Alzheimer's syndrome

Introduction to A-S syndrome Adams-Stokessyndrome (cardiac syncope) is caused by a sharp decrease in cardiac output, causing syncope and/or convulsions caused by acute cerebral ischemia. basic knowledge Sickness ratio: 0.05% Susceptible people: no specific people Mode of infection: non-infectious Complications: aspiration pneumonia

The cause of A-S syndrome

(1) Causes of the disease

Rapid arrhythmia

Cardiac syncope caused by rapid arrhythmia, more common in organic heart disease, a few are also seen in normal people.

(1) ventricular tachyarrhythmia:

1 ventricular tachycardia: not all types of ventricular tachycardia cause syncope episodes, ventricular tachycardia caused by syncope is mainly seen in patients with rapid ventricular rate and acute cardiac output caused by a sharp decline in cardiac output.

A. monomorphic ventricular tachycardia: a. sustained monomorphic ventricular tachycardia; b. non-sustained monomorphic ventricular tachycardia; c. special type of monomorphic ventricular tachycardia, such as right ventricular dysplastic ventricular tachycardia, bundle branch reentry Sexual ventricular tachycardia, usually benign idiopathic ventricular tachycardia, parallel rhythm ventricular tachycardia and accelerated ventricular autonomous rhythm do not cause syncope.

B. Polymorphic ventricular tachycardia: polymorphic ventricular tachycardia with aQ-T interval prolongation, including both congenital and acquired, the former seen in Jervell-Lange-Nielsen syndrome and Ward-Romano syndrome; the latter seen in low Blood potassium, low blood magnesium or drugs that prolong myocardial repolarization, such as antiarrhythmic drugs, tricyclic antidepressants, tinctures and organophosphates, etc., are also found in slow arrhythmias, central nervous system diseases and Autonomic dysfunction and cardiomyopathy caused by various heart diseases, normal polymorphic ventricular tachycardia at bQ-T interval, including ischemic polymorphic ventricular tachycardia and extremely short polymorphic ventricular tachycardia. Because of the polymorphic ventricular tachycardia (ie, the classic torsades ventricular tachycardia), the ventricular rate is extremely fast, similar to room ventricular fibrillation, so often accompanied by cardiac syncope.

C. Bidirectional ventricular tachycardia: Unless the ventricular rate is extremely fast, general bidirectional ventricular tachycardia does not cause cardiogenic syncope.

2 room flutter, ventricular fibrillation: seen in a variety of organic heart disease, the use of anti-arrhythmia drugs, pre-excitation combined with atrial fibrillation, severe electrolyte disorders, electric shock, lightning strikes, etc., for extremely severe arrhythmia, both The hemodynamic effects are equal to ventricular arrest, and once present, the patient rapidly develops Adams-Stoke syndrome.

3 frequent multi-source ventricular premature contraction: occasionally can cause cardiac syncope.

(2) supraventricular rapid arrhythmia:

1 Paroxysmal supraventricular tachycardia: Cardiac syncope is usually not caused. When the ventricular rate exceeds 200 beats/min and there is an organic heart disease, syncope may occur.

2 atrial flutter and atrial fibrillation: ventricular rate is very fast and people with basic heart disease can also have syncope.

3 Pre-excitation syndrome involving rapid supraventricular arrhythmia: reverse type atrioventricular reentry tachycardia, multiple bypass-induced atrioventricular reentry tachycardia, atrioventricular nodal reentry tachycardia Down the road, the speed of the room with a 1:1 bypass, atrial flutter with 1:1 or 2:l bypass, atrial fibrillation by bypass, etc., these types of rapid supraventricular arrhythmia often Cardiac syncope occurs with rapid ventricular rate.

2. Slow arrhythmia Cardiac syncope caused by this type of arrhythmia, seen in a variety of organic heart disease, such as acute myocarditis, acute myocardial infarction, various types of cardiomyopathy, congenital heart disease.

(1) Sick sinus syndrome: including severe sinus block, persistent sinus arrest, slow-fast syndrome, double knot disease, etc., are prone to cardiac syncope.

(2) High or complete atrioventricular block: Cardiac syncope can occur when the ventricular rate is extremely slow.

