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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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, ...

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) ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

OBJECTIVE: To identify predictors of left atrial appendage stunning after the use of electrical cardioversion to restore sinus rhythm in patients with non-valvular atrial fibrillation. METHODS: A total of 68 consecutive patients (45 men, 23 women, 60.5 +/- 8.7 years of age) with non-valvular atrial fibrillation undergoing electrical cardioversion were ...

Monitoring of atrial rhythm in patients implanted with ICDs may improve accuracy in identifying supraventricular arrhythmias and, therefore, prevent inappropriate therapies. Since difficulties were found in dual chamber ICDs with separate leads, a new designed single lead dual chamber ICD system was tested. Twenty-five patients implanted with a Deikos A+ ...

BACKGROUND: The atrial compartment operation was designed to convert atrial fibrillation (AF) to sinus rhythm with intentional preservation of the electrical connection between adjacent atrial compartments. However, incidental left atrial isolation was observed in some patients. This study compared the long-term clinical outcomes of left atrial isolation for AF with ...

Atrial flutter is relatively uncommon, especially among athletic populations. The case of a 19-year-old college football player who spontaneously developed atrial flutter illustrates recent advances in treatment, including electrical cardioversion and radiofrequency catheter ablation. Return-to-play decisions center around the risk of recurrence and the degree of symptoms during recurrences. Clinicians ...

A 27-year-old woman with atrial bigeminy is reported in whom long PP intervals alternate with short PP intervals. All P waves are negative in lead II and all PR intervals measure 0.12 s. In the 12-lead electrocardiogram, however, these P waves were definitely different in configuration from each other, and ...

BACKGROUND: This study was conducted to evaluate the effectiveness of the saline-irrigated radiofrequency modified maze operation for the treatment of chronic atrial fibrillation (AF) and compare the results of the left and bi-atrial procedures. MATERIAL AND METHOD: During a period of two years, 105 patients with chronic AF having concomitant ...

The P wave in the surface ECG represents atrial electrical activation and may be altered in certain pathological conditions. Atrial compartment operation has been used to convert chronic AF to sinus rhythm. However, this procedure may result in changes of impulse conduction in various atrial compartments and alters the P ...

We present a safe and easy-to-apply method of securing monitoring atrial cannulae after pediatric cardiac operations. We used Silastic ligatures together with purse strings on the tip of the atrial appendages in more than 350 cases, in a 5-year period. We never reported malfunctioning during their use, and no bleeding ...

AIM: We validated transthoracic echocardiographic measurements of left atrial appendage flow velocity by comparing them with transoesophageal echocardiographic measurements. METHODS AND RESULTS: Eighty-four consecutive patients (mean age, 64.6 years) with various cardiac diseases, who underwent both transthoracic echocardiography and transoesophageal echocardiography were studied. Thirty-two patients were in sinus rhythm, and ...

This review article summarizes recent advances in the care of patients presenting with neurologic events, in which transesophageal echocardiography plays an important role in diagnosis, prognosis, and treatment. New research on the use of transesophageal echocardiography in patients with stroke and atrial fibrillation is discussed, including left atrial clot formation, ...

Atrial tachyarrhythmias play an important role in the treatment of patients with malignant ventricular tachyarrhythmias not only with respect to inappropriate discharges but also to left ventricular function and stroke risk. A combined dual chamber defibrillator provides separate therapies for atrial and ventricular tachyarrhythmias. To assess the incidence of atrial ...

OBJECTIVE: To review the diagnosis, treatment, and outcome of fetal atrial flutter compared with supraventricular tachycardia. DESIGN: Retrospective review of published reports: 11 papers about fetal tachyarrhythmia published between 1991 and 2002 were selected for review. MAIN OUTCOME MEASURES: All selected studies were analysed for the type of arrhythmia, degree ...

We report the history of a 60-year-old patient with a multiple myeloma and Staphylococcus aureus associated sepsis to whom adenosine in a dose of 6 mg was administered, when a regular, narrow QRS complex tachycardia at a heart rate of 120 beats/minute started. Adenosine led to a complete AV-block and ...

Intraatrial conduction block at the inferior vena cava-tricuspid annulus isthmus was shown to predict successful atrial flutter ablation. However, its demonstration requires the use of several electrode catheters. Thus, a simple approach using surface 12-lead ECG to prove the conduction block would be valuable. Twenty-two patients were prospectively studied during ...

