The Complete Guide to Atrial Fibrillation

Atrial Fibrillation: How it happens, Risks of Stroke, Symptoms


Afib, Arrhythmia, Cardiology

Lesson 1: What is atrial fibrillation?

Atrial fibrillation is an abnormal heart rhythm that causes a fast and irregular pulse. In atrial fibrillation, parts of the atria send disorganized electrical impulses into the top of the heart. These abnormal discharges cause the atria to shake like jelly. This activity takes over the heart’s normal beats, and the body is not able to control how fast the heart is beating. This causes the most common symptom of atrial fibrillation: fatigue.

What is afib? : an abnormal heart rhythm

The most common symptom of afib is fatigue

Atrial fibrillation is the most common type of abnormal heart rhythm. An estimated three to six million Americans have it.  In fact, it happens so commonly, doctors have a nickname for it — “a fib.” Most often, the risk of a fib increases as we get older. As people age, so does their heart, and age is the biggest risk factor for developing a fib.  Just 2% of people under the age of 65 have atrial fibrillation, but as high as 9% of those over the age of 65 have it.

2% of people under the age of 65 have a fib, but as high as 9% of those over the age of 65 have it

What causes afib?

  • Advanced age

    This is the most important risk factor.

  • Obesity

  • Thyroid problems

  • Too much alcohol, caffeine or energy drinks

  • Lung problems like COPD

  • Sleep apnea

  • Severe illness

Afib causes two main problems:

afib causes symptoms and possibly a stroke
Afib can cause symptoms
Afib increases your chances of having a stroke

Lesson 2: Atrial Fibrillation and the Risk of Stroke

Strokes caused by afib

To understand how are strokes caused by afib, we need to look at a part of the heart called the left atrial appendage. This part of the heart is kind of like the heart’s tail.  When afib starts, the atria shakes like jelly. This type of movement does a bad job at pushing blood out of the top part of the heart and into the bottom. Because of this, some of the blood pools inside the heart’s little tail, where it settles and can form blood clots.

blood clot in heart are responsible for strokes caused by afib
The left atrial appendage can squeeze the clots out into the body. The most common place a blood clot goes after it leaves the heart is the brain.
the left atrial appendage cause strokes in afib

In afib, some of these formed clots inside the left atrial appendage can detach. If the heart breaks out of afib and starts squeezing normally again, the tail appendage can squeeze the clots out. The clots can then be launched into the body. The most common place a blood clot goes after it leaves the heart is the brain. If a clot lands in your brain, it can obstruct the blood flow and cause a stroke. A stroke can have a huge impact on a person’s life, even taking away their ability to talk and move independently. 

Calculating Your Stroke Risk

If you have afib, it is important to find out your stroke risk so you can decide if you need to protect yourself from one. Fortunately there is a tool that can help you and your doctor quickly determine your risk. This tool is called the CHADS VASc score. This score looks at all the factors that increase stroke risk in people with afib.

The CHADS VASc score looks at all the factors that increase your stroke risk if you have afib.
If your score adds up to 0 or 1, then your stroke risk is low.
For any score over 2, protection with a blood thinner or what is called an occlusion device is recommended.

Calculate your CHADS VASc Score here by adding all the conditions that apply to you:

Stroke Prevention in Atrial Fibrillation

Warfarin can prevent strokes in patients with afib.

Until recently, Coumadin, also known as Warfarin, was the only choice of blood thinner available for patients with afib. Coumadin can protect from a stroke but it is a very difficult drug to take as it requires frequent testing. Fortunately, there are now four new oral blood thinners that do not need regular blood draws for monitoring and have minor interactions with food and other medications. 

If a patient is bleeding or is at high risk of bleeding because of frequent falls, job activities or sports, or has had head trauma, an occluding device for the left atrial appendage is recommended. An occluding device may also be used if the patient has a history of not taking their prescribed medications.

Doctors in the US offer two occlusion devices that can protect you permanently from a stroke:

The Watchman Device: Plugs the atrial appendage.
The Watchman® Device:

A plug is placed inside the left atrial appendage so clots cannot settle inside of it.

The Lariat Device ties off the left atrial appendage
The Lariat® Device:

Ties off the left atrial appendage altogether so it can no longer cause the problem.

