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The Journal of International Medical... Jan 2024Atrioventricular block (AVB) is a rare cardiac manifestation of hyperthyroidism (HTH). The scientific literature contains multiple reports of AVB in patients with HTH,... (Review)
Review
Atrioventricular block (AVB) is a rare cardiac manifestation of hyperthyroidism (HTH). The scientific literature contains multiple reports of AVB in patients with HTH, ranging from subclinical to overt HTH and even thyroid storm. However, much remains unknown about the true prevalence, clinical course, optimal management, and outcomes of AVB in patients with HTH. Such patients are possibly overtreated with pacemakers because of a lack of understanding that AVB might be secondary to the hyperthyroid state and thus reversible. This narrative review discusses the pathophysiology of AVB in patients with HTH in the context of the available evidence.
Topics: Humans; Atrioventricular Block; Hyperthyroidism; Patients; Heart
PubMed: 38206211
DOI: 10.1177/03000605231223040 -
Journal of Comparative Pathology Feb 2023The cardiac conduction system was examined histologically in 13 canine cases of atrioventricular (AV) valve endocardiosis with third-degree AV block. In all cases, gross...
The cardiac conduction system was examined histologically in 13 canine cases of atrioventricular (AV) valve endocardiosis with third-degree AV block. In all cases, gross examination revealed marked thickening and distortion of the base of the central fibrous body (CFB) and varying degrees of endocardial thickening of the upper portion of the ventricular septum (VS) as well as marked thickening of the mitral and tricuspid valve leaflets due to myxomatous degeneration. Microscopically, the thickened and distorted CFB had encased or trapped, either partly or totally, the underlying penetrating and branching portions of the AV bundle. The myxomatous and/or fibrofatty tissue, which had proliferated at the base of the extensive CFB, protruded into or encroached on the AV bundle, causing severe (51-75%) to very severe (76% or more) reduction of the conduction fibres. The upper portions of the left and right bundle branches were involved in the endocardial thickening due to degenerative and fibrotic changes at the uppermost VS; however, both bundle branches were much less severely affected than the AV bundle, the degree of reduction of the conduction fibres ranging from mild (25% or less) to moderate (26-50%). These observations suggest that the sites most vulnerable to lesions in the AV conduction system are the penetrating and branching portions of the AV bundle, which would represent the anatomical basis for third-degree AV block in canine cases of AV valve endocardiosis.
Topics: Animals; Dogs; Atrioventricular Block; Bundle of His; Dog Diseases; Endocardium; Heart Conduction System; Heart Diseases
PubMed: 36709730
DOI: 10.1016/j.jcpa.2022.12.014 -
Pacing and Clinical Electrophysiology :... Sep 2018The relationship between high-grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized....
BACKGROUND
The relationship between high-grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate.
OBJECTIVE
To determine impact of HGAVB and pacing on AAs including atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT).
METHODS
All consecutive patients who underwent dual-chamber pacemaker implantation for HGAVB from 2005 to 2011 at the University of Chicago were included. AAs and percent of pacing were detected through device interrogation. Patients' data were collected from electronic medical records and clinic visits.
RESULTS
A total of 166 patients (mean age 71 ± 15 years; 54% female, 56% African American) were studied. AF was documented in 27% of patients before pacemaker implantation. During a mean 5.8 ± 2.2 years of follow-up, 47% had device-detected AF, 10% AFL, and 26% AT. New-onset AF was documented in 40 of the 122 patients without prior AF (33%). Continuous (≥ 99%) right ventricular pacing was associated with significantly decreased AF prevalence (34% vs 59%, P = 0.005), and correlated with lower incidence (26% vs 41%, P = 0.22). Pacing suppressed AF in 14% of patients with baseline AF; those patients had lower atrial pacing (3.2% vs 45%, P < 0.0001). Left atrial dilation was the only independent predictor of AF with frequent pacing (P = 0.009).
CONCLUSIONS
HGAVB is associated with high incidence and prevalence of AAs with and without pacing. Cumulative frequent (≥99%) ventricular pacing reduces risk of AF in patients with HGAVB.
Topics: Adult; Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Flutter; Atrioventricular Block; Cardiac Pacing, Artificial; Female; Humans; Incidence; Male; Middle Aged; Prevalence
PubMed: 29931776
DOI: 10.1111/pace.13425 -
Emerging Infectious Diseases Sep 2022Cardiac involvement in acute Q fever is rare. We report 2 cases of an advanced atrioventricular block in young adult patients in Israel who sought care for acute Q fever...
