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Results 451 - 500 of 1547
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Goswami Kewal C - - 2004
BACKGROUND: The purpose of this study was to prospectively evaluate a large group of consecutive, non-anticoagulated patients with severe rheumatic mitral stenosis and to analyze the left atrial appendage function in relation to left atrial appendage clot and spontaneous echo contrast formation. METHODS AND RESULTS: We prospectively studied left atrial ...
Sutton R - - 2004
This study investigated the ability to minimize pace polarization artefacts (PPA) by adjusting the post-stimulus pulse duration of a tri-phasic stimulation pulse. Adjustment of the stimulation pulse was enabled by downloading special study software into an already implanted pacemaker. Tests were performed in a total of 296 atrial leads and ...
Sasano Tetsuo - - 2004
INTRODUCTION: Rapid atrial pacing alters atrial electrophysiology, promoting initiation and maintenance of atrial fibrillation (AF). The aim of this study was to assess differences in the electrophysiologic properties of atrial tissue between patients with and without AF episodes and to determine whether electrophysiologic properties can predict the clinical efficacy of ...
Choi Kee-Joon - - 2004
The VDD pacemaker is useful for sequential pacing with a single lead but carries a risk of sensing failure. This study was designed to evaluate the relationship between the relative position of atrial lead and atrial sensitivity in different postures in patients with VDD pacemakers. Atrial sensitivity determination and chest ...
Betts Timothy R - - 2004
INTRODUCTION: This study was designed to record global high-density maps of left atrial endocardial activation during sinus rhythm and coronary sinus pacing. METHOD AND RESULTS: Noncontact mapping of the left atrium was performed in nine patients with paroxysmal atrial fibrillation undergoing pulmonary vein ablation procedures. High-density isopotential and isochronal activation ...
Da Costa Antoine - - 2004
Whether chronic typical atrial flutter differs from paroxysmal atrial flutter regarding electrophysiological properties of reentry pathways and cardiac function remains unknown. If so, can remodeling due to long duration of persistently rapid atrial or ventricular rates explain these changes? The aim of the study was to compare RA local conduction ...
Anderson Robert H - - 2004
Conduction across the atrioventricular junctions had long been controversial, with arguments raging as to whether such conduction was myogenic or neurogenic. The landmark study of Tawara in 1906 established the existence of an axis of histologically specialized myocardial cells contained within fibrous sheaths as being responsible for rapid conduction from ...
Boyaci Ayca - - 2004
Systemic thromboembolism is a major complication of mitral stenosis (MS), especially in those patients having atrial fibrillation (AF). Recent evidence has suggested that regional left atrial coagulation activity may be increased in MS and may contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation ...
Phang Robert S - - 2004
Usual assessment of left atrial size by 2-dimensional echocardiography in the anteroposterior dimension often underestimates the true atrial size. We compared 15 young patients (< or =50 years old) with lone paroxysmal atrial fibrillation to age-matched controls, and measured atrial size in the inferosuperior and mediolateral dimensions. These additional measurements ...
Sanders Prashanthan - - 2004
BACKGROUND: Experimental and clinical studies have demonstrated diffuse atrial remodeling in congestive heart failure (CHF). We hypothesized that patients with CHF would demonstrate derangement of sinus node function. METHODS AND RESULTS: Eighteen patients with symptomatic CHF (left ventricular ejection fraction, 26+/-5%) and 18 age-matched control subjects were studied. Under autonomic ...
Cioffi Giovanni - - 2004
BACKGROUND: Arterial hypertension determines distinct adaptive left ventricular geometric responses, which may differently affect left ventricular function and left atrial performance. OBJECTIVES: In this study, the effect of left ventricular geometry on left atrial size and function, and the relationship between left atrial size and left ventricular mass were assessed ...
Hanna Nessrine - - 2004
BACKGROUND: Congestive heart failure (CHF) causes arrhythmogenic remodeling in both atria and ventricles, but differences between atrial and ventricular remodeling in CHF have not been well characterized. METHODS AND RESULTS: We examined atrial and ventricular tissues from dogs with CHF induced by ventricular tachypacing (220-240/min) for 0 (control) or 24 ...
Passman Rod S - - 2004
INTRODUCTION: In patients with permanent pacemakers, mode switching events often are interpreted as surrogate markers for atrial tachyarrhythmias. The aim of this study was to determine the accuracy of automatic mode switching algorithms in patients with permanent pacemakers for the diagnosis of atrial tachyarrhythmias. METHODS AND RESULTS: Forty patients with ...
