Stefano De Castro, Maria Penco*, Federica Papetti, Domenico Cartoni, Rachele Adorisio**, Sergio Beni, Francesco Fedele**.
Dept. of Clinical Medicine, *Cardiology University of L’Aquila, **Dept. of Cardiovascular and Respiratory Sciences, “La Sapienza” University of Rome, Italy
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Atrial fibrillation is a common arrhythmia in man and occurs in 0.4% to
0.9% of the adult forthy, resulting in a prevalence of 2% to 4% in the population over 60 years of age1-3.
Thromboembolism, as a consequence of atrial fibrillation, is a major cause of morbidity and mortality. This is
due to loss of organized atrial contraction with development of spontaneous echo contrast accumulation and
fresh thrombi, which may dislodge at the time of return of atrial mechanic function, as it occurs after chemical
and electrical cardioversion4,5. The latter depresses the global and regional left atrial systolic function (atrial
“stunning”), despite the prompt resumption of sinus rhythm6-10. Since 1969, when Bjerkelund and Orning11
published their results, the benefit of anticoagulation in the pericardioversion period was recognized, and
warfarin therapy was recommended in all patients with atrial fibrillation >2 days in duration for 3 weeks before
and 4 weeks after cardioversion, despite no large randomized, standardized trials have been reported12,13.
However, the use of several weeks of anticoagulation is associated with practical clinical problems especially
among elderly persons14: a) oral anticoagulation exposes patients to a significant risk of hemorragic
complications11-13,15,16; b) the 1-month delay in reversion to sinus rhythm has also electrophysiological
consequences. The duration of atrial fibrillation is the most reliable predictor of who will remain in sinus rhythm
after cardioversion8,17. Moreover, longer duration of atrial fibrillation probably prolongs recovery from atrial
“stunning”18. Patients with atrial fibrillation (AF) <2 weeks in duration have complete return of atrial mechanical
function within 24 h of cardioversion; those with AF <6 weeks in duration and those with AF for longer period
(>6 weeks) require respectively 1 week and up to 3 weeks to recover the atrial mechanical function; c)
cardioversion is performed after a 3-week anticoagulation treatment (patient is discharged), and the need of a
second hospital admission adds considerable costs and makes the treatment strategy quite expensive.
Target for many physicians becomes, then, shortening or elimination of anticoagulation therapy before
cardioversion. Because of its excellent visualization of posterior cardiac structures, transesophageal
echocardiography has rapidly became the procedure of choice for detecting left atrial pathologies19,20. We
and other investigators have been using transesophageal echocardiography since 1995 as a tool to abbreviate
the anticoagulation and recommend the immediate cardioversion in patients with atrial fibrillation and no
detected thrombogenic sources. In particular, the first patients who underwent this procedure had coagulation
disorders and they were not allowed to receive anticoagulant therapy; many others presented atrial fibrillation
and poor documentation of anticoagulant status; and, no less important, we enrolled patients with active (at the
time of the onset of AF) bleeding such as gastrointestinal and intracranial hemorrage. The concept which justified
the use of transesophageal echocardiography is very simple: if embolic events are due to clots dislodgement
from the left atrium after cardioversion, then, when the echocardiographic images are negative for atrial thrombi
or spontaneous echocontrast, cardioversion can be attempted and anticoagulation shortened and confined to the
post-cardioversion period. We already know the disadvantages of a long-term anticoagulation, and thus the
advantages of early cardioversion from atrial fibrillation are obvious. Cardioversion from atrial fibrillation is a
procedure commonly used both to prevent thromboembolism and to improve ventricular function21,22, that’s
why it must be always contemplated.
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