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SAGE Open Medical Case Reports 2019Atrial standstill is a rare arrhythmia defined by the absence of mechanical and electrical activity in the atria. Few cases of atrial standstill have been described in...
Atrial standstill is a rare arrhythmia defined by the absence of mechanical and electrical activity in the atria. Few cases of atrial standstill have been described in children, none of which have presented with cerebral infarction confirmed by imaging. We report a unique case of a 7-year-old girl presenting with expressive aphasia, central facial palsy and irregular pulse with cerebral infarction secondary to atrial standstill. This case illustrates that cardiogenic cerebral embolism in children can be caused by rare conditions like atrial standstill and should be considered in paediatric patients undergoing evaluation for stroke. There are no established treatment guidelines for atrial standstill. We recommend that treatment be directed towards any potential underlying cause. All patients with atrial standstill should receive long-term oral anticoagulation treatment and a permanent cardiac pacemaker implant to reduce the risk of further strokes or other cardiac events.
PubMed: 30783526
DOI: 10.1177/2050313X19827735 -
Journal of Veterinary Cardiology : the... Apr 2019Pacemaker implantation is considered as a standard procedure for treatment of symptomatic bradycardia in both dogs and cats. Advanced second-degree and third-degree... (Review)
Review
Pacemaker implantation is considered as a standard procedure for treatment of symptomatic bradycardia in both dogs and cats. Advanced second-degree and third-degree atrioventricular blocks, sick sinus syndrome, persistent atrial standstill, and vasovagal syncope are the most common rhythm disturbances that require pacing to either alleviate clinical signs or prolong survival. Most pacemakers are implanted transvenously, using endocardial leads, but rarely epicardial leads may be necessary. To decide whether a patient is a candidate for pacing, as well as which pacing modality should be used, the clinician must have a clear understanding of the etiology, the pathophysiology, and the natural history of the most common bradyarrhythmias, as well as what result can be achieved by pacing patients with different rhythm disturbances. The goal of this review was, therefore, to describe the indications for pacing by evaluating the available evidence in both human and veterinary medicine. We described the etiology of bradyarrhythmias, clinical signs and electrocardiographic abnormalities, and the choice of pacing modality, taking into account how different choices may have different physiological consequences to selected patients. It is expected that this review will assist veterinarians in recognizing arrhythmias that may require permanent pacing and the risk-benefit of each pacing modality and its impact on outcome.
Topics: Animals; Bradycardia; Cardiac Pacing, Artificial; Cat Diseases; Cats; Dog Diseases; Dogs; Pacemaker, Artificial
PubMed: 30709617
DOI: 10.1016/j.jvc.2018.12.003 -
International Heart Journal Jan 2019Emery-Dreifuss muscular dystrophy (EDMD) is a group of hereditary muscular dystrophy syndrome caused by deficiency of genes encoding nuclear envelope proteins. Patients... (Review)
Review
Emery-Dreifuss muscular dystrophy (EDMD) is a group of hereditary muscular dystrophy syndrome caused by deficiency of genes encoding nuclear envelope proteins. Patients having EDMD show the triad of muscle dystrophy, joint contracture, and cardiac disease. In almost all patients, cardiac involvement is prevalent and is the most severe aspect of EDMD. Cardiac disease is predominantly shown by conduction defects, atrial fibrillation/flutter, and atrial standstill. Sudden death and heart failure because of left ventricular dysfunction are important causes of mortality, particularly in those patients that have the LMNA mutation. Medical treatment of EDMD is limited to addressing symptoms and ambulation support; moreover, pacemaker implantation is necessary when there are severe conduction defects and bradycardia occurs. Note that automated defibrillation devices may be considered for those patients who have a high risk of sudden death, rate, or rhythm control. Also, anticoagulation should be initiated in those patients who have atrial fibrillation/flutter. Thus, for optimal management, a multidisciplinary approach is required.
