Dysrhythmias Part 1 Flashcards
(52 cards)
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
tx for sinus tach
- Physiologic = None needed
- Address any underlying cause - In symptomatic pts w/ inappropriate sinus tachycardia, with/w/o correctable cause:
- βB (1st line)
- Alt: non-DHP CCBs / ivabradine (Corlanor)
PR interval > 0.2 second with all atrial impulses conducted
what is this dysrhythmia
1st degree HB
the AV conduction time (PR interval) progressively lengthens, with the RR interval shortening before the blocked beat
This phenomenon is almost always due to abnormal conduction within the AV node
what is this dyrrhythmia
Mobitz type I (Wenckebach) AV block
there are intermittently nonconducted atrial beats not preceded by lengthening AV conduction
It is usually due to block within the His bundle system.
what is this dyrrhythmia
Mobitz type II AV block