sinus rhythms Flashcards
dysfunctions of the suns node can be classified as two things- what are they?
intrinsic (pathological changes in SA node or atrial tissue eg. age related degeneration) or extrinsic (other factors- hypothyroidism, action of antiarrythmic drugs)
result of dysfunction of SA node causes what?
failure of impulse or failure of impulse spreading through atria
what are some intrinsic causes of sinus brady ?
age related degeneration, ischemic heart disease, and surgical trauma
what are some extrinsic causes of sinus brady?
inc parasympathetic tone (vagal tone)
what are some causes of inc parasympathetic tone (vagal tone)
nausea/vomitting, valsalva maneuver, carotid pressure, MI, parasympathomimetic drugs
what are the hemodynamic effects of extrinsic sinus brady
decreased SV, CO, dizziness, syncope
treatments for extrinsic sinus brady?
inc hr w anticholinergic drugs (atropine) or sympathomimetic drugs (episode, dopamine)
what are some intrinsic causes of sinus brady?
pain, decreased sympathetic tone, drugs
what can cause dec sympathetic tone?
hypothermia, hypothyroid, hypoxia, beta blockers
what kinds of drugs can cause dec sympathetic tone?
antidepressants, anesthesia, morphone, antiarrthymics, anytipsychotics
treatment for intrinsic sinus brady?
pacemaker
classification of atropine?
parasympatholytic (blocker). causes the heart to slow. blocking this effect allows the HR to increase.
action of atropine?
prevents acetylcholine from occupying cholinergic receptor sites. suppresses vagus nerves action on SA and AV nodes- inc HR
indications for atropine?
symptomatic brady, systole, pulseless electrical activity (PEA), post arrest brady
contraindications for atropine?
can precipitate VF and VT in patients with severe cAD, myocardial ischemima or infarction, hypersensitivity to anticholinergic agents, tacky, narrow-angle glaucoma
dose for atropine?
for brady- 0.5-1mg IV q3-5 min with a max of 3mg
can be given ET tube if no IV access
what are some causes of inc sympathetic tone causing sinus tachy?
pain/anxiety,stress, fever, anemia, hypoxia, Co2 retention, hyperthyroidism, MI, CHF< hypovolemia, hypotension, allergic reactions, drugs, stimulants
what are symptoms of sinus tacky?
dec SV, CO, BP, inc workload of heart, sichema, CP
if you have symptomatic ischemic heart disease what treatment ??
beta blockers, Ca channel blockers
what are some ECG clues for sinus arrhythmia?
p waves are irregular, R-R interval slightly irreg,
what is sinus arrhythmia?
slight inc or dec in rate of sinus rhythm
do the PR or QRS intervals change in sinus arrhythmia?
no
does inspiration inc or dec sinus rhythm ? expiration?
inc and dec with expiration
how can touchy vagal tone occur?
nausea/vomitting, morphne, inferior MIs
what are some hemodynamic effects of sinus arrhythmia?
palpitations, dec BP
how does a sinus pause/arrest/block present on an ECG?
p waves are absent. periods of ‘pause’
what occurs after sinus pause/arrest/block?a
bradycardia and/or asystole
what are possible causes for sinus pause/arrest/block
chronotropic incompetence, parasympathetic (vagal tone), hypoxia, hyperkalemia, excessive beta blockage, dig tox, quinidine tox, damage to SA node with inferior MI, myocarditiis
what are some hemodynamic effects of sinus pause, arrest, block
may be asymptomatic if AV junctional pacemakers takes over
if symp: slow rate or transient systole (dec BP, CO, sissiness and syncope)
treatments for sinus pause, arrest, block?
treat cause or pacemaker
steps to ECG interpretation
is the rhythm regular? are there p waves for each QRS? what is the atrial rate? ventricular rate? PR interval? QRS interval? ECG rhythm? is there more than one rhythm int the strip?
