Heart rhythm refers to the rate and pattern at which the heart beats. The electrocardiogram (EKG) strip below demonstrates the heart’s normal pattern of beating (normal sinus rhythm). A normal heart rate is 60 to 100 beats per minute. You can see that the heartbeat pattern is regular and even.

Whenever the impulse that signals the heart to beat is interrupted or distorted in some way, heart rhythm will be irregular, and the heart may not pump blood effectively. This is called dysrhythmia or arrhythmia.

Not all heart rhythm changes are harmful, and in many cases, people are not even aware of an occasional irregular heart rhythm. Many people experience either a slow or fast heartbeat every now and then.

However, you should contact your doctor if your heart rate or rhythm changes and does not return to normal. Your doctor may order simple tests to determine how often you are experiencing heart rhythm changes, how long they last, and what part of the heart they affect. In most cases, medication and/or lifestyle changes can help control dysrhythmia.

Do you experience any of the following symptoms frequently or for more than 5 minutes at a time?

• extreme weakness or fatigue
• dizziness, faintness or light-headedness
• shortness of breath
• chest discomfort or pain
• nausea
• sweating without exertion
• palpitations or a fluttering feeling in your chest

Several different types of dysrhythmia may occur by themselves or in combination. The following descriptions will help you understand the medical terms when describing the different types of dysrhythmia.

Bradycardia
Bradycardia is a slow heartbeat. Bradycardia occurs when the heart beats slower than 60 beats per minute. Many people have a slow heartbeat without even knowing it, and some medications may cause a slow heart rate. Slow heartbeat can be normal, but you should not feel dizzy, faint, weak or tired. If your heartbeat is so slow that you have these symptoms, call your doctor or go to the emergency room.

Tachycardia
Tachycardia is an unusually fast heartbeat. Tachycardia occurs when the heart beats more than 100 times per minute. It can happen suddenly and last just a few minutes, or it can last much longer. If tachycardia causes you to feel short of breath, dizzy, weak, sweaty or faint, contact a Banner Heart Care Center as soon as possible or go to the emergency department.

Premature Ventricular Contractions (PVCs)
Premature Ventricular Contractions (PVCs) are heartbeats that begin too early. PVCs are early heartbeats that start in the heart’s ventricles instead of the sinus node. They occur both in healthy people and people with heart disease. Stress, anxiety, caffeine and certain drugs can cause occasional PVCs even in young adults. PVCs may be harmless, or they can signal the beginning of more serious dysrhythmia.

You may experience any of the following symptoms:

• a fast heart rate, a “fluttering” feeling
• light-headedness or dizziness.

There are medications that can control PVCs. It may also help to make the following lifestyle changes:

• make sure you get enough sleep
• avoid caffeine, alcohol and street drugs
• try to reduce the stress in your life.
  See Control Techniques in the Risk Factors section of this book.

Atrial fibrillation
Atrial fibrillation is fast, irregular heartbeat. When atrial fibrillation occurs, the muscles in the heart’s upper chambers (atria) quiver instead of contracting. The quivering causes the heart to be less efficient, and it pumps less blood to the body. You may experience atrial fibrillation if you have valve problems or if you have had a heart attack or heart surgery.

You may experience any of the following symptoms:

• a feeling of weakness
• palpitations
• chest discomfort
• light-headedness or dizziness
• shortness of breath