Basic ECG Flashcards
What is the conducting pathway of the heart?
- SA node
- Anterior, posterior, and middle fascicles
- AVN
- Bundle of His
- Right bundle branch (RBB) and left bundle branch (LBB)
- Purkinje fibers
What are the 3 types of cardiac cells?
- Pacemaker Cells
‒Determine the heart rate and initiate heart beats - Electrical Conducting Cells
‒Deliver the impulse to the myocardial cells - Myocardial Cells
‒Contract and pump blood out of the heart
What are the two types of pacemaker cells?
- SA node (SAN)
- This is the primary pacemaker of the heart (is responsible for setting the heart rate)
- The SA node rate is 60-100 beats per minute (bpm) - AV node (AVN)
- The AV node becomes the pacemaker if for some reason the SA node fails
- The AV node rate is 40-60bpm
If the AV and SA node fail, what sends the impulse to contract?
Myocardial cells transmit current more slowly (less effectively) than electrical conducting cells
What is a normal QRS complex?
What leads to a wide QRS complex?
When current travels through the muscle, current transmission is a lot slower, and this leads to a “wide” (normal) QRS complex
What are leads 1 and 2?
What is a 3 lead ECG?
A 3 lead ECG utilizes electrodes on the right arm, left, arm, and left leg
Lead 1
Lead I (white to black) detects the electrical difference between the right arm (-) and left arm (+)
Lead 2
Lead II (white to red) detects the electrical difference between the right arm (-) and left leg (+)
Lead 3
Lead III (black to red) detects the electrical difference between the left arm (-) and left leg (+)
5 Lead ECG
What does a small and large box indicate on ECG paper?
5 large boxes
‒1 second
300 large boxes
‒1 min
What is this patients heart rate?
HR will be 300 divided by the number of large boxes between each beat
So… ~140bpm
Label waves, segments, and intervals in a ECG wave
What does a p wave represent?
What does a QRS complex represent?