Cardiac involvement in acute Q fever is rare. We report 2 cases of an advanced atrioventricular block in young adult patients in Israel who sought care for acute Q fever without evidence of myocarditis. Q fever should be suspected in unexplained conduction abnormalities, especially in febrile young patients residing in disease-endemic areas.
Topics: Atrioventricular Block; Coxiella burnetii; Fever; Humans; Israel; Q Fever; Young Adult
PubMed: 35997621
DOI: 10.3201/eid2809.212565 -
Heart (British Cardiac Society) Jul 2022Rare cases of genetically inherited atrioventricular block (AVB) have been reported; however, the heredity of AVB remains unknown. We aimed to assess the heredity of AVB.
OBJECTIVE
Rare cases of genetically inherited atrioventricular block (AVB) have been reported; however, the heredity of AVB remains unknown. We aimed to assess the heredity of AVB.
DESIGN, SETTING AND PARTICIPANTS
Using data from the Danish Civil Registration Registry, we established a nationwide cohort of individuals with parental links. Data were merged with information from the Danish Pacemaker and Implantable Cardioverter Defibrillator Registry, containing information on all pacemaker implantations performed in Denmark during the study period, to identify patients who received a first-time pacemaker because of AVB.
RESULTS
A total of 4 648 204 individuals had parental links and a total of 26 880 consecutive patients received a first-time pacemaker due to AVB. Overall, the adjusted rate ratio (RR) of pacemaker implantation due to AVB was 2.1 (95% CI 1.8 to 2.5) if a father, mother or sibling had AVB compared with the risk in the general population. The adjusted RR was 2.2 (1.7-2.9) for offspring of mothers with AVB, 1.9 (1.5-2.4) for offspring of fathers with AVB and 3.5 (2.3-5.4) for siblings to a patient with AVB. The risk increased inversely proportionally with the age of the index case at the time of pacemaker implantation. The corresponding adjusted RRs were 15.8 (4.8-52.3) and 10.0 (3.3-30.4) if a mother or father, respectively, had a pacemaker implantation before 50 years.
CONCLUSION AND RELEVANCE
First-degree relatives to a patient with AVB carry an increased risk of AVB with the risk being strongly inversely associated with the age of the index case at pacemaker implantation. These findings indicate a genetic component in the development of AVB in families with an early-onset disease.
Topics: Atrioventricular Block; Defibrillators, Implantable; Genetic Predisposition to Disease; Humans; Pacemaker, Artificial; Registries
PubMed: 35246466
DOI: 10.1136/heartjnl-2021-320411 -
Cardiovascular Journal of Africa 2015Topical beta-blockers have a well-established role in the treatment of glaucoma. We aimed to investigate the outcome of patients who developed symptomatic...
BACKGROUND
Topical beta-blockers have a well-established role in the treatment of glaucoma. We aimed to investigate the outcome of patients who developed symptomatic atrioventricular (AV) block induced by topical beta-blockers.
METHODS
All patients admitted or discharged from our institution, the Siyami Ersek Training and Research Hospital, between January 2009 and January 2013 with a diagnosis of AV block were included in the study. Subjects using ophthalmic beta-blockers were recruited and followed for permanent pacemaker requirement during hospitalisation and for three months after discontinuation of the drug. A permanent pacemaker was implanted in patients in whom AV block persisted beyond 72 hours or recurred during the follow-up period.
RESULTS
A total of 1 122 patients were hospitalised with a diagnosis of AV block and a permanent pacemaker was implanted in 946 cases (84.3%) during the study period. Thirteen patients using ophthalmic beta-blockers for the treatment of glaucoma and no other rate-limiting drugs were included in the study. On electrocardiography, eight patients had complete AV block and five had high-degree AV block. The ophthalmic beta-blockers used were timolol in seven patients (55%), betaxolol in four (30%), and cartelol in two cases (15%). The mean duration of ophthalmic beta-blocker treatment was 30.1 ± 15.9 months. After drug discontinuation, in 10 patients the block persisted and a permanent pacemaker was implanted. During follow up, one more patient required pacemaker implantation. Therefore in total, pacemakers were implanted in 11 out of 13 patients (84.6%). The pacemaker implantation rate did not differ according to the type of topical beta-blocker used (p = 0.37). The presence of infra-nodal block on electrocardiography was associated with higher rates of pacemaker implantation.
CONCLUSION
Our results indicate that topical beta-blockers for the treatment of glaucoma may cause severe conduction abnormalities and when AV block occurs, pacemaker implantation is required in a high percentage of the patients.
