias (premature ventricular contractions [PVCs], premature atrial complexes [PACs], atrial fibrillation [AF], sinus bradycardia, sinus arrhythmia), prolonged QTc, prolonged PR interval, and prolonged QRS duration. There were 29 (13.9%) cases with multiple ECG abnormalities, 57 (27.4%) had one abnormal ECG, 42 (20.2%) had minor abnormal ECGs, and 44 (21.2%) had major abnormal ECGs. Middle-aged and elderly males accounted for the majority of these ECG changes. In the central obesity group, 22 participants (10.6%) had ischemic ECGs, 18 (8.7%) had prolonged QTc, 10 (4.8%) had first-degreeAV block, 6 (2.9%) had sinus bradycardia, 7 (3.4%) had RBBB, 4 (1.9%) had LBBB, 3 (1.4%) had PVCs, 2 (1%) had ventricular preexcitation, and one (0.5%) had PACs. An elevated FBS group included 19 participants (9.1%) with an ischemic ECG, 18 (8.7%) with a prolonged QTc, 11 (5.3%) with a first-degreeAV block, 9 (4.3%) with sinus bradycardia, 6 (2.9%) with slight ST-T abnormality, 5 (2.4%) with RBBB, and 5 (2.4%) with LBBB. Finally, one (0.5%) of these patients had second-degreeAV block, RBBB with left anterior hemiblock, left anterior hemiblock, PVCs, AF, ventricular preexcitation, and sinus arrhythmia for each. Saudi Arabian populations with MetS were strongly associated with abnormal ECG findings, particularly ischemic ECG findings, AV block (firstand second degrees), and BBB (RBBB, LBBB). Middle-aged and elderly males accounted for the majority of these ECG changes. The most important factors contributing to ECG changes were elevated FBS and central obesity.

Incidental Arrhythmias During Atrial Fibrillation Screening With Repeat 7-Day Holter ECGs in a Hospital-Based Patient Population.

Screening for atrial fibrillation (AF) may reveal incidental arrhythmias of relevance. The aim of this study was to describe incidental arrhythmias detected during screening for AF in the STAR-FIB (Predicting SilenT AtRial FIBrillation in Patients at High Thrombembolic Risk) cohort study. In the STAR-FIB cohort study, we screened hospitalized patients for AF with 3 repeat 7-day Holter ECGs. We analyzed all Holter ECGs for the presence of the following incidental arrhythmias: (1) sinus node dysfunction, defined as sinus pause of ≥3 seconds' duration; (2) second-degree (including Wenckebach) or higher-degree atrioventricular block (AVB); (3) sustained supraventricular tachycardia of ≥30 seconds' duration; and (4) sustained ventricular tachycardia of ≥30 seconds' duration. We furthermore report treatment decisions because of incidental arrhythmias. A total of 2077 Holter ECGs were performed in 794 patients (mean age, 74.7 years; 49% women), resulting in a mean cumulative duration of analyzable ECG signal of 414±136 hours/patient. We found incidental arrhythmias in 94 patients (11.8%). Among these were sinus node dysfunction in 14 patients (1.8%), AVB in 41 (5.2%), supraventricular tachycardia in 42 (5.3%), and ventricular tachycardia in 2 (0.3%). Second-degree AVB was found in 23 patients (2.9%), 2:1 AVB in 10 (1.3%), and complete AVB in 8 (1%). Subsequently, 8 patients underwent pacemaker implantation, 1 for sinus node dysfunction (post-AF conversion pause of 9 seconds) and 7 for advanced AVB. One patient had an implantable cardioverter-defibrillator implanted for syncopal ventricular tachycardia. Incidental arrhythmias were frequently detected during screening for AF in the STAR-FIB study and resulted in device therapy in 1.1% of our cohort patients.

Centennial of the original description of Mobitz type II second-degree atrioventricular block.

The year 2024 marks the centenary of Mobitz's description of type II second-degree atrioventricular block. Its definition remains valid to this day with only minor modification for the diagnosis of infranodal conduction block. Mobitz a century ago indicated that his type II atrioventricular block was associated with Stock-Adams attacks and a prolonged duration of the QRS complex before the eventual description of bundle branch block.

Incidence, Risk Factors, and Outcomes Associated With Permanent Pacemaker Implantation Following Tricuspid Valve Surgery.

