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What is the primary function of the SA node in the heart's conduction system?
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The SA node generates action potentials that set the heart rate.
What part of the heart's conduction system might be affected in Mobitz Type 2 heart block?
Mobitz Type 2 heart blocks can occur in the Bundle of His or bundle branches and sometimes the AV node.
What characterizes a first degree AV heart block?
A first degree AV heart block is characterized by a prolonged PR interval (>200 ms) with a consistent QRS complex after each P wave.
In Mobitz Type 2 heart block, what remains constant, and what occurs randomly?
The PR interval remains constant, and the QRS complexes are dropped randomly.
How does the impulse travel from the atria to the ventricles?
The impulse travels from the atria to the ventricles via the AV node, Bundle of His, right and left bundle branches, and Purkinje fibers.
Which type of heart block is associated with progressively lengthening PR intervals followed by a dropped QRS complex?
Mobitz Type 1 (Wenckebach) heart block.
What is a key feature of third degree (complete) heart block?
Atria and ventricles beat independently with no electrical communication between them.
Describe the pathway an electrical impulse takes from the SA node to cause atrial contraction.
The impulse travels through the atria using the internodal pathway and Bachmann’s bundle.
Explain the heart conduction system's role in a first degree heart block.
In a first degree heart block, there's a delay in electrical transmission in the AV node, leading to prolonged PR intervals.
How does the 'Heart Block Poem' help in remembering first degree heart block?
The phrase 'If the R is far from the P, then it must be a first degree' helps in remembering first degree heart block.
What does the 'Beat independently' phrase indicate in terms of heart block?
It indicates a third degree heart block where atria and ventricles beat independently.
What memory trick phrase corresponds to Type 1 Wenckebach heart block?
The memory trick phrase is 'Longer than drop'.
Name the components of the heart conduction system that are involved after the AV node.
Bundle of His, right and left bundle branches, and Purkinje fibers.
What structure is responsible for depolarization and contraction of the ventricles?
The Purkinje fibers are responsible for ventricular depolarization and contraction.
How is ventricular activity maintained during a third degree heart block?
Ventricular activity is maintained by junctional escape rhythms.
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