3. Acute cardiac bleeding is blocked

(1) Cardiac muscle lesions: mainly seen in primary hypertrophic obstructive heart disease, patients with significant thickening of the aortic valve ventricular septum, ventricular septal thickness more than 15mm, ratio of ventricular septum to left ventricular posterior wall thickness > 1.5, when severe When exercising or changing position, the heart contraction is strengthened. The hypertrophic ventricular septum is close to the anterior mitral valve, which makes the left ventricular outflow obstruction worse, which causes syncope and even sudden death. Some patients with syncope and sudden death are related to arrhythmia.

(2) heart valve disease: mainly caused by valve stenosis.

1 rheumatic heart valve disease: A. severe mitral stenosis (valve diameter <0.8cm), change of body position or exercise can occur after syncope, individual patients due to left atrial giant wall thrombus or sputum bioincarceration, or shedding After incarceration of the valve mouth and causing syncope or sudden death, B. Aortic valve area <1cm2, syncope may occur after changing position or exercise, and some patients with syncope and sudden death are related to arrhythmia.

2 congenital or degenerative valvular disease: congenital mitral stenosis, congenital or degenerative aortic valve (membrane) mouth, valvular, subvalvular stenosis.

3 cardiac tumor: mainly seen in left atrial myxoma, is a benign tumor, when the tumor is invaded in the atrioventricular valve, the cardiac output is drastically reduced or even interrupted, leading to syncope or sudden death, more often in the change of position.

4 intracardiac wall thrombus: the left side of the large heart of the wall thrombus can also block the mitral valve mouth caused by syncope.

5 coronary heart disease myocardial infarction: in the occurrence of cardiogenic shock, due to the sharp decline in left heart discharge, leading to syncope and sudden death, some patients with acute myocardial infarction with syncope or sudden death as the first symptom to see a doctor, some patients with syncope episodes are combined with severe arrhythmia Caused.

6 acute pulmonary embolism: large area of pulmonary infarction, the left heart can reduce the amount of blood, resulting in the onset of cardiac syncope.

7 aortic dissection: syncope may occur when the aortic arch dissection involves one side of the common carotid artery.

8 cardiac tamponade: trauma, surgery, acute myocardial infarction caused by heart rupture and other causes of sudden increase of effusion in the pericardial cavity, venous return decreased sharply, leading to syncope.

4. Congenital heart disease

(1) tetralogy of Fallot: occurs more during exercise or physical activity. Exercise causes peripheral vascular resistance to decrease and right ventricular outflow tract reflects paralysis, causing an increase in right-to-left partial flow, which further reduces arterial oxygen partial pressure. The cerebral hypoxia is aggravated and syncope occurs, and there are also people who are caused by arrhythmia.

(2) Primary pulmonary hypertension: When exercising or exerting force, pulmonary artery spasm is caused by vagus nerve reflex, resulting in a sharp limitation of right ventricular discharge, and a sharp drop in left heart discharge, leading to syncope.

(3) Eisenmenger syndrome: due to pulmonary hypertension, occasionally there may be syncope episodes.

(two) pathogenesis

1. Severe or rhythmic disorders of cardiac output can cause syncope. Sometimes, obstructive damage and arrhythmia occur simultaneously and interact with each other.

(1) Severe aortic stenosis: up to 42% of these patients can experience syncope during exercise. The mechanism is: exercise can significantly increase left ventricular systolic pressure without a corresponding increase in aortic pressure, thus over-stimulating left ventricular pressure The receptors, through the heart fascinated afferent fibers, make the sympathetic inhibition and parasympathetic excitement, and hypotension and bradycardia occur. At the same time, hypotension and bradycardia also reduce coronary perfusion, and myocardial ischemia contributes to vascular decompression. Syncope, if a patient with aortic stenosis occurs syncope, indicating a poor prognosis.

(2) hypertrophic obstructive cardiomyopathy: up to 30% of patients with syncope, hemodynamic changes to left ventricular outflow tract obstruction, due to increased myocardial contractility, ventricular cavity reduction, increased afterload and decreased diastolic blood pressure Hemodynamic changes are aggravated, therefore, Valsalva action, paroxysmal severe cough, drugs such as digitalis can promote hypotension and syncope, it has been reported that 25% of hypertrophic cardiomyopathy is ventricular Tachycardia, which is also an important cause of syncope, predicts syncope: age less than 30 years, left ventricular end-diastolic volume index less than 60ml/m2, and non-sustained ventricular tachycardia, and diffuse cardiac hypertrophy and ventricular tachycardia Overspeed indicates a poor prognosis.

