Isolated left ventricular noncompaction is a recently recognized age-independent cardiac genetic disorder caused by heterogeneous defects in endo-myocardial morphogenesis. Transthoracic echocardiography and cardiac magnetic resonance are the most reliable techniques to make a diagnosis of the disease, noninvasively. Arrhythmic atrial and ventricular disorders have been reported in 20-50% of these ...

Although atrial flutter (AFL) is considered a highly regular rhythm, small fluctuations in cycle length have been described. The mechanisms responsible for these interval oscillations have been investigated by recent studies in humans which have shown that cyclic variations in atrial volume and pressure following ventricular contraction may account for ...

We measured left atrial size and function from biplane MRI data in 62 adults with thalassemia major. Age-adjusted left atrial ejection fraction was depressed in 7 out of 20 subjects having T2* < 10 ms. Left atrial size, left ventricular size and cardiac output fell with cardiac iron loading, representing ...

BACKGROUND: Atrial septal defect (ASD) is a common form of congenital heart defect in adults, which affects all cardiac chambers. Atrial myocardial function in patients with ASD has not yet been clearly elucidated. The aim of this study was to investigate atrial myocardial deformation properties in patients with ASDs. METHODS: ...

Background In patients with atrial septal defect (ASD) the P-wave is prolonged as a marker of delayed atrial conduction which is associated with atrial fibrillation. The study aim was to analyse the impact of ASD closure in adults on P-wave duration and morphology by means of signal-averaged P-waves (PSA-ECG) and ...

M-mode echocardiography has been accepted as gold standard for measuring left atrial (LA) size. Electrocardiography (ECG) offers a simple, non-invasive, cost-effective and reproducible method to assess LA size and it is mostly in agreement with echocardiography though discrepancies exist. ECGs and echocardiograms were obtained in 100 consecutive patients suspected of ...

To investigate the value of radiographic esophageal imaging in facilitating transseptal catheterization in patients undergoing percutaneous balloon mitral valvuloplasty. A total of 468 patients were randomized into either the study group (n = 234), in which radiographic esophageal imaging by the oral administration of a contrast media took place, or ...

The extraction of the Atrial Activity from the Ventricular Activity in Atrial Fibrillation episodes is a must for clinical analysis. We follow the semi Blind Source Extraction S-BSE approach to solve the problem. The proposed algorithm modifies the BSE contrast function to satisfy the prior knowledge about the spectral content ...

BACKGROUND: Left atrial enlargement by echocardiography is associated with adverse cardiovascular outcomes, yet the best method for assessing left atrial size has not been established. We sought to correlate the traditional left atrial diameter (LAD) measured in the parasternal view with the recently characterized left atrial volume index (LAVI). METHODS: ...

AIMS: There is little known about segmental atrial function in patients with atrial arrhythmias. We evaluated segmental atrial contractility using colour Doppler tissue imaging (CDTI) in patients with chronic atrial fibrillation (CAF) who were successfully restored and maintained in sinus rhythm (SR). METHODS AND RESULTS: We compared the segmental atrial ...

BACKGROUND: The aim of this study was to evaluate the association between atrial fibrillation and atrial dilation and the spatial distribution pattern of connexin 40 in the atria of patients with coronary heart disease. METHODS: Twenty-six patients with coronary heart disease undergoing cardiac surgery for coronary artery bypass graft were ...

BACKGROUND AND OBJECTIVE: Hypertension alters the diastolic properties of the left ventricle and results in deterioration in the structure and function of the left atrium. We aimed to evaluate whether olmesartan medoxomil has an effect on left atrial function in hypertensive patients. METHODS: Fifty hypertensive patients and 20 controls were ...

Regional differences in electrical action potential (AP) properties can provide a substrate for atrial arrhythmias. We quantify such differences by developing detailed AP models for the left (LA) and right (RA) rabbit atrial cells in order to study the underlying electrophysiological mechanisms, as well as their impacts on vulnerable properties ...

BACKGROUND: Analysis of high gain, signal-averaged (SA) ECG is an accepted method evaluating abnormalities of atrial repolarization--the presence of late potentials (ALP)--predictive for atrial arrhythmias. Recently it has been proven that the location of atrial leads has an influence on atrial activation and modifies the risk of atrial arrhythmias. The ...

BACKGROUND: Despite the growing number of studies using Lorenz (Poincaré) plots (LPs) for the analysis of heart rate variability (HRV), a possible correlation between the underlying ECG waveforms and the RR scatter plots has never been systematically studied. We report a comprehensive investigation of distinct Lorenz plot patterns (LPPs) encountered ...

BACKGROUND: Surgery for the treatment of atrial fibrillation may be associated with early or late postoperative atrial arrhythmias. In many cases, the arrhythmias that occur early in the postoperative course may be related to pericardial inflammation or increased catecholamine levels and tend to resolve without further therapy. In contrast, late ...

Giant left atrium (GLA) is a condition defined when the left atrial diameter exceeds 65 mm. GLA is commonly associated with mitral valve regurgitation due to excess intracavitary pressure resulting in strain and dilation of the left atrial chamber. The mechanism of lone GLA remains unknown but is possibly related ...

