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20 Cards in this Set

  • Front
  • Back
AVF Leads for ECG
Uses L foot as the + lead and arms as the - leads.
AVR leads for ECG
Uses R arm as the + lead
AVL lead for ECG
Uses L arm as the + lead
Autonomic Nervous System
Controls all organs and organ systems. Consists of sympathetic and opposing parasympathetic systems.
Sympathetic NS terminal ends secrete what?
Nor-epinephrine an adrenaline- like neurotransmitter that activates adrenergic receptors.
Parasympathetic NS terminal ends secrete what?
Acetylcholine which exclusively activates cholinergic receptors.
What does Nor-epinephrine do?
Stimulates the Beta 1 (adrenergic) receptors stimulating the SA node to pace faster.
Where else does N-epi work?
AV node in conjuction w/ SA node to improve conduction and increase the myocardial contraction
Acetylcholine does what?
Activates the cholinergic receptors that inhibit the SA node decreasing the HR and depresses the AV node.
What is the SA node?
Heart's pacemaker: 60-100 bpm dominant center of automaticity
If SA node fails what then?
Other pacemakers w/ automaticity or ectopic foci will take over. These are in the atria, the ventricles, and the AV junction.
Atrial automaticity rate?
Inherent rate: 60-80 bpm
AV junction rate?
A slower rate: 40-60 bpm
Ventricular rate?
20-40 bpm
What is Rapid Automaticity?
Suppresses the slower rates to use the highest heart rate available.
P wave?
Depolarization of the atrial myocardium. Stimulus passes down the atria to the AV node where it pauses.
Why is there a pause after the atrial depolarization?
Allows the contraction of the atria to force the remaining blood into the ventricles.
What is the QRS complex?
Depolarization of the ventricles
What is the T wave?
The repolarization of the ventricles.
When does the atrial repolarization take place?
It happens during the depolarization of the ventricles and cannot be seen electrically.