Bradycardia (slow heart rate): Symptoms and when to contact a doctor

心率过缓是指静息心率比平常慢。心率低于每分钟 60 次可能表明存在潜在的健康问题，但但情况并不总是如此。

根据美国心脏协会 (AHA) 的数据，一个人的静息心率通常为60 至 100可信来源可信来源每分钟节拍数(bpm)。

然而，经常进行体力活动或运动的人的静息心率可能低至 40 bp米。人的静息加速在深度睡眠期间又恢复。此外，某些健康问题也可能导致静息加速缓慢。

请继续阅读，了解有关心率过慢、其原因和治疗方案的更多信息。

概述

人的心脏负责将血液泵送到全身。心脏由四个腔室组成：

• 右心房
• 左心房
• 右心室
• 左心室

顶部的两个心室（心房）接收血液。底部的两个腔室——心室——从心脏泵出血液。

血液具有多种功能，例如：

• 将氧气和营养物质输送到组织和器官
• 创造抽血止血
• 运输抗体以对抗感染
• bringing waste products to the kidneys and liver, which then filter and clean the blood
• regulating body temperature

Learn more about the anatomy of the heart.

The AHA states that, generally, a resting heart rate of less than 60 bpmTrusted SourceTrusted Source means that a person has bradycardia. An individual who has bradycardia may not get enough oxygen-rich blood to certain areas of their body. If left untreated, bradycardia can lead toTrusted SourceTrusted Source life threatening complications, such as syncope.

However, a person may naturally have a slower resting heart rate due to physical fitness or age. If an individual is concerned about their slow resting heart rate, they should seek guidance from a doctor.

Symptoms

有些心动过缓的人除了心率缓慢之外没有任何症状。其他心动过缓的人可能有症状例如可信来源可信来源:

• 疲惫和虚弱的感觉
• 昏厥或头晕
• 困惑
• 气促
• 锻炼锻炼时出现严重不耐受或呼吸困难

如果一个人的心动过缓是由于严重的医疗状况引起的，如果不及时治疗，可能会导致危及生命的并发症。

未经治疗的心动过缓的并发症包括：

• 心脏停搏
• 昏厥导致的面部、头部或骨科创伤
• 胸痛
• 低血压或高血压
• 心脏衰竭
• 心输出量低导致肾衰竭

测量心率

一个人可以通过脉搏来了解自己的心率。

如果一个人想要准确测量他们的静息心率，他们应该在什么时候测量脉搏坐着或躺着可信来源可信来源。在检查静息心率之前，一个人还应该确保自己感到平静和放松。

一个人可以从身体的不同位置测量脉搏，包括：

• 他们的手腕
• 脖子的一侧
• 肘部内侧
• 脚的顶部

人们可以用两根手指检查这些区域中的每一个，以找到最容易感觉到脉搏的地方。他们不应该用拇指来测量脉搏——拇指有自己的脉搏，可能会干扰结果。

Once a person has found their pulse, they can count the number of beats they feel over 60 seconds. They may want to set a stopwatch or look at a clock while they count their heartbeats.

If a person has a heartbeat lower than 60 bpm, they have bradycardia. Bradycardia does not always mean that an individual has an underlying health condition. However, they should contact a doctor to determine the cause of their bradycardia.

Children and young people have more rapid heart rates than adults. A typical heart rate for an infant is around 140 bpmTrusted SourceTrusted Source, whereas an older child or teenager should have a resting heart rate of about 70 bpm.

Learn more about what a healthy heart rate can look like.

Causes and risk factors

A person may experience mild bradycardia or only have symptoms from time to time. If they notice that they have a slow heart rate, they should speak with a doctor to determine the cause.

Bradycardia will not alwaysTrusted SourceTrusted Source require treatment. If a person does not have any other symptoms and has a structurally normal heart, their bradycardia may be due to an additional factor, such as physical fitness.

People who engage in high amounts of physical activity tend to have more efficient hearts. This may slow their pulse because their heart does not have toTrusted SourceTrusted Source pump as hard or as fast to supply blood to the rest of the body.

