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AFib Rhythm vs rate

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York Cardiology

There are only 2 important dimensions to life as far I see it.

The first is length of life and the second is quality of life.

It is important not to mistake these two as being synonymous.

Just because we may have a great quality of life does not automatically mean that we will live till we are hundred and just because we have a poor quality of life does not mean that our death is round the corner.
Ill give you in example people with bad migraines may have a terrible quality of life but have a normal life expectancy and people with a brain tumour may not have many symptoms but their prognosis may be very limited indeed and therefore whenever we are faced with a medical condition it is always good to ask

How will this condition affect my length go life and what measures can help improve my length of life
How does this condition impact on my quality of life and what measures can improve my quality of life.

Today I wanted to talk to you about Atrial fibrillation which is a disorder both or heart rhythm, and of heart rate and one that can adversely affect both quality of life and length of life. In terms of quality of life, AF may cause symptoms just because the heart beats irregularly or because it beats irregularly and fast and therefore there are 2 strategies to improve symptoms.

The first is a rate control strategy which means that you simply try and stop the heart from racing excessively by using medications such as Beta blockers and digoxin or sometimes using a technique called PACE and ablate.

The second is a rhythm control strategy where you try and get the patient back into a normal rhythm by medications (eg Flecanide) or cardio version or an AF ablation.

The automatic assumption at first glance would be if you can get rid of the AF then that surely would be better in the long run compared to leaving the patient in AF as being in AF could put more strain on the heart etc. However what does research tell us which strategy is better for our long term outcome/ our prognosis/our length go life.

The question that we will try and address is which is a better strategy for length of life. Is it indeed better for us in the long run to be out of AF or not?

There are 3 important studies that I will talk about.

The first was a study called AFFIRM.

In AFFIRM, 4060 patients with recurrent AF were divided in 2 groups. The first group was a rate control arm where patients were allowed to remain in AF but the rate of AF was controlled. The second group was a rhythm control arm where patients were given antidysrhtyhmic medications to keep them in a normal rhythm. This trial predated AF ablations so we can not use this trial to guide us re: AF ablations.
Nevertheless at the end of 3.5 years, there was perhaps a slight decrease in allcause mortality in the rate control arm. There was no difference in the 2 groups with regards to cardiac death, arrhythmic death, or deaths due to strokes or brain bleeds. There was also no difference in global functional status. There was a much lower number of patients requiring hospitalisation in the rate control arm.
It may have been that the afntidysrhtyhmic medications could have caused the slightly higher trend towards increased mortality in the rhythm control arm.

The second study was RACE which looked at 522 patients again with AF or flutter of less than 1 year duration and again compared a rate control strategy to a rhythm control strategy. Again they found similar results to AFFIRM. There was no difference in cardiovascular mortality between the two groups but there was a trend to a higher incidence of nonfatal complications such as heart failure, blood clots, adverse drug reactions and need for permanent pacemaker in the rhythm control group. Again RACE predated AF ablation and therefore the conclusion was that ideally if you are trying to use a rhythm control strategy it would be better to do so in way which may not require long term use of antidyrhythmic agents. This is where Catheter ablation comes in.
If we use catheter ablation as a means of controlling the rhythm would we see different results.

A more recent trial looked at the same question but also enrolled patients who were having catheter ablation as a rhythm control strategy. This was called EASTAFNET 4. In this trial 2789 patients who had been diagnosed with AF within a year and who were deemed high risk (older, previous strokes, diabetes, hypertension, heart failure, kidney diesease, LVH) were assigned to either rhythm control (by meds/ablation) versus rate control. After 5 years or so, the trial was stopped early because the death from cardiovascular causes and even strokes was seen less frequently in the rhythm control group. Conversely side effects from medications etc were more common in the rhythm control; group.

So what does all this tell us?

Find out in this video:)

posted by Verpetvc