Sinus arrest

Introduction Sinus arrest is the sinus node that does not produce impulses during one or more cardiac cycles, so that it cannot excite the atrium or the entire heart, or is known as sinus rest. Young people are often caused by strong vagus nerve reflexes, such as pharyngeal stimulation, tracheal intubation, compression of carotid sinus or eyeball, application of digitalis, quinidine sulfate and other drugs. Sometimes inflammation, ischemia, injury, degeneration and other factors, damage the sinus node of the autonomous cells, causing sinus arrest, the length of time is different, the patient will feel the heart does not beat for a while, long time After the pause, the sinus beat can be restored. Most of the ectopic beats after the pause, often borderline escape or ventricular escape, sometimes atrial escape. If there is no excitement after the pause, it is a cardiac arrest, and the patient may have convulsions, fainting, and even death. Frequent sinus arrest is a serious arrhythmia, which is a manifestation of sinus node failure. It is necessary to find out the cause of the treatment, and it is often necessary to install an artificial cardiac pacemaker in time.

Cause

1. Primary sinus arrest is more common, mainly due to the damage of the sinus node itself, mostly caused by organic heart disease. For example, coronary heart disease, acute myocarditis, cardiomyopathy, sick sinus syndrome, and frequent death arrest are the pre-dying manifestations of various diseases in the late stage.

2. Secondary sinus arrest

(1) Transient sinus arrest (2 to 4 s) secondary to various tachyarrhythmia: most common in supraventricular tachycardia, after stimulation of the vagus nerve and drug therapy or esophageal pacing The sinus arrest that occurs when the supraventricular tachycardia is suddenly corrected is mostly transient.

(2) anti-arrhythmia drug overdose or poisoning can cause sinus arrest: such as digitalis, quinidine, reserpine, amiodarone and so on. Propafenone (heart rhythm), moricizine, flecainide, antazoline, adenosine triphosphate (ATP).

(3) Increased vagal tone increases the sinus node function caused by sinus arrest: for example, oppression of the eyeball, massage of the carotid sinus, stimulation of the pharynx, tracheal intubation and so on. Normal people can sometimes happen.

(4) Injury of the sinus node during cardiac trauma or cardiac surgery: sinus arrest may occur during or after surgery. Coronary angiography and the like can also lead to sinus arrest.

(5) Hyperkalemia and hypokalemia can also cause sinus arrest.

an examination

The electrocardiogram can confirm the diagnosis and has the following characteristics:

1. Transient or persistent sinus arrest The sinus node has no impulses one or more times, so there is a long interval of varying lengths on the ECG, within this long interval. The P-QRS-T wave does not appear, and the long PP interval is not an integral multiple of the basic sinus rhythm cycle. On the same electrocardiogram, one or more long PP pauses may occur, but the lengths of long PP breaks that occur with each other may be mutually inconsistent. Transient sinus arrests often do not appear to escape, and sometimes can occur, mostly for atrioventricular transitional escape. More permanent sinus arrest is often accompanied by a transient escape rhythm. Mostly the atrioventricular junction area escape rhythm.

2. Persistent or permanent sinus arrest can not see sinus P wave on the electrocardiogram, secondary escape rhythm or slow escape rhythm can be seen, often accompanied by atrioventricular junction escape rhythm . Ventricular escape rhythm, atrial escape rhythm is rare. Persistent or permanent sinus arrest can even cause cardiac arrest to die.

3. Paroxysmal supraventricular tachycardia, atrial flutter, atrial fibrillation and other sinus arrests due to these rapid heart rate can lead to overspeed inhibition, it can cause sinus arrest, but its sinus node function is only mild Lower, so the prognosis is good, long PP interval is often greater than 2s, during the transition of fast-slow syndrome, different degrees of sinus arrest can also be seen.

Differential diagnosis

1. Identification of transient sinus arrest and severe and significant sinus arrhythmia

Sometimes the two are not easy to identify. Severe and significant sinus arrhythmia is rare, and the slow phase PP interval can be significantly prolonged. In a few cases, it can be greater than the sum of two short PP intervals, similar to sinus arrest. However, the change in PP interval during sinus arrhythmia is gradual. The PP interval is gradually shortened and gradually extended, and the PP phase of the slow phase is not an integral multiple of the fast phase PP interval, which is manifested by the length of the PP interval.

