[Exam 1] Chapter 26: Management of Patients with Dysrhythmias and Conduction Problems (Page 713-720, 734-736) Flashcards
Obtaining an Electrocardiogram: Biomonitoring electrodes come in various shapes in size, but have these two components
An adhesive substance that attaches to the skin to secure the electrode in place
- A substance that reducs the skin’s electrical impendance and enhancing conductivity
Obtaining an Electrocardiogram: How to improve conduction?
Gently abrading skin with a clean dry gauze
Don’t clean with alcohol
May need to clip hair
Obtaining an Electrocardiogram: Most continuous monitors use how many electrodes?
2-5, and they create a lead which serves as a reference point from which electrical activity is viewed
Obtaining an Electrocardiogram: To prevent interference from electrical activity of skeletal muscles, limb electrodes are placed on what type of areas?
Areas that are not bony and that do not have significant movement
Obtaining an Electrocardiogram: The limb electrodes provide the first
six leads.
Leads I, II, III, aVR, aVL, and aVF.
Obtaining an Electrocardiogram: Where is V1 placed?
Locate the fourth intercostal space is where this goes.
The sternal angle and then the sternal notch can help you locate it.
V1 Location spot
Fourth intercostal space, right sternal border
V2 location spot
Fourth intercostal space, left sternal border
V3 location spot
Diagnoally betwen V2 and V4
V4 Location spot
fifth intercostal space, left midclavicular line
V5 Location Spot
Same level as V4, anterior axillary line
V6 location spot
Same level as V4 and V5, mixaxillary line
A standard 12-lead ECG reflects the electrical activity primarily in the
left ventricle
An ECG waveform reflects the function of the
heart’s conduction system in relation to the specific lead. ECG ofers important information about the electrical activity of the heart and is useful in diagnosing dysrhythmias.
When an ECG waveform moves toward the top of the paper , it is called a
positive deflection
When it an ECG waveform moves towawrd the bottom of the paper, it is called a
negative deflection
What is measured on the horizontal axis of the graph?
Time and rate
What is measured on the vertical axis?
Amplitude or voltage
What does the P Wave represent?
The electrical impulse starting in the SA node and spreading through the atria.
This represent atrial depolarization
The atrial is contracting
Size and length of the P Wave?
- 5 mm or less
0. 11 seconds or less in duration
What does the QRS represent?
Ventricular depolarization
The ventricles are contracting and then relaxing
What is the first negative deflection after the P wave?
Q Wave
Size and length of Q Wave?
Less than 25% of R-Wave Amplitude
Less than 0.04 second
What is the first positive deflection after the P Wave?
R Wave
What is the first negative deflection after the R wave.
S Wave
When the wave is less than 5 mm in height, what is used?
Small letters for qrs
When the wave is 5 mm or higher, what is used?
QRS in capitals
QRS wave length?
0.12 seconds
What does the T wave represent?
Ventricular repolarization (when the cells regain a negative charge, also called the resting state).
The T wave follows what in the same direction?
QRS
Atrial repolarization is not visible on the ECG because it occurs at the same time as
ventricular depolarization (QRS)
What is the PR Interval
Measured from the beginning of the P wave to the beginning of the WRS complex
What does PR Interval represent?
The time needed for sinus node stimulation, atrial depolarization and conduction through the AV node before ventricular depolarization
PR interval normally ranges from what time?
0.12to 0.2 seconds
What does the ST segment represent?
Early ventricular repolarization.
Lasts from end of QRS to beginning of the T wave.
If ST segment above the line, it indicates MI
Beginning of the ST segment is usually identified by a
change in the thickness or angle of the terminal portion of the QRS complex
The end of the ST segment may be more difficult to identify because it merges into the
T Wave
Why is the ST Segment analyzed?
To idetnify whether it is above or below the isoelectric line, which may be among other signs and symptoms a sign of cardiac ischemia
What is the QT interval?
Represents the total time for ventricular depolarization and repolarization. FRom beginning from QRS complex to end of T wave.
The WT interval varies with heart rate, gender, and age there the measured intervals need to be
corrected (QTc) for these variables through specific calculations.
Length of QT interval?
0.32 to 0.40 seconds if the heart is at 65-95 bpm.
What is the TP intervl?
Measured form end of T wave to beginning of P, anisoelectric period. No electrical activity is detected.
What is the PP intervl?
Measured from the beginning of one P wave ot the beginning of the next P wave.
Why is PP Interval used?
To determine atrial rate and rhythm
How is PP Interval measured?
