What are the dangers of having untreated atrial fibrillation?
Camille Frazier-Mills, MD
Camille Frazier-Mills, MD
Frazier-Mills: Atrial fibrillation (AFib) occurs when the upper chambers of the heart beat fast and irregularly. Most people with AFib will also have fatigue, chest pain, shortness of breath, or dizziness.

People who have AFib are at a much higher risk of stroke than people who don’t, but the stroke risk can be lessened with blood thinners. Also, AFib could lead to heart failure if not treated. But virtually all AFib patients can be treated successfully.

What causes atrial fibrillation?
Frazier-Mills: In older people, AFib is most likely caused by the heart muscle fibers in the atria stiffening with age. But anyone at any age can get it.

In a younger person, AFib is most likely caused by genetic predisposition. Conditions commonly associated with AFib are high blood pressure, sleep apnea, heart valve disease, and thyroid problems.

What is a normal heart rate?
Jason Koontz, MD
Jason Koontz, MD
Koontz: A normal heart rate, also known as a pulse, varies based on your age and fitness level.

For adults, a normal resting rate is 60 to 100 beats per minute. Athletes may have a rate as low as 40 bpm because their hearts are trained to efficiently pump blood. If your heart rate is consistently below 60 or above 100, you may have a heart condition, such as arrhythmia.

Talk to your doctor if you experience other symptoms including shortness of breath, chest pains, and dizziness.

Do pacemaker wires ever need to be replaced?
Jonathan Piccini, MD
Jonathan Piccini, MD
Piccini: Sometimes cardiac pacemaker or defibrillator leads (wires) may need to be removed or replaced years after the device has been implanted due to infection, malfunction, or fracture.

Removing implanted leads is potentially risky and offered only at a small number of medical centers -- many fewer than those offering implantation of these systems.

What are the predictors of sudden cardiac death?
Piccini: Risk of sudden cardiac death increases following a heart attack. In fact, studies have shown that risk of sudden death is greatest in the first 30 days after a heart attack.

While low blood pressure and a high resting heart rate are strong initial predictors of sudden cardiac death, over time, heart failure and an earlier heart attack can be even more robust predictors.

Impaired kidney function is also a risk factor; the reasons for this are not clear, but poor kidney function appears to be associated with higher likelihood of heart rhythm disorders in general, but particularly in patients who have suffered a heart attack.

What is an echocardiogram?
Bimal Shah, MD
Bimal Shah, MD
Shah: An echocardiogram is a diagnostic test for abnormalities of the heart.

In this examination, your doctor uses sound waves to create an image of your heart.

By looking at the image of your heart, your doctor can see if it is enlarged due to a disease or if it is beating abnormally.