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coffee DOES NOT cause arrhythmia?
A lot of us have been told by our doctors to cut out caffeine when we walk in the door with tach or ectopics. A lot of us report here that it doesn't help. Well, a study published this week shows an interesting trend in the data. People who drank more coffee had less arrhythmia related hospitalization. The control, those who drank decaffeinated coffee, did not show this correlation. This suggest that the mechanism of protection is the caffeine. A leading theory is that caffeine competes for adenosine receptors. This means caffeine is an adenosine antagonist. Adenosine's job is to make us feel tired and primarily works in the brain. This is why caffeine can keep you up.
Adenosine also affects the conduction system of the heart through receptors on your cardiomyocytes. This affects depolarization times and heart rate variability. Heart rate variability has big implication fo arrhythmias. HRV isn't the timing between QRS complexes or variability in your pulse rate. HRV relates to specific timing in the QRS complex itself. This means timing in the ST segment, or QT segment, etc. Changes in these timings can mean a lot, for example, prolonged QT interval can mean there's muscle damage. QT interval is the time from when the ventricles receive the AV trigger to beat to when they recover.
I think the study backs up a lot of the anecdotal evidence we see.
Here's the gotcha though. This is where epidemiologist need to be careful with studies. They show something called a "correlation" between caffeine intake and hospitalizations. This does not mean there's "causation". These are very different things and causation is difficult to prove. As an example, perhaps the reasons caffeine drinkers show less arrhythmia is because they are a population of people who aren't prone to it and thus drink more coffee. People who are prone to palps will cut the habit.
My advice, I still think caffeine does play a role in arrhythmia. This was a population study. Population studies are good at showing correlation but really bad at proving causation. A better study would be to actually observe the effects of caffeine on patients with arrhythmia to see what happens on EKGs.
If you're interested in the study please google the search terms "CCDEP coffee arrhythmia".
Adenosine also affects the conduction system of the heart through receptors on your cardiomyocytes. This affects depolarization times and heart rate variability. Heart rate variability has big implication fo arrhythmias. HRV isn't the timing between QRS complexes or variability in your pulse rate. HRV relates to specific timing in the QRS complex itself. This means timing in the ST segment, or QT segment, etc. Changes in these timings can mean a lot, for example, prolonged QT interval can mean there's muscle damage. QT interval is the time from when the ventricles receive the AV trigger to beat to when they recover.
I think the study backs up a lot of the anecdotal evidence we see.
Here's the gotcha though. This is where epidemiologist need to be careful with studies. They show something called a "correlation" between caffeine intake and hospitalizations. This does not mean there's "causation". These are very different things and causation is difficult to prove. As an example, perhaps the reasons caffeine drinkers show less arrhythmia is because they are a population of people who aren't prone to it and thus drink more coffee. People who are prone to palps will cut the habit.
My advice, I still think caffeine does play a role in arrhythmia. This was a population study. Population studies are good at showing correlation but really bad at proving causation. A better study would be to actually observe the effects of caffeine on patients with arrhythmia to see what happens on EKGs.
If you're interested in the study please google the search terms "CCDEP coffee arrhythmia".
I have to agree with claytex....up to a point. Now that I'm dealing with almost weekly episodes of a-fib, I feel like a real expert. In one way I feel like my a-fib builds...in other words, after an episode I feel deep in my heart the process almost immediately starts over again, literally deep in my heart. I could drink a margarita or glass of wine or a beer a day or two after an episode and it would not throw me into a-fib. I am drinking coffee almost daily. only a cup, and no a-fib. Chocolate-no a-fib. Herbal teas and and anything with ephedrine or pseudo-ephedrine-almost immediately. I don't do these things that trigger if I can help it. I don't care that much for coffee but I do know that the small amt I drink will not throw me into a-fib.
I have had atrial fibrillation for 10-12 years, have had 8-10 electro cardioversions and the only thing I can tell you about coffee is this: I can drink one cup of regular coffee and I will be in atrial fibrillation within thirty minuites... or can I drink anything with caffine in it such as Coke and the same will happen..If I eat very much chocolate it will make my heart irregular, if I eat lots of chocoate I will be in afib within a few minutes... as far as the study... I think it is wrong... like alot of studies... they can get the results they want depending on the way the study is conducted.... I think most of studies are worthless...sorta like political polls..they get the results they want... according to the way the poll is conducted and depending on who is conducting it. Claytex
Geeze if i drank an energy drink i would be climbing the walls! I cut out caffienated coffee many years ago (roughly 8), i still got palps, then i cut out diet soda's that had caffiene in, i also still get them! BUT i will not cut out chocolate that only raises my heart rate a little, but i don;t get the skipped beats eating that!
I still weary about drinking caffiene again though, can be annoying going into a cafe and they do not have decaff! But i would raher drink water!
I still weary about drinking caffiene again though, can be annoying going into a cafe and they do not have decaff! But i would raher drink water!
A question then: what about teas (not the herbal types) and energy drinks or sodas with boosted caffeine? Are those safe to drink for those with arrhythmias? I don't suppose those were included in the testing.
As you point out, proving causation can be tricky. Actually, let me re-phrase that. It's not possible yet with the math we have to PROVE any sort of causation factor of a single variable in such a complex process. I didn't see the actual report, but rather an article about the findings, so I'm not quite sure, but when they say 18% less likely to be hospitalized, when the overall rate of hospitalization is 2.6%, we're talking about something like five less people per thousand, right?
And another thing that isn't clear here to me, is whether or not the coffee consumption was already being affected by the subjects' hearts. Meaning, maybe they hadn't yet been diagnosed, but people with arrhythmias were already cutting back on their coffee maybe because it made them feel fluttery or something. When they say that they don't find a similar result for tea, it also raises some questions about this caffeine/adenosine blocking affect. Basically, the study seems to say that if you've got an arrhythmia and can tolerate caffeine OK, then maybe you don't really need to cut it out after all. Maybe.
And another thing that isn't clear here to me, is whether or not the coffee consumption was already being affected by the subjects' hearts. Meaning, maybe they hadn't yet been diagnosed, but people with arrhythmias were already cutting back on their coffee maybe because it made them feel fluttery or something. When they say that they don't find a similar result for tea, it also raises some questions about this caffeine/adenosine blocking affect. Basically, the study seems to say that if you've got an arrhythmia and can tolerate caffeine OK, then maybe you don't really need to cut it out after all. Maybe.
COMMUNITY LEADER
I get my caffeine from chocolate, just love the stuff. I get on fine with decaf coffee, but do have one cup of black tea in the morning.
My wife got me off of regular coffee years before I became aware of my AFib. But, I would not conclude any relationship between the stopping regular coffee (an usually 4+ cups a day) and getting AFib. I in fact was later diagnosed with a leaky mitral valve which resulted in an enlarged left atrium... now there's a likely cause. I had the valve repaired a couple of years back... but continue to enjoy AFib. Heck, it it went away I might drift away from this "fun" Community.
My wife got me off of regular coffee years before I became aware of my AFib. But, I would not conclude any relationship between the stopping regular coffee (an usually 4+ cups a day) and getting AFib. I in fact was later diagnosed with a leaky mitral valve which resulted in an enlarged left atrium... now there's a likely cause. I had the valve repaired a couple of years back... but continue to enjoy AFib. Heck, it it went away I might drift away from this "fun" Community.
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