EKG
A graphical recording of the electrical events occurring within the heart.
Natural pacemaker of heart
1. Scientific term
2. Location in the heart
1. Sinoatrial node
2. Right atrium
What does the sinoatrial node initiate?
Electrical sequence/impulse
Pathway of electrical sequence/impulse
Passes down natural conduction pathways between the atria to the atrioventricular node and from there to both ventricles
A positive deflection in an EKG tracing represents electrical activity moving toward the active _____.
lead
Electrical Activation of the Heart;
1. Signal originates at _____ node
2. Signal spreads over _____; atria contract
3. Signal delays at _____ node
4. Signal spreads down conducting fibers to bottom of _____; ventricles contract
5. _____ relax
(1) SA
(2) atria
(3) AV
(4) ventricles
(5) Ventricles
Electrical activity (mV):
Step 0 - 1: _____ mV
Step 1 - 2: 0 mV to 0.1 mV to 0 mV
Step 2 - 3: 0.01 mV to _____ mV
Step 3 - 4: -0.01 mV to 1 mV to -0.04 mV to 0 mV
Step 4 - 5: 0 mV to 0.3 mV to 0 mV
...
PQRST:
1. P wave: Spreads from the _____ node downward from atria through the _____ node and to the ventricles.
2. QRS complex: _____ activation
3. T wave: _____ repolarization - Recovery of ventricular muscle tissue to its resting state
(1) SA, AV
(2) Ventricular
(3) Ventricular
Angina
Abnormal slowing, speeding, irregular rythms, injury to muscle tissue
Myocardial infarction
Death to muscle tissue
If the length of an interval is long or short, what does this indicate? What if complex is absent
Impulse followed a longer or shorter route. Also, impulse may have not reached part of the heart.
Normal depolarization of the atria leads to an absent _____ wave
P
Abnormally shaped EKG may be caused by _____ disease and _____
heart, medicines