Persistent atrial fibrillation: rate control or rhythm control
BMJ 2003; 326 doi: https://doi.org/10.1136/bmj.326.7404.1411 (Published 26 June 2003) Cite this as: BMJ 2003;326:1411
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Dear Puzzled
Rate control is based on the acceptance that someone who is in atrial
fibrillation (AF) will remain in AF or if a treatment is performed
(electrical or drug treatment) to get back into sinus rhythm that they
will likely go back into AF in the near future. Typical drugs used for
rate control are beta-blockers, digoxin and amiodarone (alone or in
combination).
The heart beats inefficiently when in AF which is now the major
reason to try to restore sinus rhythm. However, the greatest worry for
doctors and patients is the increased risk of developing a stroke.
The risk of developing a stroke when in AF is affected by age, the
presence of coronary artery disease, high blood pressure, diabetes, heart
failure and structural abnormalities of the heart. When stroke risk is
high, doctors usually recommend thinning the blood with warfarin (the most
effective way of stopping blood clots forming). However, warfarin
increases the risk of bleeding. There is a balance between the risk of
stroke and the risk of bleeding, so that medium risk patients are
recommended to have aspirin.
It was hoped that by rhythm control, otherwise high-risk patients
could avoid warfarin. Since so many go back into AF this does not seem to
be a safe strategy for high-risk patients.
It is important to realise that trials only look at the "average"
patient and not individuals. Although I do not know your entire medical
history, I suspect you are at low or low-medium stroke risk and your
current treatment seems quite right. When you are in sinus rhythm your
heart contracts more efficiently.
In the future ablation may offer the chance to abolish the AF
entirely, which should pose a minimal risk of going back into AF, so
reducing stroke risk
Hope this helps
Andy Evans
SpR in Geriatric Medicine
King's College Hospital London
Competing interests:
None declared
Competing interests: No competing interests
I am a 64 year old lay reader who has suffered from AF for 4.5 years.
Mostly it is controlled with 100 or 200 mg of flecainide daily, also 75 mg
aspirin daily. Some of the time I manage without flecainide, I can
usually trip back from AF to sinus by going for a gentle run. Under
either regime I spend no more than 5% of my time in AF in a typical week,
the rest in sinus rhythm. I have seen no great difference from when the
problem was first diagnosed in late 1998.
This is clearly rhythm control and my experience seems at variance
with the conclusions of the studies. However the article does not
mention exactly what rate control consists of. While the target readership
will undoubtedly already
know, people like me don't. Can the authors tell us?
My cardiologist believes I will benefit from ablation when techniques
have improved a bit further. Is there any further advice you can give?
Yours faithfully
Rainer Burchett
Competing interests:
None declared
Competing interests: No competing interests
Dear Editor
The editorial by Boos et al [1], reaffirms that rate control is not
inferior to rhythm control for the prevention of death and morbidity due
to cardiovascular causes in atrial fibrillation (AF). However this
information should not be extrapolated to critically ill medical and
surgical patients. Atrial arrythmias are common in critically ill patients
and are often associated with cardio-respiratory instability and increased
mortality [2]. Both rate and rhythm control, in the acute and short term
is vital in the management of these patients. Atrial arrythmia in
critically ill is usually multifactorial there is often no need to
continue the anti-arrythmic drugs beyond the critical care unit unless
otherwise there is a strong case to do so. Amiodarone, diltiazem and
magnesium infusions, beta-blockers, procianamide have all been shown to be
safe and efficacious in achieving this goal [3-6].
Unfortunately direct
current cardioversion has not shown to be useful in achieving sustained
rate or rhythm control in critically ill [7]. Amiodarone, magnesium still
remains the preferred drug for management of new onset AF in critical care
patients and the awareness of amiodarone induced pulmonary toxicity
remains high.
Egbert Pravinkumar
Academic Department of Intensive Care,
University of Aberdeen,
Scotland UK
References:
1. Boos CJ. More RS, Carlsson J. Persistent atrial fibrillation: rate
control or rhythm control: Rate control is not inferior to rhythm control.
