Carotid sinus syndrome

Introduction to carotid sinus syndrome Carotid sinus syndrome (css) is a group of clinical syndromes of spontaneous sudden dizziness, fatigue, tinnitus and even syncope. basic knowledge The proportion of illness: 0.004%-0.007% Susceptible people: the elderly Mode of infection: non-infectious Complications: syncope

Causes of carotid sinus syndrome

(1) Causes of the disease

The carotid sinus is located in the bifurcation of the internal carotid artery. This part is called the carotid sinus. It has baroreceptors. It is connected to the nucleus of the nucleus of the vagus nerve through the lingual nucleus of the lingual nucleus and the nucleus of the vagus nerve. Arterial blood pressure, heart rate, myocardial work, cardiac output, arterial resistance and venous volume, the reflex pathway is through the sinus nerve (branch branch) to the solitary nucleus, then to the dorsal nucleus of the vagus nerve, the fiber is transmitted through the vagus nerve, and the heart rate is generated. Slowness and blood pressure drop, but under normal circumstances, heart rate slowdown is generally less than 5 times / min, systolic blood pressure and diastolic blood pressure drop are within 1.33kPa (10mmHg), carotid sinus syndrome patients, carotid sinus stimulation to the outside The sensitivity is abnormally increased. When the external stimulus is felt, the parasympathetic tone is significantly increased on the one hand, the sinus heart rate is significantly slowed down, the PR interval is prolonged, the height of the atrioventricular block is high, or the three are combined. The cardiac output is increased. Significantly reduce cerebral ischemia, can cause syncope; on the other hand, secondary to decreased sympathetic activity, can cause systemic arterial relaxation, blood pressure is significantly reduced and cause cerebral blood The perfusion pressure suddenly decreased, and syncope may occur. In some patients, although there is no obvious heart rate and blood pressure change, when the carotid sinus is stimulated, the cerebral blood vessels contract, causing cerebral ischemia, and syncope may also occur.

(two) pathogenesis

The pathogenesis of carotid sinus syndrome is still not very clear. There are two main theories at present: one is the peripheral lesion theory, which believes that the lesion causing abnormal carotid sinus reflex is around the carotid sinus receptor due to carotid atherosclerosis. Embolism, carotid body tumor, inflammation near the carotid body, swollen lymph nodes, tumor and scar compression, etc., cause carotid sinus receptors to feel abnormal, many clinical studies have found that many patients with carotid sinus syndrome have Treated or untreated neck tumors, in recent years, Tea et al found that carotid sinus syndrome patients with abnormal sternocleidomastoid EMG, also support the peripheral lesion theory, the other is the central lesion theory, that The lesions that cause carotid sinus syndrome are at the level of autonomic nucleus, but the exact mechanism remains to be elucidated.

Carotid sinus syndrome prevention

1. In patients with carotid sinus syndrome, due to the abnormal sensitivity of the carotid sinus to external stimuli, it is necessary to pay attention to the sudden change of body position and reduce the local stimulation of the carotid sinus (such as sudden turning and other actions) to prevent falls.

2. Implant a permanent artificial cardiac pacemaker for patients with recurrent carotid sinus syndrome.

Complications of carotid sinus syndrome Complications

More dizziness, syncope and other complications.

Carotid sinus syndrome symptoms common symptoms convulsion cardiac arrest cerebral ischemia syncope neck instability carotid sinus syncope

Carotid sinus syndrome has many manifestations and can be divided into the following clinical types.

Cardiac suppression

Stimulation of carotid sinus ventricular arrest 3s, ventricular arrest is often caused by the entire cardiac arrest, but occasionally can also block the P wave, this type accounts for about 60% to 80% of patients with carotid sinus syndrome The syncope of this type of patient is caused by cerebral ischemia due to reflex systolic dysfunction.

2. Simple blood pressure reduction type

When the carotid sinus is stimulated, the systolic blood pressure is reduced by 6.7 kPa (50 mmHg). This type accounts for about 5% to 11% of patients with carotid sinus syndrome. This type of syncope is mainly composed of elongated individuals, and the syncope is due to blood pressure. Low causes cerebral ischemia.

3. Mixed type

When the carotid sinus is stimulated, both cardiac inhibition and blood pressure lowering occur. Generally, the heart rate is slowed by more than 50% when the carotid sinus is massaged, and the systolic blood pressure is decreased by 5.3 kPa (40 mmHg) or more. This type is the diagnostic standard of this type. About 30% of sinus syndrome.

4. Primary brain type

When stimulating the carotid sinus, although there is no obvious heart rate and blood pressure changes, the patient has symptoms of syncope or syncope, often very transient, common in patients with carotid anterior artery and vertebral-basal artery obstructive disease, often accompanied Symptoms of autonomic dysfunction, usually caused by sudden rotation of the head or collar tightness, the mechanism of this type of syncope is unknown, may be a kind of syncope caused by cerebral vasoconstriction, this type of attack, brain The electrogram showed a slow-frequency high-amplitude wave on the side of the carotid sinus compression, and a constrictive neurological sign of convulsion or spasm on the contralateral side.

Carotid sinus syndrome

Carotid sinus stimulation test

Also known as the Czermak-Hering test, the method is to perform continuous massage on the left and right carotid arteries with a medium pressure at the patient's bedside. The massage point is generally selected in the bifurcation of the common carotid artery (equivalent to sternocleidosis). On the protrusion 1/3), it should be noted that the left carotid sinus is lower than the right side, and the horizontal point above the flat laryngeal nodule is the first point of Hering at the intersection of the inner edge of the sternocleidomastoid muscle. Decline and slow down the pulse. Take a point on the common carotid artery for Hering's second point (equivalent to the lower part of the carotid sinus). If this point is pressed, the carotid sinus pressure will decrease, and the opposite will cause the blood pressure to rise and the pulse to accelerate. Therefore, the first point of Hering should be selected for the diagnosis of carotid sinus syndrome.

Generally, the heart rate slows down the blood pressure after 2 to 4 s of massage, and reaches the lowest value when 5 to 50 s. When the normal person massages the carotid sinus, the heart rate slows down 6 to 10 times. If it slows down 10 times/min or more, it can be considered Carotid artery stimulation test is positive. At this time, ECG and heart rate changes should be closely observed. At the same time, the patient's systolic blood pressure should be monitored by cuff method to observe whether there is bradycardia and systolic blood pressure reduction. The massage time should not exceed 5s, massage on both sides. The time interval should be greater than 15s, and avoid double-sided massage at the same time. To avoid excessive pressure, the examiner should simultaneously touch the strength of the ipsilateral carotid artery. It must be noted that carotid atherosclerosis, carotid arteritis, and around the carotid artery must be noted. Elderly patients with enlarged lymph nodes should be used with caution to prevent cerebrovascular accidents. Carotid artery stimulation induces bradycardia and decreased blood pressure or syncope can often confirm the diagnosis.

2. Upright tilt test

About 50% of patients with carotid sinus syndrome are positive in this test, so the value of the upright tilt test is not significant in the identification of vasopressive syncope.

Diagnosis and differentiation of carotid sinus syndrome

It has recently been found that young women with autonomic symptoms are prone to this disease when they suddenly turn their heads or their collars are too tight.

Middle-aged and elderly patients often have syncope, especially when the syncope is suddenly turned, the head is turned or the tight collar is related to the cause of the disease, and the carotid sinus stimulation test is feasible.

It is distinguished from reflex syncope in vasopressive syncope, coughing syncope, swallowing syncope, and urinary syncope.

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