Data regarding permanent pacemaker (PPM) implantation following tricuspid valve surgery (TVS) are limited. We sought to evaluate its incidence, risk factors, and outcomes. Medicare beneficiaries who underwent TVS from 2013 to 2020 were identified. Patients who underwent TVS for endocarditis were excluded. The primary exposure of interest was new PPM after TVS. Outcomes included all-cause mortality and readmission with endocarditis or heart failure on follow-up. Among the 13 294 patients who underwent TVS, 2518 (18.9%) required PPM placement. Risk factors included female sex (relative risk[RR], 1.26 [95% CI, 1.17-1.36], P<0.0001), prior sternotomy (RR, 1.12 [95% CI, 1.02-1.23], P=0.02), preoperative second-degree heart block (RR, 2.20 [95% CI, 1.81-2.69], P<0.0001), right bundle-branch block (RR, 1.21 [95% CI, 1.03-1.41], P=0.019), bifascicular block (RR, 1.43 [95% CI, 1.06-1.93], P=0.02), and prior malignancy (RR, 1.23 [95% CI, 1.01-1.49], P=0.04). Tricuspid valve (TV) replacement was associated with a significantly higher risk of PPM implantation when compared with TV repair (RR, 3.20 [95% CI, 2.16-4.75], P<0.0001). After a median follow-up of 3.1 years, mortality was not different in patients who received PPM compared with patients who did not (hazard ratio [HR], 1.02 [95% CI, 0.93-1.12], P=0.7). PPM placement was not associated with a higher risk of endocarditis but was associated with a higher risk of heart failure readmission (HR, 1.28 [95% CI, 1.14-1.43], P<0.001). PPM implantation frequently occurs after TVS, notably in female patients and patients undergoing TV replacement. Although mortality is not increased, it is associated with higher rates of heart failure rehospitalization.

Arrhythmias among Older Adults Receiving Comprehensive Geriatric Care: Prevalence and Associated Factors.

Cardiovascular diseases and arrhythmias are medical conditions that increase with age and are associated with significant morbidities and mortality. The aim of the present study was to investigate the prevalence of arrhythmias and clinical associations in the collective of older adults receiving comprehensive geriatric care (CGC). Holter ECG monitoring (HECG) of older patients hospitalized for CGC was analyzed. The prevalence of arrhythmias and the associations between the presence of arrhythmias, patients' characteristics and the functional status regarding basic activities of daily living (assessed by the Barthel index (BI)), walking ability (assessed by the timed up and go test (TUG)), and balance and gait (assessed by the Tinetti balance and gait test (TBGT)) were examined. In the presented study, 626 patients were included (mean age: 83.9 ± 6.6 years, 67.7% were female). The most common arrhythmias detected in HECG were premature ventricular contractions (87.2%), premature atrial contractions (71.7%), and atrial fibrillation (22.7%). Atrial flutter was found in 1.0%, paroxysmal supraventricular tachycardia in 5.8%, non-sustained ventricular tachycardia in 12.5%, first-degree AV block in 0.8%, second-degree AV block type Mobitz I in 0.8%, second-degree AV block type Mobitz II in 0.3%, pause > 2.5 s any cause in 3.5%, and pause > 3 s any cause in 1.6% of the cases. Premature atrial contractions were associated with the female sex (74.8% vs. 65.3%, p = 0.018), whereas in male patients, the following arrhythmias were more common: premature ventricular contractions (91.6% vs. 85.1%, p = 0.029), ventricular bigeminus (8.4% vs. 3.8%, p = 0.021), and non-sustained ventricular tachycardia (17.3% vs. 10.1%, p = 0.014). Atrial fibrillation detected in HECG was more frequent in patients at high risk of falls, indicated by their TBGT score ≤ 18 (24.7% vs. 12.0%, p = 0.006), and premature ventricular contractions were more common in patients unable to walk (TUG score 5) compared to those with largely independent mobility (TUG score 1 or 2) (88.0% vs. 75.0%, p = 0.023). In a logistic regression analysis, atrial fibrillation detected in HECG was identified as a risk factor for a high risk of falls (odds ratio (OR): 2.35, 95% confidence interval (CI): 1.23-4.46). In our study, investigation of HECG of older adults hospitalized for CGC revealed that premature atrial contractions, premature ventricular contractions, and atrial fibrillation were the most common arrhythmias. Premature atrial contractions were found to be more frequent in female patients, while male patients were more prone to premature ventricular contractions. In the investigated population, atrial fibrillation emerged as a risk factor associated with a high risk of falls.