Topics: Administration, Ophthalmic; Adrenergic beta-Antagonists; Aged; Aged, 80 and over; Atrioventricular Block; Cardiac Pacing, Artificial; Electrocardiography; Female; Glaucoma; Heart Conduction System; Heart Rate; Hospitals, Teaching; Humans; Male; Middle Aged; Pacemaker, Artificial; Recurrence; Risk Factors; Time Factors; Treatment Outcome; Turkey
PubMed: 26659434
DOI: 10.5830/CVJA-2015-030 -
JACC. Clinical Electrophysiology Jan 2019This study sought to evaluate the incidence and significance of atrioventricular (AV) block associated with ventricular arrhythmia (VA) ablation.
OBJECTIVES
This study sought to evaluate the incidence and significance of atrioventricular (AV) block associated with ventricular arrhythmia (VA) ablation.
BACKGROUND
Attempted ablation of VAs that arise from the septum carries a risk of AV block.
METHODS
Data from 1,418 patients who had catheter ablation for drug-refractory VAs were evaluated. Two analyses were conducted. The first analysis assessed the patient and procedure characteristics associated with ablation-induced AV block. The second analysis investigated outcome differences between patients with and without AV block. For the second analysis, patients with AV block (Group I) were compared with a 1:2 propensity score-matched control group (Group II) and with patients with pre-existing AV block before ablation (Group III).
RESULTS
Twenty-one (1.6%) patients developed AV block. In multivariable analysis, nonischemic cardiomyopathy (odds ratio: 3.33; 95% confidence interval: 1.32 to 8.40; p = 0.011) and transcoronary ethanol ablation (odds ratio: 46.50; 95% confidence interval: 14.10 to 153.00; p < 0.001) were independently associated with AV block. Subsequent to the AV block, 9 patients were upgraded from an implantable cardioverter-defibrillator to cardiac resynchronization therapy with defibrillator (CRT-D), 2 had de novo CRT-D implantation, 5 had pre-existing CRT-D, and 5 had pacing without CRT. VAs recurred in 33% of patients in Group I, 17% in Group II (log-rank p = 0.842), and 35% in Group III (p = 0.636). The composite outcome of heart failure hospitalization, heart transplantation, or death occurred in 29% of patients in Group I, 17% in Group II (p = 0.723), and 45% in Group III (p = 0.303).
CONCLUSIONS
Complete AV block occurs in fewer than 2% of patients undergoing VA ablation and does not appear to be associated with the worse outcome of heart failure hospitalization, heart transplantation, or death.
Topics: Aged; Arrhythmias, Cardiac; Atrioventricular Block; Catheter Ablation; Defibrillators, Implantable; Female; Heart Failure; Humans; Male; Middle Aged; Retrospective Studies
PubMed: 30678774
DOI: 10.1016/j.jacep.2018.10.005 -
JACC. Clinical Electrophysiology Jan 2022This study aims to assess the safety and feasibility of achieving His-Purkinje conduction system pacing (HPCSP) in consecutive patients with atrioventricular block (AVB)...
OBJECTIVES
This study aims to assess the safety and feasibility of achieving His-Purkinje conduction system pacing (HPCSP) in consecutive patients with atrioventricular block (AVB) and to describe the site of conduction block in patients with infranodal AVB.
BACKGROUND
HPCSP has evolved as the preferred form of physiologic pacing. Left bundle branch area pacing (LBBAP) has emerged as an effective alternative to His bundle pacing (HBP).
METHODS
Consecutive patients with AVB referred for pacemaker implantation were included in the study. HBP or LBBAP was attempted in all patients. Site of conduction block was identified as nodal or infranodal (intra-Hisian or infra-Hisian) AVB.
RESULTS
HPCSP was attempted in 333 consecutive patients with AVB and was successful in 322 (97%) patients. HBP was achieved in 140 patients, LBBAP in 179 patients, and both in 3 patients. Site of conduction block was nodal in 55% and infranodal in 45% (intra-Hisian 89%; infra-Hisian 4%; indeterminate 7%). QRS duration at baseline was 111 ± 27 versus 129 ± 31 (P < 0.001) compared to 126 ± 24 vs 125 ± 21 milliseconds (P = 0.75) during HBP and LBBAP, respectively. HBP thresholds at implant were higher compared to LBBAP (1.2 ± 0.7 V at 0.9 milliseconds vs 0.6 ± 0.3 V at 0.5 milliseconds; P < 0.001) but remained stable during follow-up. Lead revision was required in 3% and 2% of patients with HBP and LBBAP, respectively.
CONCLUSIONS
HPCSP pacing was successfully performed in 97% of unselected patients with AVB irrespective of the site of conduction block. True infra-Hisian block (distal His-Purkinje conduction disease) is rare. HBP and LBBAP were complementary in achieving stable and low capture thresholds.
