The effects of intravenous flecainide and propafenone (2 mg/kg) administered in random order were compared in 16 patients with Wolff-Parkinson-White syndrome. Both agents prolonged significantly the anterograde refractory period of the pathway and caused complete anterograde block in the pathway in 5 patients. Atrial fibrillation was not inducible in 7 ...

Atrial overdrive pacing has been successfully used to terminate atrial flutter. This study compared the efficacy of atrial extrastimuli following a rapid pacing train to overdrive pacing without atrial extrastimuli for the termination of atrial flutter. Patients were randomized to treatments of short or long burst atrial overdrive pacing or ...

We performed a correlative electrophysiological and immunohistochemical study of embryonic chicken hearts during the septational period (Hamburger and Hamilton stages 13-31 [2-7 days of incubation]). The analyses yield conclusive evidence for slow conduction, up to 7 days of development, in the outflow tract, in the atrioventricular canal, and in the ...

OBJECTIVES: This study was designed to localize and characterize the atrial flutter reentrant circuit and the electrophysiologic effects of right atrial crush injury in a new canine model. BACKGROUND: In previous studies sustained atrial flutter was induced in the canine heart by rapid atrial pacing after a linear crush injury ...

BACKGROUND: In the management of hearts with deranged laterality, it is essential that the left and right atrial chambers are correctly identified. There are two major approaches, which are based on venous connections or on the morphology of the atrial appendages, and there is no consensus as to which is ...

This report deals with a patient reflecting atrial parasystole and episodes of atrial tachycardia. The P' waves during tachycardia were identical to the parasystolic P' waves. Atrial parasystole was at times regular, as revealed by a precise mathematical relationship between the interectopic intervals, and on other occasions irregular. Irregularity was ...

The atrial arrhythmia profile during inferior wall acute myocardial infarction (AMI) has not been systematically examined with respect to right ventricular (RV) involvement. To this end, 62 consecutive patients with first inferior wall AMI and no other conditions known to increase susceptibility for rhythm disturbances were studied by 24-hour Holter ...

The purpose of this study was to test the assumption that the cause for postoperative atrial flutter/fibrillation after cardiopulmonary bypass is inadequate atrial myocardial protection. Dogs were subjected to cardioplegic arrest for 60 minutes without augmented atrial hypothermia (seven dogs, control group) or augmented atrial hypothermia with topical atrial cooling ...

OBJECTIVE: To review data on the type, mechanism, and prevalence of the proarrhythmic effect of drugs used to treat atrial fibrillation or flutter. DATA SOURCES: English-language literature from the early 1960s to the present was identified by manual search of the literature; relevant articles were reviewed. Pertinent earlier studies were ...

In 20 patients with recurrent episodes of lone paroxysmal atrial fibrillation we assessed the onset pattern of each episode of either atrial fibrillation or of atrial flutter during a 24-h Holter monitoring. We evaluated 24 twenty-four-hour Holter tape recordings and our data are related to 168 episodes of paroxysmal atrial ...

Left atrial plication (LAP) following Kawazoe's method was performed on eight patients with mitral valve stenosis associated with a giant left atrium. To investigate the effect of LAP particularly on left ventricular function, the preoperative and postoperative left ventricular function in these patients were compared. The data were also compared ...

Blade atrial septostomy has been applied in 3 patients with transposition of the great arteries under two-dimensional echocardiography instead of fluoroscopy. The blade at the tip of the catheter was seen on an echo screen when it was in the left atrium. The blade was then extended and pulled slowly ...

The technique used for transplant recipient cardiectomy can be modified to improve exposure of the mitral valve in patients with difficult anatomy. Right atrial and septal incisions are joined at the superior end of the interatrial septum and extended across the dome of the left atrium to the base of ...

We studied atrial arrhythmias during the first 12 h of admission to the hospital in 266 consecutive patients with acute myocardial infarction who subsequently underwent coronary angiography. Ten patients developed atrial fibrillation, one atrial flutter, and one supraventricular tachycardia. Another five developed sinus dysrhythmias. All of the above patients had ...

Atrial flutter occurring after cardiac operations normally responds well to atrial overdrive pacing through epicardial atrial pacing wires and medication. When this fails, transvenous atrial overpacing offers an attractive alternative. We performed the procedure 29 times in 25 patients. Sinus rhythm returned acutely after 25 procedures in 21 patients and ...

Electrophysiological examination in a 39-year-old male disclosed an accessory pathway between the right atrium and the right ventricle and AV nodal dual pathways. Atrial and ventricular extrastimuli induced paroxysmal supraventricular tachycardia (PSVT), which was shown to be AV reciprocating tachycardia. Double atrial response was noted during ventricular extrastimuli at V1V2 ...

Transesophageal (TEE) and transthoracic (TTE) echocardiograms were performed in 110 patients with rheumatic heart disease to evaluate the usefulness of these methods for the detection of left atrial thrombi. TEE was better than TTE for detecting left atrial thrombi (21 vs 9). The thrombi not detected by TTE were in ...

