The role of atrial ectopics in initiating paroxysmal atrial fibrillation.

Aims: To characterize the nature and timing of atrial ectopics preceding clinical episodes of paroxysmal atrial fibrillation.

Methods And Results: Holter recordings (n= 177, 60 patients, 58% male, mean age 61.7 +/- 11.

Circadian variation in atrial fibrillation in patients with frequent paroxysms.

Determinants of the duration of episodes of atrial fibrillation (AF) in patients with paroxysmal atrial fibrillation (PAF) are poorly understood. However, autonomic tone shows circadian variation and is known to affect atrial electrophysiology. We therefore compared the duration of episodes of AF with an onset during the day (08:00-22:00) to those with an onset during the night in a database of 24-hour ECG recordings in patients with frequent symptomatic PAF.

New trials in atrial fibrillation.

Large-scale clinical trials in atrial fibrillation (AF) now are addressing issues other than that of thromboembolic prophylaxis. The "rate versus rhythm" debated is fundamental--whether to accept the occurrence of AF and attempt control of the ventricular rate or to strive for the restoration and maintenance of sinus rhythm. The AFFIRM, PIAF, and RACE trials will provide information about the efficacy, costs, adverse effects, and benefits of attempting to maintain sinus rhythm.

Entrapment of an ablation catheter in the cardiac venous system: a case report.

Cannulation of the coronary sinus is a common procedure with infrequent complications. We report an unusual case of a steerable "dumb-bell" catheter passed through the ostium of the coronary sinus prior to an intended radiofrequency ablation procedure becoming stuck and requiring general anesthesia for extraction. We caution against the use of such catheters with a "waist" for the cannulation of the coronary sinus.

A relationship between fluctuations in heart rate and the duration of subsequent episodes of atrial fibrillation.

A relationship between autonomic tone and the onset of paroxysmal atrial fibrillation in some patients is recognised. Episodes of PAF may vary enormously in duration, however, from a few beats to many hours. Whether autonomic tone influences the duration of the episodes has been less well investigated.

Low energy internal cardioversion of atrial fibrillation resistant to transthoracic shocks.

Objective: To investigate the efficacy of internal cardioversion using low energy shocks delivered with a biatrial electrode configuration in chronic atrial fibrillation resistant to transthoracic shocks.

Methods: Low energy internal cardioversion was attempted in 11 patients who had been in atrial fibrillation for 233 (SD 193) days and had failed to cardiovert with transthoracic shocks of 360 J in both apex-base and anterior-posterior positions. Synchronised biphasic shocks of up to 400 V (approximately 6 J) were delivered, usually with intravenous sedation only, between high surface area electrodes in the right atrium and the left atrium (coronary sinus in nine, left pulmonary artery in one, left atrium via patent foramen ovale in one).

Atrial fibrillation: maintenance of sinus rhythm versus rate control.

Atrial fibrillation represents a common and challenging arrhythmia. A rational approach to management of the individual case depends on careful assessment of the temporal of the arrhythmia, any associated cardiovascular disease, and any particular features suggesting the advisability or risks of any particular treatment regimen. The nature of an arrhythmia and of individual patient factors change over time, requiring a flexible approach to long-term treatment that may be defined only after months or years.

Heart rate variability depression in patients with unstable angina.

The degree of reduction in heart rate variability (HRV) after myocardial infarction has been shown to have prognostic significance, but HRV has not been studied extensively in patients with unstable angina. We assessed spectral and nonspectral measurements of HRV in 52 patients with unstable angina, 52 patients with acute myocardial infarction, and 41 normal subjects. The spectral bands of 0.

Efficacy and tolerability of transvenous low energy cardioversion of paroxysmal atrial fibrillation in humans.

Objectives: This study investigated the efficacy and tolerability of low energy shocks for termination of atrial fibrillation in patients, using an endocardial electrode configuration that embraced both atria.

Background: In animals, low energy biphasic shocks delivered between electrodes in the coronary sinus and right atrium have effectively terminated atrial fibrillation. If human defibrillation thresholds are sufficiently low, atrial defibrillation could be achieved in conscious patients using an implanted device.

Autonomic pathophysiology in heart failure: carotid baroreceptor-cardiac reflexes.

We evaluated reflex cardiac responses mediated by carotid baroreceptors in 14 patients with treated congestive heart failure and 14 age-matched healthy subjects. We used a neck chamber to deliver two types of pressure change: 5 s of continuous 50-mmHg suction and an R wave triggered, ramped neck pressure-suction sequence. Reflex latencies (functions of baroreflex arc duration) were comparable in heart failure patients and healthy subjects.

An antibody against revertant forms of cell-wall deficient bacterial variant in sera from patients with Crohn's disease.

Sera from patients with Crohn's disease or ulcerative colitis, and from controls were examined by indirect immunofluorescence for antibody against two strains of pseudomonas-like cell-wall-defective bacterial variants. Serum samples from 22 of 25 patients with Crohn's disease produced fluorescence of both revertant cell-wall-defective bacterial strains. Intensity of fluorescence correlated positively with the degree of disease activity.