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
Contraindications to carotid sinus massage (3)
- Carotid bruits
- recent MI
- History of CVA
Orthostatic hypotension syncope etiology
-Sudden decrease in BP after standing or during standing after exertion due to volume depletion, drugs, or autonomic dysfunction, most common in elderly and rare in those less than 40 years of age caused by autonomic failure, drugs, hypovolemia, and treated with volume replacement, avoiding precipitating factors, treatment of underlying cause
Cardiac syncope etiology
Known structural heart disease suggested, loss of consciousness during exertion or sudden onset of palpitations is characteristic, can be due to bradycardia, tachycardia, structural disease, and obstructive disease, can be brought on by drugs, hyper/hypothyroidism, or prolonged QT interval
Long QT syndrome and how it relates to syncope
Problem with heart’s electrical system that is often asymptomatic until sudden syncopal episode, may be congenital or acquired, and is linked to sudden cardiac death and torsades de pointes
DOC for torsades de pointes
-IV magnesium
Should all athletes be screened for long QT because of its risk of sudden cardiac death?
No because of many false positives unless they have relevant family history
1 treatment for long QT syndrome (and its supplement)
- IV magnesium followed (stabilize) by B blocker
- sometimes supplementary implantable cardioverter defibrillators in those with high risk for sudden cardiac death expected to live more than a year
Brugada syndrome
Genetic condition channelopathy responsible for 4-12% of all sudden cardiac deaths, high risk, manifests with specific “saddle-like” pattern ST segment elevation in leads V1-V3 and right bundle branch block
Brugada syndrome treatment
Implantable cardioverter defibrillator (ICD)
Wolff parkinson White syndrome
Frequently encountered ventricular pre-excitation syndrome, presents asymptomatic or with a paroxysmal supraventricular tachycardia or atrial fib, has triggers such as exercise or drugs, presence of delta wave on QRS complex, most have good prognosis if asymptomatic
Wolff parkinson white treatment both urgent (3) and non-urgent (1)
Urgent (in afib) - syncronized direct cardioversion, if hemodynamically stable can use vagal maneuvers or iv adenosine
Nonurgent - catheter ablation
Hypertrophic cardiomyopathy 1st line treatment, 2nd line treatment, and alternative consideration
- B blockers
- Calcium channel blockers
- septal reduction
Sick sinus syndrome and 3 subtypes
- Sinus node dysfunction (normal rate and rhythm with a pause) with associated symptoms
- 3 subtypes including chronic bradycardia, alternating sinus bradycardia with paroxysmal supraventriclar tachyarrhythmias, or tachybrady syndrome
Treatment for sick sinus syndrome
-Pacemaker if symptomatic
Syncope characteristics to look for in work up (4)
- complete loss of consciousness
- loss of postural tone
- recovery spontaneous and complete
- rapid onset and short duration
Family history of sudden cardiac death or cardiac arrhythmias is indication for…
…frequent long term observation and monitoring of patients
Specific signs of cardiac syncope (4)
- occurs during exertion
- occurs in lying down position
- family history of sudden cardiac death
- slow recovery from episode
Diagnostic tests for syncope (4)
- EKG
- echocardiogram
- holter monitor
- external loop recorder
Differences between holter monitor and external loop recorder
Holter monitor is for 24 hours, external loop recorder can stay on longer time and can shower with one just have to replace leads, press activation button on external loop recorder
Syncope vs seizure
Syncope is due to transient loss of consciousness due to cerebral hypoperfusion
Seizure is due to abnormal electrical activity in brain
Test that can differentiate between syncope and seizure
Electroencephalography (if abnormal likely seizure in origin)
Hypertrophic cardiomyopathy and how it relates to syncope
Unexplained LVH resulting in impaired diastolic filling, most often genetic and asymptomatic but can lead to syncopal episode