EKG Flashcards
Normal PR Interval
0.12 - 0.2 seconds (5 small squares)
Where is the electrical impulse generated from if the EKG is showing normal sinus rhythm?
SA node
PR interval for sinus bradycardia
Normal (0.12 - 0.2 seconds)
Where is the electrical impulse generated from in the EKG is showing normal sinus rhythm?
Could possibly be the AV node but could also be the SA node
Sinus Bradycardia Treatments
If patient is symptomatic:
- Atropine 0.5 mg IVP every 3-5 minutes with maximum total dose of 3 mg
- Transcutaneous pacing
Possible Symptoms a Bradycardic Patient might experience
- Hypotension
- Diaphoretic
- Drowsiness
- Cyanotic/Dusky
Causes of Sinus Bradycardia
- Lower metabolic needs
- Vagal stimulation
- Medications
- Increased ICP
- MI
- Hypovolemia
- Hypoxia
- Hypo/hyperkalemia
- Hypothermia
- Toxins
- Cardiac tamponade
- Tension pneumothorax
- Thrombosis
- Trauma
HR range for sinus tachycardia
More than 100 but less than 120
PR interval for sinus tachycardia
Normal (0.12 - 0.20 seconds)
Causes of Sinus Tachycardia
- Physiologic or psychological stress
- Medications
- Stimulants
- Illicit Drugs
- Autonomic dysfunction
Physiologic or Psychological Stress that can Cause Sinus Tachycardia
- Acute blood loss
- Shock
- Fever
- Exercise
- Anxiety
- Fluid overload
Medications that can cause Sinus Tachycardia
- Catecholamine’s
- Aminophylline
- Atropine
Stimulants that can cause Sinus Tachycardia
- Caffeine
2. Nicotine
Illicit drugs that can cause Sinus Tachycardia
- Cocaine
2. Ecstacy
Treatment for Sinus Tachycardia
- Correct the cause
- Beta-blockers
- Calcium-channel blockers
What does Atrial Flutter look like on an EKG?
Saw tooth or picket fence appearance
Is the rhythm regular or irregular for atrial flutter?
Regular
Atrial Flutter Rate
- Atrial rate ranges from 250 to 400
2. Ventricular rate ranges from 75 to 150
PR interval for Atrial Flutter
Not measurable
Causes of Atrial Flutter
- COPD
- Valvular disease
- Thyrotoxicosis (thyroid storm)
- S/P Cardiac Surgery
Treatment of Atrial Flutter
- Vagal maneuvers
- Adenosine
- Electrical cardioversion
- Catheter ablation
S/Sx of Atrial Flutter
- Patient may or may not be symptomatic
- Chest pain
- SOB
- Decreased BP
* If a patient is asymptomatic, they might just put them on an anticoagulant but possibly no other therapy
Atrial Fibrillation Rhythm
Irregularly irregular
Atrial Fibrillation Rate
- Atrial rate from 300 to 600
2. Ventricular rate from 120 to 200
PR interval for atrial fibrillation
Not measurable
Causes of Atrial Fibrillation
- Valvular heart disease
- Inflammatory or infiltrative disease
- CAD
- HTN
- Heart failure
- Hyperthyroidism
- Pulmonary HTN
- Pulmonary embolism
- Obstructive sleep apnea
- S/P cardiac or pulmonary surgery
Treatment of Atrial Fibrillation
- Electrical cardioversion
- Amiodarone
- Flecainide
- Propafenone
- Ibutilide
- Catheter ablation
- Antithrombotic therapy
Special Consideration for a patient with Atrial Fibrillation
First obtain an H/P, how long has the patient been in this rhythm or is it new onset?