Dofetilide (UK-68,798) is a new class III antiarrhythmic agent. In animal experiments it selectively prolongs the refractory periods parallel to the action potential duration without any influence on upstroke velocity or conduction parameters. The present double-blind, placebo-controlled study was designed to show the effect of dofetilide on basic electrophysiologic parameters ...

In a prospective study, atrial morphology was evaluated by both transoesophageal and precordial echocardiography in 86 unoperated children with congenital heart disease (age range = 0.2 to 14.8 years, mean = 3.8 years) to determine what advantages, if any, might be inherent in the transoesophageal approach. The information derived from ...

Eight cases of fetal arrhythmia were seen over a 3-year period. Two had atrial and/or ventricular extrasystoles, 1 had complete atrioventricular block and 5 had tachyarrhythmias--3 supraventricular tachycardia, 1 atrial flutter and 1 ectopic atrial tachycardia. All had structurally normal hearts. Nonimmune hydrops fetalis was the initial presentation in 3 ...

The effects of PAF and its antagonist BN 52021 were studied on the transmembrane action potential (AP) in atrial and ventricular papillary muscles of guinea-pig. PAF (10(-11)-10(-7) M) did not modify the resting membrane potential (RP) nor the maximum rate of depolarization (Vmax) either in atrial or in ventricular fibres. ...

Mechanisms which may lead to cardiac arrhythmias were studied in atrial and ventricular tissues from human hearts. In human atrial fibers, diastolic depolarization (DD) was consistently present, but did not induce spontaneous discharge. Epinephrine enhanced DD, could induce delayed afterdepolarizations (DADs) and (in combination with strophanthidin) trigger repetitive activity. The ...

Fetal and early neonatal atrial measurements correlating with plasma atrial natriuretic peptide were studied to evaluate the circulatory change before and after delivery in a longitudinal study of 10 normal fetuses from 1 week before until 5 days after delivery. Before delivery, right atrial area value was significantly larger than ...

Autopsy specimens from 14 patients who had undergone a modified Fontan operation were evaluated to correlate the extent of histopathologic disruption of the sinus node with electrocardiographic findings of sinus node dysfunction. Patients with sinus node dysfunction (n=7) and those without (n=7) were similar in age, complexity of cardiac malformation, ...

A transvenous atrioventricular pacemaker was implanted in a patient in whom junctional bradycardia and recurrent ventricular tachycardia had occurred after coronary artery bypass surgery. The period between delivery of the atrial stimulus and resultant atrial excitation was prolonged by up to 0.22 seconds and exceeded the programmed delay between atrial ...

The study was aimed at investigating the effect of atrial dilatation on the genesis of supraventricular tachyarrhythmias following myocardial reperfusion. Experiments were carried out in 26 mongrel dogs under pentobarbital narcosis with artificial ventilation. Electrophysiological study was performed for studying the arrhythmic condition of the heart. Investigations were carried out: ...

The effects of intravenous diltiazem on supraventricular tachyarrhythmias were studied in 16 patients : 6 with paroxysmal supraventricular tachycardia using an accessory pathway retrogradely, 6 with atrial fibrillation, 3 with atrial flutter and 1 with chronic atrial tachycardia. Diltiazem (0.1 or 0.2 mg/kg) was administered intravenously over 5 minutes. Termination ...

Fourteen patients with pulmonary vascular disease, either primary pulmonary hypertension or the result of cardiac defects, underwent balloon atrial septostomy (BAS) over the period of July 1981 to June 1988 because of symptoms of syncope, fatigue, right heart failure, and cardiac arrest. Ages ranged from 4 mo to 50 yr. ...

From 1965 to 1980, 249 consecutive patients underwent a Mustard procedure for simple transposition of the great arteries. Hospital mortality was 23 of 249 (9.2%); follow-up for 24 years (mean, 11.7 +/- 6.1 yr) revealed 50 of 249 (20%) late deaths, of which seven were noncardiac, six were in the ...

Narrow complex tachycardias are a common clinical problem and can be divided into those in which the arrhythmic circuit is located exclusively in the atrium (pharmacologic treatment is oriented toward altering atrial electrophysiologic properties) and those that involve the AV node or an accessory pathway (pharmacologic therapy is directed toward ...

The acute electrophysiological effects of the antiarrhythmic drugs aprindine and verapamil, injected intravenously either alone or in combination, were studied in 14 dogs during invasive electrophysiology. The AH and HV intervals during sinus rhythm were significantly prolonged, especially in the aprindine and the aprindine plus verapamil groups. The cycle lengths ...

A nine-year-old girl had an episode of atrial flutter and a nonsustained wide QRS tachycardia during her initial hospitalization after orthotopic heart transplantation. Evaluation of her ECG and telemetric tracing revealed atrial flutter of the recipient atrium and sinus rhythm of the donor atrium. The wide QRS tachycardia was an ...

The abnormal sequence of A-V contraction produces alteration of right and left heart hemodynamics reflecting the inappropriate timing of atrial contraction to ventricular filling. Some symptomatic patients may require A-V sequential pacing to improve cardiac output. The clinical effects of the atrial contribution to left ventricular function can be demonstrated ...

