What Is Sinus Arrhythmia?

The heart rhythm that originates in the sinoatrial node is called sinus rhythm. Sinus rhythm is a normal rhythm. Sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus arrest, and sick sinus node syndrome are all sinus arrhythmias. The frequency of sinus rhythm in normal adults is> 100 beats / min, which is called sinus tachycardia. The frequency of sinus rhythm is called sinus bradycardia. The origin of sinus rhythm is not changed, but the rhythm is irregular. The PP interval difference> 0.12s on the same lead is called sinus arrhythmia, which often coexists with sinus bradycardia. In regular sinus rhythm, sometimes due to increased vagal nerve tension or sinoatrial node disorder, the sinus node ceases to be excited for a period of time called sinus arrest. Pacing conduction system degenerative diseases and coronary heart disease, myocarditis (especially viral myocarditis), and cardiomyopathy can affect the sinoatrial node and its surrounding tissues to produce a series of slow sinus arrhythmias, and cause dizziness and dark The clinical manifestations of Mongolia and syncope are called sick sinus syndrome.

Basic Information

nickname

Sinus arrhythmia, sinus arrhythmia

English name

sinus arrhythmia

Visiting department

Cardiology

Common locations

heart

ECG characteristics of sinus rhythm

Generally, electrocardiographs cannot record the sinoatrial node excitatory potential, so the characteristics of the atrial excitatory wave P wave caused by sinus excitation are used to infer the activity of the sinoatrial node. The characteristics of the electrocardiogram of sinus rhythm are: P waves appear regularly, and the P wave morphology indicates that the excitement comes from the sinoatrial node (that is, the P waves stand upright at , , aVF, V4 to V6, and inverted at aVR). The frequency of normal sinus rhythm is generally 60 to 100 beats / minute.

Sinus arrhythmia sinus arrhythmia

Cause

More common in healthy children, including children after the age of 3, infants and young children are rare, often appear in slow heart rate or sleep, and when the heart rate increases or exercise, awake when the heart rhythm becomes tidy. Drugs such as digitalis, morphine, and beta-blockers can cause arrhythmias. Can also be seen in children with organic heart disease.

2. Clinical manifestations

Symptoms in children are milder than those in adults, and complaints are often lacking. Individual older children may report palpitations, chest tightness, and discomfort. Often found during auscultation or ECG examination, sinus arrhythmia may be related to the cycle of breathing, which is accelerated during inspiration and slowed during expiration. Sinus arrhythmias have no clinical significance.

3. Features of ECG

(1) Respiratory sinus arrhythmia Sinus P wave; arrhythmia is related to breathing, slowing down when exhaling, speeding up when inhaling, and turning the rhythm to regularity when holding your breath; on the same lead, the PP interval is 0.12 seconds the above;

(2) The performance of non-respiratory sinus arrhythmia is basically the same as that of respiratory sinus arrhythmia; arrhythmia has nothing to do with the breathing cycle.

4. Treatment

Sinus arrhythmias do not require treatment, and those with primary disease are treated symptomatically.

Classification of sinus arrhythmias

Sinus arrhythmia is classified into sinus tachycardia, sinus bradycardia, sinus arrhythmia, sinus arrest and sick sinus node syndrome.

Sinus tachycardia

The frequency of sinus rhythm in normal adults is> 100 beats / min, which is called sinus tachycardia. In sinus tachycardia, the PR interval, QRS, and QT time are shortened accordingly, sometimes accompanied by secondary ST-segment depression and low T-wave amplitude. Common conditions include exercise, mental stress, fever, hyperthyroidism, anemia, blood loss, myocarditis, and the effects of adrenaline-like drugs.

2.Sinus bradycardia

When the frequency of sinus rhythm is <60 beats / min, it is called sinus bradycardia. The elderly and athletes have relatively slow heart rhythms. Increased intracranial pressure, hypothyroidism, or use of beta-blockers can cause sinus bradycardia. Sinus bradycardia is less than 40 beats / min.

3.Sinus arrhythmia

The origin of sinus rhythm is unchanged, but the rhythm is irregular, and the PP interval difference on the same lead is> 0.12s. Sinus arrhythmias often coexist with sinus bradycardia. The more common type of arrhythmia is related to the respiratory cycle, which is called respiratory sinus arrhythmia, which is more common in adolescents and generally has no clinical significance. Other rare sinus arrhythmias have nothing to do with breathing, such as (ventricular phase) sinus arrhythmia related to ventricular contraction and bleeding, and migratory arrhythmia in the sinoatrial node.

4. Sinus arrest

Also called sinus rest. In regular sinus rhythm, sometimes due to increased vagal tone or sinoatrial node disorder, the sinus node stops emitting excitement for a period of time, and the P wave suddenly appears in the regular PP interval on the electrocardiogram, forming a long PP interval. And the long PP pitch has no multiple relationship with the normal PP pitch. Evasive beats or escape rhythms often occur after sinus arrest.

5. Sick sinus node syndrome

In recent years, it has been found that degenerative lesions of the pacing conduction system and coronary heart disease, myocarditis (especially viral myocarditis), and cardiomyopathy can affect the sinoatrial node and its surrounding tissues, resulting in a series of slow sinus arrhythmias, and cause the head The clinical manifestations of fainting, darkening and syncope are called sick sinus syndrome. The main ECG charts are as follows: persistent sinus bradycardia, heart rate <50 beats / min, and difficult to correct with drugs such as atropine; sinus arrest or sinoatrial block; in significant sinus tachycardia On the basis of slowness, supraventricular tachyarrhythmias (atrial tachycardia, atrial flutter, atrial fibrillation, etc.) often occur, also known as slow-fast syndrome; if the lesions also affect the atrioventricular junction, sinus arrest occurs , Can not appear for a long time in borderline escape, or with atrioventricular conduction disorder, this is called double knot disease.

Sinus Arrhythmia Treatment

The treatment of sinus tachycardia is mainly to eliminate the causes, such as pain relief, infection control, correction of anemia, improvement of heart function, control of hyperthyroidism, etc., if necessary, can be treated with -blockers. However, it should be noted that sinus tachycardia is mostly caused by physiological stress reactions, so -blockers should not be used in large quantities in the absence of incentives to prevent excessive cardiac inhibition.

Sinus bradycardia can be observed if the heart rate is above 40 beats per minute, and those with severe sinus bradycardia, such as those who are ineffective or unable to improve after treatment, need to be equipped with a pacemaker to prevent cardiac dysfunction.

The prognosis of sick sinus node syndrome is closely related to the etiology and severity of the disease. If the sinus caused by viral myocarditis is treated actively and promptly, some can be cured. For those who do not heal for a long time and the sinus node lesions are not serious, they may be asymptomatic in the early stage, but cardiac insufficiency may occur. In severe cases, cardiac arrest or sudden death may occur, and an artificial pacemaker should be installed in time.