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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".
Excellent posts. I think the only thing that study proves is that a real scientific study is justified. Meanwhile, I'll stay off the coffee, and avoid the great smelling coffee aisle at my super market.
Even 1 cup of Coffee give me a lot more PVC as well as Tachycardia.
in my book... Coffee = evil :)
in my book... Coffee = evil :)
Gee Marie, where have you been for the last 10 yrs, or do you just not post. "Most" of us do not "necessarily" know what all of our triggers are. I used to think caffeine was a culprit for me, but no, I can have a cup of coffee or glass of iced tea and no problem. If I have a glass of wine....bingo! I felt good about being able to drink coffee once again, well before this study was done. I think our triggers interact and any right combination can create the "perfect storm" for an event. New triggers can pop up anytime... just like the last discussion you posted on concerning the connection between v-tach and orgasms. :)
I'm amazed at the buzz this is generating among people with heart arrthymias. Don't most of us already know what our triggers are? I have experience with SVT, afib and PVC/PACS and I know that caffeine is a trigger for me no matter how many studies say otherwise.
Here is an exerpt from one of the better articles I have read about the study:
"So he and his colleagues analyzed data on 130,054 men and women who were treated at Kaiser. As part of a baseline medical check-up between 1978 and 1985, all participants completed a questionnaire that included information on coffee, alcohol, and tea consumption. Most were not asked to differentiate between caffeinated and decaffeinated coffee.
Through follow-up, 2.6 percent were hospitalized for an arrhythmia; half had a serious heart rhythm disturbance known as an atrial fibrillation.
When coffee drinking was evaluated as a continuous variable, increasing consumption was associated with decreasing risk of hospitalization.
In the small subset of 11,656 patients who provided specific information on their coffee consumption, it appeared the risk reduction was primarily attributed to caffeine, Klatsky said, although the small numbers precluded drawing firm conclusions.
While the observational design of the study meant that it could not establish a causal relationship, Klatsky said it was plausible that caffeine could be the protective agent involved."
WebMD had an article about this study which quoted a doctor as saying the researchers used hospital codes to determine which subjects had been hospitalized with an arrthymia and these codes were not always accurate. There is also the whole issue of being hospitalized. Does that include ER visits? Many people with afib go to the ER but are not hospitalized. What if those people were coffee drinkers? I had episodes of SVT for over 25 years before I ever sought medical care for it because my episodes were brief and not very symptomatic. I know that some of these episodes were triggered by caffeine, which is why I learned to use it very infrequently.
It does make you wonder why people would spend so much time and money researching the coffee issue. I should offer myself up as a cheap and easy study. Give me caffeine and watch my heart go into arrthymia.
And it should be noted that this study does not address the issue of the effect of caffeine on people who already have arrthymias. Just whether coffee may prevent someone from developing arrthymias in the first place.
Here is an exerpt from one of the better articles I have read about the study:
"So he and his colleagues analyzed data on 130,054 men and women who were treated at Kaiser. As part of a baseline medical check-up between 1978 and 1985, all participants completed a questionnaire that included information on coffee, alcohol, and tea consumption. Most were not asked to differentiate between caffeinated and decaffeinated coffee.
Through follow-up, 2.6 percent were hospitalized for an arrhythmia; half had a serious heart rhythm disturbance known as an atrial fibrillation.
When coffee drinking was evaluated as a continuous variable, increasing consumption was associated with decreasing risk of hospitalization.
In the small subset of 11,656 patients who provided specific information on their coffee consumption, it appeared the risk reduction was primarily attributed to caffeine, Klatsky said, although the small numbers precluded drawing firm conclusions.
While the observational design of the study meant that it could not establish a causal relationship, Klatsky said it was plausible that caffeine could be the protective agent involved."
WebMD had an article about this study which quoted a doctor as saying the researchers used hospital codes to determine which subjects had been hospitalized with an arrthymia and these codes were not always accurate. There is also the whole issue of being hospitalized. Does that include ER visits? Many people with afib go to the ER but are not hospitalized. What if those people were coffee drinkers? I had episodes of SVT for over 25 years before I ever sought medical care for it because my episodes were brief and not very symptomatic. I know that some of these episodes were triggered by caffeine, which is why I learned to use it very infrequently.
It does make you wonder why people would spend so much time and money researching the coffee issue. I should offer myself up as a cheap and easy study. Give me caffeine and watch my heart go into arrthymia.
And it should be noted that this study does not address the issue of the effect of caffeine on people who already have arrthymias. Just whether coffee may prevent someone from developing arrthymias in the first place.
You know, there is caffeine in decaf too, only a much smaller amt. Also, I very rarely go to the hospital when I go into an episode of a-fib. I'm sure people new to the experience are not so lacidasical about it and therefore end up admitted to the hospital way more often than us old-timers. lol. The other thing I wanted to comment on that is a little off track is when I went for my last stress test they gave me adenosine and it immediately sent me into a-fib to be followed by a short run of v-tach. Sure scared me. I did have to stay in the hospital and they did serve me coffee for breakfast the next morning.
I'm really cynical about the study, that's why I wanted to bring it up for discussion.
I couldn't find out in their methodology how they normalized the data so that they didn't pick up misleading results. A few of us already eluded to the point that people who are drinking more coffee probably are not prone to arrhythmia. Those who drink decaffe are doing so for a reason and probably because they have disarrhythmia. So yea, it's not a stretch to predict these results.
It's like saying people who are out of shape tend to do poorly in marathons. Well yea, duh!
The study is very focused on just coffee. In the discussion they talk about effects of caffeine but there are many more sources of caffeine than just coffee. There's soft drinks, energy drinks, diet pills. None of these was included.
I suspect the study was sponsored by the coffee industry. This is a common practice, for instance, the red wine industry always sponsors studies on the health benefits of red wine and they don't even attempt to hide that fact.
Anyone thinking about going back to caffeine because of this study should think twice.
I couldn't find out in their methodology how they normalized the data so that they didn't pick up misleading results. A few of us already eluded to the point that people who are drinking more coffee probably are not prone to arrhythmia. Those who drink decaffe are doing so for a reason and probably because they have disarrhythmia. So yea, it's not a stretch to predict these results.
It's like saying people who are out of shape tend to do poorly in marathons. Well yea, duh!
The study is very focused on just coffee. In the discussion they talk about effects of caffeine but there are many more sources of caffeine than just coffee. There's soft drinks, energy drinks, diet pills. None of these was included.
I suspect the study was sponsored by the coffee industry. This is a common practice, for instance, the red wine industry always sponsors studies on the health benefits of red wine and they don't even attempt to hide that fact.
Anyone thinking about going back to caffeine because of this study should think twice.
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