Hi all:
This nicely worded summary of some recent research is posted
on the Medscape page of WebMD, a widely read source of
medical information. It is from a recent (2003) Journal of
Geriatric Cardiology. I personally have given up on antiarrhythmics and opt for just rate control of my infrequent episodes of LAF. I do remain on Warfarin. Pam----------------------
Rate Control Compared to Rhythm Control in Atrial Fibrillation
Dennis L. DeSilvey, MD
Atrial fibrillation is a common management challenge in the
elderly patient. It has been estimated that 8%-10% of patients
over the age of 80 will be in atrial fibrillation. It is difficult to call =
atrial fibrillation a disease when it may well be a consequence of
cardiac aging with increased diastolic stiffness and inadequately
treated hypertension.
The optimal management strategy for atrial fibrillation -- rate
control with atrioventricular nodal blocking agents such as
calcium channel blockers or blockers, with or without digitalis,
or rhythm control with appropriate antiarrhythmic agents -- is not
well understood. Many of the symptoms of atrial fibrillation are
thought to be caused by inadequate rate control, particularly
during exercise. It was with these considerations in mind that the
Atrial Fibrillation Follow-up Investigation of Rhythm Management
(AFFIRM) trial[1] was conceived.
The AFFIRM trial was a randomized, multicenter comparison of
these two treatment strategies. The trial enrolled 4060 patients
(mean age 69 ± 9.0 years). This makes it a very representative
sample of the age group seen in geriatric cardiology settings. A
total of 70.8% of patients had a history of hypertension and
38.2% had a history of coronary artery disease. Of those patients
with echocardiograms, left atrial enlargement was present in
64.7% and left ventricular function was depressed in 26.0%. The
end point of the trial was mortality from all causes; the results of
the study noted 356 deaths in the rhythm-control group and 310
deaths in those assigned to rate control (mortality at 5 years,
23.8% and 21.3%, respectively).
This trial and a smaller one with a similar design in the same
issue of the New England Journal of Medicine[2] have important
implications for the management of the elderly patient with atrial
fibrillation. Most importantly, they suggest that rate or rhythm
control are acceptable choices, and when quality of life is not
significantly impacted by the presence of atrial fibrillation,
controlling the rate with drugs or even atrioventricular junction
ablation and pacing is acceptable.
Of equal interest and concern is that in the rhythm-control group
there was a higher mortality but the difference did not reach
statistical significance. Had the trial continued for more than 3.5
years the difference might have been significant. Drugs used to
control rhythm are known to be proarrhythmic, and when taken
over longer periods and in elderly patients, the risk may be more
significant.
It is also of great significance that even in the rhythm-control
group, in those patients who stopped taking warfarin the stroke
risk was higher that expected if the patients were assumed to be
in sinus rhythm. The caveat here is that if one is opting for rhythm
control to avoid the need for warfarin in this elderly population,
that is not a valid assumption.
How should one manage atrial fibrillation after these studies? I
would suggest that it is worth one trial of cardioversion off
rhythm-control medication. If atrial fibrillation returns I would opt
for rate control unless the patient is so symptomatic that a trial of
rhythm control is indicated. In either case I would recommend
continued warfarin therapy even though the patient appears to be
in sinus rhythm.
Reprint Address
Address for correspondence: Dennis L. DeSilvey, MD,
Consultants in Cardiology, 108 Houston Street, Suite B,
Lexington, VA 24450
