NUR 211 Perfusion 1
- Atrial fibrillation
Answer -rapid atrial ectopic rhythm (chaotic atrial activity)
-atrial rates 350-500 bpm
-no P waves
waves are small, quivering fibrillatory waves, R wave irregular
-if few atrial stimuli pass through the AV junction
Ventricular response is slow and the ventricular rhythm is irregular
-if too many atrial stimuli pass through the AV junction there is a rapid ventricular response
- Five lead placement
Answer preferred monitoring over 3 lead system V1 lead in 4th ICS RSB
-chest lead can be moved to monitor precordial leads -advantage is viewing two or more diff leads simultaneously
- Test strip info for EKG
- Cardiac action potential
Answer horizontal and vertical lines= 1mm apart ea horizontal small square- 0.04 sec ea large square= 5 small=0.2 sec distance b/w two vertical markings=3 sec
Answer change in the electrical charge inside the cardiac cell when it is stimulated
- The major electrical charge carriers in cardiac muscle cells are 1 / 4
Answer sodium potassium calcium
- Cardiac action potential
Answer phase 0
Rapid depolarization-rapid increase of Na, cells become positive
- Cardiac action potential
Answer phase 1
Rapid repolarization- occurs at the peak of the action potential, Close Na channels and K leaves the cell making it more negative (repolarization)
- Cardiac action potential
Answer phase 2
Plateau- K permeability is low allowing the membrane to stay depolarized, Ca enters the cell leading to contraction
- Cardiac action potential
Answer phase 3
Final repolarization- increase of Na and Ca stops, rapid outward movement of K making the cell (-) and repolarization
- Cardiac action potential
Answer phase 4 2 / 4
Resting potential- the heart is in diastole (relaxed) there is no action potential being generated to lead to contraction
- P Wave
Answer depolarization of the atria, the inside of the cell becomes more positive during depolarization bc there is a rapid increase of Na into the cell. Depolarization is the electrical event within the cells that makes contraction occur in the heart
- PR interval
Answer onset of atrial depolarization to onset of ventricular depolarization 0.12-0.20
- QRS complex
Answer ventricular depolarization (contraction) <0.12
- ST Segment
Answer end of ventricular depolarization to the beginning of ventricular repolarization (reset/resting)
- T wave
Answer ventricular repolarization (resting) Peaked T wave= hyperkalemia
- U wave
Answer rarely seen, small positive deflection after T wave, seen in hypokalemia
- QT interval
Answer varies with HR, need table to calculate 3 / 4
- sinoatrial (SA) node
Answer the pacemaker of the heart
-responsible for the depolarization (contraction) of the atria -beats 60-100 bpm -this forms the P wave
- Dysrhythmias at the sinus node
Answer sinus tach sinus brady
sinus dysrhythmia sinus arrest and sinoatrial block sick sinus syndrome
- Atrial ventricular node (AV node)
Answer the gatekeep of the heart
-beats at 40-60 bpm -job is to delay the electrical impulse to the ventricles in order to allow all the blood to empty out of the atria before the ventricles contract, this prevents backflow into the atria (through the tricuspid valve)-regurgitation
- Steps in assessing a rhythm strip
- Determine the atrial and ventricular HRs
Answer
- Examine the rhythm to see if it is regular
- Look for the P waves
- Measure the PR interval
- Evaluate the QRS complex
- Examine the ST segment
- Identify the rhythm and determine its clinical significance
- normal sinus rhythm (NSR)
- / 4