Learn About Your Heart...
Made Simple

By Nicolas Shammas, MD

A new, comprehensive sourcebook for
heart and vascular disease patients

Cardiovascular Health Topics

Statistics about Heart and Blood Vessel Diseases in the United States
Structure and Function of the Heart and Blood Vessels
Diseases of the Blood Vessels of the Heart
Surgical Therapies for the Cardiovascular Patient
Peripheral Vascular Disease
Diseases of the Blood Vessels of the Head and Neck
Strokes: How to Survive Them and How to Prevent Them
Valvular Heart Disease
Heart Rhythms: How to Recognize Them and Treat Them
Congestive Heart Failure
11. Understanding Cardiomyopathy, or Weak Heart Muscle
12. Children and Heart Disease
13. Diseases of the Pericardium
14. Systemic Illnesses, Infections and Drugs that Affect the Heart
15. Erectile Dysfunction: a Vascular Disease
16. Cardiovascular Disease Prevention
17. Heart Healthy Nutritional Tips
18. Cardiac Rehabilitation
19. Medications for Cardiovascular Disorders
20. Heart Tests You Need to Know
21. Learn What to Do in a Medical Emergency
22. How to Choose Your Doctor and Hospital
23. Medical Research and How You Can Get Involved
24. Taking the Next Step — A Few Community Resources to Help You Live More Healthfully
25. How Much Did You Learn from This Book: Take a Simple Test


Mark W. Kovach, MD, FACC

What is atrial fibrillation?

The normal heart beats approximately 60 to 100 times a minute. However, many heart patients experience problems when the heart rhythm is disrupted and their hearts beat either too quickly or too slowly.

Atrial fibrillation is among the most common heart rhythm problems that physicians treat. Atrial fibrillation is a rapid irregular electrical activity of the upper chambers of the heart, called the atria. When it occurs intermittently in some patients, it is called paroxysmal atrial fibrillation. In other patients, the atrial fibrillation can persist for many months and is called chronic atrial fibrillation.

Some patients are symptomatic when their heart rhythms go into atrial fibrillation, while others have little or no symptoms at all. Symptoms can range from mild palpitations to shortness of breath, heart racing, lightheadedness, or passing-out spells. The treatment that doctors recommend depends, in part, on how symptomatic the atrial fibrillation is in a particular patient.

What are the causes of atrial fibrillation?

There is no single specific cause of atrial fibrillation, but it is frequently seen in association with other medical problems. It is often associated with high blood pressure and becomes increasingly more common as people age. In fact, in people over the age of 80, approximately 1 in 10 has this heart rhythm problem. Occasionally, atrial fibrillation can occur in young people without any associated medical problems. In these people, we call their atrial fibrillation lone atrial fibrillation.

Atrial fibrillation can also occur because of elevated thyroid gland function. A blood test to check the level of thyroid hormones in patients with atrial fibrillation should be routinely done. In addition, patients with weak heart muscles, problems with blockages in the coronary arteries and valves of the heart, or viral infections to the heart can have atrial fibrillation. In hospitalized patients, clots migrating to the lungs (typically from the veins of the lower legs), called pulmonary emboli, can also cause atrial fibrillation.

The typical testing to uncover the cause of atrial fibrillation includes an ultrasound to the heart (echocardiogram), thyroid function tests and other blood tests, stress test to rule out blockages in the coronary arteries, and occasionally a scan on the lung to rule out a clot, if clinically suspected.

What are the 2 main types of treatment for atrial fibrillation?

There are 2 main types of treatment for atrial fibrillation: rate control and rhythm control.

What is rate control of atrial fibrillation?

With rate control, the simplest form of treatment, the heart is allowed to continue its paroxysmal or chronic atrial fibrillation without trying to force a heart rhythm back into regular rhythm. The speed by which the heart beats, however, is controlled. Certain types of medications are often used to make sure if the heart goes rapidly when it is out of rhythm that the rate is slowed down to within the normal range. The goal of this treatment is to make sure that the heart does not beat too quickly or too slowly. Occasionally, the medications used to prevent the heart from going too fast will at times cause the heart rate to go too slowly. When this happens, doctors may recommend treatment with a pacemaker to prevent the slow heart rates. While pacemakers do not prevent atrial fibrillation in general, they are good at preventing slow heart rhythms, which can cause dizziness or fainting spells.

In addition, people who have long episodes or persistent atrial fibrillation are at risk for blood clots and strokes, so doctors frequently recommend "blood thinner" medications. The most commonly prescribed medication for preventing blood clots and strokes in patients with atrial fibrillation is a medication called Coumadin. While this medication is reasonably safe in most patients as long as it is regulated closely, in some patients it can be quite difficult to regulate and can cause bleeding problems if the blood becomes "too thin." Coumadin needs to be closely regulated by your physician or special clinics called anticoagulation/Coumadin clinics.

Without adequate rate control, the fast heartbeats can lead to weakening of the heart muscle and can result in a condition of fluid buildup known as congestive heart failure. Controlling the heart rate can reverse this condition if caused primarily by the atrial fibrillation.

What is rhythm control of atrial fibrillation?

The other main treatment for atrial fibrillation is rhythm control. With rhythm control, the goal is to get the heart back into regular rhythm and to keep it in rhythm. This usually requires stronger heart medicines called anti-arrhythmics. These medications can have serious side effects in some patients and have to be followed closely by a physician.

Sometimes it is necessary to shock the heart back into rhythm using a treatment called cardioversion, during which a synchronized electrical shock is delivered to the chest of a patient who is closely monitored and sedated. The success rate for keeping the heart in rhythm is not 100%, and it is common for patients to have recurrences of their atrial fibrillation, despite receiving cardioversions and taking strong anti-arrhythmic medications. Frequently, doctors will still place these patients on blood thinners, such as Coumadin.

What are ventricular tachycardia and ventricular fibrillation?

Ventricular tachycardia and ventricular fibrillation are abnormal fast heart rhythms that arise from the bottom part of the heart, called the ventricles.

In ventricular tachycardia, the heart can beat at 200–300 beats per minute. These fast heartbeats do not allow adequate filling of the blood inside the heart chambers leading to a drop in blood pressure and frequently loss of consciousness. In ventricular fibrillation, the heart rhythm is very fast and disorganized. During this rhythm, no blood can be ejected out of the ventricles, and death is imminent if the ventricular fibrillation is not immediately corrected.

Ventricular tachycardia most frequently occurs in people who have significant heart disease. Less often, ventricular tachycardia can occur in people who have no significant heart disease, and in these patients, the rhythms are benign. However, when ventricular tachycardia and ventricular fibrillation occur in people who have heart disease, these rhythms can be life threatening. Quite often, ventricular tachycardia can cause shortness of breath, lightheadedness, and passing-out spells and can, in some instances, lead to cardiac arrest. Ventricular fibrillation and ventricular tachycardia are the most common causes of death after a heart attack.

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