Understanding AV Blocks
One of the first things I try to teach the participants in my classes is the meaning of the term atrioventricular block – commonly abbreviated as “AV block.” So many people try to equate that term with the AV node. That is understandable since they both contain the letters “AV.” But the AV node is just a small portion of the concept of atrioventricular. Atrioventricular refers to that portion of the heart from the first right atrial myocyte depolarized by an impulse generated in the sinus node to the first ventricular myocyte activated about half-way down the left side of the interventricular septum. As a matter of fact, the two most dangerous AV blocks do not involve the AV node at all! AV blocks can occur at the least expected times and can create confusion for many medical personnel attending critically ill patients – including perfusionists!
I am going to discuss first degree, second degree and third degree AV blocks and hopefully make the concept more understandable for many of you. First, let me dispel three pieces of misinformation…
Dr. Jerry W. Jones: Medicus of Houston was established by Jerry W. Jones, MD FACEP FAAEM. Graduate of Tulane University and the University of Texas Health Science Center at San Antonio. Dr. Jones has been on the teaching faculties of the University of Oklahoma and The University of Texas Medical Branch in Galveston. He is a published author who has also been featured in the New York Times and the Annals of Emergency Medicine for his work in the developing field of telemedicine. In addition, Dr. Jones is also a Fellow of the American College of Emergency Physicians, a Fellow of the American Academy of Emergency Medicine and a member of the European Society of Emergency Medicine