Flashcards in dysrhythmias Deck (74)
What are the sinus node rhythm disturbances?
- sinus arrhythmia
- sinus pause/sinus arrest
- sinus bradycardia
- sinus tachycardia
What age group is sinus arrhythmia common in?
- younger pts
- not common in older pts due to age related decrease in parasympathetic tone
What does sinus arrhythmia look like on an EKG?
- rate: variable
- P: normal
- PR: normal
- QRS: normal
- rhythm: sometimes appears irregular, but originating from the sinus node
What does sinus arrhythmia sync with? Tx?
- synchronizes with respiratory cycle: inspiratory reflex inhibition of vagal tone
- cyclic variation in HR
- tx: benign, requires no tx
When does sinus pause/arrest occur?
- healthy hearts
- vagal tone
- digitalis toxicity
- pause lasts 2 seconds to 2 minutes
- normal and fixed PR intervals and R-R intervals and lack of P wave
Tx for sinus pause/arrest?
depends on underlying condition
- atropine for hemodynamically unstable ( parasympathetic - increases HR), tx for bradycardia. Short term tx
What is sinus bradycardia?
who is it common in?
What is it caused by?
- HR less than 60 bpm
- common in young adults (athletes)
- caused by: BBs or digoxin
Tx of sinus bradycardia?
- only tx if sxs of HTN or dizziness
- short term: atropine, tempory pacer
- asx: monitor and educate
- long term: pacemaker if sx
What is sinus tachycardia?
- HR more than 100 bpm
- causes: fever, pain, exercise, anemia, hypotension, increased catecholamines, thyrotoxicosis, anxiety
tx: underlying cause,
CCB: diliazem, verapamil
BBs: for sx tachycardia
- AV node re-entrant tachycardia
- from above the HIs bundle
- most commonly caused by reentrant circuit in AV node
- likely to begin or end with premature atrial or ventricular contraction
SVT is most common in what age group? Could be caused by?
- most common in young adults
- most people are able to live without restrictions in activity, often occur in episodes with stretches of normal rhythm in b/t
- may be a SE of meds or ilicit drugs:
digitalis, asthma meds, or cold remedies, caffeine, ephedra, cocaine, meth
PSVT presentation on EKG?
P wave different from normal sinus rhythm P wave for that person
- p wave often buried in QRS
- QRS is narrow and of normal morphology
Sxs of SVT?
- dizziness, light-headedness, or syncope (rare)
- CP or tightness
Tx of SVT?
- vagal maneuvers:
hold breath for few seconds
dip face in cold water
tense stomach muscles as if bearing down to have BM
- carotid massage, start at R side for 20 seconds then move to L (not at same time)
- drug therapy: adenosine (adenocard) 6 mg IV: half life is less than 10 sec, given IV, fast push followed by NS flush, may be repeated with additional 6 mg and then 12 mg
- adenosine works in more than 90% of cases
blocks conduction at AV node
- if adenosine is unsuccessful: consider cardioversion if pt is hemodynamically unstable (sedated)
or IV BB (esmolol or propranolo) or CCB
Therapy to prevent recurrence:
- BBs (metroprolol)
CCBs (diltiazem), digoxin
- perm tx is SVT ablation
What is WPW?
- form of SVT
- accessory pathway that bypasses the AV node (bundle of kent)
- along with normal conduction pathway, there are extra pathways - accessory pathways, they conduct impulses faster than normal, conduct impulses in both directions (HR typically greater than 200)
- congenital defect, sxs can occur at any age
- one of the most common causes of fast arrhythmia in infants and children
- highest incidence b/t ages of 30-40
- more common in men than women
What is the greatest concern for people with WPW?
- possibility of having afib with a fast ventricular response that worsens to fib, a life threatening arrhythmia (can worsen to V fib)
sxs of WPW?
- rarely: cardiac arrest
EKG presentation of WPW?
- seen only after rhythm conversion from PSVT to NSR
- PR is shorter than 0.12 s
- uptake of QRS is slurred, this is the delta wave (easier to see in precordial leads)
- 12 lead is essential because delta wave may not show up on all leads
Tx of WPW
- depends on frequency and assoc sxs
- radiofrequency ablation:
ablation of accesory pathways (very effective)
How to terminate an acute episode?
- vagal maneuvers
- IV adenosine: 6-12 mg rapid IV push
- or IV diltiazem or verapamil
- have defb ready as meds may turn rhythm into fib
- if hemodynamically unstable: cardioversion
What is PAT? Tx?
- atrial rate of 150-250, may conduct to ventricles but AV node will try to block impulses
- P wave: morphology usually varies from sinus, originates from an irritable atrial focus
- may occur in normal as well as diseased heart
- often transient and usually reqrs no tx
- can usually be terminated with vagal maneuvers
- if these fail: adenosine, or cardioversion, digoxin, BBs, CCbs - prevent recurrence
What are PACs?
- d/c from non-sinus atrial pacemakers
- P wave preceding may not look like P waves that originated from sinus node
- very frequent PACs may be precursor to development of afib
who has increased likelihood of PACS?
- can occur in all ages with or w/o disease
- increased incidence with:
mitral valve disease
Tx of PACs?
- asx: no special tx, just avoid precipitants
- sx: controlled with BBs
What is a wandering atrial pacemaker?
- may occur in normal hearts as result of fluctuations in vagal tone
- seen in pts with heart disease and COPD
- rate: variable depending on site of pacemaker; usually 45-100 bpm
- p wave: needs to have 3 distinctly diff P wave morphologies (may be seen after QRS interval)
- usually no tx reqd
- may also be precursor to multifocal atrial tach
What is multifocal atrial tach?
- irregular cardiac rhythm caused by at least 3 diff sites of competing atrial activity
- presence of 3 or more P wave morph on a given lead
- heart rate greater than 100 bpm
- it usually doesn't cause hemodynamic instability
MAT is common in what pops and conditions?
- underlying lung disease
- COPD is the most common underlying cause
- acute MI
- theophylline toxicity
- low magnesium
- may be a precursor to afib