Bradycardia

Symptoms & causes Diagnosis & treatment Doctors & departments Care at Vejthani

Ever feel lightheaded, tired, or short of breath for no reason? The cause could be your heart. Bradycardia is a condition where your heart beats too slowly and it can cause these unsettling symptoms. While a slow heart rate is perfectly normal for healthy, active people and athletes, it can be a serious problem for others.

What Is Bradycardia?

Bradycardia is a condition characterized by a slow heart rate, typically below 60 beats per minute. While a slow heart rate can be normal and even healthy in some individuals like athletes, it can also be a serious problem if it prevents the heart from pumping enough oxygenated blood. When symptoms such as dizziness and fatigue occur, medical intervention like a pacemaker may be necessary to help regulate the heart’s rhythm.

Symptoms

Most cases of bradycardia do not have any symptoms, especially for those who are physically active since their hearts are more efficient. However, in some cases, bradycardia can hinder the brain and other organs from receiving enough oxygen, leading to the following signs and symptoms:

Chest discomfort, or angina which can interfere with daily activities.
Breathing difficulties, or dyspnea that can lead to shortness of breath, making it hard to perform even simple tasks like walking or climbing stairs.
Confusion or memory issues
Difficulty concentrating that can impact work, school, and other tasks that require focus.
Dizziness, lightheadedness, and fainting (syncope)
Heart palpitations
Easily exhausted when moving
Fatigue
Irritability, agitation, or other personality changes that can make a person feel on edge and may strain relationships with others.

If you notice any signs or symptoms of bradycardia, it’s crucial to seek a timely and accurate diagnosis as well as appropriate care. If you have concerns about a slow heart rate, it’s advisable to consult your healthcare provider. In the event that you experience fainting, difficulty breathing, or persistent chest pain lasting more than a few minutes, it is important to immediately call emergency medical services.

Causes

Bradycardia happens when the signals originating from the sinus node in the right atrium of the heart slow down or experience blockages. In a normal heart, there are four chambers: two atria (upper chambers) and two ventricles (lower chambers). The sinus node, a cluster of cells located in the upper right chamber, acts as the heart’s intrinsic pacemaker. It generates the electrical impulses that initiate each heartbeat.

Generally, bradycardia can be a result of:

Aging-related heart tissue deterioration
Electrolyte deficiencies, such as calcium, magnesium, and potassium
Heart tissue damage caused by heart disease or a heart attack
Congenital health defect
Inflammation in the heart, such as endocarditis, myocarditis, and pericarditis
Heart surgery or repair
Hypothyroidism
Obstructive sleep apnea
Sedatives, opioids, and pharmaceuticals used to treat heart rhythm abnormalities, high blood pressure, and some mental health disorders
Infections, such as rheumatic fever, rheumatic heart disease, and Lyme disease
Heart block (atrioventricular block): Bradycardia refers to the interruption of the heart’s electrical system, causing a blockage or reduction in the flow of electrical current during the heart’s beating process. These blocks can occur at various points within the heart’s electrical conduction system. The heart consists of four chambers – two atria (upper chambers) and two ventricles (lower chambers). The sinus node, located in the upper right chamber (right atrium), is a cluster of cells responsible for generating the heart’s natural pacemaker signal, initiating each heartbeat. However, in cases of bradycardia, these signals slow down or encounter blockages. There are three types of heart blockages:
- First-degree heart block: If there is no underlying problem with electrical signaling, first-degree heart block rarely causes symptoms and usually does not require therapy. In this degree, the electrical impulse still reaches the ventricles, but it passes more slowly through the AV node than usual. The impulses are delayed.
- Second-degree heart block: In this degree, the impulses are intermittently inhibited which means not all electrical signals are received by the ventricles. Some beats are skipped, resulting in a slower and occasionally irregular heartbeat. This heart block is categorized into two: the Mobitz Type I and Mobitz Type II.
- Third-degree heart block: The electrical transmission from the atria to the ventricles has been completely blocked. When this occurs, the ventricles normally begin to beat on their own, but the heartbeat is slower, erratic, and unreliable. Third-degree block severely impairs the heart’s ability to pump blood throughout the body.

Risk Factors

Bradycardia can occur to anyone at any age. However, certain risk factors may contribute to a higher risk. Since this condition is linked with cardiac tissue damage caused by some form of heart disease, anything that raises the risk of heart disease increases the risk of bradycardia.

Several risk factors include:

Hypertension
Smoking
Age over 65
Stress and anxiety
Excessive alcohol consumption
Drug abuse
Trauma or injury

Complications

Heart failure
Passing out
Cardiac arrest

Diagnosis

The diagnosis of bradycardia often begins with discussing the symptoms, inquiring about the medical history, and performing a physical examination. A physical examination entails inspecting the body for apparent symptoms of conditions or issues. To help with the diagnosis, the doctor may use a stethoscope to listen to the heart.

Blood tests

Electrolyte Levels: These tests assess the concentration of electrolytes, particularly calcium, potassium, and magnesium, in your bloodstream.
Thyroid Hormone Levels: Bradycardia can be caused by hypothyroidism, which is characterized by low thyroid function. Testing thyroid hormone levels helps determine if this condition is contributing to the slow heart rate.
Troponin: Troponin is a specific protein found in the cells of your heart muscle. If there is damage to these cells, troponin can be released into the blood, indicating potential heart damage. Troponin levels are a critical factor used by healthcare providers to diagnose heart attacks.
Toxicology Screen: This test is conducted to identify toxic substances present in your blood. It can detect drugs, both prescription and recreational, that may lead to bradycardia, as well as other substances that can cause damage to the heart.

