Dysrhythmias Flashcards
automacity function
Ability to generate electrical impulse
Excitability function
Ability to respond to outside impulse
conductivity function
Ability to receive electrical impulse and conduct it
contractility function
Ability of myocardial cells to shorten in response to an impulse
when does a P-wave occur?
During atrial depolarization
when does QRS complex occur?
During ventricular depolarization
when does T-wave occur?
During ventricular repolarization
which node initiates atrial depolarization?
SA node
T/F, the AV node initiates ventricular depolarization
True
normal heart rate
60 to 100 per minute
normal P-wave occurrence
Upright and rounded
One before every QRS complex
Even regular rhythm
Normal PR interval time
12 to 20 seconds
normal QRS time
less than 12 seconds
Narrow
what do normal rate, rhythm, P-wave, PR interval, QRS indicate
Sinus rhythm
sinus arrhythmia
Fluctuation in rate and initiation
Variability in heart rate
is sinus arrhythmia still normal?
Yes, no changes to cardiac output
Who is sinus arrhythmia more common in?
Younger people
Associated with respiratory and autonomic nervous system fluctuations
dysrhythmia
Abnnormal cardiac rhythm
Problem with impulse generation or conduction
do dysrhythmias alter cardiac output?
Yes
Inappropriate automaticity cause of dysrhythmia
Cell initiates action potential when it is not supposed to
Triggered activity cause of dysrhythmia
Extra impulses generated during/right after repolarization
reentry cause of dysrhythmia
Cardiac impulse in one part of heart continues to depolarize after main impulse is finished
sinus-
Triggered in/around SA node
sinus bradycardia
Slow heart rate <60 BPM
is sinus bradycardia still normal?
Yes – regular rhythm, PR, QRS
causes of sinus bradycardia
Hyperkalemia – slows depolarization
Vagal response
Digoxin toxicity
late hypoxia
meds – beta blockers, CCB
MI – ischemia
s/sx sinus bradycardia
lightheaded, dizziness
Easily fatigued
Syncope
Dyspnea
Chest pain/discomfort
Confusion
treatment for sinus bradycardia
Assess for symptoms first
If symptomatic: atropine
If atropine, not effective – pacemaker
sinus tachycardia
Fast HR 100-150 bpm
is sinus tachycardia still normal?
Yes, but P waves may be partially hidden
PR, QRS, rhythm still normal
causes of sinus tachycardia
Exercise
Pain
Strong emotions
Fluid volume deficit
Fever – increased metabolic rate
Meds – Epi, albuterol
caffeine, nicotine, cocaine
Early hypoxia
treatment for sinus tachycardia
based on cause
hypovolemia – fluids
Fever – antipyretics
Pain– analgesics
Beta blockers to lower heart rate and myocardial oxygen consumption
paroxysmal supraventricular tachycardia
HR 150 to 200 BPM
“ feeling like my heart is racing”
is PSVT normal?
Usually no P waves, if present is abnormal
QRS – normal
T/FPSVT usually begins and ends slowly
False, suddenly
causes of PSVT
Overexertion
Emotional stress
Stimulants
Digoxin toxicity
Rheumatic, heart disease, CAD, R HF
Wolf Parkinson, white syndrome
s/sx PSVT
Palpitations
Chest pain
Fatigue
Lightheaded, dizzy
Dyspnea
where does PSVT originate?
Above ventricles, AV node
where do sinus bradycardia and tachycardia originate?
SA node
which sinus rhythm is caused by early hypoxia?
Sinus tachycardia
Which sinus rhythm is caused by late hypoxia?
Sinus bradycardia
premature atrial contractions
Early P waves that have morphological changes
what should you check with premature atrial contractions?
Electrolytes
May need oxygen
T/F premature atrial contractions are fatal
false, usually no consequences
If frequent, puts patient at more risk for other dysrhythmias
does premature atrial contractions have a normal PR and QRS interval?
Yes
atrial flutter
Reentry impulse, repetitive and cyclic
rate >250, still regular
QRS is slower
P-wave looks like shark tooth
where does atrial flutter originate?
AV node
Overrides SA node
causes of atrial flutter
CAD, cardiomyopathy
Heart valve disease
Congenital, heart disease
Inflammation of heart – myocarditis
HTN
Lung disease/overactive thyroid
Electrolyte imbalance
Heart surgery
atrial fibrillation
Multiple irritable spots in atria
Irregularly irregular
HR 100-175
no identifiable P-wave
Fibrillation waves
T/F atrial fibrillation is more symptomatic than atrial flutter
True
s/sx a fib
palpitations
Heart racing
Fatigue
Dizziness
Chest discomfort
SOB
Can be asymptomatic**
causes of a fib
Electrolytes imbalance
Hypoxia
CBD
complications of a fib
Decreased cardiac output
Heart failure
Embolus – stroke risk
what is the most common type of treated dysrhythmia?
Afib
treatment for a fib
Control the rate – BB, CCB, digitalis, amiodarone
Stroke prevention – anticoagulates antiplatelets
Non-medication treatment for a fib
ablation
Cardioversion
Premature ventricular contractions
ventricular dysrhythmia
Contraction coming from ectopic focus in ventricles
Comes earlier than QRS complex should
Not a normal rhythm or P wave
what does the QRS complex look like in PVC?
Wide and distorted shape
causes of PVC
Stimulants
Electrolytes
Hypoxia
Exercise
Stress
Fever
CVD
ventricular tachycardia
Three or more PVCs together
Ectopic focus within ventricles takes control and fires repeatedly
rate 150-200 bpm
differences with ventricular tachycardia
No atrial contractions
No P-wave
PR interval not measurable
causes of ventricular tachycardia
MI
CAD
ABNORMAL ELECTROLYTES
HEART FAILURE
Drug toxicity
what is an immediate intervention for ventricular tachycardia and fibrillation?
Check for a pulse
ventricular fibrillation
Irregular waveforms of varying shapes and sizes
Ventricles are quivering
No effective contractions equals no cardiac output
