Left Atrial Chamber and Appendage Function After Internal Atrial Defibrillation: A Prospective and Serial Transesophageal Echocardiographic Study

AbstractObjectives. The purpose of this prospective study was to assess left atrial chamber and appendage function after internal atrial defibrillation of atrial fibrillation and to evaluate the time course of recovery.Background. External cardioversion of atrial fibrillation may result in left atrial appendage dysfunction (“stunning”) and may promote thrombus formation. In contrast to external cardioversion, internal atrial defibrillation utilizes lower energies; however, it is unknown whether the use of lower energies may avoid stunning of the left atrial appendage.Methods. Transesophageal and transthoracic echocardiography were performed in 20 patients 24 h before and 1 and 7 days after internal atrial defibrillation to assess both left atrial chamber and appendage function. Transthoracic echocardiography was again performed 28 days after internal atrial defibrillation to assess left atrial function. The incidence and degree of spontaneous echo contrast accumulation (range 1+ to 4+) was noted, and peak emptying velocities of the left atrial appendage were measured before and after internal atrial defibrillation. To determine left atrial mechanical function, peak A wave velocities were obtained from transmitral flow velocity profiles.Results. Sinus rhythm was restored in all patients. The mean ± SD peak A wave velocities increased gradually after cardioversion, from 0.47 ± 0.16 m/s at 24 h to 0.61 ± 0.13 m/s after 7 days (p < 0.05) and 0.63 ± 0.13 m/s after 4 weeks. Peak emptying velocities of the left atrial appendage were 0.37 ± 0.16 m/s before internal atrial defibrillation, decreased significantly after internal atrial defibrillation to 0.23 ± 0.1 m/s at 24 h (p < 0.01) and then recovered to 0.49 ± 0.23 m/s (p < 0.01) after 7 days. The corresponding values for the degree of spontaneous echo contrast were 1.2 ± 1.2 before internal atrial defibrillation versus 2.0 ± 1.0 (p < 0.01) and 1.1 ± 1.3 (p < 0.01) 1 and 7 days after cardioversion, respectively. One patient developed a new thrombus in the left atrial appendage, and another had a thromboembolic event after internal atrial defibrillation.Conclusions. Internal atrial defibrillation causes depressed left atrial chamber and appendage function and may result in the subacute accumulation of spontaneous echo contrast and development of new thrombi after cardioversion. These findings have important clinical implications for anticoagulation therapy before and after low energy internal atrial defibrillation in patients with atrial fibrillation.(J Am Coll Cardiol 1997;29:131–8)

Short QT syndrome. Update on a recent entity

SummaryThe short QT syndrome, a recently discovered ion channel disorder, combines shortened repolarization, a predisposition to atrial and ventricular fibrillatory arrhythmias, and a risk of sudden death. Few cases have been reported, but the prevalence may be underestimated. This syndrome might account for some cases of unexplained ventricular fibrillation in patients with otherwise healthy hearts. Patients have abnormally short QT intervals and refractory periods, and atrial/ventricular fibrillation can be triggered during investigations. Gain-of-function mutations have been detected in three genes encoding potassium channels. Treatment is based on defibrillator implantation, sometimes as a preventive measure. Quinidine may be beneficial in certain cases

ОСОБЕННОСТИ ЧИСЛЕННЫХ МЕТОДОВ РЕШЕНИЯ НЕСТАЦИОНАРНЫХ ЗАДАЧ ГЕОМЕХАНИКИ И ИХ ПРОГРАММНОЙ РЕАЛИЗАЦИИ

Приведен способ решения нестационарных задач геомеханики с применением методов крупных частиц и прогонки. Реализация способов осуществляется в среде разработки Visual Studio 2008

The ajmaline challenge and a strange ECG: reply.

Published in "EP-Europace" vol.11 n° 10International audienceLetter to the editor