Topics: Abnormalities, Multiple; Anticoagulants; Atrial Fibrillation; Cardiomyopathies; Cleft Palate; Contracture; Death, Sudden; Female; Genetic Diseases, Inborn; Heart Atria; Heart Block; Heart Diseases; Humans; Hydrocephalus; Interdisciplinary Communication; Limb Deformities, Congenital; Male; Muscular Dystrophies; Muscular Dystrophy, Emery-Dreifuss; Pacemaker, Artificial; Ventricular Dysfunction, Left
PubMed: 30518714
DOI: 10.1536/ihj.17-604 -
Journal of Cardiology Cases May 2018The long-term effects of enzyme replacement therapy (ERT) on cardiac function and the conduction system in Fabry disease are not clearly understood. We report a case of...
The long-term effects of enzyme replacement therapy (ERT) on cardiac function and the conduction system in Fabry disease are not clearly understood. We report a case of a 48-year-old man with non-classical Fabry disease treated with ERT for 11 years. He was diagnosed with Fabry disease at age 27 years based on the presence of decreased alpha-galactosidase A activity in the peripheral leukocytes and of the causal alpha-galactosidase A mutation (Val339Gln). Subsequently, peritoneal dialysis was initiated for renal failure at age 35 years. ERT was initiated at age 39 years to halt the progression of cardiac dysfunction. Electrical conduction disturbances progressed gradually to complete atrioventricular block with atrial standstill during 9 years of ERT despite the lack of progression of ventricular hypertrophy. Although he underwent permanent pacemaker implantation to prevent sudden cardiac death, the atrioventricular junctional rhythm remained, thereby lowering the ventricular pacing rate. Based on this case, we recognize that the effects of ERT are limited for inhibiting the progression of Fabry disease and especially for inhibiting arrhythmia and conduction disturbances. Early diagnosis of Fabry disease and early initiation of ERT might be the key to further improvements in this disease and its associated conditions. < We encountered a patient with Fabry disease treated with long-term enzyme replacement therapy (ERT) in whom conduction disturbances progressed without progression of left ventricular hypertrophy. This case suggests that ERT is limited for inhibiting the progression of Fabry disease and especially of arrhythmia and conduction disturbances. Early diagnosis of Fabry disease and initiation of ERT may be important for providing further improvements of this condition.>.
PubMed: 30279886
DOI: 10.1016/j.jccase.2018.01.004 -
Nucleus (Austin, Tex.) 2018Lamin A/C gene mutations can be associated with cardiac diseases, usually referred to as 'cardiolaminopathies' characterized by arrhythmic disorders and/or left... (Review)
Review
Lamin A/C gene mutations can be associated with cardiac diseases, usually referred to as 'cardiolaminopathies' characterized by arrhythmic disorders and/or left ventricular or biventricular dysfunction up to an overt picture of heart failure. The phenotypic cardiac manifestations of laminopathies are frequently mixed in complex clinical patterns and specifically may include bradyarrhythmias (sinus node disease or atrioventricular blocks), atrial arrhythmias (atrial fibrillation, atrial flutter, atrial standstill), ventricular tachyarrhythmias and heart failure of variable degrees of severity. Family history, physical examination, laboratory findings (specifically serum creatine phosphokinase values) and ECG findings are often important 'red flags' in diagnosing a 'cardiolaminopathy'. Sudden arrhythmic death, thromboembolic events or stroke and severe heart failure requiring heart transplantation are the most dramatic complications of the evolution of cardiolaminopathies and appropriate risk stratification is clinically needed combined with clinical follow-up. Treatment with cardiac electrical implantable devices is indicated in case of bradyarrhythmias (implant of a device with pacemaker functions), risk of life-threatening ventricular tachyarrhythmias (implant of an ICD) or in case of heart failure with wide QRS interval (implant of a device for cardiac resynchronization). New technologies introduced in the last 5 years can help physicians to reduce device-related complications, thanks to the extension of device longevity and availability of leadless pacemakers or defibrillators, to be implanted in appropriately selected patients. An improved knowledge of the complex pathophysiological pathways involved in cardiolaminopathies and in the determinants of their progression to more severe forms will help to improve clinical management and to better target pharmacological and non-pharmacological treatments.
