Cordina J, Mead G.
Atrial
fibrillation is the commonest cardiac dysrhythmia. It is
associated with significant morbidity and mortality. There are
two approaches to the management of atrial fibrillation:
controlling the ventricular rate or converting to sinus rhythm in
the expectation that this would abolish its adverse effects.
The objective
of this review was to assess the effects of pharmacological
cardioversion of atrial fibrillation in adults on the annual risk of
stroke, peripheral embolism, and mortality.
We made a
thorough search for existing evidence in the following databases: the
Cochrane Controlled Trials Register (Issue 3, 2002), MEDLINE
(2000 to 2002), EMBASE (1998 to 2002), CINAHL (1982 to 2002), Web
of Science (1981 to 2002). We also handsearched the following
journals: Circulation (1997 to 2002), Heart (1997 to 2002),
European Heart Journal (1997-2002), Journal of the American College of
Cardiology (1997-2002) and selected abstracts published on the web site
of the North American Society of Pacing and Electrophysiology (2001,
2002). We selected trials based on the following criteria:
randomised controlled trials or controlled clinical trials of
pharmacological cardioversion versus rate control in adults
(>18 years) with acute, paroxysmal or sustained atrial
fibrillation or atrial flutter, of any duration and of any
aetiology.
We identified
two completed studies AFFIRM (n=4060) and PIAF (n=252). We found no
difference in mortality between rhythm control and rate control -
relative risk 1.14 (95% confidence interval 1.00 to 1.31). Both
studies show significantly higher rates of hospitalisation and adverse
events in the rhythm control group and no difference in quality of life
between the two treatment groups. In AFFIRM there was a similar
incidence of ischaemic stroke, bleeding and systemic embolism in the
two groups. Certain malignant dysrhythmias were significantly more
likely to occur in the rhythm control group. There were similar scores
of cognitive assessment in both groups. In PIAF, cardioverted patients
enjoyed an improved exercise tolerance but there was no overall benefit
in terms of symptom control or quality of life.
There is no
evidence that pharmacological cardioversion of atrial fibrillation to
sinus rhythm is superior to rate control. Rhythm control is associated
with more adverse effects and increased hospitalisation. It does not
reduce the risk of stroke. These conclusions cannot be generalised to
all people with atrial fibrillation as most of the patients included in
these studies were relatively older (>60 years) with significant
cardiovascular risk factors.