Muscarinic acetylcholine receptors M2 are upregulated in the atrioventricular nodal tract in horses with a high burden of second-degree atrioventricular block.

Second-degree atrioventricular (AV) block at rest is very common in horses. The underlying molecular mechanisms are unexplored, but commonly attributed to high vagal tone. To assess whether AV block in horses is due to altered expression of the effectors of vagal signalling in the AV node, with specific emphasis on the muscarinic acetylcholine receptor (M2) and the G protein-gated inwardly rectifying K+ (GIRK4) channel that mediates the cardiac IK,ACh current. Eighteen horses with a low burden of second-degree AV block (median 8 block per 20 h, IQR: 32 per 20 h) were assigned to the control group, while 17 horses with a high burden of second-degree AV block (median: 408 block per 20 h, IQR: 1,436 per 20 h) were assigned to the AV block group. Radiotelemetry ECG recordings were performed to assess PR interval and incidence of second-degree AV block episodes at baseline and on pharmacological blockade of the autonomic nervous system (ANS). Wenckebach cycle length was measured by intracardiac pacing (n = 16). Furthermore, the expression levels of the M2 receptor and the GIRK4 subunit of the IKACh channel were quantified in biopsies from the right atrium, the AV node and right ventricle using immunohistochemistry and machine learning-based automated segmentation analysis (n = 9 + 9). The AV block group had a significantly longer PR interval (mean ± SD, 0.40 ± 0.05 s; p < 0.001) and a longer Wenckebach cycle length (mean ± SD, 995 ± 86 ms; p = 0.007) at baseline. After blocking the ANS, all second-degree AV block episodes were abolished, and the difference in PR interval disappered (p = 0.80). The AV block group had significantly higher expression of the M2 receptor (p = 0.02), but not the GIRK4 (p = 0.25) in the AV node compared to the control group. Both M2 and GIRK4 were highly expressed in the AV node and less expressed in the atria and the ventricles. Here, we demonstrate the involvement of the m2R-IK,ACh pathway in underlying second-degree AV block in horses. The high expression level of the M2 receptor may be responsible for the high burden of second-degree AV blocks seen in some horses.

Prospective Evaluation of High Titer Autoantibodies and Fetal Home Monitoring in the Detection of Atrioventricular Block Among Anti-SSA/Ro Pregnancies.

This prospective study of pregnant patients, Surveillance To Prevent AV Block Likely to Occur Quickly (STOP BLOQ), addresses the impact of anti-SSA/Ro titers and utility of ambulatory monitoring in the detection of fetal second-degree atrioventricular block (AVB). Women with anti-SSA/Ro autoantibodies by commercial testing were stratified into high and low anti-52-kD and/or 60-kD SSA/Ro titers applying at-risk thresholds defined by previous evaluation of AVB pregnancies. The high-titer group performed fetal heart rate and rhythm monitoring (FHRM) thrice daily and weekly/biweekly echocardiography from 17-26 weeks. Abnormal FHRM prompted urgent echocardiography to identify AVB. Anti-52-kD and/or 60-kD SSA/Ro met thresholds for monitoring in 261 of 413 participants (63%); for those, AVB frequency was 3.8%. No cases occurred with low titers. The incidence of AVB increased with higher levels, reaching 7.7% for those in the top quartile for anti-60-kD SSA/Ro, which increased to 27.3% in those with a previous child who had AVB. Based on levels from 15 participants with paired samples from both an AVB and a non-AVB pregnancy, healthy pregnancies were not explained by decreased titers. FHRM was considered abnormal in 45 of 30,920 recordings, 10 confirmed AVB by urgent echocardiogram, 7 being second-degree AVB, all <12 hours from normal FHRM and within another 0.75 to 4 hours to echocardiogram. The one participant with second/third-degree and two participants with third-degree AVB were diagnosed by urgent echocardiogram >17 to 72 hours from an FHRM. Surveillance echocardiograms detected no AVB when the preceding interval FHRM recordings were normal. High-titer antibodies are associated with an increased incidence of AVB. Anti-SSA/Ro titers remain stable over time and do not explain the discordant recurrence rates, suggesting that other factors are required. Fetal heart rate and rhythm (FHRM) with results confirmed by a pediatric cardiologist reliably detects conduction abnormalities, which may reduce the need for serial echocardiograms.

