70 Are patients with atrial flutter at risk of
embolisation when cardioverted? Do they need
anticoagulation to cover the procedure?
Suzanna Hardman and Martin Cowie
Although common clinical practice and guidelines do not
advocate routine anticoagulation of patients with atrial flutter
undergoing cardioversion, there are no data to support this
practice. Rather, recent studies suggest the prevalence of intra-
atrial thrombus in unselected patients with atrial flutter is
significant and of the order of 30–35% (compared with 3% preva-
lence in a control population in sinus rhythm). The atrial stand-
still (or stunning) that has been described post-cardioversion of
atrial fibrillation and is thought to be a factor in the associated
thromboembolic risk has also now been described immediately
post-cardioversion of patients with atrial flutter. Although some
authors argue that the stunning post-cardioversion of atrial flutter
is “attenuated” compared with the response in atrial fibrillation,
the thromboembolic rate associated with cardioversion of atrial
flutter in the absence of anticoagulation argues against this.
Indeed, the thromboembolic rate appears to be comparable with
the early experience of cardioverting atrial fibrillation.
Furthermore, atrial flutter is an intrinsically unstable rhythm
which may degenerate into atrial fibrillation and certain patients
alternate between atrial fibrillation and atrial flutter.
Like atrial fibrillation, atrial flutter may be the first manifestation
of underlying heart disease and it is likely, though not yet proven,
that the thromboembolic risks associated with both chronic atrial
flutter and with cardioversion of atrial flutter vary with the extent of
underlying cardiovascular pathology. Although existing data are
limited, on current evidence we advise that patients with atrial
flutter should be anticoagulated prior to, during and post-
cardioversion, in the same way as patients with atrial fibrillation.
FFuurrtthheerr rreeaaddiinngg
Bikkina M, Alpert MA, Madhuri M et al. Prevalence of intra-atrial
thrombus in patients with atrial flutter. Am J Cardiol1995; 7766 ;186–9.
Irani WN, Grayburn PA, Afrii I. Prevalence of thrombus, spontaneous
echo contrast, and atrial stunning in patients undergoing cardioversion