We used fetal echocardiography to measure the sizes of the foramen ovale and atrial septum in 80 human fetuses from 17.5 to 38 weeks gestation. Forty-six fetuses had normal cardiac anatomy, 19 had left heart obstructive lesions, and 15 had right heart obstructive lesions. Pulsed and color flow Doppler studies ...

Clinical and experimental data show that type I atrial flutter is due to a reentry mechanism with an excitable gap. To define the location of the reentry circuit of atrial flutter, width of excitable gap, poststimulation cycle and pattern of reset after premature stimulus were analyzed in 18 patients during ...

A patient with long QT syndrome was treated with beta blockers and had a permanent DDD pacemaker implanted. The lower rate was set to 85 beats/min because this provided the best shortening of QT interval at the lowest paced heart rate. The atrioventricular (AV) delay was programmed to 250 msec ...

Atrial fibrillation and atrial flutter are the most frequent arrhythmias encountered by the cardiologists in an everyday practice. External cardioversion, atrial temporary pacing and/or drugs are commonly and often successfully used in their treatment. The failures of these methods are rare, and for the patients who remain prone to arrhythmias ...

Transesophageal echocardiography with color flow Doppler studies was performed on 10 consecutive patients who had right atrial masses identified by transthoracic echocardiography. In one patient with right atrial myxoma, transesophageal study identified the tumor by its attachment to the atrial septum and ruled out the transthoracic finding of possible additional ...

Atrial infarction is found in approximately 17 percent of autopsy-proven cases of myocardial infarction, but is a frequently missed clinical diagnosis. The antemortem diagnosis of atrial infarction occurring in the absence of ventricular infarction has not been previously reported. We present a patient with ischemic chest discomfort associated with paroxysmal ...

It has been reported that isolated rat heart myocytes and cardiac mesenchymal cells convert arachidonic acid mainly into three types of prostaglandins (PGs): PGE2, PGF2 alpha, and PGI2. In addition, we have demonstrated that fresh atrial slices of patients with heart-valve disease contain appreciable quantities of PGE2 and PGF2 alpha. ...

VDD stimulation using a single catheter for atrial sensing and ventricular sensing and pacing has become a reality. In order to compare the quality of the cavitary atrial electrogram (AEG) and to determine the intraatrial P wave direction and conduction time (CT), we compared, in an acute study, three different ...

Sixteen patients presenting on 21 occasions with atrial flutter in association with complex congenital heart disease were treated by intracardiac stimulation techniques combined with activation mapping. Nineteen episodes of atrial flutter were successfully converted to sinus rhythm. In the remaining two episodes atrial fibrillation was induced with spontaneous conversion to ...

Discrete cryosurgical modification of atrioventricular conduction abolishes refractory atrioventricular node reentry tachycardia with preservation of antegrade atrioventricular nodal conduction. This procedure presently requires cardiopulmonary bypass. To modify atrioventricular conduction without cardiac surgery, we evaluated the electrophysiologic effects of cryolesions applied to the peri-nodal area in the closed heart in 16 ...

It has long been known that ventricular epicardial action potential duration (APD) is shorter than endocardial, and recent evidence suggests that a larger transient outward current (Ito) in epicardium is responsible for the difference. To evaluate possible corresponding regional variations in atrial tissue, we studied guinea pig atrial epicardial and ...

The goal of the present investigation was to compare quantitatively the distribution of T-tubules between regions of the myocardium. The volume fraction and surface density of T-tubules in rabbit right atrial free wall, left atrial free wall, right ventricular free wall, left ventricular free wall, right ventricular papillary muscle, and ...

Isolated myocardial infarction of the atria is a relatively understudied and underestimated entity, rarely diagnosed in life. The pathological and clinical features in 10 cases of acute isolated atrial myocardial infarction are reported. They represent 3.5% of all myocardial necrosis out of a series of 2,704 consecutive autopsies in adults. ...

We studied left atrial compliance and left atrial volume in 21 patients with mitral stenosis showing a normal sinus rhythm. 1) A significant (p less than 0.001) negative linear correlation of r = 0.72 was found between the mitral valve area (MVA) and left atrial mean pressure (LAm). 2) A ...

We evaluated the electrophysiological parameters before and after the intravenous infusion of diazepam (0.2 mg/kg) in 20 cardiac patients to investigate the drug's antiarrhythmic effect. Diazepam did not significantly change the arterial pressure. After the intravenous infusion of diazepam, the sinus cycle length significantly shortened from 847 +/- 132 to ...

BACKGROUND: Recently, we used a custom designed "jacket" electrode with 127 bipolar electrodes in a flexible nylon matrix to map the total atrial epicardial surface in the in situ canine heart. Atrial flutter in dogs with sterile pericarditis was shown to be due to a single wave front circulating around ...

Atrial arrhythmias are diagnosed on the basis of the analysis of P wave morphology, timing and rate, the surface electrocardiogram, and intracardiac recordings. Recent intracardiac studies have demonstrated dissimilar atrial rhythms with direct intra-atrial recordings, the former otherwise not evident on the surface ECG (Zipes et al. 1972, Wu et ...