Measured form one QRS complex to the next QRS complex
What is the RR interval used for?
Determine ventricular rate and rhythm
Normal conduction goes from the
SA NODe -> AV Node -> Bundle of his via the right and left bundle branches to the purjinje fibers
The HR is determined by
myocardical cells with the fastest firing rate, which are usually located in the SA node
Depolarization = stimulation =
systole.
This is when the heart is contracting
repolarization = relaxed =
diastole
When the chambers relax and allow blood to fill them.
First step in understanding an EKG strip is to get a
six second strip. You have to count 30 big boxes.
Each small box represent 0.04 seconds.
Each big box represents 0.2 seconds.
Second step in understanding an EKG strip is
Locating the Q wave in each box.
Third step in understanding an EKG strip is
Locating the QRS interval
You do not want this to be bigger than 0.12 seconds (three small boxes)
There are ticker marks located every how many boxes?
Every 10 big boxes.
Every small box represents
0.04 seconds.
Every big box represents
0.2 seconds
Fourth step in understanding an EKG strip is
Measure the PR interval measurement by
Locating the P wave and beginning of the Q wave. Time can be from 0.12-0.2 seconds.
If something stops in the middle of the small box, the time is
0.02 seconds
Fifth step in understanding an EKG strip is
Determine if HR is regular or irregular
You measure the distance between two R’s. If they are equal distance aparts, they are regular.
Sixth step in understanding an EKG strip is
Determining the HR. Within the six second strip, count the R waves and multiply by 10.
What is ST Elevation?
There is cardiac tissue that has died.
What is ST Depression?
Shows Cardiac Ischemia. Heart is lacking oxygen but hasnt died yet
How to remember ST Depression?
Imagine you are drowning and lacking surface. Once you have died, you’ll float to the surface with tissue death
The RR interval is used to determine
ventricular rhythm
The PP interval is used to determine
atrial rhythm
If the intervals are the same or if difference between intervals is less than 0.8 seconds throuhgout strip, rhythm is called
regular
What are Dysrhythmias?
DIsorders of formation or conduction (or both) of electrical impulses within heart
Dysrhythmias can cause disturbances of
Rate
Rhythm
Both Rate nd Rhythm
Dysrhythmias can potentially alter
blood flow and cause hemodynamic changes
Dysrhythmias diagnosed by
analysis of electrographic waveform
Sinus Node Dysrhythmias originiate in the
SA Node
Sinus Bradycardia occurs when
SA node creates an impulse at a slower-than-normal rate.
Causes of Sinus Bradycardia include
lower metabolic needs, vagal simulation, medications, idiopathic sinus node dysfunction, increased intracarnial pressure, and coronary artery disease
Unstable and Symptomatic bradycardia is frequently due to
hypoxemia, AMS, and acute decompensated heart failure
Sinus Bradycardia: Ventricular and Atrial Rate
Less than 60 bpm in adults
Sinus Bradycardia: Ventricular and Atrial Rhythm
Regular
Sinus Bradycardia: QRS shape and duration
Usually normal, but may be regularly abnormal
Sinus Bradycardia: P Wave
Normal and consistent shape
Sinus Bradycardia: PR Interval
Consistent between 0.12 and 0.20 seconds
Sinus Bradycardia: All haracteristics are the same as those of normal sinus rhythm, except for the
rate
Sinus Bradycardia: If decrease in heart rate results from stimulation of the vagus nerve, attempts are made to prevent
further vagal stimulation
Sinus Bradycardia: SLow heart rate may be due to
sinus node dysfunction, which has a number of risk factors including increased age, white race, obesity, hypertension
Sinus Bradycardia: Medical Management for this?
0.5 mg of Atropine via IV bolus and repeated every 3-5 minutes until a maximum dosage of 3 mg is given
Sinus Tachycardia: When does this occur?
When the sinus node creates an impulse at a faster than normal rate
Sinus Tachycardia: What Physiologic or Psychological Stress may occur?
Acute blood loss, anemia, shock, hypervolemia, hypovolemia, heart failure)
Sinus Tachycardia: Medications that can cause this?
Meds that stimulate sympathetic response, stimulants, and illicit drugs
Sinus Tachycardia: Ventricular and Atrial Rate
Greater than 100 bpm in the adult, but less than 120 bpm
Sinus Tachycardia: All aspects are same as those of normal sinus rhythm except for
the rate
Sinus Tachycardia: Other things that can cause this is
Exercise, Stress, Pain, Infection, FEar, Bleeding
Sinus Tachycardia: If this is a true conduction disorder, we would have them
Bear down , to cause vagal stimulation.
