Arrhythmias Flashcards
What are arrhythmias and the problems with them
abnormal rhythm of the heart
rate: too fast, too slow (out of normal 60-100bpm)
rhythm: how regular is the heart beat
origin
what are the types of arrhythmias
Supraventricular (atrial origin, AV junction)
Ventricular
What is premature atrial contraction
PACs
supra-ventricular premature beats
not from the SA node
may originate within other areas of the atria or the AV node
more common in pts with mitral valve pathology or ventricular pathology
what are the causes of PACs
idiopathic
Toxins (smoking, ETOH, coffee)
ACS
COPD
Atrial myopathy (changes associated with aging process)
What are premature ventricular contractions
premature ventricular beats
abnormal beat coming from ventricular myocardium
leads to premature depolarization of the ventricles
what are the causes of PVCs
reentry associated with cardiac scaring
abnormal automaticity (electrolyte abnormality, ischemia, catecholamine surge)
other unique trigger
what are the subtypes of PVCs
Bigeminy (2)
Trigeminy (3)
quadrigiminy (4)
all regularly irregular
how can PVCs be classified
based on:
morphology
Frequency
symptomatic vs asymptomatic
exertional or not
if underlying cause can be identified
what is a block
delay in conduction along the ventricular pathway
what is first degree AV block
delay in transmission from atria to ventricles
PR interval prolonged >200ms
what is the causes of first degree AV block
increased vagal tone
fibrosis/scaring
idiopathic
familial disease (associated with prolonged QT syndrome)
what is the clinical presentation of first degree AV block
asymptomatic
what is second degree AV block
intermittent AV conduction
typically in a regular pattern
Mobitz type 1 (Wenckebach)
Mobitz type 2
what is Mobitz type 1
Wenckebach: Second degree AV block
progressive prolongation until beat drop
first PR segment normal
what is Mobitz type 2
second degree AV block
PR is maintained but will occasionally wont conduct through the ventricles
more dangerous than Wenckebach
What can cause second degree AV block
MI involving/near the conduction system
cardiomyopathy
myocarditis
endocarditis (abscess)
iatrogenic: medication that are AV nodal blocking
what is third degree AV block
complete heart block, no atrial impulses reach the ventricle
atria and ventricles are not communicating, firing in silos
the ventricular rhythm will maintain cardiac circulation - typically < 45bpm
what are the causes of third degree AV block
myocardial ischemia
cardiomyopathy
myocarditis
iatrogenic
lyme disease
what is the clinical presentation of 3rd degree AV block
lightheadedness
palpitations
syncope
weakness
fatigue
chest pain
what are bundle branch blocks
disruption of electrical conduction down one of the bundle branches coming off the bundle of His
what is Right BBB
branching off the bundle of His, RBB made up of fast response Purkinje fibers
blood supply from RCA
associated with:
increased right ventricular hypertrophy
increase ventricular pressure (PE)
Mi, infraction
inflammation
iatrogenic
what is Left BBB
branching off of the bundle of His, LBB made up of fast response Purkinje fibers
blood supply from RCA
pathophysiology endocarditis (abscess), post surgical changes
what is “bunny ears” on EKG indicative of
Right Bundle Branch Block
what is the presentation of LBBB
results in slower QRS complex (wide)
what is sinus tachycardia
the most common tachycardia
narrow, regular tachy >100bpm
reactive rhythm associated with increased sympathetic tone
BENIGN DYSRHYTHMIA - NORMAL RESPONSE
what are the causes of sinus tachycardia
increased automaticity: increased SA node firing for physiologic reasons
-increased sympathetic tone (catecholamines)
- associated with: hypovolemia, hypoxia, meds, pain/anxiety, increased metabolic demand
increased triggering: problem with the myocardium
-meds
-ischemic area
- cardiomyopathy
what is the treatment for sinus tachycardia
Treat the underlying condition! (i.e. lower anxiety)
what is PSVT
Paroxysmal supraventricular tachycardia AKA SVT
sustained reentry loop within the AV node - may be associated with ectopic atrial source
tachy, regular, narrow QRS complexes
