Chapter 27- dysrhythmias Flashcards
what are the four intervals in the heart
-stimulation for the electrical impulse
-transmission to adjacent tissue
-contraction of atria then ventricles
-relaxation of atria then ventricles
what does automaticity mean
ability for the heart to generate electrical impulses
what does conductivity mean
ability of tissues to transmit electrical impulses
what is the pacemaker of the heart
SA node
what is an action potential
contraction of myocytes, controlled by voltage
what do sarcomeres, troponin, and Ca part of
neurons will stimulate muscle cells, which stimulate contraction
what is a sarcomere
contraction unit
what is troponin
binds to calcium, opening sites and causing contraction
what does calcium do
react to troponin
what electrolytes is the SA node dependent on
Na and K
what is automaticity
allows any part of the conduction system to start an impulse
what is the absolute refractory period
the cells can not respond to a new stimulus
what causes arrhythmias
irregular electrical impulse and or conduction
ectopic focus/ectopic beat and causes
impulse started by something other than SA
-hypoxia, ischemia, hypokalemia
what is an atria flutter
the atria is beating faster than the ventricles
-lub, lub, lub
what is atria fibrillation?
AV cannot keep up with SA – no p wave
what is a heart block
signal between atria and ventricles is messed up or blocked, emergency intervention is needed
the main concern when starting antidysrthmias
making the dysrhythmia worse or creating a new one
what is cardioversion
shock to the heart
what is defibrillation
emergency situation, VTAC and VFIB can be shocked
pacemaker
for tachy and brady arrhythmias to keep heart pace WNL
-some can do both if needed
what is ablation
Burnout problem areas
MOA of antidysrhythmic drugs
-reduce automaticity
-slow conduction impulses
-prolong the refractory period
when are antidysrhythmic drugs used
-treatment of atrial fibrillation or flutter
-maintaining NSR after ablation
-suppressing fast/irregular ventricle rate – isn’t filling with enough blood
-dysrhythmias that could be fatal — A fib causing clots
how do sodium channel blockers work
blocks the opening of sodium channels
what can sodium channel blockers treat
atrial dysthymia, supraventricular tachycardia – bursts of high rapid HR which are normally idiopathic
side effects of sodium channel blockers
arrhythmias, bradycardia, hypotension
-respiratory depression, dizziness, syncope, drowsiness, fatigue, confusion, anticholinergic
nursing concern for sodium channel blockers
interacts with anticoagulants and A fib pts need them
common sodium channel blockers
quinidine, lidocaine
how do beta blockers work
decrease conduction through the SA/AV node
-decreases cardiac excitability, workload, and oxygen consumption
what are beta blockers used to treat
-dysrhythmia from SNS stimulation, a fib, and flutter, post-MI and CHF to prevent v-fib
side effects of beta blockers
BRADYCARDIA, HYPOTENSION, DIZZY, SYNCOPE
-Av block, bronchospasm, dyspnea, drowsiness, fatigue, ED
nursing considerations of beta blockers
-taper off
-when taken with Ca blocker can increase risk of heart block
common beta blockers
METOPEROL and ETGENELOL
-propranolol, acebutolol, esmolo
what does potassium do for the heart
control contractility
what should potassium levels be
3.5-5
hypokalemia signs
ventricular dysrhythmias, muscle weakness, decreased deep tendon reflexes, weak peripheral pulses
issues with IV potassium
can burn, should be given in a Central line
hyperkalemia signs
dysrhythmias, v-fib, HB, cardiac arrest, muscle twitching, numbness in hands, feet and mouth
what can quickly bring down potassium levels
insulin/dextrose
how do potassium channel blockers work
prolongs action potential, slows repolarization, and prolongs the refractory period
when are potassium channel blockers used
given IV for life-threatening tacy dysrhythmias
given PO for tachycardia, V/A fib, and A flutter
side effects of potassium channel blockers
bradycardia, hypotension, weakness, dizziness, worsened/new dysrhythmias, PULMONARY TOXICITY, HEPATOTOXICITY, blurred vision
who should not take potassium channel blockers
AV block, shock, hypotension, respiratory depression, and renal/hepatic impairment
common potassium channel blockers
AMIODARONE
-dofetilide, ibutilide, sotalol
how do calcium channel blockers work
reduce automaticity of SA node and slow conduction of AV node
what can calcium channel blockers treat
supraventricular dysrhythmias (SA and AV) and tachycardia
-emergency for A-fib, SVT
side effects of calcium channel blockers
BRADYCARDIA, HYPOTENSION,
-flushed skin, MI, hepatotoxicity, peripheral edema
who shouldn’t take calcium channel blockers
HB, sick sinus, HF, hypotension, renal/hepatic, PREGNANCY
nursing considerations with calcium channel blockers
grapefruit, monitor with beta-blockers and digoxin
what is sick sinus
irregular heart rhythm
how does adenosine work and when is it used
depression of conduction at the AV node, causing NSR
-EMERGENCY MED
can digoxin treat dysrthmias
YES