Electrocardiogram (ECG or EKG)

An ECG is a primary diagnostic test for bradycardia, a condition characterized by a slow heart rate. It measures the heart’s electrical activity by placing sticky patches called electrodes on the chest, and sometimes on the arms and legs. These electrodes are connected to a computer, which displays the results. Through an ECG, it is possible to determine if the heart is beating too slowly, too rapidly, or not at all.

However, since an ECG can only detect bradycardia if the slow heartbeat occurs during the test, a portable ECG device may be recommended by healthcare providers. There are two types of portable ECG devices commonly used:

Holter monitor: This device can be carried in a pocket or worn on a belt or shoulder strap. It continuously records the heart’s activity for 24 hours or longer.
Event recorder: Similar to a Holter monitor, this device records the heart’s activity but only at specific times for a few minutes each time. It is worn for a longer duration than a Holter monitor, typically 30 days. When symptoms occur, the user usually presses a button to record the activity. Some devices can automatically detect and record irregular heart rhythms.

These portable ECG devices are crucial for diagnosing bradycardia because they allow for precise tracking of the heart’s electrical activity over an extended period. By using multiple sensors, known as electrodes, which adhere to the skin of the chest, they can detect and display the heart’s electrical activity as a waveform on either a paper printout or a computer screen.

Other tests may be requested along with ECG, such as:

Tilt table test: A tilt test is used to determine whether a change in position produces fainting. During the test, the table is tilted as if one were standing up while lying flat on it. The result of this test can assist the doctor comprehend how the bradycardia produces fainting spells.
Stress exercise test: This test is done while being active. A medicine that stimulates the heart in a manner similar to exercise may be administered to those with difficulties exercising. Normally, the ECG is performed while riding a stationary bicycle or walking on a treadmill, to monitor the activity of the heart.
Sleep study: If your healthcare provider suspects that bradycardia is being caused by recurrent interruptions in breathing during sleep (known as obstructive sleep apnea), they may suggest a sleep study.

Treatment

Treatment is usually not required when bradycardia is not causing any symptoms. Generally, treatment options may include medication, implanted devices, and lifestyle changes. If bradycardia occurs due to another medical issue, treating that illness may be all that is needed to stop bradycardia.

The appropriate treatment is usually determined by the severity of the symptoms as well as the reason for the slow heart rhythm.

Medications

If bradycardia is causing severe issues like dangerously low blood pressure, medical interventions such as intravenous (IV) or injectable medications like atropine can be used to increase heart rate. These treatments are typically administered in a hospital setting due to the need for monitoring and additional care for individuals receiving these medications. Alternatively, there are oral medications available that can be taken daily to enhance heart function, including increasing the strength of heart contractions or regulating heart rate.

Surgery or Other Procedures

Temporary pacing: Utilizes a device with electrical contacts that make contact with or attach to the skin of the chest. These contacts enable a gentle electrical current to enter the body and stimulate the heart to beat. Temporary cardiac pacing is an effective short-term treatment for individuals requiring a permanent pacemaker or those experiencing a brief period of bradycardia.
Permanent pacemaker: Is often the most effective treatment for individuals with bradycardia, particularly those with sick sinus syndrome, where the heart’s natural pacemaker cells are not functioning properly. While a permanent pacemaker cannot completely cure this condition, it provides a long-term solution by effectively managing it. Pacemakers typically have a lifespan of several years, with some models having batteries that can last over a decade. The process of receiving a permanent pacemaker involves a surgical procedure to implant the device, which delivers electrical pulses to the heart muscle. An electrophysiologist or surgeon creates a small pocket beneath the skin to accommodate the pacemaker. They then connect wires, known as leads, to various points on the heart.

New advancements in medical technology have made it possible to avoid surgery in certain cases where a pacemaker implantation is needed for bradyarrhythmia. Instead of undergoing a traditional surgical procedure, patients now have the option of receiving a newer type of pacemaker called a leadless pacemaker. This innovative device can be implanted using a catheter-based procedure, which involves the insertion of a tube-like catheter through a small incision made in a major blood vessel. The catheter is carefully guided up to the heart, where the pacemaker is directly implanted. These leadless pacemakers are incredibly small, comparable in size to a large multivitamin pill. Moreover, this minimally invasive approach allows for a shorter hospital stay, enabling patients to return home sooner than they would after traditional surgery.

Frequently Asked Questions

1. Is bradycardia an arrhythmia?

Yes, bradycardia is a specific type of arrhythmia. An arrhythmia is any condition that causes an irregular heart rhythm, whether the heart beats too fast, too slow, or with an irregular pattern.

2. Bradycardia vs tachycardia

Bradycardia and tachycardia are both types of arrhythmias, or abnormal heart rhythms, but they are opposites. Bradycardia is a heart rate that’s too slow (fewer than 60 beats per minute), while tachycardia is a heart rate that’s too fast (more than 100 beats per minute).

3. Is bradycardia lethal?

No, bradycardia is not always lethal, but it can be dangerous if it’s severe and left untreated. While a slow heart rate is harmless in many people, an extremely low heart rate can prevent the heart from pumping enough oxygenated blood, which can lead to complications like fainting, heart failure, or, in rare cases, sudden cardiac arrest.

4. Do I need to see a doctor if I have bradycardia?

Yes, you should see a doctor if you have bradycardia, especially if you’re experiencing symptoms like dizziness, lightheadedness, or shortness of breath.

Diseases & Conditions Bradycardia