Why AFib Matters

What are the consequences of atrial fibrillation (AFib)?


Although atrial fibrillation can feel weird and frightening, an “attack of AFib” usually doesn’t have harmful consequences by itself. The real danger is the increased risk for stroke. Even when symptoms are not noticeable, AFib can increase a person’s risks for stroke and related heart problems.

What causes atrial fibrillation?


Sometimes the cause of AFib is unknown. Other times, it is the result of damage to the heart's electrical system from other conditions, such as longstanding, uncontrolled high blood pressure or artery disease. AFib is also the most common complication after heart surgery.

View an animation of atrialfibrillation.

Usually, the most serious risk from AFib is that it can lead to other medical problems, including:

  • Stroke
  • Heart failure
  • Chronic fatigue
  • Additional heart rhythm problems
  • Inconsistent blood supply


Learn about the important connection between atrial fibrillation, high blood pressure and stroke.

How does AFib lead to stroke?

  • The heart quivers. The upper chambers (the atria) of the heart do not produce an effective, regular contraction.
  • The contraction fails. Imagine wringing out a sponge. Without a good squeeze, water will still be left in the sponge. In the same way, when a heart contraction is either too fast or too uneven, it doesn’t completely squeeze the blood from the atria into the next chamber.
  • Blood pools in the atria. Leftover blood remains in the atria and may pool there.
  • Risks of clotting go up. When blood has the opportunity to pool, it also has the opportunity to clot.
  • Clots can travel and cause blockages. If a blood clot forms in the atria, it can be pumped out of the heart to the brain, blocking off the blood supply to an artery in the brain, causing a stroke. This type of stroke is called an embolic stroke or some doctors call it a cardioembolic stroke.

How does AFib lead to heart failure?


Heart failure means the heart isn’t pumping enough blood to meet the body's needs. AFib can lead to heart failure because:

  • The heart is beating so fast that it never properly fills up with blood to pump out to the body.


As a result, when the heart doesn't efficiently pump the blood forward with strong contractions, symptoms develop because:

  • Blood can “back up" in the pulmonary veins (the vessels that return oxygen-rich blood from the lungs to the heart.) which can cause fluid to back up into the lungs.
  • When AFib causes heart failure, fluid in the lungs can cause fatigue and shortness of breath. Oxygen-rich blood is not being delivered to the body and brain, causing physical and mental fatigue and reduced stamina. Fluid also can build up in the feet, ankles, and legs, causing heart-failure related weight gain.


How does AFib lead to additional heart rhythm problems?


Basic answer: The heart’s electrical system stops working properly, and fails to keep the heart chambers in rhythm.

Thorough answer: Every heartbeat is controlled by the heart’s electrical system. To understand why atrial fibrillation is a problem, it is helpful to understand the normal patterns of the heart’s electrical system.

View an animation of a normal heartbeat.

The heart’s normal electrical pattern:

  • The current travels from top to bottom. The heartbeat starts at the top of the heart and – like an electrical wave – the current travels to the lower parts of the heart, signaling the tissue to contract.
  • The sinoatrial (SA) node starts the contraction in the top of the heart. The right atrium (top section of the heart) houses a group of cells called the sino-atrial node. In healthy adults, the SA node fires off between 60-100 heartbeats per minute. The electrical wave moves through the atria to “gatekeeper node."
  • The atrioventricular (AV) node regulates the timing of the lower portion of the heart. The AV node serves as a "gatekeeper" for all of the electrical pulses going through the atria (top sections) to the ventricles (bottom sections). The electrical pulses are delayed at the AV node before they are allowed to move into the ventricles. The delay gives the ventricles extra time to finish filling with blood before contracting.
  • The ventricles contract and pump blood out to the lungs and the body.

Electrical problems in atrial fibrillation:

  • In AFib, the SA node may not start the contraction. Instead, the contraction might start randomly in other areas of the atria or even in the pulmonary veins.
  • In AFib, the electrical current doesn’t flow in an organized top-to-bottom fashion. Instead, contractions are rapid and disorganized.
  • In AFib, the AV node often can’t regulate the chaotic current. It does its best to protect the ventricle from extra electrical impulses, but it can’t stop all of them. As a consequence, the ventricle beats more often than it should – giving rise to the noticeable symptoms of breathlessness and fatigue.
  • When the beat is off, the blood supply can be unpredictable. So, even though the ventricles may be beating faster than normal, they aren't beating as fast as the atria. Thus, the atria and ventricles no longer beat in a coordinated way. This creates a fast and irregular heart rhythm. In AFib, the ventricles may beat 100 to 175 times a minute, in contrast to the normal rate of 60 to 100 beats a minute.


