Lecture 1 - Intro Flashcards
What is an EKG?
graphic representation of the heart’s electrical activity
What are the two components of EKG interpretation?
descriptive analysis, clinical impression
Which part of heart dominates anterior view?
Right ventricle
Which part of heart dominates electrical view?
Levt ventricle
What is automaticity?
ability to create action potentials/pacemaking capability
What is the main function of the electrical conduction system?
create an electrical impulse and transmit it to the rest of the myocardium
Where is the conduction system in relation to the myocardium?
inside the myocardium
How are atrial myocytes innervated?
direct contact from one cell to another
What do the internodal pathways do?
transmit the impulse from the SA node to the AV node
What is the final component of the conduction system and what does it do?
purkinje system - innervates myocardial cells in ventricles
What is overdrive suppression?
pacemaker with highest rate sets the pace of all other cells that will follow
What creates the effective pumping action of the heart?
overdrive suppression - creates an organized beating of all cardiac cells in a specialized sequence
What is the order of pacemaker settings and backup system? (7)
SA node, atrial cells, AV node, Bundle of His, Bundle branch, Purkinje cells, Myocardial cells
What is the primary pacemaker?
SA (sinoatrial) node
What is the normal rate of the SA node? What is the rhythm originating from here called?
60-100 bpm. sinus rhythm
What is the SA node’s blood supply?
right coronary artery (sometime left)
What is the purpose of the internodal pathways?
transmit the impulse from SA node to the AV node
How many internodal pathways are there?
3: anterior, middle, posterior
What does the AV node?
responsible for slowing down conduction for atrial contraction-maximizes cardiac output
What is the AV node’s blood supply?
right coronary artery (always)
What is the only route of electrical communication between the atria and ventricles?
Bundle of His
Where does the left bundle branch begin and end?
begins at Bundle of His, ends at beginning of left anterior and left posterior fascicles (LAF, LPF)
What does the left anterior fascicle innervate? Where does it end and how many strands is it?
innervates anterior and superior left ventricle. terminates in purkinje fibers. single-stranded.
What does the left posterior fascicle innervate? Where does it end and what is its structure like?
Innervates inferior and posterior left ventricle. terminates in purkinje fibers. Fan-like structure.
Which is more easily blocked: left anterior fascicle or left posterior fascicle, and why?
The left anterior fascicle is more easily blocked because it is single-stranded. The left posterior fascicle is thicker, more difficult to block, and more difficult to interpret on EKG.