Heart Arrhythmias Heart Arrhythmias
  • What are heart arrhythmias?
  • What are the causes of heart arrhythmias?
  • What are the symptoms of heart arrhythmias?
  • How are heart arrhythmias treated?
  • What are the complications and related diseases of heart arrhythmias?
Heart Arrhythmias

What are heart arrhythmias?

A heart arrhythmia refers to an irregular heartbeat. Under normal circumstances, the sinus node in the right atrium of the heart acts as a natural pacemaker, producing an electrical impulse that stimulates the atria muscles to contract and pump blood into the ventricles. A slight delay allows the ventricles to fill with blood before they contract and pump blood to the lungs and the rest of the body.

A heart arrhythmia occurs when the electrical impulses are not coordinated. This causes the heart to beat too fast, too slow or irregularly.

Some people experience this as a fluttering or racing heart, which is usually harmless. Others experience more severe symptoms that can be life-threatening.

There are different types of heart arrhythmias. Tachycardia refers to a fast heartbeat with a resting rate of over 100 beats per minute, and bradycardia refers to a slow heartbeat with a resting rate of fewer than 60 beats per minute.

Common types of tachycardia include:

  • Atrial fibrillation, caused by irregular electrical impulses. These result in a rapid, irregular rhythm. This is the most common type of arrhythmia in Asia.
  • Supraventricular tachycardia broadly refers to many forms of arrhythmia originating above the ventricles in the atria or AV node. It may cause sudden episodes of palpitations that begin and end abruptly.
  • Ventricular tachycardia is a rapid, regular heart rate that doesn't allow the ventricles to fill and contract efficiently, making it difficult to pump enough blood to the body.
  • Ventricular fibrillation occurs when rapid, chaotic electrical impulses cause the ventricles to quiver ineffectively instead of pumping the necessary blood to the body. Most people who experience ventricular fibrillation have underlying heart disease.

Common types of bradycardia include:

  • Sick sinus syndrome occurs when the sinus node that is responsible for setting a regular rhythm fails to send impulses properly. When this happens, your heart may alternate between beating too fast or too slow. It is more common among elderly persons.
  • Conduction block refers to a blockage of your heart’s electrical pathway. It can occur in or near the AV node, or along other pathways to each ventricle. This leads to impulses being slowed or blocked.

In addition to tachycardia or bradycardia, you may also experience what is known as a premature heartbeat. While it may feel like a skipped heartbeat, it is actually an extra beat. It can occur while you are at rest or be triggered by stress, strenuous activity or stimulants such as caffeine or nicotine. The frequent occurrence of premature beats, especially over several years, may lead to a weak heart.

Heart Arrhythmias

What are the causes of heart arrhythmias?

Heart arrhythmia is commonly associated with heart-related conditions such as:

  • Coronary artery disease, where the arteries supplying blood to the heart are narrowed or obstructed.
  • Heart failure, in which the heart is unable to pump a sufficient supply of blood to the body’s tissues.
  • Heart valve diseases in which one or more of the heart’s valves are damaged and unable to function normally.
  • High blood pressure, when the force exerted on artery walls in the process of pumping blood is higher than normal.
  • Congenital heart disease or any heart abnormality that may affect your heart's rhythm.

Other factors that contribute to heart arrhythmia include:

  • Electrolyte imbalance in the blood.
  • Injury to the heart or as part of recovery after heart surgery.
  • Certain medications.
  • Problems with electrical signals in the heart.

Heart arrhythmia can also occur in healthy hearts as a result of exercise, strong emotions or stress, or the consumption of alcohol, caffeine or tobacco.

Risk factors for developing heart arrhythmia are:

  • Increasing age.
  • Family history of heart arrhythmia.
  • Medical conditions such as high blood pressure, diabetes, low blood sugar, obesity, sleep apnoea and an overactive or underactive thyroid.
  • Environmental exposure, such as air pollution.
Heart Arrhythmias

What are the symptoms of heart arrhythmias?

Symptoms of heart arrhythmia that is caused by rapid heartbeat (tachycardia) include:

  • Breathlessness
  • Dizziness
  • Lightheadedness
  • Feeling faint or fainting
  • Fluttering in the chest
  • Chest pain
  • Sudden weakness

Symptoms of heart arrhythmia that is caused by a slow heartbeat (bradycardia) include:

  • Chest pain arrhythmia
  • Trouble concentrating
  • Confusion
  • Difficulty exercising
  • Dizziness
  • Tiredness
  • Lightheadedness
  • Palpitations
  • Shortness of breath
  • Feeling fain or fainting
  • Sweating profusely

While some people may not experience any symptoms from heart arrhythmia, treatment is important to prevent complications, which may include stroke and heart failure.

Should you experience any of the symptoms suddenly, frequently or unexpectedly, you should see a doctor immediately as some forms of heart arrhythmia can be life-threatening. For example, ventricular fibrillation, which causes the ventricles to quiver rather than pumping blood effectively, can lead to a sudden drop in blood pressure that cuts off blood supply to vital organs. A person experiencing ventricular fibrillation may collapse in seconds and require immediate medical attention.

Heart Arrhythmias

How are heart arrhythmias treated?

Many arrhythmias do not need treatment. Your doctor will evaluate your condition and discuss with you the range of treatment options suitable for you. These may include a combination of:

Lifestyle changes:

  • Quit smoking.
  • Avoid activities that trigger an irregular heartbeat.
  • Limit consumption of caffeine.
  • Avoid stimulants used in cough and cold medications.


  • Anti-arrhythmic drugs to control heart rate.
  • Anticoagulant therapy (blood thinners) to reduce blood clot formation.

Surgery to control arrhythmias and restore a regular heart rate:

  • Pacemakers, defibrillators, and cardiac implants these small electrical devices are implanted in the chest and send electrical energy to fill in the missing beats, thus restoring heart function close to normal. These can be temporary or permanent implants.
  • Electrophysical (EP) studies. Done under a local anaesthetic, this procedure allows doctors to stimulate the heart with controlled electrical pulses, which shows the source of the block or irregular beat.

Catheter ablation usually cures arrhythmia and is usually done after EP studies and when medication is not effective or convenient. The procedure works as follows:

  • Several thin tubes (catheters) with electrodes are inserted into the blood vessels and directed into the heart.
  • A burst of radiofrequency energy (similar to microwave heat) ablates (destroys) the area of the heart muscle that is causing the irregular beats.
Heart Arrhythmias

What are the complications and related diseases of heart arrhythmias?

Most heart arrhythmias can be managed and do not lead to severe complications. However, in cases where they are not treated correctly, they can lead to fainting, stroke and heart failure.