2. Identification of short-term sinus arrest and pre-atrial contraction in the atrioventricular junction and non-transfer

(1) The characteristics of pre-trial contraction that have not been transmitted are:

1 The P' wave of the pre-atrial contraction that has not been transmitted is often superimposed on the T wave of the previous heart beat, causing the T wave shape to change. Care should be taken to find out that this is the key to the diagnosis. The P' wave can be revealed by increasing the voltage or increasing the paper speed.

2 The compensatory interval of contraction before atrial contraction is incomplete: generally less than the sum of the two PP intervals of sinus rhythm.

The long PP intervals produced by more than 3 uncontained atrial contractions were equal or approximately equal.

(2) The characteristics of the premature contraction of the uncompleted compartmental transition zone are:

1 Retrograde P' wave often overlaps the T wave of the previous heart beat, which can change the T wave shape, so it should be carefully searched.

2 The long PP interval caused by the contraction of the premature contraction without the transfer of the compartment should be equal or roughly equal to each other on the electrocardiogram.

3. Identification of transient or longer sinus arrest and sinus conduction block

(1) The second-degree type I sinus block is characterized by a gradual shortening of the PP interval after the long PP interval, and a sudden appearance of a long PP interval, which is characterized by a "sudden and short length". appear.

(2) The second degree II or even high sinus conduction block is characterized by the long interval of sinusoidal P wave is an integral multiple of the basic sinus rhythm PP interval, easy to identify, but if combined with sinus arrhythmia, Then the diagnosis is difficult.

4. Identification of persistent or permanent sinus arrest and third degree (complete) sinus block

(1) Persistent or permanent sinus arrest rarely occurs in atrial escape or atrial escape rhythm, while third-degree sinus block may be associated with atrial escape or atrial escape rhythm. The reason is that inhibition of the pathological factors of the sinus node also inhibits atrial pacing.

(2) Persistent or permanent sinus with temporary sinus arrest before permanent or permanent sinus arrest recorded by continuous electrocardiogram or 24h ambulatory electrocardiogram before permanent or permanent sinus arrest The possibility of sexual arrest is large; if there is a second degree sinus block, the possibility of third-degree sinus block is large.

(3) After intravenous atropine, the sinus conduction function did not improve to sinus arrest; there was improvement to third degree sinus block. If the two can not be distinguished, it may be diagnosed as sinus arrest.

5. Identification of persistent or permanent sinus arrest and atrioventricular transitional rhythm and ventricular escape rhythm

(1) Atrioventricular junctional escape and ventricular escape rhythm with room conduction, there is actually no sinus arrest, but a series of sinus rhythms caused by ventricular conduction in the atrioventricular junction It's just a matter of delay.

(2) With the retrograde blockage of the room, there is still no sinus P wave, it is likely to be sinus arrest.

6. Persistent or permanent sinus arrest and sinus conduction

Sinus conduction is diffuse complete atrial block, sinus agitation is transmitted along the room bundle to the atrioventricular junction and ventricular muscles, producing QRS waves, but not through the loss of conductive atrial muscle conduction, so it is not seen Any P wave. The main points that contribute to this diagnosis are: 1 Hyperkalemia. 2 has a clinical cause of hyperkalemia. 3QRS wave width deformity. The 4T wave tip is like a tent.

7. Identification of persistent or permanent sinus arrest and significant sinus bradycardia

When the frequency of obvious sinus bradycardia is lower than the atrial escape rhythm or the atrioventricular junction or ventricular escape rhythm with room conduction, the sinus P wave appears as scheduled, and the chamber is connected. Regional escape rhythm forms an interfering atrioventricular dislocation. As seen on one or several other electrocardiograms, the frequency of sinus bradycardia has slightly exceeded the frequency of escape rhythm, and it appears that simple sinus bradycardia or sinus bradycardia and escape rhythm form an interfering disjoint , it is helpful for the diagnosis of sinus bradycardia. However, the possibility of switching from sinus bradycardia to sinus arrest is also present.

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