Profound First-Degree Atrioventricular Block in a High-Level Basketball Athlete

First-degree atrioventricular (AV) block (PR interval &gt;200 ms) is commonly observed among screening electrocardiogram (ECG) in athletes. Profound first-degree AV block (PR interval &gt;400 ms) and Mobitz type I (Wenckebach) second-degree AV block are generally uncommon and often require further workup on a case-by-case basis, particularly when there is concern for a structural cardiac abnormality. In this case, we present an example of an asymptomatic profound first-degree AV block with Mobitz type I (Wenckebach) second-degree AV block. Transthoracic echocardiogram and stress echocardiogram were unremarkable and the patient was cleared to participate in sports without any restriction. Physicians managing athletes should be aware of ECG features that require additional evaluation and cardiology consultation.

Role of telemedicine network provided by pharmacies to detect electrocardiographic changes deserving cardiological evaluation in young patients

Abstract Background cardiac arrhythmias affecting adolescents and young subjects are a wide-ranging problem. Often-such conditions, in addition to being highly varied and sometimes hard to diagnose, are largely silent and onset variably and suddenly, sometimes resulting in sudden cardiac death. Such individuals, being asymptomatics, usually do not undergo cardiological evaluation, as their condition may be misrecognized or not suspected until it manifests clinically. Thus, there is a need to develop cheap and easily accessible screening systems for patients that allow early identification of electrocardiographic (EKG) findings deserving evaluation by the cardiologist. Recently, pharmacies have proposed EKG screening programs for cardiac arrhythmias using a telematics network, enabling referral to the cardiology specialist and identification of patients worthy of further diagnostic investigations. Aim of the Study to assess validity, feasibility and usefulness of an electrocardiographic screening program for the prevention of cardiac sudden death in subjects &amp;lt; 18 years old with the support of a telemedicine service available in local pharmacies. Materials and Method we analyzed 12-lead electrocardiograms (ECGs) recorded by 4,500 country pharmacies in subjects with &amp;lt; 18 years old, evaluated and stored in one telemedicine platform provided by Health Telematic Network (HTN), in cooperation with a cardiology department hospital and a university. Results from April 2010 to January 2023, 266.381 subjects with &amp;lt; 18 years old underwent electrocardiographic examination in territorial pharmacies. Of them, 142.924 (53.65%) were men. In 440 subjects (0.16%) a first or a second-degree atrio-ventricular block were found. Moreover, in 94 (0.03%) of them a delta-wave in QRS complex was found, suggesting the presence of a Wolff-Parkinson-White syndrome. In 59 (0.022%), a ST segment with Brugada-like pattern was identified, whereas in 118 (0.04%) a long QT was detected. All subjects in which an electrocardiographic alteration was found were referred to outpatient cardiological visit for further diagnostic evaluations. Conclusion These data suggest the potential validity, feasibility and usefulness of an electrocardiographic screening program for the prevention of cardiac sudden death in subjects &amp;lt; 18 years old performed in territorial pharmacies. This could be a valuable strategy to noninvasively and easily identify those subjects who need further diagnostic investigations and to rule out conditions that, especially in a young and otherwise healthy population, could manifest dramatically and suddenly, often without the possibility of intervention.

Abstract 14394: Complete Atrioventricular Block in a Young Patient With Alport Syndrome: A Case Report

