CV - clinical treatment of arrhythmias Flashcards
impulse formation starts at the ____________ node.
sinoatrial (SA)
the ____________ system is the most proximal branch of the bundle branch system.
his-purkinje
arrhythmias that are too slow are called ____________.
bradyarrhythmias
where in the conduction system can bradyarrhythmias occur?
sinus node
atrioventricular node
below the AV node
define sinus bradycardia
persistent slow rate from SA node
rate of 55 bpm
PR interval 180 ms (0.18 s)
define sinus arrest
failure of sinus node to discharge resulting in the absence of atrial depolarization and periods of ventricular asystole
rate of 75 bpm
PR interval 180 ms (0.18 seconds)
what are examples of bradyarrhythmias at the level of the AV node?
1st degree AV block
2nd degree AV block type 1 (mobitz 1, wenckebach)
describe 2nd degree AV block type 1 (mobitz 1, wenckebache)
progressive prolongation of the PR interval until a ventricular beat is dropped
ventricular rate irregular
atrial rate 90 bpm
PR interval is progressively longer until a P wave fails to conduct
when should you be concerned about bradycardia?
1 when the patient is symptomatic, no matter which part of the conduction system is affected
2 when the rhythm is infranodal, below the AV node
what are the reversible causes of bradycardia?
ischemia/infarction
hypothyroidism
neurologic causes
lyme disease
what are the acute treatments for unstable patients?
beta agonists (IV dopamine or IV isoproterenol)
transcutaneous pacing
temporary transvenous pacing
what are the long term treatments for unstable patients?
permanent pacemaker
what are the steps to approach a patient presenting with bradycardia?
determine level of block responsible for bradycardia
symptoms dictate treatment
treat reversible causes
acutely stabilize patients
long-term treatment - permanent pacemaker
tachyarrhythmias can originate ____________ or ____________.
above the ventricle
in the ventricle
it is unlikely that a ventricular tachyarrhythmia has a ____________ QRS.
narrow
tachyarrhythmias originating SVT present with a ____________ QRS on ECG.
narrow
if the QRS on ECG is narrow, the tachyarrhythmia must be an ____________.
SVT
what are the three possible causes of an SVT with an irregular rhythm?
atrial fibrillation
multifocal atrial tachycardia (MAT)
atrial flutter
typical atrial flutter courses around the ____________ valve.
tricuspid
what are the six potential causes of an SVT with a regular rhythm?
sinus tachycardia atrioventricular nodal reentrant tachycardia atrioventricular reentrant tachycardia atrial flutter atrial tachycardia junctional tachycardia
if a patient presents with a tachycardia and is hemodynamically UNSTABLE, the treatment is ____________.
shock - cardioversion or defibrillation
what are the treatment for SVTs with irregular rhythms?
rate control
antiarrhythmics
cardioversion
IV ____________ is the treatment for regular 1:1 SVTs.
adenosine
what is an alternative treatment to adenosine?
vagal maneuver
describe an atrioventricular nodal reentrant tachycardia
reentrant circuit within the AV node fast and slow pathways
atria and ventricles depolarized simultaneously
P wave buried within or on the tail end of the QRS complex
regular, narrow complex tachycardia
P waves not visible
what is Wolff-Parkinson-White syndrome?
patient is born with an accessory electrical pathway between atria and ventricles
if accessory pathway is able to propagate in the forward direction, ventricle is depolarized prematurely - pre excitation of a ventricle
presents as delta wave (“slurred upslope”) on ECG
setup for AVRT
if an accessory pathway is functional, ____________ is likely to develop.
AVRT (atrioventricular reentrant tachycardia)
if there is no gateway to slow the conduction of signals from the atria to the ventricles as in WPW syndrome, atrial fibrillation may become ____________ and may lead to ____________.
ventricular fibrillation
sudden cardiac death
what are the three main categories of SVTs?
AV nodal reentrant tachycardia
accessory pathway-mediated tachycardias
focal atrial tachycardias
what is the most common of the SVTs?
AV nodal reentrant tachycardia
what are the long-term medications used to treat SVTs?
beta blockers calcium channel blockers to block AV node class I anti arrhythmics to suppress hotspots or premature beats that may trigger tachycardia
what are the common causes of atrial fibrillation?
hypertension
mitral valve disease
alcohol ("holiday heart")
cardiomyopathies
hyperthyroidism
lone atrial fibrillationthere is an increased risk of ____________ in patients with atrial fibrillation.
thrombus formation
embolic stroke
in patients with atrial fibrillation, thrombus formation most commonly occurs in the ____________.
left atrial appendage
the acute treatment of ventricular tachyarrhythmias are determined by whether the patient is ____________ or ____________.
stable
unstable
if a patient presents with ventricular tachyarrhythmia and is unstable, the treatment is ____________.
shock
after shock, what are the treatments for unstable ventricular tachyarrhythmias?
treat underlying causes
medications
what are the treatments for stable patients presenting with ventricular tachyarrhythmias?
medications (amiodarone, lidocaine, procainamide)
treat underlying causes
