Arrhythmias and Syncope Lecture Powerpoint Flashcards
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Syncope definition
Transient loss of consciousness due to global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery (not lethargic upon return)
Fundamental cause of transient drop in cerebral perfusion
Drop in BP resulting from decreased CO, decreased PVR, or a combo of both
Diagnosis of syncope must rule out these 2 things
head trauma and epilepsy
syncope is not a ____ it is a ____!!!
disease, symptom
Syncopal recurrence is about __%
What are the 3 types of syncope and which are favorable and which are unfavorabe?
20,
- Reflex (neutrally mediated) syncope/vasovagal (favorable outcome)
- Orthostatic hypotension (favorable outcome)
- Untreated cardiac syncope (greater chance of mortality, unfavorable)
Syncope is more common in ___ than ___, and more likely ___ in children than elderly
women, men, benign
Most valuable diagnostic tools for syncope (3)
- history (details about episode)
- complete physical exam (including orthostatic blood pressure measurements)
- EKG
Orthostatic blood pressure measurements
A series of 3 measurements going from lying, sitting, to standing, if systolic BP drop greater than 20 mmHg or diastolic 10 mmHg then considered positive (or if HR increases 20-30bpm or if patient becomes symptomatic)
Sudden cardiac death may occur with ___% of cardiac syncope
30
Most common cause of syncope is ___.
Second most common is ___.
Vasovagal (neurally mediated or reflex), Cardiac etiology
Neurally mediated (reflex) syncope/vasovagal syncope mech of action
- Baroreceptors in carotid sinus and aortic arch monitor BP and HR by innervation of CN IX and X
- Decreased firing due to lack of stretch from baroreceptors activates brain stem to respond with sympathetic innervation to raise pressure
- Increased firing due to stretch from baroreceptors inhibits brain stem from responding with sympathetic innervation causing lowering of blood pressure as well as increase in vagal tone to heart to decrease HR
Vasovagal/neurally mediated syncope never occurs when…
….lying down
Tilt table test
Performed to diagnose suspicion of vasovagal/reflex syncope, no change in EKG but shifts in BP and heart rate are positive upon shifting orientation of table
Situational syncope
A type of vasovagal/neurally mediated syncope episode brought on by specific activity, most often post defecation
Carotid sinus hypersensitivity (charcot weiss baker syndrome)
Occurs when stimulation of carotid sinus causes bradycardia and hypotension often in elderly or with tight collars, can diagnose with carotid sinus massage