Your heart has a complex way of sending electrical signals through the muscle to tell the muscle to contract and squeeze blood out to the lungs or the body. When there are interuptions in these electrical signals, we call these conduction disorders.
Conduction disorders are very common.
-low amplitude fibrillatory waves without discrete p waves and an irregularly irregular pattern of QRS complexes.
-reg, sawtooth pattern, atrial rate of 250-350 BPM, narrow QRS complexes
First Degree AV Block
-PR Interval >0.2 sec
-Actually a misnomer bc it is a delay rather than a block
-Caused by conduction delay at AV node or Bundle of His, meaning the PR interval will be longer than normal at >0.2 sec
Second Degree AV Block Type 1 (Wenckebach)
-“longer, longer, longer, drop now you’ve got a wenckebach.”
-some impulses are blocked but not all
-more p waves can be observes vs. QRS
-each successive impulse undergoes a longer delay
-after 3 or 4 beats, the next impulse is dropped
Second Degree AV Block Type 2 (Mobitz)
-“some get dropped and some get through, now you’ve got mobitz 2.”
-impulse blocked at Bundle of His
-missing beat every few beats, but PR interval will NOT lengthen
Third Degree AV Block
-“p’s and q’s don’t agree, now the block is 3rd degree.”
-no atrial impulses are transmitted to ventricles
-in response, ventricles generate an “escape impulse” independent of atrial beat
-usually, atria beat 60-100 bpm while ventricles beat 30-45 bpm
Bundle Branch Block
-Left:R and R’ upward bunny ears in V4-V6, notching
-Right:R and R’ upward bunny ears in V1-V3
Paroxysmal Supraventricular Tachycardia
-Atrioventrical nodal reentrant tachycardia (AVNRT):any tachydysrythmia arising from above the level of the Bundle of His
-Wolff-Parkinson-White (WPW) Syndrome:caused by abn accessory electrical conduction pathway bt atria and ventricles (Bundle of Kent fibers). EKG hallmark includes short PR interval, wide QRS, and delta waves
A few others…
Sick sinus syndrome
Torsades de Pointes
Cardiology NCCPA Blueprint Review Course. SMARTY PANCE. https://smartypance.com/courses/cardiology/. Accessed April 24, 2018.