Arrhythmia

An arrhythmia is a disorder of the heart that causes an abnormal heart rhythm

Arrhythmia occurs when electrical impulses, which are responsible for directing and regulating heartbeats, do not function as they should. This causes the heart to beat too fast, too slow, too early or too erratically. This could result in you feeling your heart racing, skipping or thumping - often noticed after having caffeine and nicotine, or while exercising or periods of stress.

Nearly everyone will experience an abnormal heart rhythm at least once. They are common, and typically harmless but some are problematic. If an arrhythmia interferes with the flow of blood in your body, it can cause a damage to vital organs and could become life-threatening.

If you have palpitations or feel an irregular heart beat, it is imperative to consult a health practitioner to determine the cause.

Whats causes arrhythmias?

Arrhythmias are typically caused by problems in your heart’s electrical system. These problems could be due to a coronary artery disease (such as narrowing or blockage in the heart arteries) or other factors such as:

Electrolyte imbalances in your blood (such as potassium, magnesium or sodium)
Injury from a heart attack
Changes in your heart muscle
Consumption of stimulants such as caffeine, nicotine or alcohol

To check for an arrhythmia, your doctor may use tests like:

Holter monitor
Electrocardiogram
Stress test
Event monitor
Cardiac catheterisation
Electrophysiology studies

Symptoms

More often than not, an arrhythmia may be silent and not cause any symptoms. An irregular heart beat during a physical exam may be detected by your doctor through an electrocardiogram (ECG). When an arrhythmia occurs, you may feel experience the following symptoms:

Palpitations (a feeling that your heart is racing, skipping or fluttering)
Dizziness or light-headedness
Fainting
Shortness of breath
Weakness and fatigue
Pounding in your chest

The conduction system of the heart

Normal excitation originates in the sinoatrial (SA) node, then propagates through both atria.

The atrial depolarization spreads to the atrioventricular (AV) node, passes through the bundle of His, and then to the Purkinje fibers which make up the left and right bundle branches; subsequently all ventricular muscle becomes activated.

Bradycardia

Bradycardia is a heart rate that’s too slow.

What’s considered too slow can depend on your age and physical condition. Elderly people, for example, are more prone to bradycardia.

In general, for adults, a resting heart rate of slower than 60 beats per minute (BPM) is considered as bradycardia.

There are exceptions. Your heart rate may fall below 60 BPM during deep sleep. Physically active adults (and athletes) often have a resting heart rate slower than 60 BPM.

Bradycardia may be caused by problems with the SA node ( heart’s natural pacemaker), conduction pathways of the heart or an inability of the electrical impulses to pass properly from the atria to the ventricles, metabolic problems such as low thyroid hormone, damage to the heart from heart disease or heart attack, or certain medications.

Supraventricular Tachycardia (SVT)

SVT

Supraventricular tachycardia (SVT) is defined as an abnormally fast heartbeat. It's a broad term that includes many forms of heart rhythm problems that originate above the ventricles (supraventricular) in the atria or AV node.

A normal heart rate is 60 to 100 beats per minute. A heart rate of more than 100 beats per minute is called a tachycardia.

Most of the time, SVT happens without any obvious reason. It often starts when you are in your teens or early 20s. It may feel like a fluttering or racing heart.

Sometimes you are born with abnormal pathways or electrical circuits in your heart. Faulty circuits can also form out of scar tissue left behind after surgery.

Most people with supraventricular tachycardia live healthy lives without restrictions. For others, treatment and lifestyle changes can often control or eliminate rapid heartbeats.

Ventricular Tachycardia (VT)

Ventricular tachycardia (VT) is a type of regular, fast heart rate that arises from improper electrical activity in the ventricles of the heart.

Ventricular tachycardia may last for only a few seconds, or it can last for much longer. You may feel dizzy or short of breath, or have chest pain.

Although a few seconds may not result in problems, longer periods are dangerous.

Sometimes, ventricular tachycardia can cause your heart to stop (cardiac arrest), which is a life-threatening medical emergency.

Many different conditions can cause ventricular tachycardia. It's important to get a prompt, accurate diagnosis and appropriate care.

The best way to prevent ventricular tachycardia is to treat or eliminate risk factors that may lead to heart disease. If you already have heart disease, follow your treatment plan and a heart-healthy lifestyle.

See your doctor if you have any problems with the heartbeat. In some cases, urgent care is needed.

Ventricular Fibrillation (VF)

Ventricular fibrillation, or VF, is considered the most serious cardiac rhythm disturbance.

Disordered electrical activity causes the heart’s lower chambers (ventricles) to quiver, or fibrillate, instead of contracting (or beating) normally. This prohibits the heart from pumping blood, causing collapse and cardiac arrest.

This type of arrhythmia is a medical emergency. It’s life-threatening.

It is the most frequent cause of sudden cardiac death. Emergency treatment includes cardiopulmonary resuscitation (CPR) and shocks to the heart with a device called an automated external defibrillator (AED).

Treatments to prevent sudden cardiac death for those at risk of ventricular fibrillation include medications and implantable devices that can restore a normal heart rhythm.

How is an arrhythmia treated?

The best course of treatment and medication depends on the exact cause and type of the arrhythmia and how much it affects you. Some people with arrhythmias do not require any treatment; while for some, certain medicines may be prescribed by your doctor to restore or maintain a normal heart beat in the short or long term. These may include:

Anti-arrhythmic drugs, which control heart rate and include beta-blockers
Anticoagulant or anti platelet therapy, which reduce the risk of stroke and blood clots.

Lifestyle Changes

Arrhythmias are often associated with heart disease. If you are noticing that your arrhythmia occurs more often with certain activities, you should avoid them:

Limit caffeine consumption such as tea, coffee and soft drinks. Caffeine is also an active ingredient in some over the counter drugs
Avoid taking stimulants intended for treating cold and cough
Limit your alcohol intake
Quit smoking

Procedures and Devices

Implantable medical devices are used in some instances to treat certain types of arrhythmias. These include:

Pacemaker, a device used to prevent the heart from beating too slowly.
Implantable Cardiac Defibrillator (ICD), used primarily to treat ventricular tachycardia and ventricular fibrillation, which are two life-threatening heart rhythms
Catheter Ablation, a procedure used to treat atrial flutter, atrial fibrillation, SVT and some atrial and ventricular tachycardias. Ablation could be combined with other procedures to achieve the best results.