Dr. John Day, Cardiologist

6 Reasons Why There is an Atrial Fibrillation Dementia Link

Besides not feeling well, maintaining brain function is one of the main concerns of people suffering from atrial fibrillation.  Fortunately, studies show that driving atrial fibrillation into remission and optimizing your daily health decisions may preserve long-term cognitive performance.  In this article, I share six reasons why there is an atrial fibrillation dementia link. And I’ll also teach you what you can do to optimize brain function even if you have atrial fibrillation.

Does Atrial Fibrillation Affect Brain Function?

Before we ever get to the atrial fibrillation dementia link, the first question is does atrial fibrillation affect brain function? In a worrisome study, researchers from Italy showed that when the heart is out of rhythm, blood flow to the brain is compromised and cognitive function drops.

Sadly, all aspects of brain functions suffered in atrial fibrillation.  And, as atrial fibrillation progresses from paroxysmal to persistent, brain function gets even worse.

Indeed, my lawyer, physician, and CEO patients tell me their thinking isn’t sharp when their heart is out of rhythm.  This “brain fog” then affects them negatively in the courtroom, boardroom, or operating room.

We First Showed the Atrial Fibrillation Alzheimer’s Link

In the early part of my career, I saw many atrial fibrillation patients develop Alzheimer’s disease.  Based on these observations, Dr. Jared Bunch and I decided to see if an atrial fibrillation dementia association existed.

To better understand if an atrial fibrillation dementia link existed, we looked at nearly 40,000 patients.  To be sure that it was Alzheimer’s disease, we required both a brain MRI and neurologist evaluation confirming this diagnosis. We then went back through their medical history to see what role atrial fibrillation played.

In the final analysis, our study showed that atrial fibrillation roughly doubles the risk of Alzheimer’s as well as all other forms of dementia.  Probably the scariest finding was that this dementia risk was highest in our younger patients with atrial fibrillation.

6 Possible Links Between Atrial Fibrillation and Dementia

So what is the mechanism to the atrial fibrillation dementia link?  While we don’t have all the answers yet, there are some clues.  Below are my six best explanations of how atrial fibrillation may cause dementia.

1.  Macro and Micro Thromboembolism (Blood Clots)

While most doctors and patients worry about the big clots, the little ones are all of concern.  Indeed, with a transesophageal echocardiogram (TEE), you can see these micro-clots when the heart is out of rhythm.

These micro-clots, also known as spontaneous echo contrast, occur when blood isn’t moving.  As the upper chambers of the heart aren’t beating with atrial fibrillation, clots may quickly form.

Preventing strokes is critical to eliminating the atrial fibrillation dementia link. And If you want to treat the underlying cause of atrial fibrillation strokes, you have to keep the heart in rhythm and eliminate every atrial fibrillation stroke risk factor possible.   Because, as you will see below, blood thinners are not a risk-free option.

2. Macro and Micro Brain Bleeds

The top concern of every atrial fibrillation patient taking a blood thinner is bleeding.  This concern is top of mind in the U.S. where lawyers encourage anyone who has ever been on a blood thinner to sue drug maker.

No doubt about it, blood thinners are especially effective at preventing atrial fibrillation clots.  The only problem is that they also significantly increase the bleeding risk.  By bleeding risk, I’m not just talking about bleeding if you get hurt.  I’m talking about spontaneous internal bleeding.

Spontaneously internal bleeding could take the form of gastrointestinal bleeding or even a brain bleed.  And the brain bleeds can be the big ones that everyone fears or the microbleeds that develop over time.

Microbleeds don’t cause any immediate symptoms.  However, studies show that these microbleeds may lead to progressive brain injury and dementia.  Sadly, blood thinners, especially warfarin/Coumadin, may increase this risk.

If you have to be on a blood thinner, then the best option would be a “NOAC.”  The “NOAC” blood thinners are Pradaxa, Xarelto, Eliquis, or Savaysa.  When compared to warfarin/Coumadin, our studies show that these blood thinners have a much lower risk of brain bleeding and dementia.

3. Cerebral Blood Flow

The key to optimizing brain performance is to maximize blood flow.  Unfortunately, atrial fibrillation decreases blood flow to the brain. How this occurs isn’t entirely clear, but three obvious reasons arise.

First, with atrial fibrillation, you lose the pumping ability of the right and left atria.  This loss of “atrial kick” decreases cardiac performance by about 20%.  Any loss of cardiac performance is linked to dereduced blood flow to the brain.