The amount of blood pumped out of the ventricles to the body is based on the randomness of the atrial beats.

The body may get rapid, small amounts of blood and occasional larger amounts of blood. The amount will depend on how much blood has flowed from the atria to the ventricles with each beat.

Can AFib simply go away?


Yes, rarely "spontaneous remission" does happen; it simply goes away.However, it is still something you and your healthcare provider will want to monitor because some people live with AFib and do not feel the symptoms. However, the risks are still present.

Overall, most of the risks, symptoms and consequences of AFib are related to how fast the heart is beating and how often rhythm disturbances occur.

AFib may be brief, with symptoms that come and go. It is possible to have an atrial fibrillation episode that resolves on its own. Or, the condition may be persistent and require treatment. Sometimes AFib is permanent, and medicines or other treatments can't restore a normal heart rhythm.

But for all the reasons listed above, it is important to work with your healthcare provider to determine your treatment needs, and to understand your treatment options. It is also important to maintain a heart-healthy lifestyle and reduce your overall risks as much as possible.

 

Recent Discussions From The Newly Diagnosed Forum
SinusRhythm avatar

Hi.

I've been recently diagnosed with A Fib.  I was diagnosed in December 2017.  Went to the ER and ended up being admitted for 2 nights.  I'm now taking Cardizem 270mg 1 capsule daily.  Also Metoprolol 25mg twice a day and Eliquis 5mg twice a day.  What I've noticed in the past few weeks is that I'm now having shortness of breath along with the flutter.  Actually the shortness of breath seems to be the main symptom now.  I don't feel the flutter as much anymore only the shortness of breath feeling.  My cardiologist told me that my Echo shows no signs of Congestive Heart Failure.  He said that the blood flow looked good and my heart was strong.  I have a sleep study appt coming up.  I've been told about the antirhythmic meds and will consider that after I have the sleep study.  I'm also overweight and in the process of diet and exercise.  56 years old.  The doctor told me that I apparently have the gene that was passed down to me from my dad that gave me A Fib.  My question is with my shortness of breath.  I'm wondering why I now have shortness of breath at least once a day which lasts maybe 1-2 hours.  Could this be the meds? (I'm thinking it's not the meds since I've been on them since December and no shortness of breath until recently).  Could it be that blood is now backing up into my pulmonary vein causes it?  If so would a chest xray determine that?  I also can lay down at any time of day and fall sound asleep for 2-3 hours.   I'm feeling some anxiety wondering about it.  I have an upcoming appt with my doctor but thought I would put this out to the community in the meantime.  Also let me say this... When there is no shortness of breath and no flutter happening I wouldn't even know I have this disease since at those times I feel fine.


Thank you      

whackyshoe avatar

I recently had a Holter Monitor test, and was informed that there were 10 abnormal beats in the 24 hour period, and was subsequently diagnosed with AFib and put on blood thinners.  This was shocking to me.  I didn't know how to react.  And now I'm curious about, and cannot find any information on why one 10-beat "episode" is considered AFib.  We are going to repeat the test again in 1 month.  I'm guessing the blood thinners (Pradaxa) is just a precautionary exercise at this point in time.  I'm a 67 female, exercise regularly (Zone 2 most days, Zone 1 for 90 minutes every day), and work at a high stress desk job (software engineer) every day.  I am overweight (BMI 32).  I don't have any other chronic conditions (yet).  I have been following the DASH guidelines, and have started following Dean Ornish rules for the past 10 weeks (it's hard!!!).  I do not have high blood pressure (126/62).  Can someone confirm that 10 beats falls within the realm of an AFib diagnosis?

MrsZee avatar

I am just wondering if anyone knows this:  what is Metaprolol actually do?  Is it for heart rhythm control or heart rate control or both? 

My doctor only mentioned that it would slow my heart rate so I am not certain what else it does?

Thanks everyone,

Terri

 

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