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Korean Circulation Journal Sep 2015Isolated left ventricular noncompaction (LVNC) is a rare cardiomyopathy with morphologic characteristics of two distinct myocardial layers i.e., thin compacted...
Isolated left ventricular noncompaction (LVNC) is a rare cardiomyopathy with morphologic characteristics of two distinct myocardial layers i.e., thin compacted epicardial and thick noncompacted endocardial layers. The noncompacted myocardium consists of prominent ventricular trabeculae and deep intertrabecular recesses. It can lead to arrhythmias, heart failure or systemic embolisms. Electrocardiographic patterns of patients with LVNC are various and non-specific; however, the most common findings are intraventricular conduction delay, left ventricular hypertrophy, and repolarization abnormalities. We reported the first case, to the best of our knowledge, of a 29-year-old man who had recent cerebral infarction and incidental LVNC with spontaneous left atrial standstill.
PubMed: 26413113
DOI: 10.4070/kcj.2015.45.5.432 -
Blood Coagulation & Fibrinolysis : An... Dec 2015An 85-year-old man with persistent atrial flutter (AFL) with slow ventricular rate of 44/min, causing fatigue and presyncope, was referred for urgent treatment. In spite...
An 85-year-old man with persistent atrial flutter (AFL) with slow ventricular rate of 44/min, causing fatigue and presyncope, was referred for urgent treatment. In spite of thromboembolic risk scale value 4, he had not been treated with anticoagulants because of high risk of bleeding. The decision was made to perform urgent catheter ablation to interrupt and cure AFL. Intracardiac echocardiography probe was placed in the pulmonary artery and visualized left atrial appendage free from thrombus with its proper function. Heparin was administered and AFL stopped during energy application. Intracardiac echocardiography showed immediate thrombus formation in left atrial appendage owing to complete atrial standstill and no retrograde conduction during hemodynamically effective escape nodal rhythm. This case report shows that in patients with sinus node disease effective ablation of AFL with escape rhythm without retrograde conduction to the atria may result in complete 'electrically induced' atrial standstill and immediate thrombus formation.
Topics: Aged, 80 and over; Anticoagulants; Atrial Flutter; Brugada Syndrome; Cardiac Conduction System Disease; Cardiomyopathies; Catheter Ablation; Echocardiography, Transesophageal; Fatigue; Genetic Diseases, Inborn; Heart Atria; Heart Block; Heart Ventricles; Heparin, Low-Molecular-Weight; Humans; Male; Syncope; Thrombosis; Warfarin
PubMed: 26192113
DOI: 10.1097/MBC.0000000000000340 -
Europace : European Pacing,... Feb 2016Atrial standstill is characterized by the absence of atrial activity. We report about a series of cases, in which conventional atrial pacemaker lead implantation in...
AIMS
Atrial standstill is characterized by the absence of atrial activity. We report about a series of cases, in which conventional atrial pacemaker lead implantation in patients with symptomatic sinus node disease failed due to lack of excitable right atrial tissue, thus, prompting the diagnosis of atrial standstill. We hypothesized that mapping of the atria with subsequent identification of myocardium still amenable to atrial pacing would allow dual chamber pacemaker implantation.
METHODS AND RESULTS
In four patients, atrial lead implantation failed. In these patients, spontaneous or fibrillatory electrical activity was absent but the atria could not be captured despite high stimulation voltages at conventional atrial sites. We suspected partial or complete atrial standstill and subsequently confirmed this hypothesis by conventional (n = 1) or electroanatomical mapping (n = 3). Areas of fibrotic tissue were present in all patients as identified by lack of spontaneous electrical activity and inability of local electrical capture via the mapping catheter. Surviving atrial tissue, which could be electrically captured with subsequent conduction of activity to the atrioventricular (AV) node, was present in three patients. Successful targeted atrial lead implantation at these sites was achieved in all these patients. Isolated sinus node activity without conduction to the atria was found in one patient.
CONCLUSION
Partial atrial standstill may be present and prevent atrial lead implantation in patients with sinus node disease. In these patients, recognition of partial atrial standstill and identification of surviving muscular islets with connection to the AV node by mapping studies may still allow synchronous AV sequential pacing.
Topics: Adult; Aged; Atrial Function, Left; Atrial Function, Right; Atrial Remodeling; Cardiac Pacing, Artificial; Echocardiography, Doppler; Electrocardiography, Ambulatory; Electrophysiologic Techniques, Cardiac; Equipment Design; Female; Fibrosis; Heart Atria; Humans; Male; Middle Aged; Pacemaker, Artificial; Sick Sinus Syndrome; Sinoatrial Node; Time Factors; Tissue Survival; Treatment Outcome
PubMed: 25995399
DOI: 10.1093/europace/euv098 -
Research in Cardiovascular Medicine Nov 2014Atrial standstill is a rare condition, characterized by absence of atrial electrical and mechanical activity evident in surface electrocardiography echocardiography, or...