Topics: Arrhythmias, Cardiac; Atrioventricular Block; Bundle of His; Cardiac Pacing, Artificial; Electrocardiography; Humans
PubMed: 34393084
DOI: 10.1016/j.jacep.2021.07.007 -
Journal of Interventional Cardiac... Aug 2021PR interval prolongation > 200 ms resulting in the diagnosis of first-degree atrioventricular block (AVB1) is caused by a delay in the AV nodal/His conduction and/or...
PURPOSE
PR interval prolongation > 200 ms resulting in the diagnosis of first-degree atrioventricular block (AVB1) is caused by a delay in the AV nodal/His conduction and/or the right intra-atrial conduction (RIAC). The aim of the study was to assess the prevalence of AVB1 due to RIAC delay (AVB1 with normal AH and HV) in patients with atrial fibrillation (AF) and atrial flutter (AFlu).
METHODS
We included 1067 consecutive patients (33% female, age 63 ± 13 years) referred for catheter ablation of AF (AF-group) (453 patients), AF and AFlu (136 patients), AFlu (292 patients), and AVNRT/AVRT (186 patients). AH-, HV-, PR-interval, and P-wave duration were measured on the 12-lead ECG and the intracardiac electrograms in sinus rhythm. RIAC delay was defined as a prolonged PR interval > 200 ms with normal AH and HV intervals.
RESULTS
The prevalence of AVB1 is higher in patients with AFlu (41%) and AF (21%) and patients with both arrhythmias (30%) as compared with a reference group (8%) of patients with AVNRT/AVRT. AVB1 was due to RIAC delay in 42 of 67 patients (63%) in the AF-group, in 37 of 96 patients (39%) in the AFlu-group, and in 17 of 36 patients (47%) in the AF/AFlu group, respectively. AV nodal conduction delay was more common in AFlu patients compared with AF patients.
CONCLUSION
RIAC delay is a common underlying cause of AVB1 in patients with AF and AFlu. These findings may impact the prescription of antiarrhythmic and AV-nodal blocking drugs.
Topics: Atrial Fibrillation; Atrial Flutter; Atrioventricular Block; Atrioventricular Node; Catheter Ablation; Electrocardiography; Female; Humans; Infant, Newborn; Male; Prevalence
PubMed: 32734408
DOI: 10.1007/s10840-020-00838-3 -
BMC Cardiovascular Disorders Jun 2021Nationwide data on the prevalence of atrioventricular (AV) block are currently unavailable in China. Thus, we aimed to assess the prevalence and risk factors of AV block...
BACKGROUND
Nationwide data on the prevalence of atrioventricular (AV) block are currently unavailable in China. Thus, we aimed to assess the prevalence and risk factors of AV block among Chinese health examination adults.
METHODS
A total of 15,181,402 participants aged ≥ 18 years (mean age 41.5 ± 13.4 years, 53.2% men) who underwent an electrocardiogram as a part of routine health examination in 2018 were analyzed. AV block was diagnosed by physicians using 12-lead electrocardiogram. Overall and stratified prevalence (by age, sex, and city size) of all, first-, second- and third-degree AV block were calculated. Multivariable logistic regression analyses were performed to explore risk factors associated with AV block.
RESULTS
AV block was observed in 88,842 participants, including 86,153 with first-degree, 2249 with second-degree and 440 with third-degree AV block. The age- and sex-standardized prevalence rate [95% confidence interval (CI)] of all, first-, second- and third-degree AV block were 7.06‰ (7.01-7.11), 6.84‰ (6.79-6.89), 0.18‰ (0.17-0.18) and 0.04‰ (0.03-0.04) respectively. After multivariable adjustment, the risk of AV block was positively associated with older age, being male, lower heart rate, higher body mass index, hypertension, diabetes and low high-density lipoprotein cholesterol. High total cholesterol was associated with a lower risk of AV block.
CONCLUSION
First-degree AV block is relatively common while severe AV block is rare in health examination adults. Besides, AV block was highly prevalent among the elderly. The risk of AV block was associated with older age, being male and metabolic factors.
Topics: Adolescent; Adult; Age Factors; Atrioventricular Block; China; Cross-Sectional Studies; Databases, Factual; Electrocardiography; Female; Heart Disease Risk Factors; Humans; Male; Metabolic Diseases; Middle Aged; Prevalence; Risk Assessment; Severity of Illness Index; Sex Factors; Time Factors; Young Adult
PubMed: 34116630
DOI: 10.1186/s12872-021-02105-3