The purpose of the electrical conduction system of the heart?
Initiates an impulse whose purpose is to stimulate the mechanical cells of the heart to contract
What two things verify that cardiac contraction has occured?
Blood Pressure and Pulse
Sinoatrial Node
Pace maker of the heart
Sinoatrial node firing rate?
60 - 100 bpm
Atrioventricular node (AV node) firing rate?
40 - 60 bpm
Period from the beginning of one heartbeat to the beginning of the next
Cardiac cycle
Three complexes in a cardiac cycle?
P wave
QRS complex
T wave
The best view to read a ECG?
Lead 2 or MCL
When the ECG does not detect electrical current or positive and negative electrical activity are equal, a straight line is produced; which is called?
Isoelectric line
The first wave of the cardiac cycle
P wave
What does the P wave represent?
Atrial depolarization ( Contraction)
Normal P waves appear to be what shape?
Rounded
The electrical impulse that spreads from the R. to L. atrium comes from where?
When the SA node fires
Disorders that change atrial size cause what in the P wave?
Alterations of shape and size
This segment represents the time it takes the electrical impulse to travel from the SA node to the AV node.
PR interval
The normal amount of time of the PR interval?
0.12 - 0.20
Complex represents ventricular depolarization (contraction), composed of what three waves?
QRS complex
Q, R, S, waves
The first downward deflection after the P wave?
Q wave
The first upward deflection after the P wave?
R wave
The first negative deflection after the R wave?
S wave
This wave represents ventricular repolarization ( relaxation) .
T wave
The resting state of the heart, when the ventricles are filling up with blood and preparing to receive the next impulse?
Ventricular repolarization
The time from completion of a contraction to recovery of myocardial tissue for the next impulse?
ST segment
What happens to the ST segment with cardiac injury?
The ST segment elevates from the Isoelectric line
What is the 6 step process for dysrhythmia interpretation?
1. Regularity of rhythm?
2. HR
3. Is there P waves in front of QRS complex
4. PR interval
5. QRS interval normal?
6. QT segment normal?
True or False:
An irregular rhythm can be regularly irregular which means it has a predictable pattern of irritability or irregularly irregular, without any pattern of irregularity?
True
Normal cardiac rhythm?
Normal Sinus Rhythm
What makes the Normal sinus, a normal cardiac rhythm?
because it begins in the SA node, and has a complete, regular cardiac cycles at 60 - 100 bpm
Has the same cardiac cycle components as a normal sinus rhythm, except a slower HR.
Sinus bradycardia
What can cause Sinus bradycardia
Digoxin
electrolyte imbalances
MI
What are signs and symptoms of sinus bradycardia
fainting or fatigue
Has the same components as a normal sinus, except the heart rate is more than 100 bpm