Care of the patient with dysrhythmias and pacemakers Flashcards
What are the four properties of the heart?
Automaticity, Conductivity, Contractility, Excitability
How can you assess the contractility of the heart?
Check for a pulse
The hearts ability to generate an electrical signal is called…
Automaticity
The hearts property that allows it to be stimulated is called…
Excitability
What’s the normal conduction pathway of the heart?
SA node-> Atrial myocardium-> Bachmann’s Bundle->
AV node-> Bundle of His-> Left and Right Bundle Branches->
Purkinje fibers-> Ventricles
What’s the intrinsic rate of each site within the pathway of the heart?
SA node 60-100
AV node 40-60
Purkinje fibers 20-40
What cations migrate into the cell during depolarization?
Na+ (Sodium) and Ca+ (Calcium)
What does “depolarization” represent?
Initiation of a contraction
What cation migrates into the cell during repolarization?
K+ (Potassium)
What precordial chest lead is placed over the PMI during a 12 lead EKG?
V4
ECG Small block represents
0.04 secs
ECG Large block represents
0.2 secs
30 Large ECG’s blocks
6 secs
P wave reflecs
Electrical impulse from the SA node -initiates atrial depolarization
PR interval represents
Time an electrical impulse travels through the atria, AV node, Bundle of His, Bundle Branches to the Purkinje Fibers
QRS represents…
Depolarization of the ventricles
Repolarization of the atria
T wave reflects
Repolarization of the ventricles
QT represents
Complete depolarization and repolarization of ventricles
What’s a normal PR interval?
0.12-0.20 secs
What’s a normal QRS?
0.04-0.12 secs
How do you determine the most accurate rate in a regular rhythm ECG?
Count number of small blocks between R waves and divide into 1500
Elevation of ST segment means?
Injury
Depression of ST segment means?
Ischemia
Peaked T waves…
Hyperkalemia
Flat T waves…
Hypokalemia
A prolonged QT interval can lead to?
Torsades de Pointes
