Flashcards in Quiz 1 Deck (112)
Graphic representation of the heart's electrical activity.
When interpreting an EKG, what should you look at?
1. Your Patient
2. Clinical Correlation
3. Comparison with old tracing (if available)
How should you approach reading an EKG?
Anatomically, what chamber of the heart dominates the anterior surface?
Electrically, what chamber of the heart dominates?
All cardiac cells have the ability to create action potentials. This is called:
Cells in the electrical conduction system can:
Create Impulses (pacemakers) and/or trasmit impulses
What is the main function of the electrical conduction system?
Create an electrical impulse and transmit it to the rest of the myocardium.
P.S. This is the electrical energy picked up by an EKG
Where does the conduction system occur?
Inside the myocardium
How are atrial myocytes innervated?
Direct Contact from one cell to another
What is responsible for transmitting the impulse from the SA node to the AV Node
What is the final component of the conduction system that innervates the ventricular myocytes?
Purkinje Fiber System
The term for when a pacemaker cell with the highest rate sets the pace for all the subsequent cells?
What does overdrive suppression accomplish?
Organized beating of all cardiac cells in specialized sequence --> effective pumping action
Order of Pacemaker Cells
SA Nodes (60-100)
Atrial Cells (55-60)
AV Node (45-50)
Bundle of His (40-45)
Bundle Branch (40-45)
Purkinje Cells (35-40)
Myocardial Cells (30-35)
What is the primary pacemaker? It controls the heart beat based on information it receives from the nervous, circulatory and endocrine systems
Sinoatrial (SA) Node
What is the general bpm for the SA Node
If a heart rhythm originates in the SA Node, what is it called?
Where is the SA Node located?
The wall of the right atrium at its junction with the SVC
Where does the blood supply for the SA node come from? Why is this important?
Right Coronary Artery (sometimes left). It's important because if there is a disruption in blood supply then there needs to be compensation for it -- aka another node in function, or an arrhythmia is occurring (SA Node dysfunction)
What is the main purpose of the Internodal Pathways?
Transmit the pacing impulse from the SA node to the AV node.
Where are the internodal pathways located?
Walls of the Right atrium and inter-atrial septum
What are the three main internodal pathways?
This node is located in the wall of the right atrium next to the opening of the coronary sinus and tricuspid valve. It is responsible for slowing down conduction from atria to ventricles long enough for atrial contraction.
What does the AV node help do (by slowing down conduction from atria to ventricles)?
Maximizes Cardiac Output
The AV node is supplied by? (Blood)
Right Coronary Artery
Where does the Bundle of His begin?
At the AV node
Where is the Bundle of His located?
Partially in the right atrium as well as the interventricular septum
What is the only route of electrical communication between the atria and the ventricles?
The Bundle of His