Topics: Arrhythmias, Cardiac; Clinical Decision-Making; Heart Diseases; Humans; Lamin Type A; Musculoskeletal Diseases
PubMed: 30130999
DOI: 10.1080/19491034.2018.1506680 -
HeartRhythm Case Reports Aug 2018
PubMed: 30116708
DOI: 10.1016/j.hrcr.2018.04.015 -
HeartRhythm Case Reports Nov 2017
PubMed: 29387541
DOI: 10.1016/j.hrcr.2017.07.014 -
Journal of the American Heart... Oct 2017There is increasing interest in the concept of atrial cardiomyopathy, but the underlying molecular and mechanistic determinants remain poorly defined. We identified a...
Dysfunction of Myosin Light-Chain 4 (MYL4) Leads to Heritable Atrial Cardiomyopathy With Electrical, Contractile, and Structural Components: Evidence From Genetically-Engineered Rats.
BACKGROUND
There is increasing interest in the concept of atrial cardiomyopathy, but the underlying molecular and mechanistic determinants remain poorly defined. We identified a family with heritable atrial cardiomyopathy manifesting as progressive atrial-selective electromechanical dysfunction, tachyarrhythmias, and bradyarrhythmias requiring pacemaker implantation. Myosin light-chain 4 (), encoding the atrial-selective essential myosin light chain, was identified as a candidate gene. We used genetically modified rat models to investigate the role of in atrial cardiomyopathy.
METHODS AND RESULTS
Exome sequencing and systematic bioinformatic analyses identified a rare missense variant of (c.31G>A []) in a large multiplex atrial cardiomyopathy family pedigree. The mutation cosegregated with atrial standstill (selected as the principal presenting trait) with a logarithm of the odds score of 5.3. The phenotype of rats with mutation knock-in confirmed the causative role of the mutation. knockout rats showed a similar atrial cardiomyopathy phenotype, whereas rats with an adjacent 4-amino-acid deletion showed no phenotype. Both knock-in rats and knockout rats showed progressive atrial electrophysiological, contractile, and fibrotic abnormalities, similar to affected patients. Biochemical analyses of mutation rats showed activation of proapoptotic and profibrotic signaling, along with increased atrial-cardiomyocyte terminal deoxynucleotidyl transferase dUTP nick end labeling staining, suggesting enhanced apoptotic cell death, findings that were mimicked by in vitro adenoviral transfer of the mutant gene to neonatal-rat cardiomyocytes.
CONCLUSIONS
Loss-of-function gene variants cause progressive atrial cardiomyopathy in humans and rats. Our findings identify as a key gene required for atrial contractile, electrical and structural integrity. These results improve our understanding of the molecular basis of atrial cardiomyopathy and introduce new models for further mechanistic analysis.
Topics: Action Potentials; Adult; Animals; Apoptosis; Arrhythmias, Cardiac; Atrial Remodeling; Cardiomyopathies; Disease Models, Animal; Female; Fibrosis; Genetic Predisposition to Disease; Heart Atria; Heart Conduction System; Heart Rate; Heredity; Humans; Male; Mutation, Missense; Myocardial Contraction; Myocytes, Cardiac; Myosin Light Chains; Phenotype; Rats, Transgenic; Signal Transduction; Young Adult
PubMed: 29080865
DOI: 10.1161/JAHA.117.007030 -
Internal Medicine (Tokyo, Japan) 2017Objective Supraventricular arrhythmias are commonly detected in patients with anti-mitochondrial antibody M2 (AMA-M2)-associated myopathy. However, the prevalence of...