INTRODUCTION
Atrial standstill is a rare condition, characterized by absence of atrial electrical and mechanical activity evident in surface electrocardiography echocardiography, or fluoroscopy, which is associated with unresponsiveness of atria to maximal output electrical stimulation. This condition can be present with thromboembolic complication, low cardiac output, and sometimes palpitation.
CASE PRESENTATION
Here we presented a woman with right atrial stand still and left atrial tachycardia. It was confirmed by electrocardiogram, echocardiography, and intracardiac electrogram in basal state and during maximal output electrical stimulation. We treated her by implanting pacemaker to control bradycardia, oral calcium channel blocker to control palpitation episodes, and anticoagulation.
CONCLUSIONS
Atrial standstill can be present partially that can be localized in one atrium and is associated with tachycardia in the other atrium.
PubMed: 25785252
DOI: 10.5812/cardiovascmed.25173 -
Clinical Research in Cardiology :... Jul 2015
Topics: Cardiomyopathies; Diagnosis, Differential; Electrocardiography; Genetic Diseases, Inborn; Heart Atria; Heart Block; Humans; Male; Middle Aged; Tachycardia, Atrioventricular Nodal Reentry; Vena Cava, Superior
PubMed: 25777938
DOI: 10.1007/s00392-015-0842-3 -
The Journal of Pediatrics Nov 2014An 11-year-old girl on evaluation for syncope was found to have progressive sinus node dysfunction and His-Purkinje system disease with atrial standstill. Genetic...
An 11-year-old girl on evaluation for syncope was found to have progressive sinus node dysfunction and His-Purkinje system disease with atrial standstill. Genetic analysis revealed compound heterozygous mutations of the SCN5A gene in a novel combination.
Topics: Arrhythmias, Cardiac; Cardiomyopathies; Child; Electrocardiography; Female; Genetic Diseases, Inborn; Heart Atria; Heart Block; Heart Conduction System; Heterozygote; Humans; Mutation; NAV1.5 Voltage-Gated Sodium Channel
PubMed: 25171853
DOI: 10.1016/j.jpeds.2014.07.036 -
Journal of Cardiovascular... Sep 2014Although atrial arrhythmias may have genetic causes, very few data are available on evaluation of the arrhythmic substrate in genetic atrial diseases in humans. In this...
INTRODUCTION
Although atrial arrhythmias may have genetic causes, very few data are available on evaluation of the arrhythmic substrate in genetic atrial diseases in humans. In this study, we evaluate the nature and evolution of the atrial arrhythmic substrate in a genetic atrial cardiomyopathy.
METHODS AND RESULTS
Repeated electroanatomic mapping and tomographic evaluations were used to investigate the evolving arrhythmic substrate in 5 patients with isolated arrhythmogenic atrial cardiomyopathy, caused by Natriuretic Peptide Precursor A (NPPA) gene mutation. Atrial fibrosis was assessed using late gadolinium enhancement magnetic resonance imaging (LGE-MRI). The substrate of atrial tachycardia (AT) and atrial fibrillation (AF) was biatrial dilatation with patchy areas of low voltage and atrial wall scarring (in the right atrium: 68.5% ± 6.0% and 22.2% ± 10.2%, respectively). The evolution of the arrhythmic patterns to sinus node disease with atrial standstill (AS) was associated with giant atria with extensive low voltage and atrial scarring areas (in the right atrium: 99.5% ± 0.7% and 57.5% ± 33.2%, respectively). LGE-MRI-proven biatrial fibrosis (Utah stage IV) was associated with AS. Atrial conduction was slow and heterogeneous, with lines of conduction blocks. The progressive extension and spatial distribution of the scarring/fibrosis were strictly associated with the different types of arrhythmias.
CONCLUSION
The evolution of the amount and distribution of atrial scarring/fibrosis constitutes the structural substrate for the different types of atrial arrhythmias in a pure genetic model of arrhythmogenic atrial cardiomyopathy.
Topics: Adult; Arrhythmias, Cardiac; Cicatrix; Contrast Media; Electrophysiologic Techniques, Cardiac; Female; Fibrosis; Gadolinium DTPA; Heart Atria; Humans; Magnetic Resonance Imaging; Male; Models, Genetic
PubMed: 24758425
DOI: 10.1111/jce.12440 -
Turk Kardiyoloji Dernegi Arsivi : Turk... Oct 2013Despite advances in device closure for atrial septal defect, post-closure heart failure remains a clinical problem in adult patients but is seen only rarely in children....