Background: Atrioventricular block (AVB) in young adults is rare, and the etiologies and mechanisms in most cases remain uncertain. Alport syndrome is a heterogeneous, hereditary disorder characterized by nephropathy, hearing loss, and ocular abnormalities. Complete AVB has never been reported in Alport syndrome patients with normal kidney function. Case report: A 20-year-old male patient was admitted to hospital with “asymptomatic bradycardia for years”. On admission, the patient’s blood pressure was normal and electrocardiogram (ECG) showed third-degree AVB with atrial rate of 63 bpm and ventricular rate of 36 bpm. He was diagnosed with Alport syndrome at the age of 10. Genetic testing at that time showed single nucleotide variants (c.2372T&gt;C, c.2072T&gt;G) and deletion (c.1781-1949(Exon25)) in COL4A5 gene. During the subsequent 10-year follow-up, the patient was presented with consistent hematuria and proteinuria, but his renal function has never been found impaired. He denied other medical history as well as family history of arrhythmia. Laboratory tests indicated hypoproteinemia, hyperuricemia, hyperlipidemia, and hyperhomocysteinemia. The 24-hour ambulatory ECG revealed a heart rhythm consisting of sinus rhythm with second-degree AVB (2:1 downward transmission) and complete AVB with junctional escape. The mean ventricular rate was 36 bpm (ranged 25-60 bpm). Neither echocardiography nor cardiac magnetic imaging with delayed gadolinium enhancement found any significant abnormality. We then did whole exome sequencing (WES), which did not identify specific pathogenic variant (Table1). 3mg atropine was admitted to the patient for an atropine test to rule out the possibility of vagally mediated AVB and the pacemaker implantation was then performed. Conclusion: We report a case of complete AVB with unknown etiology in a young patient with Alport syndrome.

Abstract 17852: A Right Atrial Mass(querader) Causing Complete Heart Block in an Otherwise Healthy Female

Introduction: Right atrial masses are ominous and have a broad differential including thrombus, primary cardiac tumors such as myxoma vs sarcoma, metastatic processes like lymphoma, and, rarely, autoimmune etiologies. In this case, an apple watch notification of bradycardia was a simple start to a complicated course of rapidly progressive conduction disease arising from an unusual presentation of cardiac sarcoidosis. Case Presentation: A 45-year-old previously healthy female originally presented to clinic with a one-month history of exertional dyspnea and palpitations with bradycardia noted on her Apple Watch and an ongoing event monitor revealing transient type II second-degree atrioventricular block. In the office, she was normotensive but bradycardic at 33 beats per minute with electrocardiogram revealing complete heart block with junctional escape. She was admitted for additional work-up with transesophageal echocardiogram (TEE) which was unrevealing. Cardiac magnetic resonance imaging (cMRI) identified two 2 x 2 cm right atrial masses that appeared hypermetabolic on cardiac fluorodeoxyglucose positron emission tomography (FDG cPET) in addition to bilateral hilar lymph nodes. A temporary-permanent pacemaker equipped with a lead capable of floating atrial bipolar sensing was placed while biopsy plans were arranged. Transbronchial ultrasound guided biopsy of the hilar lymph node returned benign. She then underwent two different attempts at transcatheter biopsy of the right atrial masses - one TEE guided, another intracardiac echo (ICE) guided - with most samples unrevealing except one with an inconclusive amount of spindle cells raising concerns for sarcoma. The decision was made to pursue cardiothoracic surgical resection of the right atrial masses with pathology returning with granulomatous lesions consistent with sarcoidosis. Discussion: Cardiac involvement is present in 25% of cases of sarcoidosis and most commonly manifests as conduction abnormalities, ventricular arrhythmia, and/or heart failure. Only a few cases of atrial masses are reported in the literature and its presence in this woman with heart block confounded the picture before a diagnostic biopsy of this treatable condition could be obtained.

Transcatheter Aortic Valve Implantation and Cardiac Conduction Abnormalities: Prevalence, Risk Factors and Management.

Over the last decades, transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has become a potential, widely accepted, and effective method of treating aortic stenosis in patients at moderate and high surgical risk and those disqualified from surgery. The method evolved what translates into a noticeable decrease in the incidence of complications and more beneficial clinical outcomes. However, the incidence of conduction abnormalities related to TAVI, including left bundle branch block and complete or second-degree atrioventricular block (AVB), remains high. The occurrence of AVB requiring permanent pacemaker implantation is associated with a worse prognosis in this group of patients. The identification of risk factors for conduction disturbances requiring pacemaker placement and the assessment of their relation to pacing dependence may help to develop methods of optimal care, including preventive measures, for patients undergoing TAVI. This approach is crucial given the emerging evidence of no worse outcomes for intermediate and low-risk patients undergoing TAVI in comparison to surgical aortic valve replacement. This paper comprehensively discusses the mechanisms, risk factors, and consequences of conduction abnormalities and arrhythmias, including AVB, atrial fibrillation, and ventricular arrhythmias associated with aortic stenosis and TAVI, as well as provides insights into optimized patient care, along with the potential of conduction system pacing and cardiac resynchronization therapy, to minimize the risk of unfavorable clinical outcomes.

