Most patients would like to have a reason for why their atria suddenly decided to fibrillate. It’s understandable. If they could identify the reason perhaps they could stop it from happening again.
There are two variations on this question:
For the patient who has just been diagnosed with afib the question is really “what is the underlying reason for me developing this condition?”
For the patient who has had afib for a while and it comes and goes seemingly randomly the question is “what caused the afib at this time? i.e. what triggers my episodes?”
For most patients, there is no straighforward and simple answer to either one of these questions
The Underlying Cause of Atrial Fibrillation
My stock response to this first question goes like this:
“Atrial fibrillation is associated with getting older and having high blood pressure. 10 % of individual >/= 80 years have atrial fibrillation. 90% of patients with afib have hypertension.
Aging and hypertension may increase scarring or damage in the left atrium or pulmonary veins that drain into the left atrium setting up abnormal electrical signals.
There are some specific things that cause afib and we will be doing a complete history and physical and some testing to check for the most common. We’ll check you for thyroid or electrolyte abnormalities and we will do an echocardiogram to look for any structural problems with your heart.
If we do find a treatable cause such as hyperthyroidism or a cardiac valve problem we will fix that and the afib may go away, however chances are we won’t find a specific reason why you developed atrial fibrillation.
Finally, and possibly most importantly, let’s take a close look at your lifestyle. Are you overweight? If so, losing 10% of your body weight will substantially lower your risk of recurrent atrial fibrillation. Let’s get you exercising regularly and eating a healthy diet, Make sure your sleep is optimized and your stress minimized.”
If you’d like a more sophisticated look into what causes afib take a look at this graphic from a recent paper.
Current theory has it that factors that we know are associated with atrial fibrillation including obesity, hypertension and sleep apnea cause atrial structural abnormalities or remodeling which then create various atrial electrical abnormalities.
Exhaustive List of Causes
If you’d like an exhaustive list of factors associated with atrial fibrillation, you can memorize the acronym P.I.R.A.T.E.S. which is sometimes used by medical students to remember the causes of atrial fibrillation which include:
- Pulmonary disease (COPD, PE)/Phaeochromocytoma
- Ischemia (ACS)
- Rheumatic heart disease (mitral stenosis)
- Anemia (high output failure/tachycardia)/Atrial myxoma/Acid-base disturbance
- Thyrotoxicosis (tachycardia)
- Ethanol/Endocarditis/Electrolyte disturbance (hypokalaemia, hypomagnesaemia)/Elevated BP
- Sepsis/Sick Sinus Syndrome/Sympathomimetics (Drugs)
And here’s a cute mnemonic from the Family Practice Notebook using ATRIAL FIB itself (although you have to use the ph of pheochromocytoma to make the f of fib)
Looking at the 15 drinks per week point on the x-axis (about 2 drinks per day) we see that your CV mortality is reduced by 20% whereas your risk of afib has increased by 20%.
A better point on the x-axis is 7 (1 drink per day) which has a 25% lower CV mortality but only a 10% higher risk of afib.
Whatever caused you to go into afib the good news is that with lifestyle changes and the care of a good cardiologist chances are excellent that you can live a normal, happy, healthy , long and active life.