Despite advances in device closure for atrial septal defect, post-closure heart failure remains a clinical problem in adult patients but is seen only rarely in children. An eight-year-old boy, who had been followed by a local pediatrician with the diagnosis of diabetes mellitus and congenital heart disease, was consulted to us for cardiac re-evaluation. Electrocardiography demonstrated absent P waves, and echocardiography revealed enlargement of the right ventricle and both atria and secundum atrial septal defect. With the diagnosis of atrial standstill, secundum atrial septal defect and thiamine-responsive megaloblastic anemia, acute heart failure developed after transvenous closure of the atrial septal defect, which improved dramatically with thiamine and supportive treatment.
Topics: Anemia, Megaloblastic; Cardiomyopathies; Child; Genetic Diseases, Inborn; Heart Atria; Heart Block; Heart Failure; Heart Septal Defects, Atrial; Humans; Male; Thiamine
PubMed: 24164997
DOI: 10.5543/tkda.2013.63295 -
Frontiers in Physiology 2013Slowed myocardial conduction velocity (θ) is associated with an increased risk of re-entrant excitation, predisposing to cardiac arrhythmia. θ is determined by the ion...
Slowed myocardial conduction velocity (θ) is associated with an increased risk of re-entrant excitation, predisposing to cardiac arrhythmia. θ is determined by the ion channel and physical properties of cardiac myocytes and by their interconnections. Thus, θ is closely related to the maximum rate of action potential (AP) depolarization [(dV/dt)max], as determined by the fast Na(+) current (I Na); the axial resistance (r a) to local circuit current flow between cells; their membrane capacitances (c m); and to the geometrical relationship between successive myocytes within cardiac tissue. These determinants are altered by a wide range of pathophysiological conditions. Firstly, I Na is reduced by the impaired Na(+) channel function that arises clinically during heart failure, ischemia, tachycardia, and following treatment with class I antiarrhythmic drugs. Such reductions also arise as a consequence of mutations in SCN5A such as those occurring in Lenègre disease, Brugada syndrome (BrS), sick sinus syndrome, and atrial fibrillation (AF). Secondly, r a, may be increased due to gap junction decoupling following ischemia, ventricular hypertrophy, and heart failure, or as a result of mutations in CJA5 found in idiopathic AF and atrial standstill. Finally, either r a or c m could potentially be altered by fibrotic change through the resultant decoupling of myocyte-myocyte connections and coupling of myocytes with fibroblasts. Such changes are observed in myocardial infarction and cardiomyopathy or following mutations in MHC403 and SCN5A resulting in hypertrophic cardiomyopathy (HCM) or Lenègre disease, respectively. This review defines and quantifies the determinants of θ and summarizes experimental evidence that links changes in these determinants with reduced myocardial θ and arrhythmogenesis. It thereby identifies the diverse pathophysiological conditions in which abnormal θ may contribute to arrhythmia.
PubMed: 23825462
DOI: 10.3389/fphys.2013.00154 -
The Journal of Physiology Sep 2013Over the last two decades, an increasing number of SCN5A mutations have been described in patients with long QT syndrome type 3 (LQT3), Brugada syndrome, (progressive)... (Review)
Review
Over the last two decades, an increasing number of SCN5A mutations have been described in patients with long QT syndrome type 3 (LQT3), Brugada syndrome, (progressive) conduction disease, sick sinus syndrome, atrial standstill, atrial fibrillation, dilated cardiomyopathy, and sudden infant death syndrome (SIDS). Combined genetic, electrophysiological and molecular studies have provided insight into the dysfunction and dysregulation of the cardiac sodium channel in the setting of SCN5A mutations identified in patients with these inherited arrhythmia syndromes. However, risk stratification and patient management is hindered by the reduced penetrance and variable disease expressivity in sodium channelopathies. Furthermore, various SCN5A-related arrhythmia syndromes are known to display mixed phenotypes known as cardiac sodium channel overlap syndromes. Determinants of variable disease expressivity, including genetic background and environmental factors, are suspected but still largely unknown. Moreover, it has become increasingly clear that sodium channel function and regulation is more complicated than previously assumed, and the sodium channel may play additional, as of yet unrecognized, roles in cardiac structure and function. Development of cardiac structural abnormalities secondary to SCN5A mutations has been reported, but the clinical relevance and underlying mechanisms are unclear. Increased insight into these issues would enable a major next step in research related to cardiac sodium channel disease, ultimately enabling improved diagnosis, risk stratification and treatment strategies.
Topics: Action Potentials; Animals; Brugada Syndrome; Channelopathies; Humans; Long QT Syndrome; Mutation; NAV1.5 Voltage-Gated Sodium Channel
PubMed: 23818691
DOI: 10.1113/jphysiol.2013.256461