(3) Pulmonary hypertension: pulmonary hypertension can also cause exertional syncope. The right ventricular stenosis reduces the ability to increase cardiac output. Exercise reduces peripheral vascular resistance and can also cause hypotension and syncope. Similarly, pulmonary valve Labor stun can also occur in stenosis.

(4) Pulmonary embolism: 10% to 15% of patients with pulmonary embolism can develop mechanical syncope, large pulmonary embolism (>50% pulmonary vascular bed obstruction) can cause acute right heart failure, increase right ventricular filling pressure and stroke The reduction in output, followed by hypotension, leads to loss of consciousness.

(5) atrial myxoma: atrial myxoma can cause mitral or tricuspid occlusion, clinical features are syncope, dyspnea and heart murmurs vary with body position, the mechanism of syncope is ventricular inflow obstruction, cardiac output Reduced, insufficient brain perfusion.

2. Other organic heart disease 5% to 12% of patients with acute myocardial infarction may have syncope. The mechanism is: 1 sudden pump failure, causing hypotension and cerebral hypoperfusion; 2 dysrhythmia, such as ventricular tachycardia Overspeed or over-arrhythmia.

Acute inferior myocardial infarction or ischemia occurs in the right coronary artery. The left ventricular baroreceptor is stimulated to produce a vasovagal reaction that causes syncope. Unstable angina and coronary artery spasm can cause syncope.

5% of patients with aortic dissection can have syncope, and the dissection breaks into the pericardial cavity, which can cause acute pericardial tamponade and lead to loss of consciousness.

3. Arrhythmia When bradycardia is delayed, due to the prolonged ventricular filling period, the output of stroke is increased, thereby maintaining normal cardiac output. When severe bradycardia is delayed, syncope is caused by the difficulty of compensatory increase in cardiac output. Mild to moderate tachycardia increases cardiac output without fainting, and a significantly increased heart rate results in decreased diastolic filling and decreased cardiac output, which can cause hypotension and syncope.

Sinus bradycardia may be caused by excessive vagal tone, decreased sympathetic tone or sinus node disease. Athletes' sinus bradycardia is often caused by increased vagal tension and decreased sympathetic activity, but rarely causes syncope. Sinus bradycardia can also occur in ophthalmologic surgery, mucinous edema, intracranial and mediastinal tumors, and the use of multiple parasympathomimetic drugs, antisympathetic blockers, beta blockers, and other drugs.

In patients with sick sinus syndrome, 25% to 70% have syncope. The syndrome is characterized by sinus impulse formation or conduction disorder. Electrocardiographic findings include sinus bradycardia, sinus arrest, sinus rest and Outbreak block, supraventricular tachycardia or rapid atrial fibrillation (slow-fast syndrome) may occur, and the sick sinus syndrome may have occasional reflex vasodilatation despite the placement of an artificial cardiac pacemaker. A stable syndrome attack.

Ventricular tachycardia has more organic heart disease. The severity of the symptoms is related to its frequency, duration and cardiac function. Torsades ventricular tachycardia, congenital long QT syndrome (with or without deafness) And acquired acquired QT syndrome can occur syncope, the latter is related to drugs, electrolyte abnormalities and central nervous system diseases, anti-arrhythmia drugs are the most common cause of torsades de pointes, such as quinidine D-syncope), procainamide, propiamine, flucaine, encaine, amiodarone and statin.

Other tachyarrhythmias that can cause syncope include: fast ventricular rate atrial fibrillation and atrial flutter, atrioventricular nodal reentry tachycardia, etc., in addition to the diastolic filling and decreased cardiac output due to increased heart rate In addition to hypotension and syncope, at this time, the heart volume is reduced and the ventricular contraction is strong, thereby exciting the cardiac mechanoreceptor, leading to nerve-mediated syncope. The syncope of the pre-excitation syndrome is caused by rapid reentry supraventricular tachycardia or atrial fibrillation. When the fast chamber rate response is caused.

A-Syndrome Prevention

prevention:

1. Patients with vasovagal syncope should avoid induced factors such as emotional agitation, fatigue, hunger and panic.

2. Patients with episodic syncope should pay attention to body position when urinating, defecation, coughing and swallowing.

3. Patients with orthostatic hypotension should avoid standing suddenly from the lying position. Before starting to get up, they should first move their legs, then slowly sit on the edge of the bed to observe the feeling of dizziness and dizziness before they can walk down; they can also use elastic stockings. Or abdominal band; ephedrine can increase blood pressure; salt can increase the extracellular volume, which has certain effects.

