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Definition of Bradycardia

Bradycardia, also known as Sinus Bradycardia, or Bradyarrhythmia is a condition where the heart beats regularly but slowly, and less than 60 beats per minute whilst resting, which is considered to be the minimum normal rate. It is commonly grouped into the category of palpitation or irregular heart rate conditions known collectively as Arrhythmia. However, for some people, a slow heart rate is sometimes normal and can be an indication of physical fitness.

Causes of Bradycardia

The action of the heart pumping blood produces the pulse, which defines the heart rate and rhythm. The heart has a natural pacemaker called the Sinoatrial (SA) Node which controls the rate of beating. The Sinoatrial node functions as a pacemaker by sending electrical signals through the heart muscle, causing it to react by contracting in the way that we associate with a heartbeat. When the electrical system develops a problem it can cause a disruption to the normal regular steady pattern, or an arrhythmia.

There are several possible causes of Bradycardia, and these are described briefly below :-

  • A disease of the sinoatrial node itself, which is known as sick sinus syndrome
  • Problems with other parts of the electrical conductivity within the heart, which is known as heart block. This also causes an abnormally slow heart beat, and may happen following damage to the heart muscle, following a heart attack, an injury or a disease.
  • Age related changes to the heart structure
  • Diseases that can damage the electrical system of the heart, including coronary artery disease and heart attack
  • Infections such as endocarditis and myocarditis.

Secondary causes may also be responsible for the condition, for example hypothyroidism or an electrolyte imbalance, which can be caused by excessive levels of potassium in the blood.

Sinus Bradycardia Symptoms

Some people suffering from slow heart rate do not have any symptoms or only experience mild symptoms. A heartbeat of less than 60 beats per minute can cause various distressing symptoms which are summarised as follows :-

  • Dizzy, lightheaded feeling or fainting
  • Shortness of breath or difficulty exercising
  • Tiredness
  • Chest pain or heart flutter
  • Confusion or lack of concentration

Patients often diagnose themselves with potential Bradycardia by taking their own pulse readings to confirm that they have a slow heart rate, or in association with other symptoms that they are experiencing.  

Who is likely to suffer from Bradycardia ?

Bradycardia symptoms are most commonly experienced by men and women aged over 65, as the aging process may be cause the accumulation of fibrous tissue in the heart, that can interfere with the operation of the heart’s electrical system. Sportsmen and women, especially athletes have a higher incidence of Bradycardia, and it can also occur when the core body temperature drops too low as a result of exposure to very cold weather. People with very healthy hearts, such as athletes, often have a natural and healthy slower heart rate than the average of 60 to 100 beats per minute. These slower heart rates reflect a healthy heart that is in good condition. 

How are heart rhythm problems diagnosed ?

Many people diagnose themselves initially as having some sort of abnormal heart rhythm, and seek the advice of their doctor. If you experience the above symptoms your doctor will firstly use a stethoscope to listen to the sound of your heart, and also ask about your symptoms and previous medical history. Depending on the outcome of this initial consultation, if symptoms of Bradycardia are confirmed, you may then be sent to a hospital or ER medical center, where you will most likely have an electrocardiogram (ECG or EKG) to assist a cardiologist to assess the nature of the heart rhythm defect.

 The results of the ECG or EKG are analysed by a computer, and this information is used by the cardiologist to decide on the correct treatment. However, the symptoms may occur intermittently, so further testing may need to be conducted over an extended period of time by the use of a portable (ambulatory) electrocardiogram in order to ‘trap’ the condition when it does occur. This device is also called a Holter monitor or a cardiac event monitor. Blood tests may also be used as an additional diagnostic tool.

Is Bradycardia serious ?

In severe forms of bradycardia, the heart beats so slowly that it does not pump enough blood to meet the requirements of the body, which can be life-threatening. Another serious problem is the possibility of suffering a seizure. Other less serious, but distressing side effects are from injuries from falling after a fainting episode.

Treatment for Bradycardia

Treatment is not usually recommended unless the condition is causing symptoms. Where treatment is required, the primary goal is to restore the heart rate and blood flow to a normal level. Depending on the severity of the condition, it may treated by simple lifestyle changes :-

  • Controlling blood cholesterol
  • Eating a low-fat, low-salt diet
  • Taking regular exercise (under the guidance of your doctor)
  • Stopping smoking
  • Reducing or eliminating alcohol
  • Ensuring any medicines are correctly dosed

In more serious cases, it may be necessary to fit a Bradycardia pacemaker underneath the skin in the patients body. The pacemaker is a small artificial device which is used to supply the correctly timed electrical signals to control and correct the abnormal beating rate of the heart. In the case of secondary causes, then treating that problem may cure the sinus bradycardia with no additional factors. If a medicine is found to be the cause, then your doctor may adjust the dose or prescribe a different medicine. If this is not possible, then you have to have a pacemaker fitted