Clin Med - Arrhythmias Flashcards
What are the types of AV blocks?
- first degree
- second degre: mobitz typ I (Wenckenbach) and mobtiz type II
- third degree
general presentation on EKG of first degree AV block
-PR interval > .21 sec with ALL atrial pulses CONDUCTED
general presentation on EKG of second degree AV block
-INTERMITTENT blocked beats
general presentation on EKG of third degree AV block
- COMPLETE heart block
- no atrial impulses are conducted to the ventricles
medications in the etiology of first and second degree heart block
- digitalis
- Ca++ channel blockers
- beta blockers
chronic or transient etiologies of first and second degree heart block
- ischemia
- inflammatory dzs (lymes)
- fibrosis
- calcifications
- infarction
in a second degree, mobitz type I (Wenchenbach), what is the pattern of the PR interval? and the cause?
- PR interval progressively lengthens w/ RR interval shortening before a dropped beat
- almost always d/t AV node conduction abnormality
What are the characteristics of a second degree mobitz type II AV block?
- no lengthening of AV conduction
- intermittent non-conducted atrial beats
- usually d/t dz involving bundle of His
- may progress to 3rd degree block
which AV block is usually “nodal so narrow” ?
-Mobitz I
narrow in terms of QRS
Which AV block is usually “infranodal so wide” ?
-Mobitz II
A third degree heart block is usually d/t what?
a lesion distal to the bundle of His
3rd degree heart block may be associated with what other arrhythmia?
bilateral BBB
characteristics of a third degree heart block
- QRS wide and ventricular beats usual <45 BPM
- atrial conduction through atrial node is completely blocked
- may be asymptomatic
- may feel fatigues, SOB, have syncope
EKG notes from a 3rd degree block
- no dropped beats
- all p waves come at the same interval
- atria and ventricles are working just not working together
- p wave may show up in the QRS
How is an AV block diagnosed?
- incidental finding or
- symptomatic patient gets EKG
PE of pt w/ AV block
- bradycardia
- may be asymptomatic
When does AV block only need monitoring?
-asymptomatic pts w/ good perfusion
What is the treatment for AV block when they do not qualify for monitoring only?
permanent pacing
When does AV block require permanent pacing as treatment?
- symptomatic bradyarrhythmias
- asymptomatic mobitz type II
- complete heart block
BBB definition
- a complete or partial interruption of the electrical pathways of the bundle of his
- can be right, left, bifasciular or trifasicular
bifasicular
- when 2 pathways are blocked
- right bundle, left bundle, posterior fascicle, left anterior fascicle
trifasicular
- RBBB with alternating left hemi-block
- alternating RBBB and LBBB
- bifasicular block w/ prolonged infranodal conduction
T or F; BBBs can occur in normal hearts.
True
What dz processes can cause BBBs
- ischemic heart dz
- inflammatory dz
- infiltrative dz
- cardiomyopathy
- postcardiotomy
what dz processes are specific to RBBBs
- pulmonary embolism
- chronic lung dz
symptoms of BBB
- most have none
- syncope
- the symptoms of the underlying cause
diagnosing BBB
- incidental finding
- EKG if symptomatic
tx of BBB
- tx underlying disorder
- may need pace maker if syncope is occuring
- most need none
paroxysmal supraventricular tachycardia (PSVT) definiton
-regular, fast (160-200) HR that originated in heart tissue other than the ventricles
etiology of PSVT
- accessory pathways of electrical conduction b/w the atria and the ventricles
- AV node is bypassed
sx of PSVT
- some can have very mild sx
- palpitations
- dizziness
- syncope
- light headed
- chest pain
- SOB
- weakness/fatigue
PE findings in PSVT
-tachy and regular rhythm
What will diagnose PSVT when using and EKG or holter monitor?
- rapid regular rhythm
- QRS could be narrow or wide
- may have delta wave present (preexcitation)
vagal stimulation treatments
- plunging face into ice water
- rubbing neck just below jaw line
- bare down
- cough
when do you use medical intervention as opposed to vagal stimulation?
- if vagal stim. doesn’t work
- if episode lasts more than 20 min
- if symptoms are severe
What defines a PSVT patient as unstable?
- hypotension
- altered mental status
- signs of shock
- chest pain
- heart failure