carotid sinus syndrome Flashcards
what is the carotid sinus?
an area of dilatation in the ICA which contains a number or baroreceptors, to maintain homeostasis when pressure increases within the vessel wall the resultant effect is peripheral vasodilatation and reduced heart rate
what is carotid sinus syndrome (CSS)?
a condition of abnormal activation of this structure which leads to symptoms secondary to cerebral hypoperfusion
why is it increasingly common with advancing age?
combination of increased baroreceptor sensitivity and reduced cerebral auto-regulatory mechanisms
when should CSS be investigated for?
when there is unexplained syncope
types of CSS investigations
carotid sinus massage
tilt-table and CSM if locally available
types of CSS from carotid sinus massage result
o Cardio-inhibitory CSS – pause in HR >3 seconds.
o Vasodepressor CSS – drop in systolic BP of 50mmHg
o Mixed CSS – simultaneous combination of both
what do you need to do before carrying out carotid sinus massage?
o Assess for contraindications – MI or CVA in last 3 months, hx of VT, carotid artery stenosis.
o Consent – 0.1% risk of transient visual or sensory disturbance. 0.01% risk of completed stroke.
how do you do a carotid sinus massage?
o Connect to cardiac monitor and BP cuff and take baseline values.
o Lie patient flat and start rhythm strip printout.
o Apply pressure for 5 seconds to carotid sinus whilst a friend hits ‘mark’ to signify start of CSM.
o Check blood pressure – maximal drop at 15secs
o Repeat for other side when HR returns to normal.
when do you do the tilt table +CSM
if CSM alone is negative, there is unexplained syncope and it is locally available
what is the tilt table test
o Blood pressure and heart rate (by means of RR intervals on ECG) are measured continuously in the supine position and during passive head-up tilt (usually at 60°).
