sinus arrest



Overview

Definition

Sinus arrest refers to the inability of the sinus node to generate impulses.

Epidemiology

No epidemiologic studies are available, but symptomatic individuals are usually older and usually have other underlying medical conditions.

Classification

Transient arrest: a period of time in which the sinus node has reduced autonomy and fails to emit an excitation on time. The ECG shows a long PP interval with no sinus activity.

Persistent pacing arrest: the sinus node loses its autonomy and no longer emits excitation. The ECG shows the disappearance of sinus P waves and the presence of only atrioventricular junctional or ventricular autonomic rhythms.

Etiology

Causes

Cardiac factors

Such as degeneration and fibrosis of the sinus node, coronary artery disease (e.g., acute inferior wall myocardial infarction), myocarditis, cardiomyopathy, and other pathologies.

Non-cardiac factors

Can be seen in increased vagal tone (such as swallowing, pharyngeal stimulation, massage of the carotid sinus, etc.), carotid sinus hypersensitivity, cerebrovascular accidents, hyperkalemia, etc., as well as about 30% seen in sleep apnea syndrome.

Apply digitalis drugs, quinidine, acetylcholine, amiodarone, beta-blockers and other drugs.

Pathogenesis

Cardiac or non-cardiac factors cause the sinus node pacemaker cells to stop issuing impulses.

Symptoms

Symptoms depend largely on the severity of the hemodynamic impairment due to sinus arrest.

A single sinus arrest, with a pause of less than 2 seconds, usually causes no symptoms or only atypical symptoms such as palpitations, mild dizziness, or chest tightness.

Frequent consecutive sinus arrests, such as arrests lasting more than 2 seconds, blackouts can occur; arrests lasting more than 5 seconds, such as there is no atrioventricular junction or ventricular escape beats, can lead to syncopal episodes; such as lasts more than 10 seconds, there will be a – S (Adams-Stokes) syndrome (i.e., the heart rate is abnormally slowed down or increased significantly to make the cardiac blood volume decreased abruptly, resulting in insufficient blood supply to the brain, acute cerebral ischemia, syncope and convulsions, etc.), and the heart rate is not enough to prevent the heart from beating. (i.e., abnormally slow heart rate or significant increase in heart rate causing a sudden decrease in cardiac output, resulting in insufficient cerebral blood supply, acute ischemic attack, fainting, convulsions, etc.), or even death.

Consultation

Department of Medicine

Cardiovascular Medicine

Routine physical examination reveals abnormal electrocardiogram results, or symptoms such as fatigue, panic, blackouts, dizziness, etc. It is recommended to consult the Department of Cardiovascular Medicine in a timely manner.

Emergency Department

Sudden and severe palpitations and dyspnea, etc., it is recommended to go to the Emergency Department immediately.

In case of loss of consciousness, respiratory and cardiac arrest, immediately call 120 emergency and perform CPR on the patient at the same time.

Preparation

Preparing for your visit: registration, information preparation, common problems

Tips for seeking medical treatment

If the attack time of sinus arrest is short, there may be no obvious clinical symptoms, and asymptomatic patients without organic lesions usually do not need treatment; if the attack time is long, fainting occurs, and timely treatment is needed; if there is a primary disease, the primary disease needs to be actively treated.

Preparation checklist for medical treatment

What are the main symptoms?

What are the precipitating and relieving factors for the symptoms?

About how many times during the day do these symptoms occur? How long do they last?

Is there a family history of the condition?

Are there any drug or food allergies?

Are there any other medical conditions?

What medications have you been taking recently?

Specialized tests: electrocardiogram (including routine electrocardiogram, 24-hour ambulatory electrocardiogram, electrocardiogram exercise test, etc.), echocardiogram, coronary arteriogram, cardiac magnetic resonance test

Routine tests: blood test

Calcium channel blockers: verapamil, diltiazem

β-blockers: propranolol, nadolol

Diagnosis

Disease diagnosis

Diagnosis is based primarily on routine electrocardiogram and ambulatory electrocardiogram performance.

Medical history

There is often a history of coronary heart disease, myocarditis, cardiomyopathy and other cardiac diseases.

Clinical manifestations

Clinical symptoms may be asymptomatic, or palpitation, chest tightness, dizziness, blackout, or even syncope.

Conventional electrocardiogram

Conventional electrocardiogram (ECG) is the simplest and most reliable way to diagnose sinus arrest. The disadvantage is that it can only record the rhythm for a short period of time, and may not be able to capture the attack. The diagnostic criteria for sinus arrest on conventional ECG are as follows.

The sudden appearance of a long PP interval in a normal sinus rhythm, i.e., the absence of P-QRS-T waves for a longer period of time.

The long PP interval of the arrest has no multiplicative relationship with the normal sinus cycle.

Normal sinus rhythm may return after the long interval, but junctional or ventricular escape beats, as well as escape rhythms, are usually present.

Ambulatory electrocardiogram (Holter)

It is important for both qualitative and quantitative diagnosis of arrhythmia in patients by recording the ECG for 24 to 48 hours to understand the time of disease onset and the relationship between the onset and daily life, and to clarify the cause and severity of the disease.