BMJ 2003;326:1411-1412
2. Edwards JD, Kishen R Significance and management of intractable
supraventricular arrhythmias in critically ill patients. Crit Care Med
1986;14:280-282
3. Delle Karth G, Geppert A, Neunteufl T, et al. Amiodarone versus
diltiazem for rate control in critically ill patients with atrial
tachyarrhythmias. Crit Care Med. 2001;29:1149-53
4. Kumar A. Intravenous amiodarone for therapy of atrial fibrillation and
flutter in critically ill patients with severely depressed left
ventricular function. South Med J. 1996;89:779-85
5. Moran JL, Gallagher J, Peake SL et al. Parenteral magnesium sulfate
versus amiodarone in the therapy of atrial tachyarrhythmias: a
prospective, randomized study. Crit Care Med. 1995;23:1816-24
6. Chapman MJ, Moran JL, O'Fathartaigh MS, et al. Management of atrial
tachyarrhythmias in the critically ill: a comparison of intravenous
procainamide and amiodarone. Intensive Care Med. 1993;19:48-52
7. Mayr A, Ritsch N, Knotzer H, et al. Effectiveness of direct-current
cardioversion for treatment of supraventricular tachyarrhythmias, in
particular atrial fibrillation, in surgical intensive care
patients.Critical Care Medicine 2003; 31:401-405
Competing interests:
None declared
Competing interests: No competing interests
Rate control of atrial fibrillation
A recent editorial in the BMJ (1) summarises the results of
randomised controlled trials that demonstrate control of ventricular rate
in patients with AF (atrial fibrillation) is comparable in efficacy to
rhythm control.
One of the unresolved issues in clinical practice is to determine the
optimal ventricular rate that should be achieved in our patients. Analysis
of the degree of rate control in these studies may be helpful. The AFFIRM
investigators (2,3) aimed for a target heart rate of <80 beats per
minute and <110 beats per minute during a six minute walk test or an
average of <100 beats per minute on 24 hour Holter monitoring. The RACE
(4) study aimed for a less aggressive target of a resting heart rate of
<100 beats per minute.
The PIAF (5) study used no target heart rate but used other
indicators of efficacy such as improvement in symptoms of dyspnoea,
palpitations, fatigue and dizziness.
There are several unresolved issues concerning the correct manner to
achieve rate control in patientsd with AF. We do not know the optimal
resting heart rate that is to be achieved (6). To reach a target heart
rate of, for example, <80 beats per minute may be technically difficult
and may predispose the patient to adverse effects of rate lowering
medication such as digoxin toxicity. Control of heart rate during exercise
is thought to be important yet the desirable target is also not known (6)
and may be difficult to measure in many of our physically dependant
patients.
Optimal rate control for an individual patient is usually decided by
the treating physician and may depend on factors such as symptom control
and quality of life without the benefit of adequate guidelines concerning
control of ventricular rate.
(1) Boos CJ, More RS, Carlson J. Persistent atrial fibrillation: rate
control or rhythm control. BMJ 2003;326:1411-1412
(2) The Atrial Fibrillation Follow-Up Investigation of Rhythm
Management (AFFIRM) Investigators. A comparison of rate control and rhythm
control in patients with atrial fibrillation. N Eng J Med 2002;347:1825-
1833.
(3) The Planning and Steering Committee of the AFFIRM Study for the
NHLBI AFFIRM Investigators. Atrial fibrillation follow-up investigation of
rhythm management-the AFFIRM study design. Am J Cardiol 1997;79:1198-1202.
(4) Van Gelder IC, Hagens VE, Bosker HA, Kingma JH, Kamp O, Kingma T.
A comparison of rate control and rhythm control in patients with recurrent
atrial fibrillation. N Eng J Med 2003;347:1834-1840.
(5) Hohnloser SH, Kuck KH, Lilienthal J. Rhythm or rate control in
atrial fibrillation-pharmacological intervention in atrial fibrillation
(PIAF): A randomised trial. Lancet 200;356:1789-1794.
(6) Campbell RWF. How do we achieve optimal cardiovascular function
in atrial fibrillation? Proceedings of the Royal College of Physicians of
Edinburgh 1999;29 Suppl 6:16-19.
Competing interests:
None declared
Competing interests: No competing interests