Supraventricular Tachycardia Rhythm
Regular
Supraventricular Tachycardia Rate
140 - 220
PR interval for Supraventricular Tachycardia
Depends on site of supraventricular pacemaker (where is the impulse coming from)
Where is the electrical impulse coming from in a patient with SVT
Impulses stimulating the heart are not being generated by the SA node, but instead are coming from a collection of tissue around and involving the AV node
Causes of SVT
- Caffeine
- Nicotine
- Hypoxemia
- Stress
- CAD
- Cardiomyopathy
Treatment of SVT
- Vagal maneuvers
- Adenosine (6 mg, then 12 mg)
- Calcium channel blockers
- Cardioversion
Premature Ventricular Complex Rhythm
Depends on the underlying rhythm
Premature Ventricular Complex Rate
Irregular due to early QRS
PR interval for Premature Ventricular Complex
Normal (0.12 - 0.20 seconds)
Causes of Premature Ventricular Complex (PVC)
- Caffeine
- Nicotine
- Alcohol
- Cardiac ischemia or infarction
- Heart failure
- Digitalis toxicity
- Hypoxia
- Acidosis
- Electrolyte imbalances
Treatment for PVC
- If the patient has no underlying disease or infrequent changes, no treatment is required
- Amiodarone
- Lidocaine
* if not treated, they can progress to V-tach
PVC’s can cause problems if…
- More than 6 per minute
- Multifocal/polymorphic
- Occur 2 in a row
- Occur on the T wave
Ventricular Tachycardia Rhythm
Regular
Ventricular Tachycardia Rate
Range from 100 to 200
Causes of Ventricular Tachycardia
- CNS disease
- Hypokalemia
- Hypocalcemia
- Hypomagnesemia
Treatment of Ventricular Tachycardia
- Cardioversion if patient has a pulse
- Defibrillation if patient is pulseless
- Replace electrolytes
- Amiodarone
- Isuprel
Ventricular Fibrillation Rhythm
Extremely Irregular
Ventricular Fibrillation Rate
Greater than 300
Causes of Ventricular Fibrillation
- CAD
- MI
- Untreated V-tach
- Cardiomyopathy
- Vavlular heart disease
- Acid-base imbalance
- Electrolyte imbalance
- Electrical shock
Treatment of Ventricular Fibrillation
Defibrillation
Causes of Asystole
- Hypoxia
- Acidosis
- Severe electrolyte imbalance
- Drug overdose
- Hypovolemia
- Cardiac tamponade
- Tension pneumothorax
- Coronary/pulmonary thrombosis
- Trauma
- Hypothermia
Treatment of Asystole
CPR
Third Degree AV Block Rhythm
Regular
Third Degree AV Block Rate
Varies
PR interval for 3rd Degree AV Block
Irregular
3rd Degree AV Block is also called what?
Complete Heart Block
Treatment of 3rd Degree Heart Block
Pacing
* This patient will have decreased cardiac output
Potential Complications of Dysrhythmias
- Cardiac Arrest
- Heart Failure
- Thromboembolic Event
Defibrillation
Shocking the patient is depolarizing the patient. It resets polarization so that the SA node picks up and starts
Defibrillation is the treatment for what arrhythmias?
- Pulseless V-tach
2. V-fib
Nursing Responsibilities for Defibrillation
- Start CPR before defibrillation
- Turn device on (apply gel if needed)
- Ensure device in defibrillation mode
- Select electric charge 300-360 joules (or follow MD order)
- If using paddles, apply 20 lbs of pressure
- Ensure all personnel are clear of patient/bed prior to shocking the patient
- After defibrillation, check the patient an monitor
Cardioversion is the treatment for which arrhythmias?
- SVT
- A-Fib
- A-Flutter
- Stable V-tach (pulse is present)
Cardioversion
- The shock is synchronized with the rhythm
- The MD can control the amount of joules
- Synchronized hits in the QRS complex during ventricle depolarization
- Even if the pads are pushed a little too early, it’s ok, it will wait until the QRS complex
Nursing Responsibilities for Cardioversion
- Consent may be obtained if not emergent
- Patient may be given a sedative: diazepam or midazolam
- Usually try 3-4 times
Pacemaker Therapy
- Used to treat conduction defects or dysrhythmias
- Uses a pulse generator to provide an electrical stimulus to the heart when the heart fails to conduct its own at a rate that maintains cardiac output
Fixed (Asynchronus) Pacemaker
Pacemaker is set at a rate determined by the MD
Demand (Synchronus) Pacemaker
Pacemaker fires when rate falls below set rate determined by MD
Temporary Pacemaker
Uses an external pulse generator attached to a lead threaded intravenously into the right ventricle
Types of Temporary Pacemakers
- Epicardial - directly in the heart
2. Endocardial - threaded through a central vein
Permanent Pacemakers
Use an internal pulse generator placed in a subcutaneous pocket in the subclavian space or abdominal wall
What kind of arrhythmias would require a pacemaker?