Long-Term Follow-Up of Second-Degree Heart Block in Children.

Little is known about the outcomes of children with second-degree heart block. We aimed to determine whether children with structurally normal hearts and Mobitz 1, 2:1 block or Mobitz 2 are at increased risk for progressing to complete heart block (CHB) or requiring a pacemaker (PM) at long-term follow-up. We searched our institutional electrophysiology database for children with potentially concerning second-degree block on ambulatory rhythm monitoring between 2009 and 2021, defined as frequent episodes of Mobitz 1 or 2:1 block, episodes of Mobitz 1 or 2:1 block with additional evidence of conduction disease (i.e. first-degree heart block, bundle branch block), or episodes of Mobitz 2.Ambulatory rhythm monitor, ECG, and demographic data were reviewed. The primary composite outcome was CHB on follow-up rhythm monitor or PM placement. 20 patients were in the final analysis. Six (30%) patients either developed CHB but do not have a PM (4 = 20%) or have a PM (2 = 10%). Median follow-up was 5.8years (IQR 4.4-7.0). Patients with CHB or PM were more likely to have second-degree block at maximum sinus rate (67% vs. 0%, p = 0.003), a below normal average heart rate (67% vs. 14%, p = 0.04), and 2:1 block on initial ECG (50% vs. 0%, p = 0.02). In this study of children with potentially concerning second-degree block, 30% of patients progressed to CHB or required a PM. Second-degree block at maximum sinus rate, a low average heart, and 2:1 block on initial ECG were associated with increased risk of disease progression.

Mobitz typeII second-degree atrioventricular block during sleep: true or false?

Anumber of publications have claimed that Mobitz typeII second-degree atrioventricular (AV) block can occur during sleep apnea. None has provided adefinition of typeII block used in the articles, and representative electrocardiograms have been generally missing. Despite these reports, the existence of typeII AV block during sleep must remain questionable.

Prediction of atrioventricular conduction disturbance after ablation of persistent atrial fibrillation.

The prevalence of atrioventricular conduction disturbance (AVCD) in patients with persistent atrial fibrillation (AF) has not yet been fully investigated. We sought to identify the predictors of AVCD in patients with AF by analyzing the relationship between pre-ablation heart rate during AF and the PR interval in sinus rhythm after ablation. We analyzed pre-ablation 24-h Holter electrocardiogram (ECG) and 12 lead ECG 12months after ablation of 121 consecutive patients with persistent AF who underwent their first ablation procedure and maintained sinus rhythm at 12months. AVCD was defined as a first-degree atrioventricular block (AVB), second-degree AVB, high-degree AVB, or third-degree AVB observed on ECG at 12months after ablation. Seventeen out of 121 patients (14.0%) had AVCD at 12months. In the group with AVCD, total heartbeat (THB) and maximum heart rate (Max HR) were significantly lower, and the prevalence of concomitant Cavo-tricuspid isthmus-dependent atrial flutter before ablation and the appearance of macro reentrant atrial tachycardia (AT) during the procedure were significantly higher than those in the group without AVCD. Multiple regression analysis revealed that maximum HR and macro reentrant AT were significant predictors of AVCD. Receiver operating characteristic curve analysis revealed that Max HR of <165.0bpm predicts AVCD with a sensitivity of 76.47% and a specificity of 74.00%. In patients with persistent AF, low Max HR and the presence of macro reentrant AT during the ablation procedure were predictors of AVCD.

