Ch.18 Egans Flashcards
The _____ is the most important diagnostic tool that in some settings is obtained by the respiratory therapist
ECG
Why is the ECG so popular?
- inexpensive
- noninvasive
- easy to obtain
Why is the ECG used?
To help evaluate a pt with signs and symptoms of cardiac disease
What can an ECG also be used for?
To detect abnormalities that already occur in pts w/ an MI or preoperative screening
The muscle cells of the heart normally are stimulated and pace by the electrical activity of the cardiac______?
Impulse conducting system
The cardiac muscle cells generate electrical imbalance across the cell membrane with a ________charge on the outside, and a _______charge on the inside
Positive ; negative
What is the resting or polarize state?
When there is no electrical activity
Stimulation of _______ cells causes an influx of ______into the interior portion of the cell?
Polarized ; Na+
An influx of Na+ into the interior portion of the cell is called what?
Depolarization
Depolarization causes the cardiac muscle cells to ________momentarily?
Contract
Depolarization is immediately followed by what?
Repolarization
What is a repolarization?
A rapid return of the cell to the “polarized” position in which an electrical imbalance across the membrane is reestablished
The impulse conduction system has three types of cardiac cells capable of electrical excitation. What are they?
• Pacemaker cells
• specialized rapidly conducting tissue
• AV muscle cells
The ability of the cells to depolarize without stimulation is known as_______?
Automaticity
The impulse conduction system is responsible for_____ and _______? It also does what?
Initiating the heartbeat ; controlling the heart rate ; coordinates the contraction of the heart chambers
A deceptive the impulse conduction system may lead to what?
Inadequate cardiac output and decreased tissue perfusion
Where is the SA node located?
Upper portion of the right atrium
T or F the SA node has the greatest degree of automaticity and paces the heart
True
The AV node is the _______ pacemaker
Backup
T or F the AV node has the second greatest degree of automaticity in a healthy heart
True
The AV node paces ventricular activity at a lower heart rate of _______?
40 to 60 bpm
Once the impulse exits the AV node where does it go?
It enters the bundle of His and rapidly moves to the bundle branches
The bundle branches_______ the purkinje fibers
Terminates
What is the equipment that is gathered for a 12 lead ECG?
• portable ECG unit
• lead wires
• electrodes
The 12 leads are subdivided into two groups:
6 extremity (limb) leads
6 chest (percordial) leads
The 12 leads are bipolar which means what?
They permit the measurement of electrical activity in two different directions
What are the limb leads called?
1,2,3,aVr, aVL, aVf
What are the six chest leads called?
V1, V2, V3, V4, V5, V6
Where is the V1 lead located?
The fourth intercostal space to the right of the sternum
Where is the V2 lead located?
In the fourth intercostal space just to the left of the sternum and ending with a V6
How large is one box on an ECG?
0.20 seconds
How large is one small box within one box on the ECG?
0.04 seconds
If the QRS complex is longer than three small boxes, what does that mean?
There are ventricular problems
The QRS complex on the ECG equals how many small boxes?
3 small boxes
What is the number one cause of sinus tachycardia?
Hypoxemia
What is the treatment for bradycardia?
Atropine
What are the steps to interpreting an ECG?
- Identify the atrial and ventricular rates
- Measure the PR interval
- Evaluate the QRS complex
- Evaluate the T-wave
- Evaluate the ST segment
- Identify the RR interval
- Identify the mean QRS axis
A normal sinus rhythm has what type of P wave?
Upright
How long does the PR interval last?
0.12 to 0.20 seconds
How long does the QRS complexes last?
0.12 seconds
The ST segment is _____?
Flat
How long does the PR interval last?
0.12 seconds between QRS complexes
What is the normal adult heart rate?
60-100bpm
What is sinus arrhythmia?
It’s recognized by the irregular spacing between QRS complexes
How long does the RR interval last during a sinus arrhythmia?
More than 0.12 seconds
Sinus arrhythmia may occur with affects of breathing on the heart, or as a side effects of medication, such as______?
Digoxin
Most cases of sinus arrhythmia are______ and do not need treatment?
Benign
What is first-degree heart block?
The PR interval is longer than 0.20 seconds
What is another name for second-degree heart block?
Type 1(Wenckebach or Mobitz type 1)
What is third-degree heart block?
It indicates that the singnal between the atria and the ventricles is completely block
The atria and ventricles are paced by _____ sources?
Independent
In 3rd degree block the P-P and R-R intervals are _____ but have no correlation with each other
Regular
What is atrial flutter?
The rapid depolarization of the atria resulting from an ectopic focus that depolarizes at a rate of 250 to 350 times per minute
What kind of pattern will you see in atrial flutter?
Sawtooth baseline pattern
What kind of conditions can produce atrial flutter?
Rheumatic heart disease, coronary heart disease, pulmonary embolism, stress, renal failure, and hypoxemia
What is the treatment for atrial flutter?
Digoxin, beta blockers, calcium channel blockers
What is atrial fibrillation?
The atrial muscle quivers in an irregular pattern
The ventricular rate is often very______ in atrial flutter
Irregular
What is ventricular tachycardia?
A run of three or more PVCs
What do the waves look like on ventricular tachycardia?
A series of wide bizarre QRS complexes that have no preceding P wave
What is the ventricular rate for ventricular tachycardia?
100 to 250 bpm
What is ventricular fibrillation?
Erratic quivering of the ventricular muscle mass it causes the cardiac output to drop to zero
What is the most life-threatening arrhythmia?
Ventricular fibrillation
What kind of shape will you see in ventricular fibrillation?
Irregular fluctuations with a zigzag pattern
How do you fix ventricular fibrillation?
• Rapid defibrillation
• cardiopulmonary resuscitation
• administration of O2
• anti-arrhythmic medications
A V-tach is left untreated what could it progress to?
V-fib
What are some meds for V fib?
Amiodarone or adenosine
What is some medication for PVCs?
Lidocaine
What is PEA?
A serious condition characterized by a disassociation between the electrical and mechanical activity of the heart
What happens during PEA?
The heart generates an electrical signal that produces an ECG pattern on the monitor but the heart does not mechanically generate a pulse
PEA is relatively_______?
Rare
What kind of conditions will you see with PEA?
• Pneumothorax
• MI
• Drug overdose
• Severe electrolyte or acid base disturbance
What are the Hs? 7 total
• Hypovolemia
• hypoxia
• hyperkalemia
• hypokalemia
• hyperthermia
• hypoglycemia
• acidotic state too much H+ ions
What are your Ts? 6 total
• Trauma
• Tension pneumothorax
• Toxins (poison)
• Tamponade (cardiac)
• Thrombosis (coronary)
• Thrombosis (pulmonary)
Name this arrhythmia?
Normal sinus rhythm
Name this arrhythmia?
Sinus tachycardia
Name this arrhythmia?
Sinus bradycardia
Name this arrhythmia?
Sinus arrhythmia
Name this arrhythmia?
First-degree heart block
Name this arrhythmia?
Second-degree heart block type 2
Name this arrhythmia?
Third-degree heart block
Name this arrhythmia?
Atrial flutter
Name this arrhythmia?
Atrial fibrillation
Name this arrhythmia?
PVC
Name this arrhythmia?
Ventricular tachycardia
Name this arrhythmia?
Ventricular fibrillation