Certain medical conditions can cause bradycardia. These conditions include:

Sick sinus syndrome

Also known as sinus node dysfunction (SND), this condition affects a person’s sinoatrial (SA) node, a structure in the top of a person’s right atrium that generates the electrical impulse that starts a heartbeat. This can mean a person’s heart rate speeds up, slows down, or does a combination of both.

Other symptoms of SND include:

• palpitations, where a person’s heart feels like it is fluttering, pounding, or pausing
• tiredness
• lightheadedness
• feeling faint or fainting

Although SND can develop at any time, the average age of someone who has it is 68 years oldTrusted SourceTrusted Source. SND is a commonTrusted SourceTrusted Source cause of bradycardia.

Other heart electrical issues

If the heart is unable to send electrical signals due to a blockage or heart disease, this can lead to bradycardia.

Complete heart block is when there is a total loss of communication between a person’s atria and the ventricles. This occurs when the SA node is unable to passTrusted SourceTrusted Source a signal to the AV node.

Complete heart block results in a person’s atria and ventricles activating independently of each other. It can be fatal if a person does not receive treatment for complete heart block quickly.

Metabolic issues

Some metabolic disorders can slow the heart rate. One of the most common is hypothyroidism, which is when the thyroid gland does not produce enough hormones. Hypothyroidism can affect the health of the blood vessels, which may slow the heart rate.

Thyroid disorders are common and may affect young and otherwise healthy people. Between 4 and 10%Trusted SourceTrusted Source of individuals in the United States have hypothyroidism.

Other metabolic conditions that can cause bradycardia include:

• acidosis, a condition where there is too much acid in bodily fluids
• hyperkalemia, where a person’s potassium levels are too high
• hypokalemia, which is when a person’s potassium levels are too low
• hypothermia, which happens when the body temperature becomes too low

Heart-damaging conditions

Damage to the heart due to certain conditions can cause it to pump more slowly and less effectively. Conditions that can damage the heart include:

• congestive heart failure
• coronary artery disease
• heart attack
• myocarditis, which is inflammation of the heart muscle
• Lyme disease
• thickened heart muscle
• hypertension
• diabetes

Heart medication

Certain medicationsTrusted SourceTrusted Source, including those for heart disease and high blood pressure, may lower heart rate.

Beta-blockers or calcium channel blockers, which doctors prescribe for a rapid heart rate and some other heart conditions, may also slow heart rate.

Individuals taking a new medication who experience symptoms of bradycardia should contact a doctor.

Oxygen deprivation

Hypoxia is a term that health experts use when a person is unable to get enough oxygen to the tissues of their body. Hypoxia is a medical emergency, and can occur when a person is choking or having a severe asthma attack. Chronic medical conditions, such as chronic obstructive pulmonary disease, may also cause hypoxia.

If hypoxia lowers a person’s heart rate, it is essential to treat the underlying cause.

Types of bradycardia

There are different types of bradycardia, depending on which part of the heart they start in.

Sinus bradycardia

Sinus bradycardia is a form of slow heart rate that begins in a person’s SA node.

If a person has sinus bradycardia, their SA node is sending the impulses to start a heartbeat but is generating them at a slower rate. This leads to a slower heart rate.

The majorityTrusted SourceTrusted Source of people who have sinus bradycardia will have no symptoms. Sinus bradycardia can occur in individuals who are physically active or athletic or during deep sleep. However, sinus bradycardia can also develop due to various health conditions, such as heart disease.

Learn more about sinus arrhythmia.

Junctional bradycardia

Junctional bradycardia occurs when the electrical impulse to start the heartbeat begins in the atrioventricular (AV) node rather than in the SA node.

The AV node is a structure at the bottom of the right atrium that can be a pacemaker when the SA node does not function properly.

It is also the location of the pause of the impulse generated from the SA node. This pause provides time for the atria of the heart to finish beating, which causes blood to pool inside the ventricles of the heart. Once the ventricles have filled with blood, the impulse passes to the His-Purkinje system, which causes the ventricles to contract and pump blood out of the heart.

If a person has junctional bradycardia, they may have an issue with their SA node that causes the AV node to take over. Additionally, physically athletic individuals, young children, and people in deep sleep may also experienceTrusted SourceTrusted Source junctional bradycardia.

