First Degree Heart Block || When the AV Node Just Won't Let Go

What happens when the AV node is too clingy and wants to spend a little more time with the impulse than needed? 

A first degree heart block!

Let’s talk 1st degree heart blocks!

In a normal heart, 🫀 the SA node (aka the pacemaker of the heart) will generate impulses that the AV node (aka the gatekeeper of the heart) promptly allows to pass through. When a 1st degree AV block is present, the original impulse is delayed at the AV node. This causes the PRI to be slightly longer than normal. Normal length is .12-.20 seconds (3-5 small boxes).

A first degree heart block can be caused by a STEMI because of the heart muscle injury, but can also be attributed to different medications, electrolyte imbalances and cardiac problems (chronic or acute). One of the most common causes, however, is just advanced age…..aka an old heart.

A 1st degree heart block is typically of no immediate concern to EMS providers unless in conjunction with a life-threatening condition or injury. As always, treat your patient’s complaint.

These patients do not typically present with any symptoms due to the heart block itself.

🚨 Disclaimer: This is not meant to be used as or in the place of professional medical advice. Remember to abide by your local protocol & stay within your scope of practice.  🚨