Heart Arrhythmia

Types of arrhythmias

Doctors classify arrhythmias not only by where they originate (atria or ventricles) but also by the speed of heart rate they cause:

• Tachycardia (tak-ih-KAHR-dee-uh). This refers to a fast heartbeat — a resting heart rate greater than 100 beats a minute.
• Bradycardia (brad-e-KAHR-dee-uh). This refers to a slow heartbeat — a resting heart rate less than 60 beats a minute.

Not all tachycardias or bradycardias mean you have heart disease. For example, during exercise it's normal to develop a fast heartbeat as the heart speeds up to provide your tissues with more oxygen-rich blood. During sleep or times of deep relaxation, it's not unusual for the heartbeat to be slower.

Symptoms

Arrhythmias may not cause any signs or symptoms. In fact, your provider might find you have an arrhythmia before you do, during a routine examination. Noticeable signs and symptoms don't necessarily mean you have a serious problem, however.

Noticeable arrhythmia symptoms may include:

• A fluttering in your chest
• A racing heartbeat (tachycardia)
• A slow heartbeat (bradycardia)
• Chest pain
• Shortness of breath

Other symptoms may include:

• Anxiety
• Fatigue
• Lightheadedness or dizziness
• Sweating
• Fainting (syncope) or near fainting

Risk factors

Certain conditions may increase your risk of developing an arrhythmia. These include:

• Coronary artery disease, other heart problems and previous heart surgery. Narrowed heart arteries, a heart attack, abnormal heart valves, prior heart surgery, heart failure, cardiomyopathy and other heart damage are risk factors for almost any kind of arrhythmia.
• High blood pressure. This increases your risk of developing coronary artery disease. It may also cause the walls of your left ventricle to become stiff and thick, which can change how electrical impulses travel through your heart.
• Congenital heart disease. Being born with a heart abnormality may affect your heart's rhythm.
• Thyroid problems. Having an overactive or underactive thyroid gland can raise your risk of arrhythmias.
• Diabetes. Your risk of developing coronary artery disease and high blood pressure greatly increases with uncontrolled diabetes.
• Obstructive sleep apnea. This disorder, in which your breathing is interrupted during sleep, can increase your risk of bradycardia, atrial fibrillation and other arrhythmias.
• Electrolyte imbalance. Substances in your blood called electrolytes — such as potassium, sodium, calcium and magnesium — help trigger and conduct the electrical impulses in your heart. Electrolyte levels that are too high or too low can affect your heart's electrical impulses and contribute to arrhythmia development.