A-Syndrome complications Complications, aspiration pneumonia

If there is no protective measure during the onset of syncope, it can cause brain trauma, fracture, and may also be complicated by aspiration pneumonia and even suffocation.

A-Syndrome Symptoms Common Symptoms Pale pubic compartment block, dizziness, limbs, numbness, sleepiness, loss of consciousness, convulsions, sigh-like breathing

Symptom

(1) The light is only dizzy, short-term black eyes, severe cases of syncope or convulsions, mainly depends on the time and extent of cerebral ischemia.

(2) Loss of consciousness when syncope occurs, should not be called, after the episode, there may be general fatigue, soreness, lethargy and other discomfort.

(3) Repeatedly the author of syncope, the above phenomenon can be repeated.

(4) The onset time of syncope is usually short (<30s=, which is characteristic of cardiogenic syncope.

2. Signs

(1) When the syncope occurs, it looks pale, and the breathing often has a snoring sound. If the heart beats for 20 to 30 seconds, there may be sigh-like breathing, or even Chen-spiring.

(2) When the syncope caused by arrhythmia occurs, the body does not have a pulse or can not count the pulse rate per minute, the heart test has no heart sound, or the heart rate is very low and the heart sound is weak. Because the heart is blocked by blood, the auscultation heart has a heart sound. Change and corresponding noise.

(3) There may be limb convulsions when syncope occurs.

(4) After the heart resumes normal pulsation, the complexion turns red, the breathing gradually turns stable, and the consciousness recovers quickly, but there is a near forgotten phenomenon.

A-S syndrome

1. ECG examination If cardiogenic syncope is caused by arrhythmia, ECG monitoring or ordinary body surface electrocardiogram can find whether the arrhythmia is rapid or slow, is supraventricular or ventricular arrhythmia, for a clear diagnosis and Treatment is extremely valuable. The 24h dynamic electrocardiogram can detect some related arrhythmias, and can judge the relationship between arrhythmia and symptoms. If necessary, perform electrophysiological examination to identify the cause of syncope.

2. It is difficult to implement the echocardiogram syncope episode. It is feasible to check the episode during the episode, which is beneficial to exclude the cardiogenic syncope caused by "cardiac disease blocked by heart" and "congenital heart disease".

3. Clinical trial on differential diagnosis of syncope

(1) Tilt test: It is the only means to detect vasovagal syncope in clinical practice.

1 indications: a history of syncope; only one syncope episode but caused serious damage, or special occupations (such as drivers, pilots, surgeons, etc.).

2 contraindications: those with severe cardiovascular and cerebrovascular disease should not do the tilt test.

3 method: 60 ° ~ 80 ° tilt, tilt time is 45 min.

4 Judgment criteria: Symptoms of syncope or syncope before the test were accompanied by a decrease in blood pressure and/or a slow heart rate.

(2) carotid sinus massage: is one of the main methods for diagnosing carotid sinus syndrome (CSS, carotid sinus syncope, carotid sinus allergy syndrome), can be combined with esophageal cardiac electrophysiological examination, atropine test and other tests.

1 indications: patients with a history of syncope.

2 contraindications: severe cerebrovascular disease, recent myocardial infarction and carotid artery murmurs.

3 Methods: The patient was placed in the supine position with the head slightly biased to the opposite side. The electrocardiograph and cuff sphygmomanometer were prepared to observe the changes of heart rate and/or arterial systolic pressure. The surgeon used the thumb to massage the neck corresponding to the upper edge of the thyroid cartilage. Arterial enlargement or the strongest point of carotid pulsation, start to gently apply force, gradually increase the pressure of the thumb, generally lasting no more than 15s, intermittently after 10 ~ 15s massage the contralateral carotid sinus, taboo simultaneously press the bilateral carotid sinus.

4 Judgment criteria: The following cases are judged as positive and the classification diagnosis is performed: A. Cardiac inhibition type (59% to 80%): ventricular arrest 3s; B. Simple blood pressure type (11% to 15%) %): systolic blood pressure drops 50mmHg (6.65kPa); if there are neurological symptoms, even systolic blood pressure drops only 30mmHg (4.0kPa) is the same type; C. mixed type (30%): cardiac inhibition type combined with blood pressure reduction D. Primary brain type: no change in blood pressure and heart rate, the patient has pre-syncope symptoms, caused by obstructive diseases of the carotid artery, anterior cerebral artery and vertebrobasilar system.