Objective Supraventricular arrhythmias are commonly detected in patients with anti-mitochondrial antibody M2 (AMA-M2)-associated myopathy. However, the prevalence of supraventricular arrhythmias in unselected AMA-M2-positive patients and the impact of AMA-M2 on supraventricular arrhythmias have yet to be fully investigated. Methods We analyzed 384 patients (116 men; age, 60 [48-69] years), who underwent AMA-M2 testing following the detection of elevated hepatobiliary enzymes. Supraventricular arrhythmias involving atrial fibrillation, atrial flutter, atrial tachycardia, sick sinus syndrome, and atrial standstill were confirmed by a 12-lead electrocardiogram, 24-hour ambulatory monitoring, and physician-assigned diagnoses within the three years before and two years after the AMA-M2 test. Results Seventy-seven (20%) patients were positive for AMA-M2. The prevalence of supraventricular arrhythmias among AMA-M2-positive patients was higher than that among AMA-M2-negative patients (14% vs. 6%, p=0.008). A univariate analysis showed that supraventricular arrhythmias were associated with AMA-M2 positivity, aging, congestive heart failure, and the CHADS score. The multivariate analysis determined that AMA-M2 positivity was an independent risk factor for supraventricular arrhythmias (odds ratio 3.52, p=0.011). Among the AMA-M2-positive patients, the AMA-M2 titer did not differ to a statistically significant extent, regardless of the presence or absence of supraventricular arrhythmias. Multiple supraventricular arrhythmias with extremely low atrial deflections was a characteristic finding in AMA-M2-positive patients with supraventricular arrhythmias. Conclusion AMA-M2 enhances the risk of supraventricular arrhythmias, indicating the possible involvement of the atrial myocardium and the formation of an arrhythmogenic substrate. The results highlight the need for clinical attention to supraventricular arrhythmias in AMA-M2-positive patients.
Topics: Aged; Antibodies; Atrial Fibrillation; Atrial Flutter; Electrocardiography; Enzymes; Humans; Male; Middle Aged; Mitochondria; Multivariate Analysis; Prevalence; Risk Factors; Tachycardia, Supraventricular
PubMed: 28717071
DOI: 10.2169/internalmedicine.56.8183 -
Journal of the American College of... Jul 2017Inherited cardiac conduction disease is a rare bradyarrhythmia associated with mutations in various genes that affect action potential propagation. It is often...
BACKGROUND
Inherited cardiac conduction disease is a rare bradyarrhythmia associated with mutations in various genes that affect action potential propagation. It is often characterized by isolated conduction disturbance of the His-Purkinje system, but it is rarely described as a syndromic form.
OBJECTIVES
The authors sought to identify the genetic defect in families with a novel bradyarrhythmia syndrome associated with bone malformation.
METHODS
The authors genetically screened 15 European cases with genotype-negative de novo atrioventricular (AV) block and their parents by trio whole-exome sequencing, plus 31 Japanese cases with genotype-negative familial AV block or sick sinus syndrome by targeted exon sequencing of 457 susceptibility genes. Functional consequences of the mutation were evaluated using an in vitro cell expression system and in vivo knockout mice.
RESULTS
The authors identified a connexin-45 (Cx45) mutation (p.R75H) in 2 unrelated families (a de novo French case and a 3-generation Japanese family) who presented with progressive AV block, which resulted in atrial standstill without ventricular conduction abnormalities. Affected individuals shared a common extracardiac phenotype: a brachyfacial pattern, finger deformity, and dental dysplasia. Mutant Cx45 expressed in Neuro-2a cells showed normal hemichannel assembly and plaque formation. However, Lucifer yellow dye transfer and gap junction conductance between cell pairs were severely impaired, which suggested that mutant Cx45 impedes gap junction communication in a dominant-negative manner. Tamoxifen-induced, cardiac-specific Cx45 knockout mice showed sinus node dysfunction and atrial arrhythmia, recapitulating the intra-atrial disturbance.
CONCLUSIONS
Altogether, the authors showed that Cx45 mutant p.R75H is responsible for a novel disease entity of progressive atrial conduction system defects associated with craniofacial and dentodigital malformation.
Topics: Adolescent; Adult; Animals; Atrioventricular Block; Child; Child, Preschool; Connexins; DNA; DNA Mutational Analysis; Dentofacial Deformities; Disease Models, Animal; Disease Progression; Electrocardiography; Female; Humans; Male; Mice; Mice, Transgenic; Middle Aged; Mutation; Pedigree; Phenotype; Young Adult
PubMed: 28705318
DOI: 10.1016/j.jacc.2017.05.039