Marshall Audrey C - - 2004
BACKGROUND: Infants born with hypoplastic left heart syndrome and an intact or highly restrictive atrial septum face a neonatal mortality of at least 48% despite early postnatal left atrial decompression and palliative surgery. Prenatal left atrial decompression has been suggested as a means of improving these outcomes. This study reports ...
Nogami Akihiko - - 2004
A 66-year-old woman underwent mitral valve replacement and surgical isolation of the posterior part of the left atrium for persistent AF. During sinus rhythm an isolated atrial rhythm was recorded from the isolated posterior left atrium using an esophageal electrode catheter. After the intravenous administration of adenosine triphosphate sinus rhythm ...
Thomas Eapen - - 2004
Contrary to what the name implies, the left atrial appendage is increasingly becoming an organ of clinical importance. Its role in the pathogenesis of thromboembolism is now well established. Enlargement of the appendage due to haemodynamic disturbances or anatomic weakness increases this risk, along with the potential for arrhythmia. We ...
Fowler S J - - 2004
Stimulation of sensory branches of the trigeminal nerve is known to cause sudden bradycardia (trigeminocardiac reflex). However we report a case where percutaneous balloon rhizotomy of the trigeminal ganglion provoked atrial tachyarrhythmias during two separate treatments. On both occasions the patient was treated with antiarrhythmic drugs and reverted to sinus ...
Horlitz M - - 2004
Differentiation between typical and atypical atrial flutter solely based upon surface ECG pattern may be limited. However, successful ablation of atrial flutter depends on the exact identification of the responsible re-entrant circuit and its critical isthmus. Between August 2001 and June 2003, we performed conventional entrainment pacing within the cavotricuspid ...
Erdo─čan Hasan B - - 2004
Various surgical procedures have been employed to treat a greatly enlarged left atrium. We review the use of partial cardiac autotransplantation to reduce left atrial volume in 7 patients with rheumatic mitral valve disease and left atrial and ventricular volume in 2 patients with idiopathic dilated cardiomyopathy. There were 5 ...
Xu Zhen - - 2004
The ability of ultrasound to produce highly controlled tissue erosion was investigated. This study is motivated by the need to develop a noninvasive procedure to perforate the neonatal atrial septum as the first step in treatment of hypoplastic left heart syndrome. A total of 232 holes were generated in 40 ...
Hanna Ibrahim R - - 2004
OBJECTIVES: This study was designed to evaluate the effects of percutaneous left atrial appendage transcatheter occlusion (PLAATO) on the anatomic and hemodynamic properties of the mitral valve (MV) and left upper pulmonary vein (LUPV). BACKGROUND: PLAATO is a device designed to seal the neck of the left atrial (LA) appendage ...
Wong Tom - - 2004
BACKGROUND: The growing population with Fontan operation surviving into adulthood has significant morbidity and mortality rates from recurrent atrial tachyarrhythmias. We hypothesized that the structural characteristics and electrical behavior of atria may differ in these patients compared with those without arrhythmias. METHODS AND RESULTS: We studied 33 consecutive patients (age, ...
Vlahos Antonios P - - 2004
BACKGROUND: Hypoplastic left heart syndrome (HLHS) with intact or very restrictive atrial septum is a highly lethal combination. We review our 13-year institutional experience treating this high-risk subgroup of patients with emergent catheter therapy. METHODS AND RESULTS: Infants with HLHS requiring catheter septostomy within the first 2 days of life ...
Raitt Merritt H - - 2004
INTRODUCTION: In animals, atrial fibrillation results in reversible atrial electrical remodeling manifested as shortening of the atrial effective refractory period, slowing of intra-atrial conduction, and prolongation of sinus node recovery time. There is limited information on changes in these parameters after cardioversion in patients with persistent atrial fibrillation. METHODS AND ...
Popescu Bogdan A - - 2004
To evaluate the existence, timing, and determinants of post-infarction left atrial remodeling, we studied a subgroup of 514 patients from the Third Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico Echo Substudy who underwent 4 serial 2-dimensional echocardiograms up to 6 months after acute myocardial infarction. This study is ...
