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JACC. Clinical Electrophysiology Jan 2023
Topics: Humans; Child; Cardiomyopathies; Heart Atria; Heart Block
PubMed: 36697202
DOI: 10.1016/j.jacep.2022.11.025 -
JACC. Clinical Electrophysiology Jan 2023Atrial standstill (AS) is a rare condition characterized by absence of electrical activity within the atria. Studies to date have been limited.
BACKGROUND
Atrial standstill (AS) is a rare condition characterized by absence of electrical activity within the atria. Studies to date have been limited.
OBJECTIVES
The authors sought to describe the clinical characteristics, genetics, and outcomes of patients with AS.
METHODS
This was a retrospective multicenter study of patients <18 years at AS diagnosis, defined as absence of atrial activity documented during an electrophysiology study, device placement, or noninvasive rhythm tracings and confirmed by echocardiogram. Patients with acquired disorders were excluded. Clinical details and genetic variants were recorded and analyzed.
RESULTS
Twenty patients were diagnosed at a median age of 6.6 years (IQR: 2.9-10.8 years). Arrhythmias included 16 (80%) with atrial/supraventricular arrhythmias and 8 (40%) with ventricular tachycardia, including 4 with cardiac arrests. A type 1 Brugada pattern was documented in 4. Pacemakers were implanted in 18 (90%). Although atrial leads were attempted in 15, only 4 achieved pacing at implantation. During a median follow-up of 6.9 years (IQR: 1.2-13.3 years), 7 (35%) had thromboembolic events. Of these, none had atrial pacing, 6 were not on anticoagulation, and 1 was on aspirin. Genetic testing identified SCN5A variants in 13 patients (65%). Analyses suggest SCN5A loss-of-function may be one mechanism driving AS. Ventricular arrhythmias and cardiac arrest were more commonly seen in patients with biallelic SCN5A variants.
CONCLUSIONS
AS may be associated with loss-of-function SCN5A variants. Patients demonstrate atrial and ventricular arrhythmias, and may present challenges during device placement. Patients without the capacity for atrial pacing are at risk for thromboembolic events and warrant anticoagulation.
Topics: Humans; Child; Child, Preschool; Atrial Fibrillation; Heart Atria; Heart Block; Heart Arrest; Anticoagulants
PubMed: 36435694
DOI: 10.1016/j.jacep.2022.08.022 -
Biology Mar 2022Cardiolaminopathies are a heterogeneous group of disorders which are due to mutations in the genes encoding for nuclear lamins or their binding proteins. The whole... (Review)
Review
Cardiolaminopathies are a heterogeneous group of disorders which are due to mutations in the genes encoding for nuclear lamins or their binding proteins. The whole spectrum of cardiac manifestations encompasses atrial arrhythmias, conduction disturbances, progressive systolic dysfunction, and malignant ventricular arrhythmias. Despite the prognostic significance of cardiac involvement in this setting, the current recommendations lack strong evidence. The aim of our work was to systematically review the current data on the main cardiovascular outcomes in cardiolaminopathies. We searched PubMed/Embase for studies focusing on cardiovascular outcomes in mutation carriers (atrial arrhythmias, ventricular arrhythmias, sudden cardiac death, conduction disturbances, thromboembolic events, systolic dysfunction, heart transplantation, and all-cause and cardiovascular mortality). In total, 11 studies were included (1070 patients, mean age between 26-45 years, with follow-up periods ranging from 2.5 years up to 45 ± 12). When available, data on the -mutated population were separately reported (40 patients). The incidence rates (IR) were individually assessed for the outcomes of interest. The IR for atrial fibrillation/atrial flutter/atrial tachycardia ranged between 6.1 and 13.9 events/100 pts-year. The IR of atrial standstill ranged between 0 and 2 events/100 pts-year. The IR for malignant ventricular arrhythmias reached 10.2 events/100 pts-year and 15.6 events/100 pts-year for appropriate implantable cardioverter-defibrillator (ICD) interventions. The IR for advanced conduction disturbances ranged between 3.2 and 7.7 events/100 pts-year. The IR of thromboembolic events reached up to 8.9 events/100 pts-year. Our results strengthen the need for periodic cardiological evaluation focusing on the early recognition of atrial arrhythmias, and possibly for the choice of preventive strategies for thromboembolic events. The frequent need for cardiac pacing due to advanced conduction disturbances should be counterbalanced with the high risk of malignant ventricular arrhythmias that would justify ICD over pacemaker implantation.
PubMed: 35453731
DOI: 10.3390/biology11040530 -
PloS One 2022The mouse is a useful preclinical species for evaluating disease etiology due to the availability of a wide variety of genetically modified strains and the ability to...
