Rapid Interpretations of EKGs - Chapter 4 highlights Flashcards
When examining an EKG, you should determine the ______ first.
rate
What is the normal rate of the SA node?
60 - 100 bpm
Focal areas of automaticity in the heart are known as?
automaticity foci (pronounced “FOE-sigh”) (also known as ectopic foci)
Where are other automaticity foci located? (3)
the atria the AV junction the ventricles
Does the AV node have automaticity foci?
no, the proximal end of the AV node has no automaticity foci (however, the middle and distal regions of the AV node, known as the AV junction DOES HAVE automaticity foci)
What is the inherent pacemaking rate of automaticity foci in the atria?
60 - 80 bpm
What is the inherent pacemaking rate of automaticity foci in the AV junction?
40 - 60 bpm
What is the inherent pacemaking rate of automaticity foci in the ventricles?
20 - 40 bpm
When rapid automaticity (pacemaking activity) suppresses slow automaticity, this is known as what?
overdrive-suppression (the SA node overdrive-suppresses the (slower) inherent pacemaking activity of all the automaticity foci below it)
What is another name for the rhythm when ventricular automaticity foci take over the pacemaking?
idioventricular rhythm
What are the two instances when idioventricular rhythms are present? (not patho problems, just think basic)
- all pacemaking centers above have failed 2. there is a complete block of conduction below the AV node (including the AV junction) that prevents any pacing stimulus above it from reaching the ventricles
In a physiological or pathological emergency, an irritable automaticity focus (singular of foci) may suddenly discharge at a rapid rate. What is this emergency rate?
150 - 250 bpm
What are the two triplets of numbers you should know when determining the rate the quick and dirty way? (using the thick lines on the EKG for reference)
With bradycardia, what is a quick and dirty way to determine the heart rate?
count the number of cardiac cycles in a 6 second strip and multiply that number by 10
