Dysrhythmias Part 1 Flashcards
A cyclic increase in normal HR w/ inspiration and decrease w/ expiration
Sinus arrhythmia
Not a pathologic arrhythmia, and therefore, no tx required
sinus arrhythmia results from ?
reflex changes in vagal influence on nml pacemaker and disappears w/ breath holding or increase of HR
T/F: sinus arrhythmia is common in both young and elderly
troo
sinus brady is defined as a HR slower than?
< 60 bpm
sinus brady is due to ?
increased vagal influence on nml pacemaker/organic disease of sinus node (sick sinus syndrome, etc)
sinus brady rate usually increases during when?
exercise or administration of atropine
Severe sinus bradycardia (< 45 beats/min) may be an indication of ?
sinus node pathology, especially in elderly patients and individuals with heart disease
sx - weakness, dizziness, confusion, or syncope
causes of sinus brady
-
drugs
- Sympatholytics: βB, methyldopa, clonidine
Cimetidine, digoxin, CCB’s, amiodarone, lithium - increased ICP - Exclude in sinus bradycardia & neurologic dysfunction
- AMI - IWMI → RCA supplies SA node in 60% of population
- OSA - HR ↓ < 30bpm during apneic episodes; Tx the OSA – not an indication for pacemaker
- Other - hypothyroidism, hypothermia
Commonly have recurrent SVA (ex. Afib) and bradycardia (tachy-brady syndrome)
sick sinus syndrome
presentation of sick sinus syndrome
Sinus arrest occurs on monitoring; persistent sinus bradycardia can also be common presentation
Chronotropic incompetence is another form of SSS
sick sinus syndrome is MC in who
elderly – usually indicates more significant conduction disease
what can cause sick sinus syndrome
meds
These should be held prior to invasive pacemaker insertion, for at least 24-48 hrs
tx for sick sinus syndrome
Symptomatic → PPM
- Withhold possible offending agents
- r/o possible causes
- Determine if symptomatic and if sx correlate with the bradycardia (KEY!)
- Once all of the above are done, and sx are determined to be related to bradycardia = permanent pacemaker implantation (1st line)
- acute - transcutaneous pacing, transvenous pacing, or atropine (ACLS protocol)
sinus tach is defined as a HR of ?
> 100bpm (adult) - (220-Age) d/t impulse formation from SA node
causes of sinus tach and which is MC?
- exercise, anger/stress (MC)
- Others - hyperthyroidism, fever, sepsis, pain, anemia, volume depletion, pheochromocytoma, hypoxia, PE, heart failure, acute coronary ischemia, alcohol/alcohol withdrawal, stimulants
sinus tach at rate > 140 bpm what may be hard to visualize on ecg?
P waves - superimposed on preceding T wave
Consider carotid sinus massage or vagal maneuvers
sx of sinus tach
Palpitations, lightheadedness
how can high HR affect structural heart disease?
- ↑ myocardial O₂ consumption
- ↓ coronary blood flow
- ↓ C.O. by shortening ventricular filling time
- Exacerbate myocardial/valvular heart disease
what is Inappropriate Sinus Tachycardia
- Occurs in absence of heart disease or secondary causes
- ↑ resting HR and/or exaggerated HR response to exercise
- Exact cause unknown; possible abnormal autonomic control
what is Postural orthostatic tachycardia syndrome (POTS)
Young women w/o heart disease w/ normal resting HR
Exaggerated sinus tachycardia elicited by upright TTT
Occurs in absence of orthostatic hypotension