Joseph Jacob - - 2004
Studies from our laboratory and others indicate that, in addition to its purported atherothrombotic effects, hyperhomocysteinaemia (Hhe) is a powerful stimulus for ventricular remodelling, dysfunction and clinical heart failure. Because changes in atrial structure and function can impact on cardiac function in progressive ventricular remodelling and dysfunction, we conducted experiments ...
Daubert Jean-Claude - - 2004
Atrial conduction disorders are frequent in elderly subjects and/or those with structural heart diseases, mainly mitral valve disease, hyperthrophic cardiomyopathies, and hypertension. The resultant electrophysiological and electromechanical abnormalities are associated with a higher risk of paroxysmal or persistent atrial tachyarrhythmias, either atrial fibrillation, typical or atypical flutter or other forms ...
Poirier Nancy C - - 2004
OBJECTIVES: Systemic right ventricular failure after atrial switch procedures for transposition of the great arteries has been addressed at Melbourne's Royal Children's Hospital (1981-1993) and the Cleveland Clinic Foundation (1993-2001) with reconditioning of the morphologically left ventricle by means of pulmonary artery banding followed by an arterial switch operation and ...
Zhang Shulong - - 2004
BACKGROUND: Right atrial reentrant tachycardia resulting from lower loop reentry (LLR) around the inferior vena cava (IVC) has been described recently. However, all reported cases of LLR in the literature have negative flutter waves on the inferior surface ECG leads similar to that of counterclockwise typical atrial flutter around the ...
Sanders Prashanthan - - 2004
BACKGROUND: The normal sinus pacemaker complex is an extensive structure within the right atrium. We hypothesized that patients with sinus node disease (SND) would have evidence of diffuse atrial abnormalities. METHODS AND RESULTS: Sixteen patients with symptomatic SND and 16 age-matched controls were studied. The following were evaluated: effective refractory ...
Miyauchi Yasushi - - 2004
The influence of threshold electrical currents (EC) during regular drive on pulmonary vein (PV) and atrial myocardial cell action potential (AP) duration (APD) is unknown. We determined the effects of EC on cellular APD of PV, atria, and ventricles in isolated perfused and superfused male rat hearts (Fisher-344 strain, 3-4 ...
Sou Takenaka - - 2004
BACKGROUND: Surgical isolation of the left atrial posterior wall (LA-PW isolation) can terminate chronic atrial fibrillation associated with mitral valve disease. However, atrial contraction after LA-PW isolation has not been evaluated. METHODS AND RESULTS: The study group comprised 14 patients (mean age, 63+/-14 years) with mitral valve disease who recovered ...
García-Villareal O A - - 2004
Left atrial reduction is a surgical procedure designed in order to eliminate the chronic atrial fibrillation caused by mitral valve disease. However, this surgical technique is not high-risk free. Since a mount of tissue is excised from the left atrium, misalignment of the left atrium can be present. Bleeding of ...
van Erven Lieselot - - 2004
In patients with resynchronization devices and intact intrinsic AV conduction, atrial tachyarrhythmias may give rise to high ventricular rates, resulting in inhibition of (bi)ventricular pacing and concomitant lack of therapeutic effects of the device. This report presents a patient with atrial arrhythmias in whom mode switching and back switching of ...
Isbell David C - - 2004
Transesophageal echocardiography (TEE) is very useful in the evaluation and management of selected patients with atrial fibrillation, primarily by clear visualization of left atrial appendage thrombus. Insights gained from two-dimensional and Doppler interrogation of the appendage include recognition of the association of dense spontaneous contrast and reduced mechanical appendage function ...
Suda Kenji - - 2004
A 12-year-old boy presented with tachycardia and cardiomegaly. An electrocardiogram showed atrial flutter with a ventricular rate of 170 beats/min. The echocardiogram showed left ventricular dilation, with decreased contractility. Electromyography confirmed the diagnosis of myotonic dystrophy. The atrial flutter was converted to sinus rhythm by electroversion, leading to restoration of ...
Block Peter C - - 2004
Anticoagulation with warfarin for atrial fibrillation is frequently difficult. A transcatheter method to exclude the left atrial appendage from the circulation could be an advantage for selected patients. Percutaneous left atrial appendage transcatheter occlusion is a catheter-based delivery of an occlusive nitinol cage to the neck of the left atrial ...