Sinus Tachycardia: Synchronized Cardio Version
Low shock is given to reset the SA node to reset into a normal heart
Sinus Tachycardia: Medical Management
6 mg Adenosine and then followed by 12 mg dose.
If it doesn’t work, you can do synchronized cardio version.
QRS Complex and Hypokalemia
QRS will be widened if you have low potassium.
Caring for Patient with a Dysrhythmia - Assessment: Causes of dysrhythmia and contributing factors
Health history and medications
Caring for Patient with a Dysrhythmia - Assessment: Physical assessment include
Skin (pale and cool)
Signs of fluid retention (JVD, lung auscultation)
Signs of decreased CO
Rate, rhythm of apical, peripheral pulses (want to make sure theyre the same)
Heart sounds blood pressure ,pulse pressure
Caring for Patient with a Dysrhythmia - Diagnoses: These include
Decrease CO
Activity Intolerance
Decreased tissue perfusion
Anxiety
DEficient Knowledge
Caring for Patient with a Dysrhythmia - Complications and PRoblems
Cardiac Arrest
Heart Failure
Thromboemboli Event (especially with atrial Fibrillation)
Caring for Patient with a Dysrhythmia - Goals: This includes
Eradicating or decreasing occurence of dysrhythmias to maintain cardiac output
Minimizing Anxiety
Acquiring knowledge about dysrhythmia and its treatment
What does Cardiac Stress Testing Determine?
CAD
Cause of Chest Pain
Function of heart after MI or surgery
Effectiveness of antiaginal and antiarrythmic meds
Occurrence of dysrhythmias
Contraindications of Cardiac Stress Testing
Severe Aortic Stenosis or Hypertension,
Acute myocarditis
Suspected left main CAD
HF
Unstable Angina
Cardiac Stress Testing Patient Preparation
Fasts for four hours and avoid stimulants prior to test
Cardiac Stress Testing can be done how many ways?
Through medicine or exercise
Cardiac Stress Testing, ECG applied and pt is monitored for
HR
Rhythm
Perceived Exertion
VS
Skin Temp
Cardiac Stress Testing stopped when
target HR reached or if pt shows signs of ischemia
Pharmacologic Stress Testing uses what two medications
Adenosine and Dipyridamole
Pharmacologic Stress tTesting; what medicine cannot be used
No Theophylline , Aminophylline or Dipyridamole 24/48 hours before test
Pharmacologic Stress Testing : May feel sick due to
the adenosine the pt may feel flushing and nausea
Pharmacologic Stress Testing: Monitored for 1-3 hours because
it takes time ot wear off
Echocardiography: TRansthoracic goes through
ultrasound via chest well
Echocardiography: TEE works how?
Ultrasound via esophagus
Echocardiography: Prior to TEE, pt
is NPO for 6 hours, dentures removed
Echocardiography: During TEE
Moderate sedation and topical anesthetic, monitor VS, LOC, ECG, O2 Sat
Echocardiography: TEE recovery
Keep HOB 45 degrees, bedrest 2 hours, gag reflex assessed after2 hours and monitor vs.
Sore throat for 24 hours
How does Radionluclide Imaging Work
Myocardiac perfusion imaging
Can be done with stress test to check perfusion
Pt is injected with radionuclear dye
Cardiac Catherization: What is this?
Invasive procedure study used to measure cardiac chamber pressures, assess patency or coronary arteries
Cardiac Catherization: What does this require?
Recquires ECG, hemodynamic monitoring; emergency equipment must be available
Cardiac Catherization: Assessment prior to test
Test for allergies, blood work, pt to fast 8-12 hours prior, need someone to drive pt home
Cardiac Catherization: Duration
Take up to 2 hours and pt will be lying on hard table
Cardiac Catherization: Prior to procedure
Consent signed, Fast 8-12 hours, allergies to dye
Cardiac Catherization: During Procedure
Will experience pounding sensation in chest due to extrea beat when catheter touches endocardium
Injected with contrast agent (will give a flushed sensation)
May have to cough and deep breathe during procedure
Cardiac Catherization: Post Procedure
Assess pulses every 15 minutes, then every hr
Assess for bleeding
Assess for dysrhythmias by monitor
Assess temp, color, cap refill
Bedrest 2-6 hrs with effected leg straight
Increase fluid to flush dye to protect kidneys
Assess for orthostatic hypotension
