Atrial Fibrillation
Rhythm Control in Atrial Fibrillation
Restoration of normal sinus rhythm is a commonly pursued goal in atrial
fibrillation. Potential benefits of this strategy versus leaving the
patient in atrial fibrillation and simply controlling the heart rate
response include:
- Improved cardiac output
- Reduced symptoms: fatigue, palpitation and
shortness of breath
- Reduced thromboembolic risk
- Prevention of tachycardia induced cardiomyopathy
Whether to pursue a course
of repeated cardioversions and administration of anti-arrhythmic therapy
to maintain sinus rhythm has been recently
studied in several clinical trials. No differences in clinical outcomes
between rate and rhythm control strategies were identified in these
trials. In all cases, anti-coagulant therapy to minimize thrombo-embolic
risk
is indicated throughout the period when rhythm restoration is being
attempted as well as chronically as per the patient’s thromboembolic
risk indications.
AFFIRM Trial 1
- 4060 patients with atrial fibrillation of less than 6 months
duration
- Rate control with digoxin, beta blocker or calcium channel
blocker and anticoagulation with warfarin or
- Rhythm control with the
most effective anti-arrhythmic drug and anticoagulation with warfarin
- Amiodarone 39% (60% at 3 years), sotalol 33%,, other Rx 1-10%
- Follow-up 3.5 years
- Results:
- No difference in all cause mortality (1° endpoint)
- Trend towards
better survival with rate control
- No difference in death, ischaemic
stroke, anoxic encephalopathy, major bleeding or cardiac arrest
(2° endpoints)
- No difference in quality of life or functional
status
including cardiovascular death, CHF,
thromboembolism severe bleeding,
pacemaker implantation or
side effects of anti-arrhythmic
therapy
between the two strategies:
RACE Trial 2
- 522 patients with persistent atrial fibrillation
or atrial flutter (24 hours-1
year)
- 2 cardioversions within 1 year
- Rate control to HR < 100
bpm and no symptoms
- Rhythm control: Sotalol followed by Flecainide or Propafenone followed
by Amiodarone
- Primary endpoint: cardiovascular death, admission or CHF, Thromboembolic
events, severe bleeding, pacemaker implantation or severe anti-arrhythmic
side effects
- Results: non-significant trend to higher incidence of primary
endpoint with rhythm control (22.6 versus 17.2%
- In patients with hypertension,
rhythm control had a higher incidence of the primary
endpoint 30.8 versus 12.5 % for rate control)
Two smaller trials PIAF
3 (252 patients) and STAF 4 showed similar results. A trial of maintenance
of sinus rhythm in CHF patients the
AFIB-CHF trial
is still
ongoing.
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