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What is bradycardia (slow heart rate)?

Bradycardia is a heart-rhythm disturbance, or arrhythmia. An electrical signal in the heart causes a contraction of the heart muscle, which not only pumps blood but creates your heartbeat. A problem along this electrical pathway causes an abnormal heartbeat. Bradycardia refers to the heart beating too slowly, fewer than 60 beats per minute.
Douglas E. Severance, MD
Family Medicine
Bradycardia refers to a slow heartbeat that is less than 60 beats per minute. If you are physically fit, you may have a slow heart rate at rest, and this is perfectly normal for you. But a heart rate lower than 60 beats a minute at rest may indicate a more serious problem for someone who is not physically fit.

Sometimes bradycardia means that the heart is not pumping enough blood through the body. Types of bradycardia include sick sinus syndrome and conduction blocks. With sick sinus syndrome, the sinus node, or the heart's natural pacemaker, isn't sending the electrical impulses properly. Sick sinus syndrome may be the result of scar tissue near the sinus node, which can result in stopping or disrupting the travel of the impulses. With a conduction block, the electrical impulses between the upper and lower sections of the heart may slow down or stop. Sometimes there are no symptoms when the impulse is blocked, yet other times you will experience bradycardia (slow heartbeat) or even skipped heartbeats.
Vivek Y. Reddy, MD
Clinical Cardiac Electrophysiology
Bradycardia is a slowed heart rate. It can cause people to faint or feel as if they will faint. They may also experience chest pain, fatigue, or shortness of breath. Aging, chemical imbalance, or low thyroid hormone levels can cause bradycardia. Uneven electrical flow across the heart can also be a factor.
Anthony L. Komaroff, MD
Internal Medicine
Bradycardia usually refers to a resting heart rate under 60 beats per minute. While that may be low for someone who doesn't exercise, it isn't unusual for someone who does. (Spanish bicyclist Miguel Indurain, for example, once had his resting heart rate measured at 29 beats per minute!)

Your cardiologist might want you to have a stress test to see how your heart accelerates with exertion. An appropriate increase indicates that the sinus node (the heart's natural pacemaker) is working properly, which decreases worries about a low heart rate. A poor increase in heart rate with exertion, whether the resting heart rate is slow or fast, suggests the sinus node is failing and a pacemaker may be needed.
Bradycardia is the medical term often used to describe a slow heart rhythm. In a slow arrhythmia, the heart signals do not fire as they should, causing the heart rate to slow down.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.