Test 4 - Cardiac Flashcards
(139 cards)
What are the key ions for Cardiac function?
Sodium: rapid influx
Potassium: leaves cells
Calcium: slow influx
What is the function of the ions Na/K?
Initiation of muscle contraction
What is the function of the ion Ca?
To strengthen contractility
What is the order of signals being sent by the heart?
SA Node
AV Node
Bundle of His
Right/Left Bundle Branches
What bpm can be stimulated by SA node function?
60 - 100 bpm
What bpm can be stimulated by AV node function?
40 - 60 bpm
What bpm can be stimulated infranodally (below the nodes)?
20 - 40 bpm
What do Beta-1 receptors target?
Increase HR and contractility
What do Beta-2 receptors target?
Bronchodilation
What do Alpha receptors target?
Vasoconstriction and increased contractility
no HR increase
What happens during the “P Wave?”
Atrial depolarization
What happens during the “QRS Complex?”
Ventricle depolarization
What happens during the “T Wave?”
Ventricular repolarization (rest)
What happens if a patient is shocked on a “T wave?”
Ventricular Dysrhythmias
Bradycardia: Causes
Athletes, during sleep, in response to vagal stimulus, inferior MI
What is Bradycardia a S/E of?
Beta Blockers Digoxin Calcium Channel Blockers Inferior MI Hypoxia
Bradycardia: Treatment
Only treat if symptomatic (get rid of cause)
Sequence: Atropine -> Pacemaker -> Dopamine -> Epi
Tachycardia: Causes
Physical activity, pain, stress, fear, hypoxemia, hyperthyroid, caffeine, ETOH, nicotine
Compensatory response to decreased CO or BP
Tx: treat cause
A Fib and A Flutter: increased risk
Increased risk of clots and stroke
A Fib and A Flutter: Treatment
-Reduce ventricular rate
Ca Channel Blocker, Amiodarone, Beta blockers, digoxin
-Cardioversion: onset <48 hrs prior
-Anticoagulants: onset >48 hrs prior
Check coag studies, TEE
Chronic A Fib Treatment
-Coumadin, Pradaxa, Xarelto
SVT/PSVT
No P wave
HR >150 bpm
Narrow QRS
SVT/PSVT: Causes
- Stress
- Caffeine
- Cocaine/ETOH abuse
- Rheumatic HD
- MI
SVT/PSVT: S/S
- SOB
- Chest tightness
- Palpitation
- Dizziness
- Hypotension
- Syncope