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Understanding is the key to finding answers.


A stroke happens when a blood vessel in the brain is suddenly blocked or bursts, resulting in damage to the brain tissue.

The majority of all strokes are ischemic, which means they occur as a result of an obstruction, such as a blood clot, within the blood vessel. This blockage prevents or greatly reduces the delivery of oxygen and essential nutrients to the brain.

In some cases, despite testing during the hospital stay, the cause of a stroke cannot be determined. This is what is known as a “cryptogenic” stroke or a stroke of unknown cause. It’s estimated that 25-30% of ischemic strokes are cryptogenic or unexplained.1

Atrial fibrillation (AFib) is a major risk factor for stroke. It’s a common condition in which the upper chambers of the heart beat very fast and irregularly. As a result, blood is not pumped effectively to the rest of the body and may pool and clot. If a clot dislodges, it can travel to the brain and result in a stroke. People with AFib are five times more likely to have a stroke.2

Having a stroke means you are at greater risk for having another (recurrent) stroke. At least 1 in 4 Americans who have a stroke will have another stroke within their lifetime.3 Determining the cause of your stroke will help your physician take steps to minimize the risk of having a recurrent stroke.


Atrial fibrillation (AFib) increases the risk of stroke more than 5 times2 but it often goes undetected since it can happen infrequently or without symptoms.

Normal Heartbeat

Normal heartbeat

A small pulse of electric current spreads quickly through the heart to make the muscle contract.

Atrial Fibrillation

Atrial Fibrillation

In atrial fibrillation, the heart’s upper chambers quiver faster than the rest of the heart.



  • Irregular heartbeats
  • Thumping or pounding heartbeats
  • A feeling that the heart is racing
  • Chest discomfort
  • Fainting or light-headedness
  • Fatigue, shortness of breath or weakness

However, some people have no symptoms and discover that they have AFib at a doctor’s appointment. 

MANAGEABLE Risk factors

Some risk factors that contribute to AFib can be controlled or modified, like managing high blood pressure and reducing alcohol consumption. Controllable risk factors include:

  • High cholesterol
  • High blood pressure
  • Heart disease
  • Smoking
  • Excess weight
  • Metabolic syndrome
  • Stress
  • Alcohol abuse
  • Lack of exercise
  • Some medications
  • Sleep apnea
  • Thyroid disorders

non-controllable risk factors

  • Family history
  • Advancing age
  • Heart disorders from birth
  • Gender — males have a higher incidence of AFib


If the cause of your stroke is unknown (cryptogenic), heart monitoring may be necessary to help determine if atrial fibrillation (AFib) is a factor.

You may be asked to wear a portable heart monitor for several days to try to identify AFib but, in some cases, a longer-term option may be needed. A recent study showed that for many cryptogenic stroke patients, it could take more than 80 days for AFib to appear because the episodes happen infrequently, often without symptoms.4

With continuous, long-term monitoring, your doctor can get information about your heart to help make a diagnosis and find the right answer for you.


These talking points will help you remember important information related to your symptoms to share with your healthcare team.

Remember to Share:

  • A description of your symptoms (if applicable)
  • The number of episodes you’ve had in the past 2 years
  • What you were doing before you had symptoms
  • Any concerns you have (e.g., safety, your job, driving)
  • Any treatments you are receiving for your heart
  • If your family has a history of heart conditions
  • How your symptoms are affecting your home and work life

Remember to Ask:

  • How will you determine if I have a heart condition?
  • What tests will you perform?
  • Would long-term monitoring with an insertable cardiac monitor lead to a faster diagnosis?
  • What should I do when I experience symptoms?
  • Should I be concerned about my symptoms?
  • Will I need treatment? If so, what kind of treatment? What other alternatives are there?
  • Do I need to restrict any activities?


If it is determined that you have experienced episodes of atrial fibrillation (AFib), your doctor will recommend the most appropriate treatment to help prevent another stroke from occurring.

These treatments may be used to help manage your AFib and prevent another stroke.

Lifestyle Changes

Making certain lifestyle changes may improve your overall heart health. Your healthcare team may recommend that you:

  • Eat heart healthy foods
  • Choose a low-salt diet
  • Exercise
  • Stop smoking
  • Limit alcohol intake


Medication may be prescribed to control your heart rate or rhythm. In addition, anticoagulation (blood-thinning) drugs are aimed at preventing clots from forming that can lead to a stroke.


A procedure called cardioversion may be used to reset an abnormal heart rhythm back to normal. Cardioversion is performed either with medications called anti-arrhythmics or with an electric shock delivered to your heart when you are sedated.

Catheter Ablation

If medications or cardioversion don’t work or if you have side effects, catheter ablation is another option. During catheter ablation, either radiofrequency energy or cryotherapy  is directed through a catheter inserted in an artery, toward abnormal electrical pathways in the heart tissue. Either method scars the tissue and may normalize the erratic electrical signals to correct the arrhythmia.

Pacemaker or Implantable Cardioverter Defibrillator (ICD)

A medical device like a pacemaker or an ICD can detect and treat AFib early and suppress the onset of AFib.


Liao J, Khalid Z, Scallan C, Morillo C, O’Donnell M. Noninvasive cardiac monitoring for detecting paroxysmal atrial fibrillation or flutter after acute ischemic stroke: a systematic review. Stroke 2007;38:2935–2940.


2014; 370(26):2478-2486.American Heart Association. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: The Framingham Study. Stroke. August 1991;22(8):983-988. Accessed October 2013.


Sanna T, Diener HC, Passman RS, et al. Cryptogenic Stroke and Underlying Atrial Fibrillation (CRYSTAL AF). N Engl J Med. June 26, 2014;370(26):2478-2486.