Differential diagnosis

Sinus atrial block and blocked atrial pre-systole should be differentiated from each other.

Sinus atrial block

Similarity: palpitations, chest tightness, blackouts, precordial pain and even syncope in severe cases.

Difference: different electrocardiogram performance.

Second-degree type I sinus block: PP interval is short and long, appearing week after week.

Second-degree type II sinus block: long PP interval and short PP interval are multiples, usually 2~3 times.

Third-degree sinus block: it cannot be differentiated from sinus arrest on the electrocardiogram, but its cardiac electrophysiologic examination reveals continuous sinus node potentials followed by no atrial potentials.

Block atrial pre-systole

Similarity: both may have palpitations, pause feeling of heartbeat, blackout, precordial pain and even syncope in severe cases.

Differences: The electrocardiogram is different, the long PP interval formed by blocked atrial pre-systole is usually < the sum of 2 sinus PP intervals; transient sinus pause is long PP interval > the sum of 2 sinus PP intervals.

Treatment

In asymptomatic patients, no treatment is usually needed; in symptomatic patients, treatment is mainly directed at the cause of the disease, and pacemaker implantation is required in severe cases.

Treatment of etiology

Discontinue drugs that may cause sinus arrest, such as digitalis drugs, quinidine, acetylcholine, amiodarone, β-blocking drugs.

Actively treat the primary disease, such as coronary heart disease, hyperkalemia, etc.

Patients with severe respiratory sleep apnea wear ventilators at night.

Catheter ablation of the cardiac ganglion plexus may be effective in some patients.

Symptomatic treatment

Patients with symptoms such as dizziness, chest tightness, palpitations, etc. can be treated with anti-M cholinergic receptor drugs and isoprenaline in the acute phase.

Anti-M cholinergic receptor drugs: can eliminate the inhibition of the vagus nerve on the sinus node, so that the heart rate increases, but has no effect on the sinus node itself.

Isoproterenol: mainly acts on myocardial β1 receptors to increase the heart rate, but has no effect on the sinus node itself.

Implantation of pacemaker

A pacemaker should be implanted promptly if sinus arrest episodes are frequent and symptoms are evident, especially if accompanied by syncope or A.S. syndrome.

A pacemaker is an instrument placed in the heart to control the heart rate, temporarily or permanently increasing the heart rate and reducing the risk of serious conditions.

Precautions for using a pacemaker

Try to stay away from electronic devices such as cell phones.

Stay away from magnetic cards, magnets, induction cookers, and other items with magnetic properties.

Avoid magnetic resonance imaging tests.

Seek medical attention in case of abnormal function.

Prognosis

Cure

Generally good, with poor prognosis for those with severe organic heart disease.

Those who present with A. S. syndrome have 1-year and 5-year survival rates of 87% and 74%, respectively, and cardiac pacing therapy improves the survival rate of patients with A. S. syndrome for more than 6 years.

Hazards

Symptoms may lead to syncope and affect the patient’s life if left untreated.

In severe cases, A. S. Syndrome can occur and even lead to death.

After installing a pacemaker, there are restrictions on places to move around and living things.

Daily life

Daily life

Reasonable diet

Ensure adequate intake of protein, unsaturated fat, vitamins, minerals, dietary fiber and water. You may choose soybean products, dairy products, lean meat, fish (may be 1~2 times a week), fresh fruits, fresh vegetables and nuts.

Control sugar intake appropriately, and choose cereals and potatoes instead of refined rice and noodles.

Avoid diets high in salt and fat. Control salt intake to less than 6 grams per day, and avoid deep-fried, pickled and barbecued foods.

Avoid raw, cold, hard or too hot food, chew slowly and avoid overeating.

Eat less irritating foods such as chili peppers, coffee, strong tea and mustard.

Improve lifestyle habits

Quit smoking and stay away from “second-hand smoke”.

Quit drinking.

Ensure adequate sleep and avoid staying up late.

Exercise in moderation, choose fast walking, jogging, playing tai chi, swimming, square dancing, cycling and other sports, or follow the doctor’s guidance to choose exercise programs, avoid excessive exercise. If you feel uncomfortable during exercise, you should stop and rest immediately.

Pay attention to safety

If dizziness occurs, sit down or lie down immediately to avoid falling.

Regular follow-up

Follow your doctor’s instructions for regular follow-up; if symptoms do not improve, or new symptoms appear, consult a doctor promptly.

Prevention

Active treatment of primary diseases

Such as coronary heart disease, myocarditis, cardiomyopathy, hyperkalemia and other diseases.

Reasonable use of medication

Use the medication according to the doctor’s requirements. If there is any discomfort during the use of medication, consult a doctor promptly.

Reasonable diet to prevent heart disease

Improve dietary structure to ensure adequate nutrition; avoid overeating and maintain appropriate body weight.

Avoid diets high in salt, sugar and fat, and try to avoid pickled, smoked, barbecued and fried foods.

Eat less stimulating foods, such as chili peppers, coffee, strong tea and mustard.

Eat more foods rich in dietary fiber, such as whole grains, fresh vegetables and fruits, etc. Food types should be diversified and alternated.