Cardiac Dysrhythmias (Exam 3) Flashcards
Atrial depolarization
Atrial systole
First P wave bump
Ventricular Depolarization
Ventricular systole
Big bump
QRS complex
Ventricular Repolarization
The T wave
Flow of the heart
SA node
P wave
AV node
Bundle of HIS-Purknje Fibers
QRS Complex
T wave
What stimulates Atrial Depolarization?
SA Node
Sinoatrial Node
What node sense atrial depolarizations and tells the ventricles to depolarize
The AV node
Atrioventricular node
What is responsible for left ventricle contraction
Bundle of HIS
Purkinje fibers
Normal Electrical Conductivity of Heart: SINUS RHYTHM
Rate: 60-100
Rhythm: Regular
P waves: Upright - Rounded - One before overy ORS
PR interval: 0.12-0.20 sec
ORS: <0.12 sec
PR interval should be
0.12-0.20 seconds
ORS should be
Narrow
< 0.12 seconds
Sinus Arrhythmia
A degree of variability in the heart rate (Still between 60-120)
PR = still .12 -. 20
QRS = <12
Sinus Arrhythmia: Causes
Respirations and autonomic NS
Common in young people
Each box on ECG =
0.04 seconds
Dysrhythmias are problems because they
alter our CO
Sinus in front of something means
It is triggered in or around the SA node
Sinus Bradycardia
Originates in the SA node
Rate: < 60 bpm
Rhythm: Normal
PR: 0.12-0.20
ORS: <0.12
Causes of Sinus Brady
Hyperkalemia (Slow depolarizations)
Vagal response
Late hypoxia
Clinical Manifestations of Sinus Bradycardia
Brain and Lungs are not getting prefused
Light Headed
Fatigue
Syncope
Dyspnea
Chest pain
Confusion
Treatment of Symptomatic Bradycardia
atropine
pacemaker
Sinus tachycardia
Originates SA node
Rate: 100-150 bpm
Rhythm: Regular
PR: 0.12-0.20 (Normal)
QRS: <0.12 (Normal)
Sinus tachycardia causes
Fluid Volume Deficit (check first)
Exercise
Emotions (catecholamines)
Early Hypoxia
Treatment for Sinus tachycardia
hypovolemia
fever
pain
rate
Hypovolemia = fluids
Fever = antipyretics
Pain = Analgesics
Beta blockers to reduce HR and myocardial oxygen consumption
Paroxysmal Supraventricular Tachycardia (PSVT)
Orginiates in the AV node
HR: 150- 250
No P wave
QRS: <0.12
Begins suddenly and ends suddenly. HEART RACING
PSVT Causes
Over exertions
Emotional Stress
Stimulants
Wolff-Parkinson White Syndrome
PSVT: S/S
Palpitations
Chest Pain
Lightheadedness
Dyspnea
Premature Atrial Contractions (PACs)
Early p waves that usually look a little strange
Usually has no consequences, but if frequent indicates that patient at high risk for other dysrhythmia (usually afib)
Check ELECTROLYTES
Atrial Dysrhytmias
Atrial Flutter
Atrial Fibrillation
Atrial Flutter
Originate: AV node - Overrides the SA node
Reentry impulse that in repetitive and cyclic
Atrial Rate = Super high
Ventricular = Normal
P wave sawtooth: 2:1 - 3:1 - 4:1
ORS: <0.12
Causes of Atrial Flutter
HEART RELATED diseases
Electrolytes abnormalites
Atrial Fibrillation
Occurs: Multiple irritable spots in the atria
Irregularly irregular (both atrial and ventricular)
Rate: 100- 175 bpm
No identifiable P wave or T wave
R’s to R’s not regular
A fib: Clinical Manifestations
Palpitations
Heart Racing
Fatigue
Dizziness
Chest discomfort
Shortness of breath
May be asymptomatic
What do we want to know about atrial fibrillation
Is it a controlled rate?
If not controlled then we are worried that tissues are not being perfused?
Atrial Fibrillation Causes
Electrolytes
Hypoxia
Cardiovascular disease
New onset atrial fibrillation.. need to think
Are the electrolytes normal?
Are they hypoxic?
Complication of Afib
Embolus in atria –> Stroke (Blood is pooling in the atria)
Treatment of A fib
Pharmacological
Non pharmacological
Beta blocker, CCB, Digitalis, amiodaron (Control Rate)
Stroke prevention: Anticoagulants and antiplatelets (Prevent Clots)
Non pharmacological: Ablation - cardioversion
Ventricular Dysrhythmias
PVCS (Premature ventricular Contractions)
VTACH (Ventricular Tachycardia)
VFIB (ventricular Fibrillation)
Premature Ventricular Contractions
Occurs within ventricles
Comes earlier than QRS should come and does not follow P-wave
Wide and distorted QRS. Larger than .12 secs
PVC causes
Stimulants
Electrolytes
hypoxia
fever
exercise
emotional stress
CVD
PVS Subtypes
Bigeminy (every 2nd beat)
Trigeminy (every 3rd beat)
Quadrigeminy (every 4th beat)
Ventricular Tachycardia: Definition
3 or more PVCS together
Seriously decreases cardiac output
VTACH causes
MI
CAD
Electrolytes abnormalities
Heart failure
Drug toxicity
VTACH
Occurs within ventricles
Rate: 150-200
No p-wave
PR: not measurable
ORS Long
Immediate interventions
Treat VTACH
ACLS – depend on pulse, patient symptomatic very quickly unless convert back to other rhythm
First question for VTACH patients
Any pulse?
Ventricular Fibrillation
Irregular waveforms of varying shapes and sizes
The ventricles are just quivering
No effective contraction = NO Cardiac Output
Check pulse and start CPR
What causes dysrhythmias?
Inappropriate Automaticity
Triggered activity
Re-entry
Inappropriate Automaticity
A cell initiates action potential when it isn’t supposed to.
Triggered activity
An extra impulse generated ruing of just after repolarization
Re-entry
Cell is one part of the heart continues to depolarize after main impulse is over