P waves typically not visualized
who is PSVT/SVT most common in
women, early 20s and no CV disease
what is the average HR for SVT
150-250 bpm
What is afib
irregularly irregular rhythm with narrow QRS complex
due to multiple areas of automaticity that are desynchronized within the atria - SA node is not in control
what is RVR
rapid ventricular response
what is afib with RVR
tachyarhythmia; rapid heart rate
what are the causes of afib
typically a secondary disease process
ischemic heart disease
valvular heart disease
congestive cardiomyopathy
HTN
myocardidits
holiday heart
thyrotoxicosis
blunt chest trauma
genetic link
in younger pts, associated with ANS (exercise induce- sympathetic, parasympathetic source)
what is paroxysmal afib
lasts less then 7 days with spontaneous conversion
what is persistent afib
over 7 days or needs cardioversion
what is seen on ECG with afib
no clear P wave or isoelectic baseline
QRS narrow
irregularly irregular QRS complexes
seen best in V1
what are the different types of afib
paroxysmal
persistent
permanent
what is Atrial flutter
atrial tachycardia with single reentrant circuit
fixed degree of AV conduction resulting in a regular rhythm
atrial rate typically 250-250 bpm
regular ventricular rate 150bpm
what is a sawtooth on ECG
pathopneumonic for atrial flutter
what are the ECG findings for atrial flutter
regular rate
narrow QRS
Single morphology P waves in sawtooth pattern
typically tachycardic rhythm around 150bpm
what is the most common wide complex regular tachycardia
ventricular tachycardia (VTAC)
impulse originates in the myocardium of the ventricles
sustained or nonsustained
what is vtac usually associated wtih
underlying etiology that causes pathologic myocardium
reentrant circuit associated with scar formation(often associated with previous MI)
Young people: myocarditis, hypertrophic cardiomyopathy, long QT, congenital causes, drugs
what causes Vtac
channelopathies
cardiomyopathy
myocarditis
substance use
CAD
valvular disease
what is the number one cause of VTAC
QT PROLONGATION
what are the symptoms of VTAC
may range from asymptomatic to sudden cardiac death
anxiety, feelings of fluttering in chest, dizziness, pain or pressures in chest, heart palpitations, fatigue, SOB, fainting
what is the presentation of VTAC on ECG
wide complex >120ms
HR >100bpm
consecutive beats uniform
lasts > 30 seconds
What is Torsades de points
polymorphic VTAC
associated with electrolyte abnormality
leads to prolonged QT
increased automaticity
what electrolyte is associated with torsades de points
magnesium*
What is vfib
chaotic depolarization of the ventricular myocardium
no true mechanical activation
no cardiac output
what is Vfib most commonly associated with
ischemic disease
may be acute or chronic - occurs suddenly, without warning
secondary disease cause more of a long progressive of LV failure
what needs to be assessed with any concern of Vfib
check a pulse
what is seen on ECG with Ventricular fib
may be course or fine
no P waves, defined WRS, T waves
unable to determine real rate
what happens with bradyarrhythmias
may be associated with decreased automaticity
vagus nerve stimulation via parasympathetic NS decreasing HR
Decreases conduction of the SA node
what causes sinus bradycardia
increased vagal tone (parasympathetic)
Medications that slow AV conduction: BB, CCB, digoxin
Metabolic changes (hypothermia, hypothyroidism)
Electrolyte abnormality (potassium)
Brain herniation
What is sick sinus dysfunction
also called tachybrady syndrome
dysfunction with the SA node
- often associated with aging process
- dose not generate impulse to keep up with the demand
what may be seen with sick sinus dysfunction
bradycardia
pause
arrest
inadequate HR based on physiologic demands
what is the pathophysiology of Sick sinus dysfunction
fibrosis of the SA node
medications
familial disease - cardiac sodium channel SCN5A, HCN4
what is the treatment of sick sinus syndrome
exercise intolerance
fatigue
dizziness
HA
Nausea
palpitations
Chest pain
SOB
what is the treatment of sick sinus syndrome
observation
possible need for artificial pacemaker
medications: atropine, warfarin