When is bradycardia a concern?

If a baby has a low pulse, a parent or caregiver should take them to the emergency room.

Adults and children who have a low pulse and experience symptoms such as chest pain, fainting, or exercise intolerance should also go to the hospital.

A person should contact a doctor about bradycardia when they:

• experience an unexplained change in heart rate that lasts for several days
• have bradycardia and other heart health risk factors, such as diabetes or smoking
• have heart disease and bradycardia
• experience bradycardia and other symptoms, such as fainting spells
• experience episodes of bradycardia and tachycardia, which is a rapid heartbeat

If a person is concerned about their slow heart rate, they should also consult a doctor.

A person should seek emergency medical help if they experience symptoms that could indicate a heart attack.

Is it a heart attack?

Heart attacks occur when there is a lack of blood supply to the heart. Symptoms include:

• chest pain, pressure, or tightness
• pain that may spread to arms, neck, jaw, or back
• nausea and vomiting
• sweaty or clammy skin
• heartburn or indigestion
• shortness of breath
• coughing or wheezing
• lightheadedness or dizziness
• anxiety that can feel similar to a panic attack

If someone has these symptoms:

1. Dial 911 or the number of the nearest emergency department.
2. Stay with them until the emergency services arrive.

If a person stops breathing before emergency services arrive, perform manual chest compressions:

1. Lock fingers together and place the base of hands in the center of the chest.
2. Position shoulders over hands and lock elbows.
3. Press hard and fast, at a rate of 100–120 compressions per minute, to a depth of 2 inches.
4. Continue these movements until the person starts to breathe or move.
5. If needed, swap over with someone else without pausing compressions.

Use an automatic external defibrillator (AED) available in many public places:

1. An AED provides a shock that may restart the heart.
2. Follow the instructions on the defibrillator or listen to the guided instructions.

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Treatment options

A doctor may not always need to treat a slow heart rate. However, when a slow heart rate causes serious health problems, it is essential that a person receives treatment.

The treatment an individual receives for their bradycardia will depend onTrusted SourceTrusted Source the underlying cause. A doctor may use certain testsTrusted SourceTrusted Source to diagnose the cause of a person’s bradycardia. These tests include:

• physical tests
• questions about medical history
• blood tests
• heart monitors
• imaging tests

If a person has a condition that interferes with the electrical impulses of their heart, they may requireTrusted SourceTrusted Source a pacemaker. This is a device that is implanted under a person’s skin and connected to their heart. The pacemaker then sends impulses to the heart that cause it to beat regularly.

Depending on the cause, a doctor might also recommend:

• changing heart medications
• taking medication to treat thyroid or other metabolic disorders
• making lifestyle changes, such as eating a low fat diet, getting more exercise, or quitting smoking
• monitoring heart rate or blood pressure frequently

Learn how a person can check their own blood pressure.

Frequently asked questions

Here are some common questions people often ask about bradycardia.

What is the main reason for bradycardia?

The main reasonTrusted SourceTrusted Source for bradycardia is an issue with the heart. These may be due to age, cardiovascular disease, an infection, or an inherited condition. Using heart medication can sometimes lead to bradycardia. It can also happen with diseases such as lupus, sleep apnea, and hypothyroidism.

When is bradycardia an emergency?

Bradycardia is not always serious, but it can haveTrusted SourceTrusted Source severe consequences in some cases. A person should seek immediate medical help if there are signs of cardiac arrest, heart failure, or a heart attack. They should contact a doctor as soon as possible if they are fainting frequently.

How low is too low for a heart rate?

心率的典型范围是每分钟 60-100 次。如果一个人的心率是低于 60可信来源可信来源每分钟节拍数。然而，在睡眠期间，心率可能会低于平时，一些体力活跃的心率可能会经常降低。

百年

心脏病可能是致命的，因此认真对待心脏健康、血压或脉搏的任何变化至关重要。

然而，逐渐缓慢并不总是令人担忧。心跳过缓有时可能表明一个人的身体状况良好。

只有医生才能评估一个人的心血管危险因素。如果一个人担心自己的心率过慢，应该咨询医生。

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