Class 1 Flashcards
(26 cards)
Properties of heart cells
1. Automaticity To spontaneously initiate an action potential SA node: 60/100/min AV node: 40-60/min Purkinjes: 20-40/min
- Excitability
To respond to an impulse and then generate it’s own action potential - Conductivity
To conduct impulses
Depolarization wave
From the SA node to the AV node & over to the LA = P wave
Thru the AV node, Bundle of His, bundle branches and perkinjes = PR interval
Thru the ventricular wall = QRS
Repolarization wave
Of the atria = hidden
Of the ventricles = T wave
Of the perkinjes? = U wave (sometimes)
SA node arrhythmias
Sinus bradycardia Sinus tachycardia Sinus arrest Sick sinus syndrome Premature atrial complexes (PAC) Paroxysmal supraventricular tachycardia (PSVT) Atrial flutter Atrial fibrillation
Sinus bradycardia
Sinus tachycardia
>100 Normal with exertion/fever Ischemia, hypoxemia (low blood volume) Increases myocardial workload Decreases coronary artery perfusion
Sinus arrest
Failure of SA node, usually intermittent
Sick sinus syndrome
D/t SA node injury
Premature atrial complexes (PAC)
Early depolarization originating in the atria (not SA node)
Common
Paroxysmal supraventricular tachycardia (PSVT)
140-240/min
Sudden onset and cessation
D/t ischemia, reentry
Wolff parkinson white syndrome (heart rate goes very fast and can go for days)
Atrial flutter
Ectopic atrial tachycardia 240-450/min
D/t reentry
Atrial fibrillation
Chaotic depolarization with only occasional contraction
Paroxysmal/chronic
D/t MI, HF
Atrial fibrillation
What is happening in the heart?
Quivering muscle
Poor emptying of atria
Poor filling of ventricle = decreased CO
How will your patient present?
Heart rate will be irregularly irregular
Pulses will be irregular with varying strength
BP will be low
AV conduction arrhythmias
Blocks (1st, 2nd and 3rd degree)
AV node/bundle of his/bundle branch issue
1st degree AV block
Consistent long PR interval, followed by a QRS
2nd degree AV block
Mobitz type 1/wenckebach Increasing PR until QRS dropped Mobitz type 2 Occasional dropped QRS PR stable
3rd degree AV block
No electrical communication between atria and ventricles
Ventricular arrhythmias
Premature ventricular complexes (PVC)
D/t irritability (ischemia/necrosis)
Ventricular fibrillation
Ventricle is vibrating
No blood will be pumped
Asystole
Heart is not doing anything at all
Cannot be fixed
Cardiac conduction diagnosis
ECG (12 lead or 16 lead)
Holter monitor (send people home with electrodes on for 24 hours and keep a diary about what they are doing and it shows what the heart is doing at the same time)
Exercise stress test
Electrophysiologic studies
Treatments for conduction disorders
Cardioversion (someone is still conscious, awake and in rhythm you don’t want)
Debrillation (lethal rhythm so electrical zapping)
Pacemaker
Surgical
Cardioversion
Pharmacological (meds)
Physiologic (bare down or cough to stun heart to go back into proper rhythm)
Electrical
Defibrillation
Electrical
Lethal rhythm so electrical zapping