The mouse is a useful preclinical species for evaluating disease etiology due to the availability of a wide variety of genetically modified strains and the ability to perform disease-modifying manipulations. In order to establish an atrial filtration (AF) model in our laboratory, we profiled several commonly used murine AF models. We initially evaluated a pharmacological model of acute carbachol (CCh) treatment plus atrial burst pacing in C57BL/6 mice. In an effort to observe micro-reentrant circuits indicative of authentic AF, we employed optical mapping imaging in isolated mouse hearts. While CCh reduced atrial refractoriness and increased atrial tachyarrhythmia vulnerability, the left atrial (LA) excitation patterns were rather regular without reentrant circuits or wavelets. Therefore, the atrial tachyarrhythmia resembled high frequency atrial flutter, not typical AF per se. We next examined both a chronic angiotensin II (Ang II) infusion model and the surgical model of transverse aortic constriction (TAC), which have both been reported to induce atrial and ventricular structural changes that serve as a substrates for micro-reentrant AF. Although we observed some extent of atrial remodeling such as fibrosis or enlarged LA diameter, burst pacing-induced atrial tachyarrhythmia vulnerability did not differ from control mice in either model. This again suggested that an AF-like pathophysiology is difficult to demonstrate in the mouse. To continue searching for a valid murine AF model, we studied mice with a cardiac-specific deficiency (KO) in liver kinase B1 (Cardiac-LKB1), which has been reported to exhibit spontaneous AF. Indeed, the electrocardiograms (ECG) of conscious Cardiac-LKB1 KO mice exhibited no P waves and had irregular RR intervals, which are characteristics of AF. Histological evaluation of Cardiac-LKB1 KO mice revealed dilated and fibrotic atria, again consistent with AF. However, atrial electrograms and optical mapping revealed that electrical activity was limited to the sino-atrial node area with no electrical conduction into the atrial myocardium beyond. Thus, Cardiac-LKB1 KO mice have severe atrial myopathy or atrial standstill, but not AF. In summary, the atrial tachyarrhythmias we observed in the four murine models were distinct from typical human AF, which often exhibits micro- or macro-reentrant atrial circuits. Our results suggest that the four murine AF models we examined may not reflect human AF well, and raise a cautionary note for use of those murine models to study AF.
Topics: AMP-Activated Protein Kinases; Animals; Atrial Fibrillation; Atrial Flutter; Atrial Function, Left; Atrial Remodeling; Carbachol; Cardiac Pacing, Artificial; Disease Models, Animal; Electrocardiography; Mice; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Tachycardia, Ventricular
PubMed: 34995278
DOI: 10.1371/journal.pone.0256512 -
Cardiovascular Journal of Africa 2021Atrial standstill is an uncommon but serious clinical entity that is often unrecognised in the clinical setting. Its diagnosis and treatment should be swift as malignant...
Atrial standstill is an uncommon but serious clinical entity that is often unrecognised in the clinical setting. Its diagnosis and treatment should be swift as malignant arrhythmias and thromboembolic complications can arise. We present a 79-year-old man brought to our emergency department with acute confusion, heart failure and severe bradycardia in the context of diabetic ketoacidosis, and discuss the diagnosis and management of this arrhythmic condition.
Topics: Aged; Arrhythmias, Cardiac; Bradycardia; Diabetic Ketoacidosis; Electrocardiography; Heart Atria; Humans; Male
PubMed: 34143176
DOI: 10.5830/CVJA-2020-026 -
European Heart Journal. Case Reports Jun 2023Juvenile onset of extensive atrial electromechanical failure, including atrial standstill, is a rare disease entity that may precede ventricular cardiomyopathy. Genetic...
Juvenile-onset multifocal atrial arrhythmias, atrial standstill and compound heterozygosity of genetic variants in : sentinel event for evolving dilated cardiomyopathy-a case report.
BACKGROUND
Juvenile onset of extensive atrial electromechanical failure, including atrial standstill, is a rare disease entity that may precede ventricular cardiomyopathy. Genetic variants associated with early-onset atrioventricular (AV) cardiomyopathy are increasingly recognized.
CASE SUMMARY
A 16-year-old patient presented with atrial brady- and tachyarrhythmias and concomitant impaired atrial electromechanical function (atrial standstill). The atrial phenotype preceded the development of a predominantly right-sided AV dilated cardiomyopathy with pronounced myocardial fibrosis. A His-bundle pacemaker was installed for high-degree AV conduction block and sinus arrest. Using familial-based whole-exome sequencing, a missense mutation and a copy number variant deletion (compound heterozygosity) of the gene (involved in ribosomal RNA synthesis) were identified.