Previous cardiac electrophysiologic studies of blockers of the slowly activating delayed rectifier (IKs) current have focused primarily on ventricular repolarization. This report summarizes an extensive in vivo cardiac electrophysiologic profile of four 1,4-benzodiazepine IKs blocker analogues (L-761334, L-763540, L-761710, and L-768673) in dogs. At 3.0 mg/kg intravenously, all four analogues ...

It has been appreciated for a long time that atrial flutter and atrial fibrillation have a clinical relationship. Now, with the technological advances that permit more sophisticated electrophysiological studies, especially mapping studies, we have significantly advanced our understanding of this interrelationship. Regarding the relationship at atrial fibrillation to atrial flutter: ...

We report a rare case of an inverted left atrial appendage without prior cardiac surgery. A left atrial mass was incidentally found during routine echocardiography in a 19-year-old man with mitral valve prolapse. Echocardiography revealed a hyperechoic mass in the left atrium, and a neoplastic lesion could not be excluded. ...

OBJECTIVE: To evaluate the racial differences in the efficacy and safety of ibutilide in patients with recent-onset (<2 weeks) atrial fibrillation and atrial flutter. METHODS: This study included 58 consecutive patients with recent-onset atrial fibrillation (n = 34) and atrial flutter (n = 24). The mean age was 65.7 +/- ...

BACKGROUND: There is little information about the surface expression of non-cavotricuspid isthmus (CTI)-dependent right atrial (RA) or left atrial (LA) flutter circuits. METHODS AND RESULTS: We retrospectively evaluated 32 episodes (in 26 patients) of atypical RA and 22 episodes (in 21 patients) of LA flutter. The surface ECG of 13 ...

BACKGROUND: The anatomic-electrophysiological correlation of AV nodal reentry is unclear. To localize reentrant circuits during atrial and ventricular echoes and to characterize sites of slow conduction and block, we correlated histology with electrophysiology of the AV node. METHODS AND RESULTS: In 10 isolated dog hearts, extracellular electrical activity was recorded ...

The aim of this study was to analyze the onset mechanisms of atrial tachyarrhythmias using a dedicated diagnostic system in 83 recipients of DDDR pacemakers implanted for standard clinical indications. The pulse generator was programmed in DDD mode, at 60 beats/min, and the diagnostic instrument was programmed to document atrial ...

In humans, and certain animals, the atrioventricular conduction system is capable of bidirectional conduction. Depolarization impulses, originating in the ventricle itself, may thus be conducted in a retrograde direction towards the atria. Two common causes for this phenomenon of ventriculo-atrial (retrograde) conduction are premature ventricular complexes and ventricular pacing. The ...

Immediate reinitiation of atrial tachyarrhythmia (IRAT) has been observed after cardioversion. After spontaneous restoration of sinus rhythm (SR), incidence and characteristics of IRAT have not been described. Therefore, in patients with atrial tachyarrhythmias (ATs) and bradycardia, a pacemaker with dedicated memory functions was implanted. Devices were interrogated after 1 month ...

BACKGROUND: Atrial stunning is a transient depression of atrial and atrial-appendage mechanical function after successful cardioversion of atrial fibrillation compared with its precardioversion state. METHOD: Atrial stunning associated with different methods of cardioversion of atrial fibrillation and the determinants and cellular mechanisms of atrial stunning were elaborated by thoroughly examining ...

BACKGROUND: Thromboembolism in patients with nonvalvular atrial fibrillation is secondary to emboli arising from atrial cavities, particularly left atrial appendage. Stroke Prevention Atrial Fibrillation (SPAF) III study showed washing flow, left appendage ejection fraction, natural echocontrast, and left appendage volume and morphology, as risk parameters of thromboembolism. METHODS: The authors ...

The failing ventricular myocardium is characterized by reduction of high-energy phosphates and reduced activity of the phosphotransfer enzymes creatine kinase (CK) and adenylate kinase (AK), which are responsible for transfer of high-energy phosphoryls from sites of production to sites of utilization, thereby compromising excitation-contraction coupling. In humans with chronic atrial ...

The heterogeneous process of atrial electrical remodeling (AER) in the canine rapid atrial stimulation model has been previously reported although it has been reported that a sodium channel blocker might suppress the shortening of the atrial effective refractory period (AERP), its effect on long-term electrical remodeling is unknown. In the ...