What is bradycardia?

Bradycardia is the condition in which the heartbeat is less than 55 beats per minute. But this is not always abnormal. The heart rate depends on the following:

• The state of health and age. Older people tend to have a lower heart rate.
• The physical condition. Fit people usually have less than 60 beats per minute.
• Sleep. In sleep the pulse rate is reduced considerably. Measuring the heart rate per minute is easily done by palpating the pulse in the wrist, carotid and femoral arteries.

The heartbeat comes from the sinus node. The sinus node is an area of the heart located in the right atrium, where the electrical signals that make the heart beat at 50-100 beats per minute are produced. After the sinus node, the impulse is directed to the ventricles, which are the lower chambers of the heart. Any damage to this system of the heart leads to a reduction or cessation of rhythm production or conduction.

What is sinus tachycardia?

Bradycardia is mainly associated with sinus node disease. The sinus node is the primary pacemaker of the heart. It is the one that produces the electrical signals that make the heart beat. Bradycardia that occurs in a damaged sinus node is considered abnormal. Also, damage to the pacemaker or its connections to the rest of the heart can cause a slow heart rhythm.

Symptoms of bradycardia

Bradycardia can cause hemodynamic disturbances in the brain, leading to:

• Fatigue
• Zali
• Fainting episode
• Cardiac arrest
• Dyspnea

When bradycardia is left for a long time, it can lead to:

• Heart failure
• Angina pectoris
• High blood pressure

When should you go to the doctor?

If you faint, have shortness of breath or chest pain, call for help immediately, even if you are alone. Your priority is to get to the hospital and get medical care. There are many causes that can lead to bradycardia. See a doctor if you or another family member develops symptoms of bradycardia.

Causes of bradycardia

 Bradycardia varies depending on the cause of the problem. Some of the most common causes of bradycardia are the following:

• Suffering of the neurosis that controls the speed of the heartbeat (the autonomic nervous system)
• The sinus node that activates the heartbeat (the electrical impulse of the heart) is affected 
• The system that carries electrical signals throughout the heart muscle is affected
• Metabolic problems of the body
• Hypothermia  
• Neurological conditions, such as epilepsy
• Good physical condition (sport)
• Infections such as diphtheria, acute rheumatic fever and viral myocarditis
• Increased intracranial pressure
• Icteros
• Glaucoma
• Acute myocardial infarction in the setting of coronary artery disease
• Medication

Risk factors for bradycardia

A risk factor is defined as anything that increases a person's chances of developing a particular disease. The factors that can increase the risk of bradycardia are the following:

• Age. Age is probably the most determining factor in terms of the risk of bradycardia. Older adults are more likely to have heart problems associated with bradycardia.
• Cardiovascular disease risk factors. Often, bradycardia is associated with abnormal myocardium that is a result of cardiovascular disease. Therefore, factors that increase the risk of cardiovascular disease also increase the risk of tachycardia. Some examples are hypertension, smoking, alcohol consumption, drug use and stress.

How is bradycardia diagnosed?

First, your doctor will take your medical history. After asking you a few questions about your symptoms and lifestyle, he or she will move on to the clinical examination, where he or she may measure your heart rate and blood pressure. He may also need to listen to you to hear how your heart is working and to identify any abnormal findings. However, the diagnosis of bradycardia is based on an investigation of the patient, with the following tests:

• Electrocardiogram of the heart. An electrocardiogram is a basic and valid test to diagnose bradycardia. However, if the patient does not show signs of bradycardia during the ECG, a portable ECG, such as Holter, may be needed.
• Laboratory testing. Routine blood tests are important to check for bradycardia due to infections, hypothyroidism or changes in electrolyte levels.
• Echocardiographic evaluation. Simple exercise stress test and/or exercise stress test with scintigraphic imaging of myocardial perfusion.

Treatment and management of bradycardia

The treatment and management of bradycardia depends on many factors, such as the symptoms and the cause of the condition. When bradycardia has no symptoms, it may not need treatment. In general, we treat bradycardia in the following ways:

• We fight the cause of bradycardia.
• We make changes to the medications the patient is taking if any of them are responsible for the bradycardia.
• When the dizziness or syncopal episodes persist, a cardiac pacemaker is put in place. 

What is a pacemaker?

A pacemaker is a device that is implanted under the skin of the chest, in a relatively simple operation. The pacemaker is designed to maintain the rhythm of the heart when there are diseases that disturb the rate at which the heart beats. The implantation is carried out under aseptic conditions, in a haemodynamic laboratory with an X-ray machine and with local, mainly local, anaesthesia. 

How does it work?

It is a small battery operated device. It has one, two or three thin wires, which reach up to the heart and conduct electrical stimulation. The purpose is for the heart to pulse at a specific rate when its own rate falls below a critical threshold, depending on the pacemaker's programming. So pacemakers work on demand. 

How does the pacemaker affect the patient's normal activity?

The normal activity of a person who has a pacemaker is not substantially affected. Regular medical monitoring is necessary in order to properly adjust the pacemaker and check that it is working properly. Monitoring is carried out by the doctor who implants the device every six months, using a special external machine with a head that analyses all the data from the pacemaker for the period since the last check.  

Battery and pacemaker replacement

The battery of the pacemaker has a lifespan that depends on the type of pacemaker and the patient's needs. Replacement of the pacemaker involves only the generator and not the leads. It is done by opening the area, but the procedure is very quick and the recovery is very fast. 

Types of pacemaker

There are single-cavity and dual-cavity pacemakers. Univentricular pacemakers are needed by patients who are in permanent atrial fibrillation when they develop bradycardia because the atrium is no longer involved in the contraction of their heart. All other patients who have a functioning sinus node need an interstitial pacemaker. (Fig. 1) 

Fig.1: Two-cavity pacemaker

Amphibiocaval pacemaker

In the last 20 years, a special pacemaker has been added to our pharmaceutical quiver for patients with heart failure, regardless of whether they have bradycardia. This pacemaker is called a biventricular pacemaker because it has a third lead that is not placed in a cavity, but in the venous network that takes blood away from the heart that feeds it - the coronary sinus. The coronary sinus is adjacent to the left ventricle and so its electrical stimulation stimulates the left ventricle. In this way, we synchronize the electrical stimulation of the right and left ventricles, which in heart failure become desynchronized and, while normally the stimulation of the left ventricle comes first, in heart failure the stimulation of the right ventricle comes first, resulting in a significant deterioration of heart function. ( Fig. 2)

Wireless pacemaker

In the last 5 years, a cordless pacemaker - a wireless pacemaker - has been added, which is implanted in seniors with atrial fibrillation with inability to access the veins. It is inserted by a special procedure through the femoral vein and the device stays inside the right ventricle. There is no dual-chamber pacemaker without a lead. Also, it is still unclear what will be done with its replacement. (Fig. 3)

What we do at the "Agios Loukas" Clinic

A very large number of pacemakers and biventricular pacemakers are implanted in the "Agios Lukas" Clinic per year. There is a huge experience in this field of electrophysiology. 

What can I ask the implant specialist?

To better understand your condition and its symptoms, you can ask the implant doctor some of the following questions. Feel free to make a list of anything else you want to ask your doctor.

• What makes my heart beat slowly?
• What is my condition?
• What tests do I need?
• How dangerous is my situation?
• What do I need to change about my activities?
• Which pacemaker do I need?
• What restrictions will I have in my life?
• What are the complications of the surgery?
• Will I be able to have an MRI scan?