We report the case of a 71-year-old man with two atrial tachycardias evolving simultaneously and independently in two dissociated regions after extensive ablation for chronic atrial fibrillation. One tachycardia was a focal tachycardia originating from the right inferior pulmonary vein and activating the posterior left atrium with a 2:1 conduction ...

The supraventricular arrhythmias include a wide spectrum of disorders including, in descending order of frequency, atrial fibrillation, atrial flutter, atrioventricular nodal reentry, Wolff-Parkinson-White syndrome, and atrial tachycardia. While not life-threatening in most cases, they may cause important symptoms, such as palpitations, chest discomfort, breathlessness, anxiety, and syncope, which significantly impair ...

BACKGROUND: In atrial-based pacing, appropriate therapy and reliable diagnostics depend on detection and discrimination of atrial signals. Accurate classification of atrial events is mainly confounded by oversensing of ventricular far-field R-wave signals (FFRW), but attempts to reject FFRWs by manipulating atrial sensitivity and/or postventricular atrial blanking period (PVAB) may result ...

BACKGROUND: Automatic management of atrial stimulation by verification of atrial threshold (ACM) has recently been made feasible. We investigated circadian atrial threshold variability over the long term and the predictors of successful automatic atrial threshold measurement, in order to provide practical clues for programming ACM features, in such a way ...

Atrial electrical remodeling (ER) after spontaneous or pacing-induced atrial fibrillation has been previously described in humans. We investigated atrial ER induced by a 5-minute period of rapid atrial pacing and the pharmacologic effects of verapamil and procainamide on this atrial ER phenomenon. The atrial effective refractory periods (ERPs) at drive ...

A 56 year-old woman presented with palpitations. Her ECG revealed PQ segment depression and a prolonged QTc. Echocardiogram revealed a 2 x 3 cm right atrial mass. The pathological diagnosis was benign cardiac fibroma. Clinicians should remember that subtle ECG changes may reflect unusual structural changes in the heart.

BACKGROUND: Conversion of atrial fibrillation (A-Fib) to sinus rhythm is associated with transient mechanical dysfunction of left atrium and appendage, termed atrial stunning. OBJECTIVES: The aim of the present study was to evaluate the relationship between nutritional status and atrial stunning after conversion of A-fib. METHODS: Fifty-eight hemodynamically stable patients ...

A Labrador retriever, presented for a routine yearly wellness exam, shows on ECG a normal sinus rhythm with first degree atrioventricular blockade and atrial dissociation (AD). A detailed cardiologic examination was performed including thoracic radiography, echocardiography and blood pressure measurement, all of which were considered normal. The dog described in ...

We discuss the implications of accurate knowledge of the human atrial chambers for those seeking to model atrial structure, and correlate the muscular activity with electrical signals. We stress first the importance of describing atrial components in attitudinally appropriate fashion, a feature sadly ignored by generations of morphologists. When considered ...

BACKGROUND: Surgical ablation procedures are an established surgical procedure for restoration of sinus rhythm and reestablishment of atrial function in patients with chronic atrial fibrillation. The purpose of this study was to evaluate the feasibility and reproducibility of steady-state free precession magnetic resonance imaging (SSFP MRI) for examination of atrial ...

Atrial infarction is rarely diagnosed before death because of its characteristically subtle and nonspecific electrocardiographic findings. These findings may be overshadowed by changes associated with concomitant ventricular infarction. A case of right atrial infarction accompanied by inferior myocardial infarction with rapid decompensated atrial fibrillation is reported. To increase awareness and ...

Gap junctions provide direct cytoplasmic continuity between cells forming a low resistivity barrier to electrical propagation. As such, aberrant regulation of these low resistive conduits has been blamed for electrical conduction disorders in diseased myocardium. While there is a plethora of evidence that abnormalities in gap junctional communication underlie many ...

A four-month-old baby presented with failure to thrive and congestive cardiac failure precipitated by a lower respiratory tract infection. He was found to have a large ostium secundum atrial septal defect measuring 18 mm. This was successfully closed percutaneously by a device (Blockaid). A month after the device deployment the ...

BACKGROUND: Intensive sport may induce cardiac modifications. No recent study has been performed in elite tennis players. The aim of this cross-sectional study was to analyze the cardiac characteristics in a population of professional tennis players. METHODS: During the 2004 French Open Tennis Tournament, we offered complete echocardiographic screening to ...

Recurrence of atrial fibrillation is more common in patients with atrial conduction delay. In the present study, we evaluated whether findings obtained from transesophageal echocardiography (TEE), a semi-invasive method, correlate with those from an invasive method, electrophysiologic study (EPS), in measuring interatrial conduction time. We compared two methods of calculating ...

The recent identification of a second mesodermal region as a source of cardiomyocytes has challenged the views on the formation of the heart. This second source of cardiomyocytes is localized centrally on the embryonic disc relative to the remainder of the classic cardiac crescent, a region also called the pharyngeal ...

PURPOSE: We previously developed and validated diagnostic criteria for the differentiation of atrial flutter from atrial fibrillation. In this study we examine if the criteria (F waves in the frontal plane and a partially or completely regular ventricular response) can improve the diagnostic accuracy of internists. METHODS: Two groups of ...

