Heart rhythm problems

If your heart doesn't beat with an even, regular rhythm, it is called arrhythmia or dysrythmia.

When you have extra heartbeats

Premature ventricular contraction

If the ventricles or bottom chambers of your heart contract before the atria or top chambers, it is a premature ventricular contraction, or PVC. Many people have an occasional PVC without any symptoms; however, if you have a history of heart disease, or if you have frequent PVCs, your health care team needs to know. Symptoms include palpitations, weakness, shortness of breath or chest pain. You may be monitored closely and may be treated by medicines.

Premature atrial contraction

Early heartbeats start from the upper chambers of the heart. Usually, no medicine treatment is needed.

When your heart beats too fast

You may have one of the following problems if your heart is beating too fast.

Sinus tachycardia

Sinus tachycardia is when your heart speeds up when you are exercising, being active, feeling anxious or afraid and when you have a fever. This is normal. If your heart rate stays at this fast rate for a long period of time, you may feel pounding in your chest (palpitations), lightheadedness, weakness, shortness of breath or other symptoms. (It is normal for your heart to speed up with exercise or exertion, and then slow down when you are at rest.)

Atrial fibrillation

In atrial fibrillation, electrical impulses travel through the top part of your heart (atria) in a random or disorganized way. This causes the atria to beat (or contract) many times for each one time that the ventricles contract. When your atria are fibrillating, they are not able to pump blood effectively. If you have atrial fibrillation, your risk of stroke is up to five times greater than people with a normal rhythm. Your doctor will recommend medicine to decrease your risks and regulate your heart rhythm. Sometimes atrial fibrillation occurs in healthy people, but usually it happens if you also have high blood pressure, a history of valve or heart disease, coronary artery disease or hyperthyroidism.

Ventricular tachycardia

If you have multiple premature (early) ventricular contractions, in a row, it's called ventricular tachycardia (V-tach). Some people tolerate this, while others may faint. It can be life-threatening. An electrophysiology study can tell your doctor if you have this rhythm, or one that looks similar.

Ventricular fibrillation

In ventricular fibrillation, electrical impulses in your heart travel through the bottom chambers of your heart (the ventricles) in a disorganized way. This prevents your ventricles from contracting correctly. When your ventricles are fibrillating, they are not able to pump blood to your body. You will pass out or lose consciousness. An electrical shock or defibrillation can put your heart back into a normal rhythm.

When your heart beats too slowly

You may have one of the following problems if your heart is beating too slowly.

Sinus bradycardia

If your heart beats slower than normal — less than 60 beats a minute, it's called bradycardia (a normal adult heart rate is 60 to 100 beats per minute). A slow heart rate may be caused by medicines and is not a problem, unless it causes symptoms such as fatigue, shortness of breath, or lightheadedness. Your doctor may recommend a temporary or permanent pacemaker for you or may also change your medicine if your heart rate is too slow.

Heart block

Heart block is the blocking of electrical impulses through the heart. Some heart blocks do not need to be treated. It becomes serious when your heart beats too slowly to maintain good circulation. Heart block is caused by certain medicines, disease, or wear on the electrical conduction path. It may cause your heart to beat out of rhythm. If it worsens into complete heart block, impulses from the heart's atria don't reach the ventricle. The ventricles beat independently at a very slow rate. You'll become weak, dizzy or lightheaded. If you have a complete heart block, you may need a permanent pacemaker.

First published: 10/04/2002
Last updated: 06/01/2007

Reviewed by: Allina Patient Education experts