The second possible explanation is the irregularity of the pulse with atrial fibrillation.  Indeed, studies show that even if the heart is in atrial fibrillation, if you can normalize the pulse with a pacemaker then you can also normalize blood flow to the brain.  This study argues that it is the irregularity, not the loss of atrial function, that decreases blood flow to the brain.

Lastly, either too slow or too fast of a heart rate with atrial fibrillation could impact cerebral blood flow.  In another study (see abstract PO06-103) from our hospital, we have observed that the optimal atrial fibrillation heart rate to preserve brain blood flow is probably somewhere around 100 beats per minute.  Of course, sinus rhythm would be preferable but if you have to be in atrial fibrillation, then a higher heart rate may be necessary to preserve blood flow to the brain.

4. Systemic Inflammation

Keeping inflammation as low as possible may be the secret to living to 1oo and beyond without any significant medical problems.  Indeed, studies of semi-supercentenarians, or those older than 105, have shown that the secret to their health is keeping inflammation barely detectable.

Years ago we published a study showing that inflammation levels, as measured by C-reactive protein, are much higher in people with atrial fibrillation.  Likewise, elevated inflammation levels have also been seen with dementia.  Thus, it is quite possible that the same inflammatory factors causing atrial fibrillation are also causing dementia.

5. Other Medical Problems

Atrial fibrillation doesn’t usually occur in isolation.  Generally, the same people with atrial fibrillation are also the same people suffering from obesity, high blood pressure, diabetes, sleep apnea, etc.  As all of these conditions also increase the risk of dementia, it is hard to know the exact atrial fibrillation dementia link.

The bottom line is that if you want to minimize your risk of atrial fibrillation, you can’t ignore your other medical challenges.  In other words, you can’t just focus on maintaining sinus rhythm while not also addressing the obesity, high blood pressure, diabetes, sleep apnea, etc.

This is where lifestyle optimization becomes so important.  Fortunately, most of these conditions can all be reversed by eating real food, keeping your body mass index below 25, exercising daily, and optimizing your sleep and stress levels.

6. Genetic Factors

Despite every effort at optimizing your lifestyle, genetics always play a role.  Fortunately, studies show that only about 25% of your health and longevity is determined by your genes.  The good news here is that the other 75% is completely up to you.

Interestingly, the Nigerians have the highest rates of the the Alzheimer’s gene.  Despite having the worst genes in the world, the Nigerians living in Nigeria rarely get dementia.  However, if they give up their healthy ancestral ways and migrate to the US then they lose these protective effects.

If you want to know whether your genes code for atrial fibrillation or dementia, there is a simple test you can do to find out. 23andMe offers a simple genetic analysis with a saliva sample at a cost of $199 USD.  While the FDA limits what 23andMe can share with you, by allowing Promethease access to your 23andMe raw data, you can unlock everything that is currently known about your genes for an additional $10 USD.

Atrial Fibrillation and Dementia in China’s Longevity Village

In our book, The Longevity Plan, we deconstructed the secrets of China’s Longevity Village.  In this village, which has the highest percentage of centenarians in the world, atrial fibrillation and dementia are almost non-existent.  Indeed, during our five years of research, we couldn’t find any cases of atrial fibrillation or dementia.

Initially, my assumption was that the only way these people could live to 100 and beyond without atrial fibrillation or dementia had to be due to their genes.  However, when we analyzed the genes of these centenarians, we found nothing special.  As with us, they also had genes that predicted heart disease and dementia.  Clearly, it was something else that protected them.

After five years of research, the protective factor was that they had unknowingly optimized all aspects of the their daily health decisions.  Indeed, this book showed just what kind of heath and longevity is possible if you can optimize all of your health decisions.

How Do You Protect the Brain from Atrial Fibrillation?

For those who are unable to reverse their atrial fibrillation with lifestyle changes, in 2011 we published a follow-up study  of 37,908 people showing that if you could eliminate atrial fibrillation with an ablation, then the increased dementia risk was completely gone.  Indeed, we have learned that the two key factors to preventing dementia are to maintain sinus rhythm and optimize your lifestyle.

For those in whom sinus rhythm is no longer possible, all is not lost.  When it comes to maintaining long-term brain function, the most important thing is to optimize your daily health decisions. Study after study has confirmed that healthy lifestyles trump genes and just about everything else.

Practical Tips

The key message is that despite the atrial fibrillation dementia risk, you can preserve long-term brain function by maintaining sinus rhythm and optimizing your health.  Do everything possible to keep your heart in rhythm.  Keep your weight in check.  Include vegetables with every meal and stay as far away from sugar, flour, and processed foods.  Never miss your daily workout and always look for ways to optimize your sleep and stress levels.