BACKGROUND: Atrial flutter is a common cause of exacerbation of congestive heart failure (CHF). Typically, during atrial tachycardia, pacemakers, both dual and biventricular, are programmed to ignore atrial tracking. Virtually all current pacemakers and defibrillators use a programmable mode switch algorithm to switch between atrial tracking modes (DDD, DDDR) to ...

Transesophageal echocardiography (TEE) has been proposed as a screening tool to exclude the presence of atrial thrombi and left atrial spontaneous echocontrast before cardioverting persistent atrial flutter (AFl) and atrial fibrillation (AF). However in pure AFl a very low prevalence of atrial thrombi has been observed by many investigators: a ...

Atrial fibrillation is a very common cardiovascular disease in clinical practice. One relevant issue to understand its pathophysiological mechanisms is the analysis and interpretation of atrial electrograms (AEG). To study these signals properly, ventricular activity has to be removed from the AEG. In this work, a new application of independent ...

Infarction of the cardiac atria occurs more frequently than is commonly considered. Ischemic damage to the atrial myocardium is usually associated with infarction of cardiac ventricles, but isolated infarction of an atrium can occur and may be of clinical significance. We present an unusual case of an isolated right atrial ...

OBJECTIVES: We tested our hypothesis that, in atrial flutter (AFL) dependent on the cavotricuspid isthmus (CTI), lower loop reentry is the common pathway route at the coronary sinus posterior site, and thus, dual loop reentry is a common circular pattern. METHODS AND RESULTS: We studied 25 patients with CTI-dependent AFL, ...

A nine-year-old boy presented with progressively-increasing exertional dyspnoea for the last three months. The only significant finding in the general survey was polydactyly. His vital signs were normal. He had a prominent apical diastolic thrill, a prominent S1 with a low-pitched grade 4/6 mid diastolic rumbling murmur over the apex. ...

Terbutaline is used to treat fetal bradycardia in the setting of complete heart block (CHB); however, little is known of its effects on atrial and ventricular beat rates or patterns of heart rate (HR) acceleration. Fetal atrial and ventricular beat rates were compared before and after transplacental terbutaline treatment (10 ...

INTRODUCTION: Atrial fibrillation and atrial flutter often coexist. The long-term occurrence of atrial fibrillation in patients presenting with atrial flutter alone is unknown. We report the long-term follow-up in patients who underwent cavotricuspid isthmus ablation for treatment of lone atrial flutter. METHODS AND RESULTS: Between January 1997 and June 2002, ...

PURPOSE: To document the frequency and variations in number and anatomical shape of accessory appendages of the left atrium as seen on 64-slice cardiac CT. METHODS AND MATERIALS: Retrospective review of the anatomy of the left atrium as depicted by cardiac CT using the acquisition protocol designed for coronary CT ...

BACKGROUND: The Frank-Starling law describes the relation between left ventricular volume and function. However, only a few studies have described the relation between left atrial volume (LAV) and function. OBJECTIVE: To describe an LA Frank-Starling law by studying changes in LAV measured by real-time, three-dimensional echocardiography (RT3DE). METHODS: LAV was ...

The mesenchymal tissues involved in cardiac septation are derived from different sources. In addition to endocardial-derived mesenchyme, the heart also receives contributions from the neural crest, the proepicardium, and the dorsal mesenchymal protrusion (DMP). Whereas the contributions of the neural crest and proepicardium have been thoroughly studied, the DMP has ...

BACKGROUND: The use of DDIR mode has been limited since the advent of mode switch in the DDDR mode. In patients with AV block, DDDR is necessary to maintain AV synchrony. However, DDIR mode may still be beneficial for patients with intact AV conduction. The aim of this study was ...

Hemodynamics influence cardiac development, and alterations in blood flow may lead to impaired cardiac growth and malformations. The developing myocardium adapts to augmented workload by increasing cell number (hyperplasia). The aim of this study was to determine the influence of alterations in ventricular preload on fetal myocyte proliferation by manipulation ...

BACKGROUND: The three-dimensional contributions to human atrial activation in sinus rhythm have not been specifically characterized. We evaluated the sequence of endocardial and epicardial activation and voltage of the atria during normal sinus rhythm. METHODS AND RESULTS: The study group includes 35 patients with history of symptomatic atrial fibrillation. Prior ...

The cardiac electrophysiologic effects of ISQ-1, an isoquinolinone I(Kur) blocker, were characterized in vivo. In rat, ISQ-1 elicited maximal 33% to 36% increases in atrial and ventricular refractoriness at a plasma concentration of 11.5 microM. In African green monkey, ISQ-1 increased atrial refractory period (maximal 17% at plasma concentration up ...

BACKGROUND: Cigarette smoking (CS) promotes endothelial dysfunction and atherosclerosis in the vascular bed. The impact of smoking on atrial myocardium is not defined in humans. OBJECTIVE: To determine the effect of CS on the development of interstitial fibrosis in atrial myocardium. DESIGN: Case-control study. PATIENTS: 95 patients (46 smokers and ...