What is sinus rhythm?

Many people, especially young people, often get the diagnosis of "sinus arrhythmia" when checking ECG. Most people know that the heartbeat should be regular and tidy, so when they hear of "arrhythmia", many people think it is an abnormal phenomenon. Although there are no symptoms, you should seek medical advice everywhere and seek experts to cure the "disease" quickly. But doctors often say, "Don't treat it." These people are playing drums again. Are they incurable?

Actually, sinus arrhythmia is a normal physiological phenomenon, not a disease. "Sinus arrhythmia" is most common in children and adolescents, and it is not uncommon in adults.

The beating of a normal person's heart is commanded by a high-level command called sinoatrial node. Sinus node sends out signals to stimulate the heart to beat. This kind of heart beat caused by the signal from sinus node is called normal sinus rhythm, and its frequency is about 60- 100 times per minute. The number of beats per minute, that is, the heart rate, comes from this. But this frequency may be affected by many factors, even breathing.

Generally speaking, the heartbeat rhythm is regular and tidy. If the heart beats irregularly, we call it arrhythmia. From this point of view, "sinus arrhythmia" is the most common arrhythmia, which is caused by irregular signals from sinus node. But this kind of "arrhythmia" mostly belongs to "respiratory sinus arrhythmia", which is a normal physiological phenomenon. Its characteristic is that it changes with the change of breathing. When inhaling, the heart rate can be accelerated by several jumps, and when exhaling, it can be slowed down by several jumps. Its fast and slow cycle is exactly equal to a breathing cycle, and when you hold your breath, your heart rate becomes regular. This kind of "sinus arrhythmia" which changes with breathing is completely normal, so there is no need to worry or treat it.

Therefore, people diagnosed with sinus arrhythmia can pay attention to whether the acceleration and deceleration of their heart rate are related to breathing. As long as there are no other symptoms, you don't need treatment and you can engage in normal study and life.

Now many doctors have noticed the panic caused by sinus arrhythmia, so they will write "sinus rhythm" when diagnosing.

In addition, mental stress and other factors may also cause "sinus arrhythmia", which does not need treatment.

Sinus irregularity

Sinus arrhythmia is characterized by irregular excitation of sinus node and obviously uneven cardiac cycle speed. Clinically, sinus arrhythmia is divided into the following types:

(1) Respiratory sinus arrhythmia:? Respiratory sinus arrhythmia is the most common sinus arrhythmia. Most of them occur in children, young people and the elderly, and middle-aged people are rare. The mechanism of respiratory sinus arrhythmia is that the tension between vagus nerve and sympathetic nerve changes during breathing, which makes the autonomy of sinoatrial node change periodically and regularly. When inhaling, the sympathetic nerve tension increases and the heart rate increases, while when exhaling, the vagus nerve tension increases and the heart rate slows down. The period of heart rate change is exactly equal to a breathing period, and the heart rate becomes regular when breathing stops. Its ECG features are as follows:

①P wave is a "sinus P wave" from the sinoatrial node (I, II leads are positive, aVR leads are negative), and its shape is constant.

(2) The heart rate changes with the change of breathing. When inhaling, the heart rate increases, and when exhaling, the heart rate slows down, and the period of its speed change is exactly equal to one breathing cycle.

③ The difference of R-R spacing or P-P spacing in the same lead is more than 0. 12 seconds.

④P？ R interval is greater than 0. 12 seconds.

(2) Non-respiratory sinus arrhythmia:

Non-respiratory sinus arrhythmia is rare, and the specific reason is not clear. Some people think it is related to anger, emotional instability, or the use of certain drugs (such as digitalis and morphine). Its ECG features are as follows:

①P wave is a "sinus P wave" from sinoatrial node (lead I and II are positive, lead aVR is negative), and its shape is relatively constant.

② The change of P wave frequency has nothing to do with breathing, and the heart rate sometimes suddenly increases.

(3) On the same lead, P-P spacing or R? R spacing difference is greater than 0.12s.

④P？ R interval is greater than 0. 12 seconds.

(3) Sinus node migration rhythm:

The exciting point moves in the sinoatrial node, so the shape, size and direction of P wave on ECG change gradually, and its ECG characteristics are as follows:

①P wave is sinus P wave (I and II lead positive, aVR leads negative).

② The shape and size of P wave are inconsistent.

③P？ The length of the r interval has changed, but it all exceeds 0. 12 seconds.

(4) Sinus arrhythmia related to ventricular contraction and blood discharge:

Sinus arrhythmia related to ventricular contraction and blood discharge is caused by abnormal ventricular contraction and blood discharge, which leads to uneven blood supply of sinus node and autonomic changes of sinus node.

(5) Sinus arrhythmia induced by ectopic rhythm: ectopic excitation, especially ectopic excitation from atrium, can sometimes make the excitation of sinus node occur in advance, and then sinus node is inhibited, thus causing sinus arrhythmia induced by transient ectopic excitation.

When the sinus rhythm is less than 60 beats per minute, sinus bradycardia is called sinus bradycardia. It can be seen that healthy adults, especially athletes, the elderly and sleep. Other causes include increased intracranial pressure, hyperkalemia, hypothyroidism, hypothermia and the use of digitalis, beta blockers, reserpine, guanethidine, methyldopa and other drugs. Among organic heart diseases, sinus bradycardia can be seen in coronary heart disease, acute myocardial infarction, myocarditis, cardiomyopathy and sick sinus syndrome.

Clinical manifestations:

1. If the heart rate is not less than 50 beats per minute, sinus bradycardia is generally asymptomatic.

2. If the heart rate is lower than 40 beats per minute, it can often cause angina pectoris, cardiac insufficiency or syncope.

Diagnostic basis:

Electrocardiogram showed sinus P wave, the rate of P wave was less than 60 times per minute, and the PR interval was more than 0. 12 seconds.

Principles of treatment:

1. Sinus bradycardia, if the heart rate is not less than 50 beats per minute, is asymptomatic and does not need treatment.

2. If the heart rate is less than 40 beats per minute and symptoms appear, drugs (such as atropine, ephedrine or isoproterenol) can be used to increase the heart rate.

3. Patients with sinus bradycardia accompanied by sinus arrest and syncope may consider installing artificial pacemakers.

4. Treatment of primary disease.

5. Symptomatic support treatment.

Medication principle:

1. After eliminating the cause or inducement, the symptoms of most patients can disappear.

2. If there is a clear primary disease, it should be actively treated.

Auxiliary inspection:

1. The heart rate of sinus bradycardia is not less than 50 beats per minute.

2. Sinus bradycardia with a heart rate lower than 40 beats per minute.

Efficacy evaluation:

1. cure: the heart rate increased to more than 60 beats per minute, and the symptoms of consciousness disappeared.

2. Improvement: the heart rate is increased to more than 50 times per minute, and the symptoms are improved.

3. Ineffective: the heart rate did not change before and after treatment, and the symptoms did not relieve.