Physiology-Syncope Flashcards
What are the three symptoms of cardiology?
Chest pain, syncope and dyspnea
What is syncope?
Transient loss of consciousness not due to seizure or trauma.
Why do you not need to doppler carotid arteries in syncope?
Both cortexes, or the brainstem must have hypoperfusion…global hypoperfusion does not occur in blockage of a single carotid artery.
How do you differentiate between syncope and seizure? Why are the two often confused?
In syncope, patients will wake up and know exactly where they are. In seizure, it takes 10 minutes after waking up for people to become aware again. Synocope can be confused with seizure because they both can have tonic-clonic activity.
What is your differential diagnosis with syncope?
Cardiovascular (if it is their mortality is 20-30% because it can be a precursor to cardiac death) or not?
What are the two categories of cardiovascular syncope?
Electrical instability or a mechanical obstruction
What types of electrical instability can cause syncope?
Fast arrhythmias (ventricular tachycardia) and slow arrhythmias (sick sinus syndrome or AV block)
What types of mechanical obstruction can cause syncope?
Aortic stenosis in the elderly. Hypertrophic cardiomyopathy in the youth. Pulmonary emboli. Anomalous coronary artery that goes between the pulmonary artery and aorta (compresses and causes sudden death when the pulmonary artery dilates during exercise). Atrial myxoma (tumor obstructs AV valve). Subclavian steal (exercising your arm steals blood away from your head via carotids).
What causes 95% of non-cardiovascular syncope? What causes the other 5%?
Vasovagal syncopy (neurally mediated reflex). Temporal lobe epilepsy and psychogenic (faking it) cause a small percent.
Why do people pass out with neurally-mediated syncope?
1) Sympathetic activation (pain) 2) Hypovolemia (knees locked). Decrease in venous return + vigorous heart contraction = heart walls slam together causing vagal reflex (contractility decreases, slows heart rate and vasodilation) and a sudden brief decrease in blood pressure.
Two patients come to see you after having syncopic episodes. One had wooziness for 30 seconds prior to the episode and felt awful afterwards. The other had no prior symptoms and felt normal afterwards. Which patient had cardiovascular-related syncope?
The patient with no symptoms before or after. This is because in cardiovascular syncope the parasympathetic nervous system remains unactivated.
What symptoms prior to syncope point you towards cardiovascular origin?
Chest pain. During exercise (post-exercise usually = neurally mediated). Family history (sudden death, hypertrophic cardiomyopathy). BP lowering medications. Previous MI.
What are high risk populations with syncope?
Pilots, bus drivers and elderly.
What are the most important things to analyze in your physical exam for syncope?
Orthostatic pulse and blood pressure. If BP drops > 20mmHg or HR increases > 20 when standing up, this suggest hypovolemia or inability to maintain blood pressure and a diagnosis of non-cardiovascular syncope. Valsalva maneuver will help you rule out hypertrophic cardiomyopathy (HCM). Listen for murmurs (aortic stenosis, HCM and mitral regurgitation from heart failure). Crackles in lungs = heart failure.
What labs do you do for people with syncope?
EKG (long QT, Torsades de Pointes). Echocardiography.
