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Situational syncope is often triggered by urination, swallowing, or coughing. [2] Carotid sinus syncope is due to pressure on the carotid sinus in the neck. [2] The underlying mechanism involves the nervous system slowing the heart rate and dilating blood vessels, resulting in low blood pressure and thus not enough blood flow to the brain. [2]
The carotid sinus baroreceptor can be oversensitive to manual stimulation from the pressure applied at the carotid sinus at the carotid bifurcation. It is a condition known as 'carotid sinus hypersensitivity' (CSH), 'carotid sinus syndrome' or 'carotid sinus syncope', in which manual stimulation causes large changes in heart rate and blood ...
Neurally mediated syncope may also occur when an area in the neck known as the carotid sinus is pressed. [1] A normal response to carotid sinus massage is reduction in blood pressure and slowing of the heart rate. Especially in people with hypersensitive carotid sinus syndrome this response can cause syncope or presyncope. [9]
Baroreceptors can also become oversensitive in some people (usually the carotid baroreceptors in older males). This can lead to bradycardia, dizziness and fainting (syncope) from touching the neck (often whilst shaving). This is an important cause to exclude in men having pre-syncope or syncope symptoms.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow in the posterior circulation of the brain.The posterior circulation supplies the medulla, pons, midbrain, cerebellum and (in 70-80% of people) supplies the posterior cerebellar artery to the thalamus and occipital cortex. [1]
The carotid branch of the glossopharyngeal nerve (carotid sinus nerve or Hering's nerve) is a small branch of the glossopharyngeal nerve (cranial nerve IX) ...
An increase in blood pressure can be caused by increased cardiac output, increased total peripheral resistance, or both. The baroreceptors in the carotid sinus sense this increase in blood pressure and relay the information to the cardiovascular centres in the medulla oblongata.
Often sinus node dysfunction produces no symptoms, especially early in the disease course. Signs and symptoms usually appear in more advanced disease and more than 50% of patients will present with syncope or transient near-fainting spells as well as bradycardias that are accompanied by rapid heart rhythms, referred to as tachycardia-bradycardia syndrome [4] [5] Other presenting signs or ...