- 3rd degree AV Block
- Sick Sinus Syndrome
- Asystole
S/Sx of Low Cardiac Output
- Dizziness
- Bradycardia
- Restlessness
- Hypotension
Potential Complications after Pacemaker Placement
- Infection
- Pneumothorax
- Arrhythmias
Patient Care of Pacemaker
- Monitor incision
- Avoid large magnetic fields
- Avoid heavy lifting for 2 weeks
- Medical identification
Pacemaker on an EKG
- Pacing is detected on ECG by sharp spike noted before the P wave with atrial pacing or before the QRS with ventricular pacing
- If nurse caring for patient does not see pacer spikes, the voltage must be increased so that spikes are seen
Implantable Cardioverter Defibrillator
- Detects life threatening changes in the rhythm (tachycardia, fibrillation)
- Automatically delivers an electrical shock to convert the dysrhythmia
- Life vest are used until a patient can have an AICD placed
Electrophysiological Studies
- An electrophysiology study (EPS) is one of the most accurate and reliable methods of evaluating heart rhythms
- The procedure is performed by an electrophysiologist who will attempt to reproduce dysrhythmias to determine the type and location
Cardiac Conduction Surgery
- Maze procedure is performed to treat atrial fibrillation (refractory)
- Catheter ablation therapy is a curative procedure that involves the application of energy through a catheter tip to cauterize electrical tissue causing the dysrhythmias
P Wave
Atrial Depolarization (atrial contraction)
QRS Complex
Depolarization of ventricles (contraction of ventricles)
What does the SA node do?
- It is the primary pacemakers
- Highest degree of automaticity, causes depolarization
What does the AV node do?
- It is the backup pacemaker in the 40-60 bpm range
- Atrial junction, slower to allow the ventricle chamber to fill more completely
Purkinje Fibers
Could take over as pacemaker if HR gets to 20-30 bpm range if needed
Bundle of His
Ventricle sends blood to pulmonary artery and the aorta
Stroke Volume
Injected blood into the system circulation in one beat
Contractility
The ability of the cells to shorten when depolarized by an electrical impulse
Automaticity
The ability of the cell to spontaneously generate and discharge an electrical impulse
Excitability
The ability of the cell to respond by depolarization. The response can be influenced by: hormones, electrolytes, meds, O2, nutrition
Refractory
The period which the cells resist stimulation
- Relative refractory
- Absolute refractory
Relative Refractory
A greater than normal stimulus is required to generate another action potential
Absolute Refractory
Depolarization will not occur no matter how strong the stimulus
What is the PR interval?
Measures the amount of time it takes for impulse to travel from atrial depolarization to the beginning of ventricle depolarization (0.12-0.20 seconds); SA node to AV node
Normal length of QRS interval
Complex is normally less than 0.12 seconds in duration
ST segment
End of ventricle depolarization to the beginning of ventricle repolarization
- Isoelectric or flat
- Elevated or depressed may indicate disease or injury of ventricle muscle
T Wave
Repolarization of ventricles (return to resting state) and are most vulnerable to dangerous stimuli
- Should be up, if downward displacement = injury, ischemia, or infarction
QT interval
The amount of time for ventricle to depolarize and repolarize (usually 0.32-0.40 seconds)
Conditions that can change the shape and size of PR interval
- Digitalis
- Beta-blockers
- Age and conduction disease
- Atrial enlargement
- Valvular heart disease
Conditions or medications that change the QRS
- Ventricle enlargement
- Dysrhythmic meds, Quinidine, Procainamide, Flocainidine
- Ventricle electrical conduction defects
- COPD
- Hyperkalemia
- Hypokalemia
Conditions that cause the QT interval to prolong
- Low HR
- Hypocalcemia
- Hypokalemia
- Ischemia
- Infarction
P Wave for Normal Sinus Rhythm
Visible before each QRS complex
QRS Duration for Normal Sinus Rhythm
Normal (< 0.12 seconds)
QRS Duration for Sinus Bradycardia
Normal (< 0.12 seconds)
P Wave for Sinus Bradycardia
Visible before each QRS complex
QRS Duration for Sinus Tachycardia
Normal (< 0.12 seconds)
P Wave for Sinus Tachycardia
Visible before each QRS complex
QRS Duration for Atrial Flutter
Usually normal (< 0.12 seconds)
P Wave for Atrial Flutter
Saw-tooth shape (referred to as F waves)
P Wave Rate for Atrial Flutter
300 beats per minute
QRS Duration for Atrial Fibrillation
Usually normal (< 0.12 seconds)
P Wave for Atrial Fibrillation
Not distinguishable as the atria are firing off all over
QRS Duration for SVT
Usually normal (< 0.12 seconds)
P Wave for SVT
Cannot be seen
QRS Shape for PVC
Bizarre and abnormal
P Wave for PVC
Ratio 1:1
P Wave Rate for PVC
Normal and same as QRS rate
QRS Duration for V-tach
Prolonged with a bizarre abnormal shape
P Wave for V-tach
Not seen
QRS Duration for V-fib
Not recognizable
P Wave for V-fib
Not seen
QRS Duration for 3rd Degree Block
Usually abnormal
P Wave for 3rd Degree AV Block
Unrelated to QRS complex
P Wave Rate for 3rd Degree AV Block
Normal but faster than QRS rate