Lesson 3: Atrial Fibrillation and its Symptoms

What are afib symptoms?

Afib can feel like

Symptoms of atrial fibrillation (afib) can be different for everyone. The same irregular heart rhythm can cause severe symptoms in one person and literally nothing in others. The most common symptom of afib is fatigue, but people with afib can also feel their heart racing (palpitations), shortness of breath, chest pain, and even anxiety.

Symptoms of afib can be fatigue, shortness of breath and palpitations.
The most common symptom of atrial fibrillation is fatigue.

Afib treatments

There are medications available that can help treat the heart so that afib happens much less often; this can lead to an improvement in symptoms. These medications are called “antiarrythmics”, and as a group have only a modest ability to help and several potential side effect. The most common and powerful of these medications is called Amiodarone.

Amiodarone side effects: thyroid problems, skin color changes, and lung scaring

Although amiodarone is very effective at controlling atrial fibrillation, its down side is that it can potentially cause serious side effects. Amidorone can affect the thyroid gland, making it either over-or underactive. Also, taking amiodarone for a long time can lead to changes in skin coloration and lead to an untreatable condition that scars the lungs permanently.

Over the last two decades, atrial fibrillation has also been treated with a procedure called an ablation. The ablation procedure was invented in the 1990s and has been dramatically improved over time. It can offer patients improvement in symptoms and mortality while reducing the need for medications and their side effects. 

Atrial fibrillation ablations can improve symptoms and reduce mortality while at the same time reducing the need for medications and their side effects.

With an ablation, doctors can precisely target the root of the problem that causes afib. Using space age technology, doctors trace the abnormal electrical discharges that provoke the irregular heart beat and locate the parts of the heart where they occur. Up to 85% of these happen in the part of the heart that receives blood from the lungs: the pulmonary veins . Once they locate these trigger areas, doctors then enter the heart using a minimally invasive approach. Inside the atrium they target and zap or “ablate” these abnormal trigger areas while leaving the normal parts alone.

How afib ablations are done: the pulmonary veins.

How effective are atrial fibrillation ablations?

The earlier the problem is treated the more effective an ablation will be.

90% effective at treating afib that comes and goes, called “paroxysmal”.
70-80% effective at treating “persistent” afib that has been occurring for less than one year.
60% effective at treating afib that has been happening for over a year.

Since 2016, the procedure of afib ablation has begun to expand to include the left atrial appendage. When the left atrial appendage is ablated in addition to the ablation around the pulmonary veins, the procedure’s effectiveness improves by approximately 20%. Many studies have shown that this updated ablation procedure is safe and does not increase the risks related to ablation.

afib ablations can be effective up to 90%

Regardless of how long afib has been going on, it is never too late for treatment. Even in those who have had it for a long time, reducing the amount of time the heart stays in afib can lead to an improvement in symptoms.  

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Last Modified: Jul 5, 2018 @ 1:58 am
About the Author

Jorge Romero M.D. F.A.C.C. F.H.R.S.


Jorge Romero, MD, is an Attending Physician and Assistant Professor of Medicine in the Arrhythmia Service of the Cardiology Division at the MontefioreEinstein Center for Vascular Care. He specializes in the treatment of complex arrhythmias, particularly in catheter ablation of ventricular tachycardia and atrial fibrillation using cutting-edge technology. Dr. Romero is a member of the American Heart Association (AHA), and a fellow of the Heart Rhythm Society (FHRS) and the American College of Cardiology (FACC).


Jose Taveras M.D. F.A.C.C.


Dr Taveras works as a cardiologist caring for spanish speaking communities in the Bronx. He completed a dual residency in Internal Medicine and Pediatrics and then served as chief resident of internal medicine at the St. Vincent’s Catholic Medical Center of New York. He went on to specialize in cardiovascular disease at NYU Winthrop Hospital , under the mentorship of Dr. Kevin Marzo, chief of Cardiology at Winthrop. He is board certified in both internal medicine and cardiovascular diseases, and sub specializes in echocardiography, nuclear cardiology and computed tomography of the heart. Apart from his work in community outreach, Dr. Taveras' career focuses on innovation and technology. Dr. Taveras is a fellow of the American College of Cardiology. 

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