(3) Determination of blood pressure and pulse rate in the vertical position: This test can diagnose whether or not the orthostatic hypotension (also known as orthostatic hypotension) is caused by syncope, mainly reflecting autonomic nervous function.

1 Method: Blood pressure and heart rate after 5 minutes of standing and lying position were measured.

2 Judgment criteria: standing systolic blood pressure drop 30mmHg (4.0kPa) or mean arterial pressure drop 20mmHg

(2.7kPa) was positive, may be associated with erectile cerebral ischemia symptoms, heart rate does not increase after standing, also reflects autonomic dysfunction.

(4) Valsalva's test: This test can diagnose whether it is a syncope caused by vascular motility regulation, and also mainly reflects the regulation function of vascular nerve.

1 method: first let the patient take the upright position, take a deep breath 3 times, then make a deep inhalation and then hold the breath, then slowly squat, and at the same time force the exhalation action until the breath is not standing upright.

2 Judgment criteria: If there is a syncope or syncope, the patient is suggested to have defects in vascular motion regulation.

Diagnostic identification of A-S syndrome

Diagnostic criteria

History

(1) Onset form: syncope lasts only a few seconds, with high-sensitivity carotid sinus syndrome, orthostatic hypotension, atrioventricular block, cardiac arrest or ventricular tachycardia, the symptoms are in a few minutes Gradually develop, should consider hyperventilation syndrome, physical syncope occurred in physical activity, mostly caused by organic heart disease, cough, urination, defecation, swallowing, attention should be paid to the situation of syncope, turn neck, Shaving, fainting when wearing a tight neckcoat should consider carotid sinus syncope.

(2) Post position at the time of onset: orthostatic hypotension occurs when the position changes rapidly from the supine position to the standing position, the syncope caused by the heart block is not related to the body position, the heart palpitus is accompanied by sudden syncope, and in the supine position The quick recovery instructions are mostly caused by supraventricular arrhythmia.

(3) Accompanying symptoms: There are lips and limb numbness before syncope are common in hyperventilation syndrome, limb convulsions during syncope, seen in atrioventricular block, cardiac arrest or ventricular tachycardia, palpitations in anxiety, atopic Tachycardia.

2. Special inspection

For some patients with unexplained syncope, some inducing tests can be performed to facilitate diagnosis. Patients with high carotid sinus sensation can gently press one carotid sinus area, orthostatic hypotension and tachycardia can be used for lying-reflex test, coughing. Sexual syncope can be induced by Valsalva method. Continuous ECG monitoring or Holter recording can understand the relationship between arrhythmia and syncope. Intracardiac electrophysiology can further understand the arrhythmia and treat it.

The upright tilt test is mainly used to diagnose vasovagal syncope. Normal people from the lying position to the vertical tilt of 60 ° only cause mild systolic blood pressure drop, diastolic blood pressure rise and heart rate, while patients with vasovagal syncope are inclined at 60 ° upright. ~70 °, after 10 to 30 minutes, there is syncope. Recently, some people have been supplemented with nitroglycerin or isoproterenol stimulation test, which has limited tolerance due to poor tolerance and limited use.

EEG examination can identify syncope and epilepsy. In epileptic patients, about 40% to 80% of patients show abnormalities, while patients with syncope are always normal.

Differential diagnosis

Should be associated with other diseases that may cause syncope, such as vasovagal syncope, orthostatic hypotension, carotid sinus syncope, physiological reflex syncope, cerebrovascular disease syncope, metabolic diseases and changes in blood components caused by syncope and mental nerves The difference between syncope caused by disease and seizure:

1. Seizures can occur in any position, sudden onset, pre-existing before the attack, but lasting only a few seconds, often caused by trauma, convulsions, eye turn, urinary incontinence, bite lip and confusion, unconscious The time often lasts for a few minutes, and there is a long period of drowsiness after the attack. The syncope starts slowly and has no premonition. The episode is short and the mind recovers quickly; there is no drowsiness after the attack.

2. Hemorrhoids appear in patients with snoring personality, without blood pressure, heart rate or skin color changes, no convulsions at the time of attack, biting the lips and turning up the eyes.

3. There is hunger, rapid heartbeat, nervousness and other sympathetic stimulation before the onset of hypoglycemia. Following the loss of consciousness, the loss of consciousness gradually progresses. Untreated can enter deep coma, and the low blood sugar in the emergency examination can be surely diagnosed.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.