Heart block is when signals that control the heartbeat are partly or fully blocked. This leads to slow or skipped heartbeats. It also makes it hard for the heart to pump blood. Heart block can range from mild to serious and life-threatening.
There are 3 types of heart block:
First-degree (mildest type)—The heart signals move more slowly from one heart node to another.
Second-degree—Signals from the upper to lower heart are blocked, off and on.
Third-degree, or complete (most serious)—The heart signals cannot pass from the upper to the lower heart at all. This needs care right away.
Atrioventricular (AV) conduction disorders. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/atrioventricular-av-conduction-disorders. Accessed September 14, 2021.
Atrioventricular block. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/cardiovascular-disorders/arrhythmias-and-conduction-disorders/atrioventricular-block. Accessed September 14, 2021.
Bolourchi M, Silver ES, et al. Advanced heart block in children with Lyme disease. Pediatr Cardiol. 2019;40(3):513-517.
Heart block. Heart Rhythm Society website. Available at: https://upbeat.org/heart-rhythm-disorders/heart-block#axzz2OHs4EXZq. Accessed September 14, 2021.
Heart conduction disorders. American Heart Association website. Available at: https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disorders. Accessed September 14, 2021.
Last reviewed July 2021 by
EBSCO Medical Review Board
Nicole Meregian, PA
Last Updated: 9/14/2021
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at firstname.lastname@example.org. Our Health Library Support team will respond to your email request within 2 business days.