DISCUSSION
Juvenile onset of severe atrial electromechanical failure with atrial arrhythmias should prompt deep pheno- and genotyping and calls for vigilance for downstream cardiomyopathic deterioration.
PubMed: 37501913
DOI: 10.1093/ehjcr/ytad255 -
Cureus May 2022Atrial standstill is a rare condition in which the atrium loses its mechanical contraction with or without losing the electrical conduction. In this report, we discuss...
Atrial standstill is a rare condition in which the atrium loses its mechanical contraction with or without losing the electrical conduction. In this report, we discuss a case of a 64-year-old male patient with a history of hypertrophic cardiomyopathy (HCM) and persistent refractory atrial fibrillation (AF). He underwent ablation therapy with a successful return to sinus rhythm. However, post-procedure echocardiography imaging showed the absence of left atrium mechanical activity. We aim to highlight the importance of assessing atrial mechanical activity by imaging after sinus cardioversion in order to treat any preventable complications promptly.
PubMed: 35755564
DOI: 10.7759/cureus.25293 -
The Journal of Innovations in Cardiac... Jan 2024
PubMed: 38304085
DOI: 10.19102/icrm.2024.15016 -
Frontiers in Cardiovascular Medicine 2023To characterize the cardiac phenotype associated with the novel pathogenic variant (c.1526del) of gene, which we identified in a large, six-generation family.
OBJECTIVE
To characterize the cardiac phenotype associated with the novel pathogenic variant (c.1526del) of gene, which we identified in a large, six-generation family.
METHODS AND RESULTS
A family tree was constructed. The clinical data of living and deceased family members were collected. DNA samples from 7 family members were analyzed for mutations using whole-exome high-throughput sequencing technology. The clinical presentation of pathogenic variant carriers was evaluated. In this six-generation family ( = 67), one member experienced sudden death at the age of 40-years-old. Three pathogenic variant carriers were identified to possess a novel heterozygous deletion mutation in gene (HGVS: NM_170707.4, c.1526del) located at exon 9 of chr1:156137145, which creates a premature translational stop signal (p.Pro509Leufs*39) in the LMNA gene and results in an mutant lamin A protein product. The main symptoms of the pathogenic variant carriers were palpitation, fatigue, and syncope, which typically occurred around 20-years-old. AV-conduction block and non-sustained ventricular tachycardia were the first signs of disease and would rapidly progress to atrial standstill around 30-years-old. Significant right atrial enlargement and bicuspid aortic valve malformation was also commonly seen in patients who carried this pathogenic variant.
CONCLUSION
The pathogenic variant of c.1526del p.P509Lfs*39 was a frameshift deletion located at exon 9 of chr1:156137145 and causes severe right atrial enlargement, sick sinus syndrome, atrial standstill, ventricular tachycardia, and bicuspid aortic valve malformation. Our findings expand the phenotypic spectrum of novel gene mutations.
PubMed: 37465451
DOI: 10.3389/fcvm.2023.1109008 -
ESC Heart Failure Oct 2021Giant cell myocarditis (GCM) is a rare condition. Its association with SARS-CoV-2 has not been described before. The 46-year-old female patient was admitted to the...
Giant cell myocarditis (GCM) is a rare condition. Its association with SARS-CoV-2 has not been described before. The 46-year-old female patient was admitted to the clinic on September 2020. She had 7 year adrenal insufficiency history and infarct-like debut of myocardial disease in November 2019. After COVID-19 in April 2020, cardiac disease progressed. The examination showed low QRS voltage, QS complexes in V -V leads, atrial standstill, left ventricular systolic and restrictive dysfunction, elevated anti-heart antibodies, and subepicardial late gadolinium enhancement by magnetic resonance imaging. Endomyocardial biopsy and pacemaker implantation were performed, but the patient died suddenly due to ventricular tachycardia or ventricular fibrillation (the resuscitation was ineffective). The autopsy revealed GCM, SARS-CoV-2, and Parvovirus B19 were detected in the myocardium. The role of SARS-CoV-2 in the pathogenesis of autoimmune myocarditis is discussed.
Topics: COVID-19; Cardiomyopathies; Contrast Media; Death, Sudden, Cardiac; Female; Gadolinium; Genetic Diseases, Inborn; Giant Cells; Heart Atria; Heart Block; Humans; Middle Aged; SARS-CoV-2
PubMed: 34327860
DOI: 10.1002/ehf2.13520