Euler David E - - 2003
Therapies to treat atrial tachyarrhythmias need to be evaluated in controlled, randomized clinical trials in order to optimize patient outcomes. If the maintenance of sinus rhythm is the ultimate goal, then atrial tachyarrhythmia burden may serve as a useful endpoint. Atrial tachyarrhythmia burden is defined as the total duration of ...
Khan Ijaz A - - 2003
Conversion of atrial fibrillation and flutter to sinus rhythm results in a transient mechanical dysfunction of atrium and atrial appendage, termed atrial stunning. Atrial stunning has been reported with all modes of conversion of atrial fibrillation and flutter to sinus rhythm including both transthoracic and low energy internal electrical, pharmacological, ...
Ricci Renato - - 2003
In patients with conventional indication for ICD implantation, atrial fibrillation may occur in more than 50% during the life-span of the device and may lead to severe adverse events. Dual chamber defibrillators with atrial antitachycardia functions, including prevention algorithms, arrhythmia detection capability and atrial therapy options (antitachy pacing and cardioversion) ...
Schuchert Andreas - - 2003
Heart rate variability (HRV) measurements are usually performed from ventricular beat-to-beat intervals because of the difficulty to precisely locate the P wave fiducial point in surface ECG recordings. The aim of the study was to describe an approach to determine the atrial and ventricular HRV using pacemaker-mediated intracardiac electrograms. Twelve ...
Orem Randall C - - 2003
Chronic recurrent junctional and ectopic atrial rhythms are a challenge to manage as they are not responsive to pharmacologic therapy and will usually inhibit standard pacemakers. This report presents two patients with junctional and low atrial rhythms who were successfully managed with a recently introduced atrial overdrive suppression algorithm intended ...
Musat Iulian - - 2003
We report the occurrence of an intraoperative left atrial hematoma during coronary artery bypass grafting surgery. Echocardiography proved to be of great help in diagnosis and monitoring of this patient. After severe hemodynamic impairment the patient recovered and could be transferred on postoperative day eight. Follow-up examination showed no signs ...
Meier Bernhard - - 2003
It is assumed that over 90% of clinically apparent embolisms in atrial fibrillation originate from the left atrial appendage. Recently, a percutaneous method (PLAATO technique) to occlude the left atrial appendage to the end of preventing thromboembolic complications of atrial fibrillation has been introduced into clinical practice. This technique is ...
Maltagliati Anna - - 2003
BACKGROUND: Transesophageal echocardiography (TEE) is the method of choice for the evaluation of the left atrium and of left atrial appendage (LAA) thrombosis. However, the anatomy of the left appendage is complex and reverberations from anatomical structures may create images and ghosting which mimic left atrial thrombosis. The purpose of ...
Chandra Parag - - 2003
OBJECTIVE: Transiently altering the atrial activation sequence induces atrial memory, manifested as an altered atrial gradient as measured in electrocardiographic XYZ leads. We hypothesized that protracted periods of left atrial impulse initiation alter the atrial gradient in a manner predictive of arrhythmias. METHODS: A total of 12 chronically instrumented mongrel ...
Barold S Serge - - 2003
This report describes the occurrence of prolonged atrial escape intervals (AEI) initiated by sensing of ventricular premature complexes (VPC) without a preceding atrial depolarization or an AV delay in two patients with DDD pacemakers with an atrial-based lower rate response. The prolonged AEIs were due to ventriculoatrial cross-talk so that ...
Lee Pi-Chang - - 2003
Dual AVN physiology can be demonstrated by a variety of maneuvers. To determine whether AVN recovery times following a blocked extrastimulus facilitate or obscure detection of dual AVN physiology, 11 patients (9-17 years) were studied with dual AVN pathways by using single and double atrial extrastimuli. With a single atrial ...
Huang Chengqun - - 2003
The requirement for atrial function in developing heart is unknown. To address this question, we have generated mice deficient in atrial myosin light chain 2 (MLC2a), a major structural component of the atrial myofibrillar apparatus. Inactivation of the Mlc2a gene resulted in severely diminished atrial contraction and consequent embryonic lethality ...
Berdougo Eli E Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, - - 2003
The embryonic vertebrate heart is composed of two major chambers, a ventricle and an atrium, each of which has a characteristic size, shape and functional capacity that contributes to efficient circulation. Chamber-specific gene expression programs are likely to regulate key aspects of chamber formation. Here, we demonstrate that epigenetic factors ...
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