Frequency of Cardiac Arrhythmias Detection on 24 Hours Holter Monitoring

To determine the clinical outcomes and assess the diagnostic yield of Holter monitoring and its potential use in diagnosing and managing abnormal rhythms, along with identifying patterns or trends in the prevalence of different arrhythmias, which could modify and design future research and clinical practice. It was a descriptive cross sectional study carried out at MMC Mardan on around 1000 patients, from June 2017 to December 2022. Three trained Cardiologists having more than 03 years of experience reviewed the 24-hour monitor data through the system. Among these 1000 patients, 31% had at least one arrhythmia detected on 24-hour Holter monitoring. The most common arrhythmias detected were premature ventricular contractions (54%), followed by Atrial fibrillation (18%) and supraventricular tachycardia (15%) while 2.3% had first-degree AV block, 4.5% had second-degree AV block, and 0.8% had third-degree AV block. In conclusion, our study showed that Holter monitoring for 24 hours is a useful tool for detecting a range of cardiac arrhythmias, with premature ventricular contractions being on the top, with some forms of AV block also being detected in a small group of patients, having first-degree AV block being the most common type.

Risk Factors of Secondary Cardiovascular Events in a Multi-Ethnic Asian Population with Acute Myocardial Infarction: A Retrospective Cohort Study from Malaysia.

This retrospective cohort study investigated the incidence and risk factors of major adverse cardiovascular events (MACE) after 1 year of first-documented myocardial infarctions (MIs) in a multi-ethnic Asian population. Secondary MACE were observed in 231 (14.3%) individuals, including 92 (5.7%) cardiovascular-related deaths. Both histories of hypertension and diabetes were associated with secondary MACE after adjustment for age, sex, and ethnicity (HR 1.60 [95%CI 1.22-2.12] and 1.46 [95%CI 1.09-1.97], respectively). With further adjustments for traditional risk factors, individuals with conduction disturbances demonstrated higher risks of MACE: new left-bundle branch block (HR 2.86 [95%CI 1.15-6.55]), right-bundle branch block (HR 2.09 [95%CI 1.02-4.29]), and second-degree heart block (HR 2.45 [95%CI 0.59-10.16]). These associations were broadly similar across different age, sex, and ethnicity groups, although somewhat greater for history of hypertension and BMI among women versus men, for HbA1c control in individuals aged >50 years, and for LVEF ≤ 40% in those with Indian versus Chinese or Bumiputera ethnicities. Several traditional and cardiac risk factors are associated with a higher risk of secondary major adverse cardiovascular events. In addition to hypertension and diabetes, the identification of conduction disturbances in individuals with first-onset MI may be useful for the risk stratification of high-risk individuals.

The Success of a New Protocol for Early Diagnosis and Management of Congenital Atrioventricular Block: A Follow-up Study of 15 Fetuses from November 2007 to August 2022

Background: Congenital atrioventricular heart block (CAVB) is a relatively rare condition that can lead to long-term complications. Early diagnosis and management of CAVB is currently the ideal goal, particularly in high-risk pregnancies. Methods: The Fetal Heart Center at Kurdistan University serves as the primary referral center for pregnant mothers residing in the western region of Iran. Fifteen fetuses with CAVB were admitted between November 2007 and August 2022. They were referred for one or more of the following reasons: Fetal bradycardia or arrhythmia, abnormal ultrasound findings, and previous maternal or fetal risk factors. After obtaining a complete medical history, we conducted fetal echocardiography and ordered testing for maternal Lo/Ra autoantibodies. Our therapeutic approach was based on the type of atrioventricular block (AVB), serum titer of Lo/Ra antibodies, and specific risk factors associated with each type of AVB. Consequently, we used a combination of different medications, including dexamethasone, Hydroxychloroquine (HCQ), IVIG, beta-agonists, and inotropes. Results: We admitted 15 fetuses with CAVB, including seven females (47%) and eight males (53%). Most of our cases had positive tests for Lo and Ra autoantibodies, with varying degrees of AVB. A previous fetal death was common in our case series, accounting for 47% of cases. Moderate and high antibody titers were present in 80% of our cases. Mild bradycardia was a relatively common finding in our cases of first and second-degree atrioventricular block (AVB), occurring in 33% of patients. All of the above-mentioned findings, commonly referred to as major risk factors, were used for either early evaluation or therapeutic goals. No cases with first-degree AVB developed a higher grade of AVB after our therapeutic approach. One fetus with second-degree AVB developed CCHB, and another with mixed second/third-degree AVB reverted to second-degree AVB with the use of appropriate medications. Conclusions: Our therapeutic approach for the current cases yielded satisfactory results. Subsequently, we attempted to develop a rudimentary approach for early managing and treating fetuses with various types of CAVB. We are looking forward to future multicenter studies.